Best AA Batteries and Chargers: 2016 Update

Fujitsu Charger and 3 batteries
1 AAA and 2 AAA batteries in Fujitsu’s excellent budget charger

Over the past 5 years, I’ve written many articles about pre-charged, low self-discharge AA and AAA rechargeable NiMH batteries. Such batteries, used in conjunction with a high quality charger, offer consumers the best combination of quality, durability, environmental sustainability, and cost-effectiveness, as compared with other types of rechargeable batteries or single-use Alkaline batteries. I explained why in my original AA battery article, and more briefly review below.

This article has been replaced with a 2018 AA Batteries update, due to various changes and other developments in the AA/AAA batteries category.

In this post I update everything for 2016. I will also update this post with any significant developments for at least 11 additional months.

This year’s post is the longest yet, so use the following section links if you want to skip around:


Introductory Remarks

Poor quality is rampant among rechargeable battery and charger brands, causing many consumers to give up on rechargeable batteries. Sifting through thousands of potential items to find the good stuff takes time. I’ve done that, through a combination of personal testing, speaking with industry professionals, examining tests from other battery enthusiasts, and just enthusiastically learning everything I can about AA and AAA batteries over the past 5 years. Changes happen slowly in this category, so an update once every year or two is about right.

For years I have tried to keep battery advice simple by emphasizing the Eneloop brand, which could always be counted on to have the highest quality low self-discharge rechargeable NiMH batteries. I still recommend low self-discharge batteries over all others for general purpose AA and AAA battery use.

However, my recommendations this year are not so Eneloop-centric, because . . .

The highest quality low self-discharge rechargeable NiMH batteries ship from a factory in Takasaki, Japan. To date, this level of quality has not been duplicated elsewhere.

Starting in mid-2014, Panasonic began shipping China-sourced Eneloops to Australia and some markets in Asia. Low self-discharge batteries sourced from China cost less but have inferior quality to batteries sourced from the Takasaki factory in every respect.

There have been no reports to date of China-sourced Eneloops sold through reputable retailers in North America, Europe, or Japan. However, Eneloops purchased through e-bay or third-party merchants could potentially be sourced from anywhere.

Previously, I referred to batteries which matched Eneloop quality as “rebranded Eneloops.” This was not strictly accurate . . . they are Takasaki-sourced batteries. Sanyo did own both the Eneloop brand and the Takasaki factory through 2009. However, since December 2009, Fujitsu’s FDK subsidiary has owned the Takasaki factory, while Panasonic has owned the Eneloop brand. It is this factory which produces the highest quality low self-discharge batteries in the world, and this is where all Eneloops were produced prior to 2014.

It was fair to say that no other brand produced superior low self-discharge NiMH batteries to Eneloop through 2014. With Panasonic now sourcing some Eneloops from China, it’s no longer that simple.

Given that these batteries last for decades, I recommend purchasing only the highest quality low self-discharge rechargeable batteries. How can you do this? By making sure they come from the Takasaki factory, as follows (in order of greatest to least assurance of quality):

  1. Buy Fujitsu-branded low self-discharge batteries. Given that Fujitsu owns the Takasaki factory, they have every incentive to use it for their own batteries.
  2. Buy Eneloops from reputable retailers in North America, Europe or Japan, who sell Eneloops which are “Made in Japan.” In the U.S., reputable retailers of Eneloop include Amazon (but not necessarily third-party merchants on Amazon), NewEgg, and Costco. There are surely others but I’m certain about these three. There are other brands besides Eneloop which source from the Takasaki factory, but some of them do not clearly label where batteries come from. Genuine Eneloop batteries have historically always been labeled clearly and accurately.
  3. Buy Amazon Basics low self-discharge batteries. They are from the Takasaki plant and appear to match 2nd generation Eneloops when tested. They are not as good as the currently shipping 4th/5th generations, but they are less expensive and work reasonable well.
  4. You can take a chance on some other brand or merchant. When you receive the batteries, carefully read the packaging, including the fine print on the batteries themselves, to be certain they are from Japan. This will work most of the time, though there have been occasional reports of batteries which falsely claim “Produced in Japan.”

For more details about the history of Sanyo, Eneloop, Panasonic, Fujitsu, and the factory in Takasaki, Japan, skip to the Takasaki section of this article.

Just Tell Me What to Buy

Some publications like to give you that one single best thing to buy. I typically don’t, as I attempt to match product to desired specifications and price points. But . . . if you don’t already own a good charger or any low self-discharge batteries, the following bundle is a great way to get started at a very reasonable cost:

Panasonic KJ17MCC82A Eneloop Power Pack for 8AA, 2AAA, 2 C Spacers, 2 D Spacers, Advanced Individual Battery Charger

If you have a good charger and just want to buy batteries, then you can’t go wrong with Fujitsu, which owns the Takasaki factory that makes the best low self-discharge batteries in the world:

Fujitsu Ready-to-use 8 AA rechargeable NiMH batteries HR3UTC 2000mAh

Fujitsu Ready-to-use 8 AAA rechargeable NiMH batteries HR4UTC 800mAh

For a slightly more nuanced “best battery summary recommendation, just scroll up a few lines to read your four choices for buying high quality, low self-discharge rechargeable batteries.

The rest of this article explains relevant features, describes quality differences between different brands, and recommends a number of other models and brands depending on features of interest and budget.

Why Low Self-discharge AA NiMH Batteries Beat Other Types of Batteries

For a thorough explanation of different battery chemistries, read Best AA Batteries You Never Heard of. This section provides a short recap:

The two broad classifications of AA or AAA batteries are single use and rechargeable. Single-use batteries must be disposed of after a single use, while rechargeable batteries can be recharged hundreds of times using a battery charger suitable for AA or AAA batteries.

Single-use batteries have been produced from a number of different battery chemistries over the last few decades. The two most popular chemistries for single-use batteries in recent years are Alkaline and Lithium.

Alkaline batteries continue to be very popular due to low cost, convenience, slightly higher voltage, and longevity (amount of time before first use). Alkaline batteries can be obtained for as little as 25 cents each when purchased in 48-packs. However the low cost of Alkaline batteries is not so low when you consider that they can only be used once.

Consider a digital camera that uses 4 AA batteries. Perhaps it runs through 12 sets of 4 batteries per year. That comes out to 48 batteries per year which can be purchased in bulk for $11.50. The Eneloop alternative is to purchase a battery/charger pack that includes 4 low self-discharge rechargeable AA batteries and a charger for $18 or so. The latest Eneloops can be recharged up to 2100 times, which means that they’ll last over a century. The total cost will include approximately 10 cents/year in electricity costs, so the total costs over a century of use will be $28.00 for the Eneloops, versus $1,150.00 for the Alkaline batteries. You won’t live for a century, but even after two years the Eneloops cost less at $18.20 versus $23.00.

Actually, I was being generous to Alkaline batteries, by assuming they last as long as Eneloops in a digital camera. They don’t. Alkaline batteries drain much faster in high drain devices than NiMH or Lithium. If you have Alkaline batteries that you want to use for something, use them in low-drain devices such as remote controls for TVs or game consoles to get the most out of them.

For the majority of applications, low self-discharge batteries perform the same or better than Alkaline batteries, at a lower cost over time. However, some devices assume the 1.5V starting voltage of Alkaline batteries. Such devices may not function properly or even at all with 1.2V NiMH batteries inserted. For such devices, Alkaline or Lithium batteries must be used.

I personally avoid devices that require 1.5V AA batteries. Not only do they prevent me from using low self-discharge rechargeable batteries, but such devices quit working after only 1/3 of the Alkaline battery’s stored energy is used. This is because Alkaline battery voltage decreases with use, typically falling below 1.2V with only one third of the stored energy depleted.

Lithium batteries don’t suffer from either high drain or low voltage issues. So for those rare devices that require high voltage, lithium batteries are ideal. They could also be used on a long trip to power a high drain device (i.e. digital camera) when there is no access to electricity for recharging. However, lithium batteries are by far the most expensive type of battery and can only be used once, so you’ll want to keep their use to a minimum.

Rechargeable batteries come in many different chemistries, but over the past decade NiMH (Nickel Metal Hydride) is by far the most efficient, cost-effective and popular chemistry for use in AA or AAA batteries. There are two broad classifications of NiMH rechargeable batteries: high self-discharge, and low self-discharge.

High self-discharge NiMH AA batteries have been around for two decades. Improvements to early versions quickly led to NiMH with high capacity and low internal resistance, which made them the most popular alternative for rechargeable AA or AAA batteries. They were recommended for use in high-drain devices and many people used them that way.

However, two issues led to dissatisfaction, which caused many consumers to give up on them and return to using less expensive Alkaline batteries:

  • Low quality chargers bundled with these batteries often led to poor user experiences with batteries being undercharged (therefore not lasting as long) or overcharged (thus deteriorating in quality over the course of months instead of years).
  • When not being used, such NiMH batteries discharge at a very high rate. After 4-6 months of non-use, they are essentially dead. This makes them poorly suited for use in devices that are only used occasionally.

I do not recommend high self-discharge NiMH batteries for any use, because of the much superior kind of NiMH battery that has been available since 2005:

Low self-discharge NiMH batteries, first invented and popularized by Sanyo’s Eneloop brand, are now by far the best option for most applications requiring AA or AAA batteries. Unlike high self-discharge batteries, the rate of discharge is low, with 85% of charge retained after a year of non-use, and 70% after 5 years of non-use. Such batteries are typically labeled “pre-charged” or “ready-to-use”, because they retain their charge after leaving the factory. But that is a minor benefit compared to the low self-discharge rate. This type of battery also typically lasts for over 1000 recharges, as compared with 500 at most for the high self-discharge variety, and sometimes much less. The superior low self-discharge variety is more expensive, but most definitely worth it, lasting decades with no drawbacks.

A low self-discharge battery paired with a poor charger can still lead to a poor user experience. But there are several great chargers on the market, which I discuss later in this post. Before doing that, here’s some more detail on the different generations of low self-discharge batteries.

Low Self-discharge Batteries Since 2005: Generations 1-5

Flashlight and camera enthusiasts are so excited about low self-discharge batteries that they have tested and documented many aspects of the technology on various sites, especially CandlePowerForums. I love this chart about the different Eneloop generations. A more accurate and updated version of this chart has been created by the same author on his eneloop101 site: Complete Eneloop Lineup (click at the top for PDF chart).

It is clear from the chart that the biggest improvements occurred by 2010. In 2009, second generation Eneloops increased battery lifetime from 1000 to 1500 recharges while also discharging at a lower rate. A high capacity version came out in 2010, labeled XX at first but now called the Eneloop Pro.

Since 2010, improvements have been very gradual, so marketing claims have shifted slowly. I’m not even sure that the so-called 5th generation Eneloop is any different than the 4th generation . . .

I interviewed a Fujitsu employee familiar with the Takasaki factory. He requested not to be identified. While he was not at liberty to supply me with as much detail as I would have liked, I did ascertain that there are numerous small process and technology improvements that occur gradually over time at this factory. A change in the marketing claims listed on the package of Eneloops or other low self-discharge NiMH battery brands does not represent a discreet, brand new generation of the technology. Rather, it represents gradual change accumulated over several years, enough to warrant a change in marketing claims.

The implication of gradual process improvement is that a set of batteries purchased months before a packaging change might not be significantly different from the batteries purchased after the packaging change. But there likely are significant differences between batteries which are produced years apart, after years of accumulated improvements.

It’s unclear to me that there is any difference between regular capacity 5th generation Eneloops and 4th generation Eneloops. The marketing claims changed, but they don’t contradict each other. The 4th generation cells claimed 70% capacity after 5 years, while 5th generation claims 70% capacity after 10 years or 90% after 1 year, depending on the packaging. These claims are all consistent with each other—it could be that after 5 years the cells lose capacity very slowly. Furthermore, the manufacturing codes on the batteries are the same as well, lending support to my theory that this type of battery has changed very little over the past year, possibly not at all.

When I asked my contact at Fujitsu whether there really was a 5th generation, he said that there has been no recent significant breakthrough and there are none about to come out (at least that he was willing to tell me). He reiterated that process improvements happen frequently but very gradually. Changing claims is simply a marketing call. Fujitsu has not changed claims for its own brand of low self-discharge battery cells and has no imminent plans to do so.

So far as I was able to ascertain, it doesn’t matter who claims what. 4th or 5th generation batteries coming out of the Takasaki factory right now are all of similar high quality, whether it’s Eneloop, Fujitsu, or some other brand (though note that capacity and longevity differ, depending on specifications). And they are probably very similar to batteries that shipped out of Takasaki a few months prior, though perhaps very slight improvement may have occurred.

Several battery enthusiasts do claim, however, that budget-priced Amazon Basics low self-discharge batteries are 2nd generation, based on how they test out. The performance of 6-year-old 2nd generation low self-discharge NiMH batteries definitely lags currently shipping batteries, as you can see from this Eneloop generations chart (click at the top for PDF chart).

It does appear as though there have been some improvements over time to the high capacity versions (which Panasonic calls Eneloop Pro, and Fujitsu calls High Capacity). Panasonic now claims a slightly higher minimum capacity for both AA and AAA high-capacity batteries, as shown on page 17 (or page 9 by PDF numbering) of the current European version of the Eneloop catalog.

Recommended Low Self-discharge AA Battery Brands

So which brands are good to buy? First of all, make sure you’re getting low self-discharge NiMH batteries. They typically say the words, “pre-charged” or “ready-to-use” or “low self-discharge” on the packaging or as part of the online product description. NiMH will also be in the description.

Once you’re sure they are low self-discharge NiMH batteries, pay attention to the words, “Made in Japan” which is more important than the brand name. If they are genuinely “Made in Japan,” they come from the Takaski factory, which at this point in time produces the highest quality low self-discharge NiMH AA and AAA batteries in the world, according to every third-party test to date. Therefore, if I am ordering low self-discharge AA or AAA batteries online, I need to be assured they come from Japan.

I can be assured low self-discharge NiMH batteries come from Japan when I buy from Fujitsu, or Eneloop for those of us living in North America, Europe, or Japan. I’m also confident that the Amazon Basics low self-discharge batteries are at least 2nd generation cells from Japan. Thus, my recommendations are:

For basic performance low self-discharge batteries, get Fujitsu or Panasonic’s Eneloop brand for the latest generation, or for the budget conscious, second generation cells from Amazon which lag slightly behind in overall performance:

Regular Capacity AA LSD NiMH batteries:

Fujitsu Ready-to-use 8 AA rechargeable NiMH batteries HR3UTC 2000mAh

Panasonic Eneloop 8 Pack AA NiMH Rechargeable Batteries

Budget brand (lower quality for lower price):

AmazonBasics AA Rechargeable Batteries (8-Pack) Pre-charged


Regular Capacity AAA LSD (Low Self-Discharge) NiMH batteries:

Fujitsu Ready-to-use 8 AAA rechargeable NiMH batteries HR4UTC 800mAh

Panasonic BK-4MCCA8BA Eneloop AAA 2100 Cycle Ni-MH Pre-Charged Rechargeable Batteries (Pack of 8)

Budget brand (lower quality for lower price):

AmazonBasics AAA Rechargeable Batteries (8-Pack) Pre-charged

The above batteries are fine for virtually all ordinary applications, but in high drain devices used very frequently such as digital cameras, portable fans, or microphones, you may want higher capacity so as to avoid frequent recharging. This will be especially important for those who use such devices professionally. High capacity low self-discharge NiMH cells cost more and only last for 500 rechargers, but they typically have a much higher capacity of 2550 mAh for AA batteries, and 950 mAH for AAA batteries:

High Capacity AA LSD (Low Self-Discharge) NiMH batteries:

Panasonic Eneloop Pro 4 Pack AA NiMH Rechargable Batteries

Budget brand (lower quality for lower price):

AmazonBasics AA High-Capacity Rechargeable Batteries (8-Pack) Pre-charged

High Capacity AAA LSD NiMH batteries:

Panasonic BK-4HCCA4BA eneloop Pro AAA New High Capacity Ni-MH Pre-Charged Rechargeable Batteries, 4 Pack

Budget brand (lower quality for lower price):

AmazonBasics AA High-Capacity Rechargeable Batteries (8-Pack) Pre-charged

You need to make sure you have a good charger, as explained in the next section. If you use a low quality charger, it will end up undercharging, overcharging, and/or decreasing battery longevity.

If this is your first time buying low self-discharge batteries, or this is a gift for someone who doesn’t have any yet, you may want a starter bundle that includes one of the good budget chargers. Both the Pansonic and Fujitsu chargers included in the following bundles are great chargers that are discussed below.

Panasonic has several Eneloop Bundles that include both AA and AAA batteries along with it’s competent charger:

Panasonic Eneloop Kit 10 AA 4 AAA batteries & Charger 2100 Newest 4thGen

Panasonic KJ17MCC82A Eneloop Power Pack for 8AA, 2AAA, 2 C Spacers, 2 D Spacers, Advanced Individual Battery Charger

Panasonic K-KJ17MC124A eneloop Super Power Pack, NEW 2100 Cycle, 12AA, 4AAA, 2 “C” Spacers, 2 “D” Spacers, Charger

Panasonic K-KJ17KHC82A eneloop pro NEW High Capacity Power Pack, 8AA, 2AAA, with “Advanced” Individual Battery Charger

And if you want a faster charger (bundled with AA batteries only), you can get the following Fujitsu bundle:

Fujitsu FCT344AUFX(CL) AA / AAA Ni-MH Battery Quick Charger with 4-pack 2000 mAh AA Rechargeable Batteries

What Every Charger Needs, Including Budget Models


This section was moved to the most recent battery update post.

Extra Features that Justify Buying a More Costly Premium Charger

This section was expanded and moved to the most recent battery update post.

Recommended Budget Battery Chargers

This is the category that has changed most over the past few years, as budget chargers seem to come and go. Last year I only recommended one budget charger at first, as several models I had previously recommended were all discontinued. Another was available for a few months in the U.S. but it was discontinued and quickly sold out.

This year, I’m aware of 3 good models. The 2 available in the U.S. are:

Panasonic BQ-CC17SBA Eneloop Advanced Individual Battery Charger with 4 LED Charge Indicator Lights, White

Fujitsu FCT344AUFX(CL) AA / AAA Ni-MH Battery Quick Charger with 4-pack 2000 mAh AA Rechargeable Batteries

Update 3/13/17: For more detail than is provided in this section, see this site’s recently published comparison of 3 budget chargers: BQ-CC55 vs FCT344 vs BQ-CC17.

I have tested the Pansonic Eneloop BQ-CC17SBA charger extensively and recommended it last year. It is still my top recommendation this year it for its simplicity, effectiveness, and gentle treatment of batteries. You can read my in-depth Eneloop Charger review for detail, but the most relevant thing you need to know is that it does exactly what is outlined above in the budget charger requirements section, and no more. It charges at the slow rate of 300 mAH for AA, 150 mAH for AAA, so batteries never get hot. Part of what makes it so great is that it works with a wide variety of NiMH battery types and quality, including old high self-discharge NiMH batteries.

However, for those who want faster charging and who use nothing but low self-discharge batteries, the Fujitsu charger (which only comes as part of a bundle with four AA batteries) is currently a good second option. I found after months of use that it does exactly what is claimed on the package: charges at a moderately high rate when 3 or 4 bays are occupied, and a very high rate when 1 or 2 battery bays are occupied:

Charging Rates for the Fujitsu Quick Charger FCT344
Battery Type Number of Batteries Charging Rate
AA 3-4 (normal) 550mA
AA 1-2 (quick) 1100mA
AAA 3-4 (normal) 280mA
AAA 1-2 (quick) 560mA

When charging at such high rates, there is a danger that batteries can overheat, so some form of heat detection is needed. This charger has it, and it was in fact triggered every time I attempted to charge some low-quality high self-discharge NiMH batteries I had lying around (6 years old).

In fact, that is a significant drawback of this charger—you don’t want to charge 1 or 2 old, low-quality high self-discharge NiMH batteries that have high internal resistance. They will overheat and stop charging in less than 15 minutes. This occurred even with 4 such batteries charging at the lower rate, though they took longer to warm up and trigger the cutoff.

But there’s no reason to keep using old NiMH batteries of the high self-discharge variety. I only keep mine around in order to test chargers—I’ve long ago quit using them in any of our devices.

When I first published this article, I recommended this Fujitsu charger above the Panasonic. But I have since changed my mind. Occasionally, the Fujitsu charger refused to charge my older Eneloop batteries that have developed some internal resistance over time and have lower maximum capacity than they used to.

If you’re willing to stick with high quality, low self-discharge batteries, occasionally weeding older ones (that have begun to decline in capacity and increase internal resistance), the Fujitsu Quick Charger is still a good choice among budget chargers. And you can get it, plus four low self-discharge AA Fujitsu batteries, for less than $30. That is a great deal.

TIP: AA and AAA NiMH batteries will function better for longer if you usually charge them at a slow or moderate rate. Therefore, with the Fujitsu Quick Charger or other chargers that offer high charging rates, only use the quick charging feature sparingly. Charging 3 or more batteries at a time in the Fujitsu model keeps the charging rate lower, and will prolong battery life over the long run.

Panasonic also makes a similar fast charging model, the BQ-CC16 charger, but it is not available for sale in the U.S.

Recommended Premium Chargers

My recommendations in this section are nearly identical to last year’s recommendations: Choose between 5 chargers and 3 brands: Powerex Maha, and 2 each from Opus and La Crosse. I have extensively tested and used the 2 La Crosse models, and the others I know about from poring through many reviews.

One thing about La Crosse you should be aware of is that, despite producing a quality product, they have a reputation for poor customer service. I have never had a problem with either of my two La Crosse chargers. However, if you look through Amazon reviews, you’ll find that those who do experience issues with their charger have a very difficult time getting through to customer service. Chances are low you’ll experience a charger failure, but keep in mind it could be quite a hassle if you do.

At roughly $35, one of the least expensive models that does what a premium charger should do is the La Crosse BC-700. It is easy to use and it does everything the other more expensive La Crosse models do except that charging is limited to a maximum rate of 700mA. Included with the charger is a wall power supply, and nothing else:

La Crosse Technology BC-700 Alpha Power Battery Charger

If you’re never in a rush to recharge batteries, then there’s no reason to charge faster than 700mA. In fact, 500mA is a great charging rate for AA batteries, and 200mA for AAA batteries, in order to maximize battery life. Charging at a higher rate on occasion won’t hurt the battery much, but if there’s no reason to rush, then don’t, because charging at a high rate generates heat. Heat reduces battery life.

If you want to charge at higher than a 700mA rate, use one of the other 4 chargers. The La Crosse model that does this is:

La Crosse Technology BC1000 Alpha Power Battery Charger

The BC1000 charges at a rate of up to 1800mA for AA batteries. That can overheat many batteries but the BC1000 contains circuitry that prevents overheating. Two prior models of La Crosse, BC-900 or the BC9009, were not able to prevent overheating in all cases so avoid these two models which can harm batteries and in rare cases melt batteries and/or cause fires.

The BC1000 overheat detection circuitry works reliably. This more expensive model also includes a carrying case, adapters for C and D battery sizes, and low quality, high-discharge NiMH batteries.

There is one issue with all La Crosse models that has tripped people up, including me the first month I used it. If NiMH battery voltage drops too low, it triggers a cryptic “null” message when inserted into the La Crosse charger. The manual suggests that this means the battery is no longer usable. Rarely is this true. It usually just means that the voltage is very low.

There are 3 different ways to correct this if you own a La Crosse charger:

  1. Insert the battery into a different charger, even a dumb charger, for 30-60 minutes. Then reinsert into the La Crosse charger.
  2. Leave the battery in the La Crosse charger for several days. There is a tiny trickle charge that will eventually revive the battery enough to start charging normally and make the “null” message goes away.
  3. For more rapid revival, use the paperclip trick.

Of course, you can avoid this hassle altogether by getting an Opus or Maha charger.

The Maha charger tends to be the charger preferred by geeks diehard battery enthusiasts. It offers more control and options and a slightly higher charging rate than other premium chargers. It is larger for better heat dissipation. It doesn’t have difficulties charging excessively drained batteries.

However, the Maha is by some accounts the most difficult charger to use. For example, according to popular Amazon reviewer NLee the Engineer, it needs many more button presses than the La Crosse to increase the charge rate for a set of 4 batteries. This is a very common action that I take whenever I insert 4 AA batteries. With the La Crosse, that takes just 2 button presses. With the Maha, it takes many more, as each bay must be independently programmed. Another issue is a backlit display that rotates through all information every 48+ seconds. Accessing information on an individual bay or all 4 bays is much easier on a La Crosse charger.

Once you get past the interface issues, the Maha gets the job done very well. Some people are willing to take the usability hit to get the extra control and flexibility:

Maha PowerEx MH-C9000 Maha WizardOne Charger-Analyzer for 4 AA/AAA Batteries

Older versions of Opus chargers had a poor reputation for years due to overheating battery issues. However, that was solved in 2014 with a firmware upgrade to version 2.1. If you get this model, make sure you see “2.1” or higher briefly displayed on the leftmost column when turning it on. Nearly all models shipping currently should have firmware 2.1 or higher.

This model has most of the advantages of the other 3 recommended models combined into 1 package: Easy to use, flexibility/control (though not quite as much flexibility/control as Maha), and a big display. It even has a QUICK TEST feature that measures internal resistance, which is very useful for weeding out sub-par batteries. So far as I know, this is the only premium charger with this feature. On top of that, it comes in several variants, including a no frills version that is slightly less expensive than even the least expensive La Crosse model:

Opus BT-C2400 Battery Charger Analyzer Tester for AA AAA NiMH NiCd rechargeable batteries

If you also want C and D adapters, get:

Opus BT-C2000-charger-set AC 100-240V Battery Charger Tester Analyzer with C and D adapters

And here are other Opus models, which include different combinations of accessories:

Complete List of Opus Models

Storing Your AA and AAA batteries

This section was expanded moved to the most recent battery update post.

It’s not about the Brand (Eneloop), it’s about the Factory (Takasaki)

There are several NiMH manufacturing plants in China and Indonesia, but there is only one in Japan. It’s in Takasaki, Japan. So says the Fujitsu employee I interviewed in January 2016 (who asked not to identified).

This plant was owned by Sanyo until 2009. Panasonic purchased Sanyo in 2009. In order for the transaction to satisfy the authorities with regards to anti-trust issues, Panasonic was allowed to keep the Eneloop brand, but not the Takasaki factory. Panasonic quietly found a new owner for the factory: Fujitsu. Fujitsu’s FDK subsidiary has owned the Takasaki plant since December 2009.

All Eneloops were produced in this plant while it was owned by Sanyo, and for a number of years thereafter. So battery geeks consumers who actually cared about these things assumed that the Eneloop brand and the factory in Japan that produced them were one and the same.

Because other low self-discharge batteries with identical electrical characteristics existed, most people figured that Eneloop’s parent company (first Sanyo, then Panasonic) had struck deals with other battery brands, so that batteries identical to Eneloop were shipping out of the same factory. Such batteries were given cute names such as Duraloop, to represent that some of Duracell’s low self-discharge batteries were actually rebranded Eneloops.

Consumers, including myself, might have continued to believe this a good while longer. But Eneloops sourced from China began appearing in Australia in 2014. This raised questions. Why wasn’t Panasonic producing all of its batteries from its factory in Japan? The answer was that Panasonic no longer owned the factory and presumably wanted to cut costs. The FDK subsidiary of Fujitsu has owned it since December 2009.

My source told me that after the Sanyo transaction, Panasonic got full rights to the Eneloop brand, while Fujitsu’s FDK subsidiary not only acquired the Takasaki factory, but also all the intellectual property associated with the production of low self-discharge batteries. Some of the intellectual property is documented by battery enthusiasts. My source told me that not all of the technology and processes are protected by patents. Issuing patents can give out hints that may actually help the competition. So whatever advantages the Takasaki factory enjoys over the competition are a combination of intellectual property and undocumented intellectual capital.

I wish I could provide more detail than I have in this section, but my source from Fujitsu was unwilling to provide much detail, for competitive reasons. In fact, most of this story is information I pieced together from CandlePowerForums, and the websites of Panasonic and Fujitsu. My source from Fujitsu didn’t contradict any of this information, suggesting that I have the story correct. However, I’ll be sure to update this section with any additional details I manage to come across.

However, the bottom line is clear. Takasaki has superior knowledge of how to produce low self-discharge batteries, some of which is protected by intellectual property, some not. If you want the highest quality rechargeable low self-discharge NiMH batteries, make sure it says “Made in Japan.”

When it Makes Sense to Use Alkaline or Lithium Batteries (hint: rarely)

This section was expanded and moved to the most recent battery update post.

Concluding Remarks

The product landscape for AA and AAA batteries and chargers hasn’t changed all that much over the past 5 years, when I first began writing about it. A bit of upfront investment in rechargeable, low self-discharge NiMH batteries along with a decent charger continues to be the most effective and most economical way to use AA and AAA batteries. The majority of people don’t know this, because for most people the cost of AA and AAA batteries is low enough that they don’t want to spend much time thinking about it.

However, there are people (i.e. families with young kids) who have dozens of AA or AAA batteries in their various devices at any given time. If you think about how much that costs financially and environmentally over time, and how often batteries need to be changed, you’ll realize that it’s worthwhile to learn about the best AA batteries.

The best of the best AA and AAA batteries continue to be low self-discharge rechargeable NiMH batteries sourced from a factory in Takasaki, Japan. Given that this factory is owned by Fujitsu, the Fujitsu branded AA and AAA NiMH batteries will always be a safe buy. Eneloop and other “pre-charged” NiMH battery brands will also be of high quality, so long as they are “Made in Japan” because the Takasaki plant is the only NiMH battery plant in Japan.

As I mentioned in a prior article, buying low self-discharge NiMH batteries is like buying a cast-iron skillet. It’s a little more expensive up front and it has a little bit of a learning curve, but it will last a life time. We live in a world where we continue to generate exponentially increasing amounts of garbage. I would rather use my batteries for a lifetime, rather than just once. I’m hoping that hundreds of millions of people will join me.

Author: Joe Golton

I’m a dad with a son who loves baseball. Professionally, I’ve been a software developer, investor, controller, and logistics manager. I now make my living from this blog, supplemented with occasional consulting gigs.

119 thoughts on “Best AA Batteries and Chargers: 2016 Update”

  1. Completely flabbergasted with the quality content on this post.

    Thank you for being so thorough on the subject at hand.

    PSA: The Newegg eBay vendor account also lists the Fujitsu charger, just in case someone wants to buy it, already has an eBay account, and does not want to register at Newegg’s website:

    Fujitsu FCT344AUFX(CL) Advance Individual AA / AAA Ni-MH Battery Quick Charger


  2. Thanks for the extensive article! Loved it! Question: why haven’t you done testing con Tenergy Centuria LSD batteries? They seem to be just as good as eneloops.

  3. Bill – There are at least two dozen brands of LSD batteries these days. I’m just one guy so I haven’t tested very many of them. I’ve seen tests of many different brands and the overall conclusions of my article sums them up: If they are truly “Made in Japan” then they are generally all pretty similar to each other (except that some sacrifice number of charging cycles to get higher capacity) and all very good. If they are not “Made in Japan” then they are going to be worse.

    It looks like many Amazon Customers are very happy with their Chinese-made Tenergy LSD batteries which cost less than half of Eneloops. Testing seems to show that they live up to their capacity claims. However, in all tests I’ve seen for longevity, Chinese-produced LSD batteries don’t come close to those made in Japan. I would expect not much difference in the first year or two of use but eventually (3 years? 4 years?) the battery capacity of Tenergy or other Chinese-sourced LSD batteries will go into rapid decline while Eneloops will hold up.

    I have only used Japan-sourced LSD batteries myself and all but one of my 5-6 year old Eneloops and Duraloops are charging to capacities above 1900 mAh, and most above 2000.

  4. Thank you for this comprehensive information. You may be interested in learning about a new rechargeable battery entering the market, the Boost FP AA/AAA 1.5v rechargeable battery from Volt Technology. This battery has no discharge curve. It outputs 1.5v from start to finish until it needs to be recharged. It lasts up to 5x longer than NiMH batteries, depending on the device. In low voltage devices like a flashlight, the battery’s smart tech will adjust the voltage output down so as to not burn it out. What’s more, you can recharge the battery 1000 times. The Boost FP has outperformed the Eneloop in every head-to-head test we’ve conducted. The battery debuted at CES in January and will be launching on Kickstarter April 26th. Check it out!

  5. I would like to see details missing about chargers above concerning “pulse charging”. My inexpensive Duracell QuickCharger (CEF 12N) has been doing excellent duty for 8 years now and getting a good long cycle life from my AA’s because of it. I didn’t know it was a “pulse charger” until I moved it to a spot near my FM radio and heard “pssst…. pssst…. pssst” about every second. So, yes, it isn’t well shielded, but this reminded me of articles in places like Home Power and Mother Earth News magazines about how best to charge batteries. Pulsing the voltage/amperage appears to have many benefits that help the cells and reduce the amount of electricity used to charge the cell. Of course these mags were mainly referring to Lead-Acid then, but it sure seems to help other designs. Please full us in on a 2016 take.

  6. Jopower – Every recommended charger in this post uses pulse charging. It is my understanding that the Negative Delta V method for detecting a full battery works more reliably with higher current, so Negative Delta V and pulse charging are usually found together. And, as you say, there are benefits to pulse charging that improve charge acceptance of NiMH batteries, which enhances performance and increases service life. See:

  7. That Fujitsu charger with the 4 AA batteries was on sale a few weeks back for $12 shipped. I ended up picking it up. So far the charger is pretty good. Nice fast charge for 2 AA in 2 hours.

  8. Alex – The BC-700 has several different brand names that are different by country. The technoline BC-700 is indeed identical to the La Crosse BC-700.;

    I am not aware of a 2 pack that includes the charger. Best way to find all the options is to search for Eneloop Pro in amazon and look at all the options. The closest that comes to that is a 4 pack with charger.

  9. Should I buy the Technoline BC-700(European version) or the La Crosse BC-700(American version)?

  10. Thanks again Joe. Will buy the German version from since I’m from EU and postage & packaging costs are less expensive then

  11. If I use an item once per week(like a beard trimmer) for 10 minutes, should I use rechargeable AA Nimh LSD batteries(like Eneloop, Eneloop Pro or Energizers)?

  12. Alex – It is fine to use LSD AA batteries anywhere you would use single use AA batteries, including infrequently used devices like beard trimmers or emergency flashlights. The only exception is devices that require 1.5V, which I cover above in the “When it makes sense to use Alkaline section,” which is the second-to-last section above.

  13. Vast majority of devices that use AA batteries work fine with 1.2V. Unfortunately, those truly requiring 1.5V are often not labeled clearly. One hint is to look for the words, “Alkaline batteries required” which implies that it won’t work with any form of rechargeable battery that is mostly around the 1.2V to 1.3V area.

  14. Lee – I will be publishing a Fujitsu Quick charger review within a couple months. I like to get a few months of real world use behind me before doing a review, but we just haven’t been recharging as many batteries as usual the last couple months. I think May or June is when I’ll be ready.

    I will say that so far I’m less enthusiastic about this charger than I was at first. It’s too easy to set off the blinking lights, which then means they won’t charge one (or sometimes any) battery(s). The charger is great with relatively recently purchased low self-discharge batteries but can refuse to charge lower quality batteries, older low self-discharge batteries with reduced capacity, or batteries that were so heavily used that the voltage dropped to unusually low levels (a temporary thing until charged). So I can tell you right now that in my review, I will say that this can’t be your only charger. Use it in conjunction with another more forgiving charger in case you get a case of the blinking lights.

  15. Thank you for the fast reply Joe. I have a BQ-CC17 as a back up. I mainly picked up the Fujitsu Charger because it was on sale with 4 AA Fujitsu battery’s for $12 shipped so i couldn’t pass it up. I also needed it more battery’s and a faster charger. SO far i haven’t gotten the flashing lights yet.

  16. Quick question, I see that you say on the fujitsu quick charger to not use the 1-2 cell charge much since it charges it at 1100mA. Is that because of the heat? i see the charger also has High temperature detection so would that really matter? Thank you for your time.

  17. Lee – The Fujitsu Quick Charger does have high temperature detection and it does work. So your batteries will not melt or be destroyed.

    However, exposure to even mild heat decreases battery life time. 1100 mA charging will generate a moderate amount of heat in even the highest quality batteries, so they won’t last for as many recharges if you do this often, and their capacity will be reduced faster than if you had always used gentle charging current (600 mA or less for AA, 300 mA or less for AAA).

    In the storage section above, I suggest that you store your AA and AAA batteries in a dry, cool place. Storing them on a window sill on sunny days, for example, is a bad idea. Also a bad idea to store in cars in the summer.

  18. Thank you for the info! When the cell’s are done charging does it do some kind of trickle charge to keep them topped off or does it completely turn off the charge?

  19. The Fujitsu Quick Charger does not trickle charge. It shuts off completely. I got that information by communicating with my contact at Fujitsu. I believe all other chargers I reviewed here trickle charge after batteries are full.

  20. Im guess the Panasonic BQ-CC17 also doesn’t trickle charge after its fully charged up??

    So it would be ok to leave the cells in the charger for a few hours after it finishes charging right?

  21. Just looked it up to refresh my memory – BQ-CC17 does not have a trickle charge.

    Note that it is always okay to leave batteries in a smart charger for a few hours after it’s done charging whether it has trickle charging or not. The point of trickle charge is to keep the batteries topped up without over charging or generating heat. Trickle charge is a good thing. However, trickle charge is not a critical feature and in low self-discharge batteries it’s irrelevant because the batteries lose charge so slowly. Trickle charge is helpful with less expensive high-discharge NiMH batteries because they lose charge quickly.

  22. Oh ok, ive seen on the forums people saying that trickle charging after the battery is finished for LSD cells damages them. Thats why i was wondering about it.

  23. How do I know if a device will accept a rechargeable NiMH 1.2V AA battery? It won’t start at all, or over time it will stop working?

  24. Alex – you can usually get a hint from the manual when it says “Alkaline AA battery required.” But if you don’t know, then the result will either be that it doesn’t work at all, or it works for just a few minutes and then stops working. Low self-discharge batteries may operate above 1.3V for the first few minutes after being fully charged but they fairly quickly drop below 1.25V.

  25. Thanks. If the device works for more then a few minutes(for ex. 10 or 20 minutes) then it will work with NiMH 1.2V batteries I guess.

  26. I noticed something after my Fujitsu Quick Charger is done charging i left my cells in the charger for a few hours and it seemed like it was topping them off as when i tested the voltage it was as if it was just finished charging a few moments ago.

  27. This is because the charge and voltage in lsd batteries decreases very slowly. If you left it in for 1 year, the voltage would noticeably decrease.

  28. Yes but usually after i pull them from the charger right away they usually settle. When i leave them in the charger for a extended time i notice they are just like i took them out moments ago. Just feels like its still topping them off for some reason.

  29. Can I leave a rechargeable NiMH AA battery in a device that I don’t use for 2 weeks?

  30. Alex – You can leave a battery in a device that isn’t being used for years if you like so long as it’s stored at reasonable temperatures (i.e. temperatures in a typical home). Extreme heat is bad. We have child toys in our home that have sometimes gone over a year without use. Flashlights in our house sometimes don’t get used for months.

  31. Ive been messing around more with my Fujitsu Quick Charger and my BQ-CC17. Seems like when i leave the cell’s in the Fujitsu Quick Charger after the charge is done it keeps them topped off till i pull the cells. My BQ-CC17 doesn’t do this. Once its done charging it stops the charge. Not sure why it does this. Don’t both the Chargers have the same Features?

  32. Lee – I don’t know how you can conclude it’s topping them off unless you attach measuring equipment. It is quite possible though that the cutoff point is a little higher for the Quick Charger (that is – it stops charging when the battery charge and voltage is slightly higher than the other charger). It does not say anywhere in the specs that there is a trickle charge, and as I said before, I even contacted a Fujitsu employee to verify that there is indeed no trickle charge with the Quick Charger.

  33. When i pulled the cells out of the Fujitsu Quick Charger after a couple of hours after it was finished it shows up 1.47v vs The cells i had in the BQ-CC17 were at 1.38v after i pulled them several hours after they were done charging.

  34. Lee – I have a number of different chargers I’ve tested. The charge cutoff point varies slightly between the chargers. I think it likely that’s what you’re seeing. The difference between 1.47v and 1.38v is only going to last a few minutes of battery use for LSD batteries. This type of battery will very quickly drop to below 1.25V as it’s being used.

  35. Oh ok, I just find it odd that with the Fujitsu Charger no matter when i pull the cell its always 1.47v as if its still some what charging them when its already done.

  36. Dude, you’re the best.
    Please keep on informing us.
    You’re always my “go check him before buying” guy.

    Thanks for your useful posts over the years, appreciate it!

  37. For some reason i still feel the Fujitsu Quick Charger keeps trickle charging the cell’s as i can hear the pulses and no matter when i pull the cells after its done charging its always 1.47v vs my BQ-CC17 will stop charging once the cells are done.

  38. If I use a 1.2V NiMH rechargeable AA battery in a device that requires a 1.5V alkaline AA battery will it work with the same power?

  39. Lee – What do you mean by timer on the Quick Charger? Mine does not stop charging after a set time.

    As for your continued suspicions that it is topping off, you have me wondering.

    It does do pulse charging, which is good because it makes delta V detection reliable.

  40. Alex – Power is defined by following equation: P = V X I. Given a constant current, higher voltage means higher power. That is why a 1.2V NiMH battery will not work in a device that requires a 1.5V battery (or it it does work, only for a few minutes until the voltage drops to the usual 1.25 or lower Volts).

  41. Lee – Here is what I found out in the past couple hours by doing my own little test. I put in 3 batteries, one of which was a low quality high self-discharge battery. I can hear the pulses. It does one for each battery inserted, lasting maybe 1/4 second each. When the two LSD batteries were full, I still heard 3 noises, but one was the 1/4 second pulse for the remaining battery, while the other two pulses were extremely brief.

    I don’t know what the brief pulses means. It is possible that you are right and that the brief pulses are trickle charges. Or maybe not. I’ll look into it more.

  42. Joey – It shows it under features. “Safety Protection High temperature detection, timer, over-discharge cell detection, reverse mounting cell protection, primary cell detection”

    Yeah the topping off has me scratching my head as once the cells are done charging you can still hear it giving pulses to the battery like its trying to top it off. One of the reasons why i can tell is that no matter when i pull the cells its always the same voltage as if i just pulled them after they were done charging. I do not have issue like this with the BQ-CC17. When the charge is done on the BQ-CC17 it stops charging.

  43. Joe – Thank you very much for looking into this.

    I wonder why it trickle charges after the battery’s are done charging. I ended up going back to my Panasonic bq-cc17

  44. Lee – Thanks to your persistence, I contacted Fujitsu again and confirmed that you are correct: The Fujitsu Quick Charger does trickle charge. Here are the exact words from my contact:

    I have confirmed with our engineering team that our FCT-344 does trickle-charge for a certain period of time after a normal charge cycle is complete.

    Our engineers are hesitant to share with me more detailed charge specifications as they are part of our proprietary technology.

  45. Great thanks for looking into this for me, I figured it did since it always seemed the batteries were topped off. Now i wonder if i should even use the charger anymore since it trickles after the charge is complete.

  46. Hello.

    What about the radiation concerns with getting Japan sourced batteries. After the Fukushima incident in 2011, I have no longer bought anything made in Japan.

    And please someone give me a better answer than “Oh don’t be a sissy.” or “Do you hide from the sun to?”


  47. Thanks for this article! I have a BC-9009 (and am careful about the heat issue). My question is do I need a different charger to charge High Capacity 2550mah AA batteries to their full extent? (My understanding is that the batteries will then last longer… 500 charges seems like enough for me… but I would rather not be charging as often.) Thanks

  48. Greg – so long as you’re careful about the heat issue, the BC-9009 is fine. To extend the life of your batteries, limit the charging rate to 500mA for AA, 200 mA for AAA. Higher charge rates generate a little heat, which reduces long-term battery life.

    If you’re talking about how full the batteries are after one charge – there are some chargers that might say “full” when the battery has slightly more charge than the BC-9009, but the differences between charger cutoff thresholds are small. If you want the batteries charged up slightly higher, simply leave the batteries in the charger for a few more hours after it first says “full” and it will receive trickle charge. Not a good idea to do this for days, though.

  49. Thanks for your valuable information.
    Currently I am looking for suitable chargers and browsed your blog. That is really helpful.
    I planned to buy the latest Panasonic charger BQ-CC55 but noticed that heat will reduce batteries’ life. After reading this article, I will buy BQ-CC17 or BQ-CC53. (I have checked Panasonic Taiwan and they said they are the same model. The slightly different is CC53 charge rate is twice higher than CC17 when we charge two batteries.)
    It is very glad to know your blog, and I already subscribe it.
    Hope I can read more articles in the future.

  50. Fantastic info, thanks so much for the extensive testing. I’ve been a long-time Eneloop fan, so it’s good to know about the change in ownership/Panasonic/Fujitsu info.

    I did have one question though. Due to this article I began shopping and ran across Fujitsu high capacity AAA’s. I would have assumed these would be recommended in your “High Capacity AAA LSD NiMH batteries:” section, but they’re not. Is this simply because they were released after this article, or is there a reason they should be avoided?

  51. Hi Paul – There is no reason to avoid Fujitsu’s high capacity AAA NiMH batteries. They should be nearly identical to Eneloop’s high capacity AAA NiMH – both are very high quality. I can’t remember why I left them out – maybe they were frequently out-of-stock at the time I wrote the article.

  52. The updated Ikea LADDA batteries appear to be Takasaki-sourced LSD NiMH cells. In US:
    4 x AA 2450mAh $6.99
    4 x AA, 1000mAh $3.99
    4 x AAA 900mAh $6.99
    4 x AAA 500mAh $3.99

  53. How about new panasonic charger bq-cc55 ??
    This is very new version of panasonic charger… Can you make a review in dept about this charger? From pros and cons, safety feature and what the new feature.. ?

  54. Rico – The BQ-CC55 is not a charger I’ve tested yet. I plan to come out with a new battery guide about once/year so it’s possible I’ll examine this charger in time for the 2017 guide, which will likely come on in February or so.

  55. I just charged a new set of EBL 2800’s in the BQ-cc17 charger. The batteries got very warm, I’d say hot. I believe they were shipped depleted. The channels did eventually shut off one by one like they should but hot batteries make me wonder something is wrong.

    Are they charging too fast? Over charging? A bad charger?

  56. Scott – I have never experienced batteries getting hot with the BQ-cc17. I have experienced hot batteries with a few other chargers. To me, this suggests something wrong with the batteries – namely extremely high resistance. But given that they are new, that seems unlikely, and maybe your idea that there’s something wrong with the charger could be right.

    Without having the charger in my hands, I can’t really know what’s going on. The way I would troubleshoot is to test the charger with some other batteries, and test the batteries with other chargers.

  57. I have the BQ-CC55 charger purchased from Costco. This charger refuses to charge any other brand of battery. All my Duracell (with white eneloop caps), IKEA, Energizer, Rayovac.. every other brand turns red and refuses to charge. Eneloops, no problem. Sounds like Panasonic is pulling a Keurig

  58. Returned my BQ-CC55 eneloop set to Costco and got another set because I couldn’t find anyone with the same charger problem anywhere online. The second charger behaved itself and cooperated with other brands. It looked so much like it might be another case of the DRMs. Still a very interesting and awfully suspicious defect.. But I guess not evil–sorry Panny, my mistake.

  59. Thanks for your comments, Richie. After several mentions recently of this new BQ-CC55 charger, I just purchased the Costco Eneloop set. It will probably be a couple months at least before I’ve tested it enough to have my own comments.

  60. Greetings
    Today, 14.11 in 2016, I bought a Fujitsu rechargeable battery (LSD), and on the side of the battery, I recognize manufacturing date 14 05th Do you have an explanation how come he sold two and a half year old batteries? I know it does not hurt. I’m just puzzled that age. The capacity of the box was 560mAh. Which is + – 72% after two and a half years.

  61. DavidCZ – You are correct that it doesn’t hurt that the AAA batteries you purchased are nearly 3 years old. That does seem surprisingly old, which suggests the possibility that whoever you purchased them from managed to obtain overstock from somewhere else that hadn’t been selling well. There are other possible reasons, such as low sales rates, a return (which in turn was resold), etc. But the great thing about LSD batteries is that they are good for years. The only minor down side is that the manufacturing process improves very gradually over time, so it’s possible that cells manufactured over the last few months are slightly superior to cells produced nearly 3 years ago.

  62. Hi, thanks for the excellent report. Based on your report, I have decided to buy the charger and the NiMH batteries separately. I’m totally sold with NiMH Fujitsu brand (made in Japan).

    On the charger, however, what do you think of EBL 8 bay battery charger that currently sells at $10 at Amazon?

    This charger seems to charge the batteries at low mA, much like the more expensive La Crosse that you covered in this article.

    Charging Time Table:
    2 to 8 pcs AAA 500-1200mAh: 3 – 8 hours(180mA output)
    2 to 8 pcs AA 1300-2800mAh: 6 – 15 hours(200mA output)


  63. Hi Sam,

    I haven’t tested this EBL model. One of the best battery and charger reviewers on Amazon is NLee the Engineer, and I can see that his review is on top. He is not impressed. This model charges in pairs and does not use the negative Delta V method. Every model I recommend has independent charging channels (does not charge in pairs, but singly), and uses the negative Delta V method.

    As I mentioned in the post, the best low cost charger I’m aware of is the Panasonic BQCC17, which can usually be found for under $20. It can be had for even less if you acquire it as part of an Eneloop bundle, several of which are mentioned in the above post.

  64. On low or no voltage cells

    A simple trick I use is two pennies and another cell
    of the same size with good voltage

    Place the two cells side by side (in parallel) both positive
    on one end and both negative on the other

    Then put one penny on both ends connecting the two cells

    In a few seconds the low cell will come up to 1.2 volts and
    ready to install in the charger that requires voltage to start

    I use the same process on waking up 100AH NiMH modules for
    electric vehicles but use jumper clamps to a copper bar for the
    final connection. This has to be done do to the amount of current.
    Which is not a problem in AA or AAA cells

  65. John – I haven’t tested the BQ-CC55 yet. The specs seem pretty similar to the Fujitsu model I described above, but I don’t know if it’s identical or has any of the same issues I mentioned. I did buy the Costco pack recently with the BQ-CC55 and hope to test it soon.

  66. Panasonic BQ-CC55 smart charger vs Fujitsu FCT344 smart charger

    The Panasonic BQ-CC55 uses 27% higher charging current when using 1 – 2 or 3-4 AA batteries.
    When charging AAA batteries, both charge at similar rates.

    The bottom line is that with AA Ni-MH batteries, the BQ-CC55 charger is faster, but heats the batteries much more than the FCT344 charger.

    Charging Rates for the Fujitsu Quick Charger FCT344

    Battery Type	         Number of Batteries	     Charging Rate
          AA		        3-4 (normal)		     550mA
          AA		        1-2 (quick)		    1100mA
         AAA		        3-4 (normal)		     280mA
         AAA		        1-2 (quick)		     560mA

    BQ-CC55 charging specs:

     Input : AC 1 00–240 V / 50–60 Hz 0.3 A
    Output : AA: 1.5 V x 4 ---> 3.2 A max		750mA x4 for AA
             AAA: 1.5 V x 4 ---> 1.2 A max		275mA x4 for AAA
    			                     Charging time          Charging time
                          Capacity               1-2 pcs                3-4 pcs
    AA	       2400 – 2550 mAh 	             2    hours	            4   hours	
    	       1900 – 2000 mAh 	             1.5  hours	            3   hours
    	        950 – 1000 mAh 	             0.75 hours             1.5 hours
    	         900 – 950 mAh 		     2 hours		    4 hours
    	         750 – 800 mAh 		     1.5 hours	            3 hours
    	         550 – 650 mAh 		     1.25 hours	            2.5 hours

    A brand new set of eneloop 2000mAh batteries was used for both of these tests.
    Each battery kit was initially discharged to 0.9 volts at 300mA using my Powerex MH-C9000 analyzer/charger.

    Fujitsu FCT344 charging results

    maximum centigrade temperatures for each battery:
    27.6 — 30.5 — 32.9 — 32.3 <— degrees centigrade
    elapsed time: less than 3 hours, 45 minutes

    Panasonic BQ-CC55 charging results

    test #1, maximum centigrade temperatures for each battery:
    38.1 — 42.7 — 43.1 — 40.8
    elapsed time: 2 hours, 57 minutes

    test #2, maximum temperatures for each battery:
    25.1 — 26.6 — 26.8 — 24.8
    elapsed time: 2 hours, 52 minutes

    Ambient temperature for all tests were at 19 -20 degrees centigrade.

    test #2: The second test was with a 120mm, 1200 rpm (50 cfm) computer case cooling fan placed 7 inches in front of the BQ-CC55 charger blowing room air directly into the front of the charger. Placing the fan closer to the charger provided additional cooling, but too much cooling might cause problems with proper termination of the charging process.

    Newegg sells four different Fujitsu Ni-MH charger kits, but the FCT344 model is the only Fujitsu advanced/smart charger.
    Do not buy any of the remaining three dumb chargers.

    Fujitsu Battery Charger + Ni-MH AA Battery Kits at Newegg, as of December 9, 2016:

  67. Hello, Joe.

    Thanks for keeping such an amazing blog. I’m already a fan.

    I have one question. Would you recommend storing freshly recharged batteries in the refrigerator? Would that be a good or bad idea? Would that affect its charge or voltage in any way?

    I work in photography and already keep some things (rolls of film, mainly) in a compartment in my household’s fridge. I was wondering if this would benefit my rechargeable batteries in any way, since I’ve got to always keep a batch of fresh batteries for my speedlites and other devices.

    Hope hearing from you soon.

    Have a nice holiday.

  68. Hi Alejandro – Happy Holidays!

    Heat is not good for batteries. Refrigerator temperature is ideal, though room temperature really isn’t so bad. The benefit of keeping batteries cool and dry is that you extend their life. Batteries subjected to heat a lot will build up internal resistance over time and hold less charge. So as a photographer, if you are buying the most expensive type of LSD battery which holds more charge, that might be an added incentive to storing them in the refrigerator.

  69. Thanks for the fast reply, Joe. That’s a very kind thing for you to do.

    Considering I live in South America, and temperatures down here tend to be higher than in the States, I’ll stick to your advice of keeping my batteries in the refrigerator.

    As for the “buying the most expensive type” part of your response, recently I’ve been thinking about upgrading to the Eneloop Pro batteries from the regular Eneloop kind. What are your thoughts on this matter? Are they really worth the extra money? I worry about their inferior cycle life (500 vs. 2100) and don’t really know if that is truly a smart decision in the long run, since I can get more regular units for the same price of the Pro ones.

    Would love to know your informed opinion on this subject.

    Once again, thanks a lot for your kind attention.

  70. Alejandro – I’m not a professional photographer so really you would know better than me what your needs are. If you find that you occasionally do so many pictures and videos in one photo shoot that you completely drain the batteries, then upgrading to the PRO is worth the extra cost. As you say, they are much more expensive in the long run. If you have never run your standard LSD batteries down in a single day, then no need to put in the extra money into higher capacity batteries.

  71. Thanks for taking the time to share your insight, Joe. I greatly appreciate it.

    Looking forward to read more of the interesting content on your blog.

    Happy Holidays!

  72. Thanks for putting up together all this information on batteries, really appreciate that as a user. Do you recommend an USB-powered charger ?

  73. Hi Terry – I haven’t ever personally used a USB-powered charger. Sometimes, the Amps provided by USB chargers is not always same which may cause the performance of a USB-powered charger to vary. That being said, the following one on Amazon gets pretty good reviews:

    and here’s one with fewer features that costs a little less:

  74. I just received two chargers I ordered after reading this site, but I’m not confident that they’re working correctly. In my OPUS BT-C24000, I charged a brand-new Eneloop AAA battery at 200 mA until “FULL”. When I switched to “DISPLAY” mode for that slot, it reported capacity of 18mAh and 1.45 volts. I took the battery out of the charger, put it back in the same slot and it registered 1.45v, but 0 mAh capacity. Another brand new Eneloop AAA battery indicated “full” with 1.46v and 172mAh. I also removed that battery, reinserted immediately, and the voltage stayed the same, but it indicated 0 mAh, again. I put that slot in “charge” mode at 200 mA, and the battery capacity seemed to start over from 0 mAh, indicating 1 mAh, then 2 mAh … as I watched it. The label on the battery indicates 1.2V and a “minimum” capacity of 750 mAh. A brand new Eneloop AA battery, “fully charged” on my Panasonic Advanced CC17 charger, when placed in the Opus charger, indicated 1.42v and 1 mAh! I must be misunderstanding what these values mean and what they truly indicate. Can you help me understand? How can I determine the “true” charged capacity?

  75. P.S. I REALLY appreciate your website, and your comprehensive but easy-to-understand explanations and evaluations. Thank you.

  76. Dale – I’m not sure I understand what you’re doing. If all you’re doing is topping off a nearly fully charged battery, then probably what you are seeing is not the capacity of the battery, but rather how much charge was put into it.

    To see the capacity, you need to do a full discharge followed by a charge. This is called “CHARGE TEST” on the Opus charger. If you choose that mode, it will completely discharge the battery followed by charging it full, and then you’ll get the mAh displayed.

    Look at the manual to get the sequence of button presses correct. Let me know if that works for you.

  77. Dale, think of it like trying to determine the capacity of a pail where you first need to fill the pail with water, then you have to empty the pail using a measuring cup until you’ve measured all of the water that was in the pail when the pail was full.

    With your charger/analyzer, you first need to gradually charge the battery until it is full, then you need to run a gradual discharge cycle to accurately determine how much energy the battery can hold.

    A natural question you might want to ask is why can’t I just measure how much current the battery stored during the charge cycle? To keep it simple, the charger can measure how much charging current is “sent” to each battery, but some of this energy is converted to heat while charging the battery. In some cases 30% – 40% of the charging energy is converted to heat and this is why we can’t accurately determine the battery’s capacity just by running a charge cycle.

    Once you understand these basics, you will better understand other options where you can run a charge/discharge/charge test or you can run a cycle test repeatedly until your battery’s capacity has reached its maximum limit.

    Is this as clear as mud?
    Hopefully not.

  78. Jim and Joe – thank you! Both of your responses were very helpful. I believe I do understand, now. If I’m “topping off” a pre-charged battery, then the mAh represents the charge added. A “charge test” will tell me how much capacity the battery had held BEFORE the test, but only by completely discharging the battery and measuring what was discharged. Upon recharging the battery, it should be known by the indicated mAh how much charge was used to “fill” the battery. Again, thank you for your prompt response. How might a casual visitor to your site help to support your efforts?

  79. Hi Dale – It’s nice to be appreciated.

    In answer to your question, “How might a causal visitor to your site help to support your efforts?” . . .

    It does take a lot of effort to put together comprehensive guides. One of the things I most appreciate is when someone spreads the word about my site. Next time you get into a conversation about AA batteries, perhaps you could forward a link to one of my battery posts. You can subscribe to all future content if you desire (scroll to top right of page to see your options: RSS, email, or Twitter). If subscribing by email, you can subscribe to only the categories you care about.

    I don’t display ads on FilterJoe because ads tend to distract when trying to read a long article. When readers click over to Amazon and buy something, I earn some income as described on the FilterJoe About page.

    Most content on FilterJoe does not discuss products and and therefore does not generate income. However, whether an article discusses products or not, I do my best to provide accurate information.

    Thanks for asking!

  80. I did subscribe to your website, and I will be happy to access Amazon via links posted on your website. When I get the chance, I will forward a link to and my recommendation for your website.

    Is it okay to mix rechargeable batteries which have different capacities in the same device?

    I’ve always wanted a “professional-grade” in-fielder’s mitt for softball. Do you know of a good source? Thanks. – dale.

  81. Thanks Dale!

    Mixing batteries of different capacities won’t harm them but it is not efficient, because some batteries run out while others still have a bit of charge remaining. Ideally, you’ll save yourself the most time changing batteries if you can match together batteries of very similar capacity.

    I have only looked at baseball, not softball gloves. I have recently learned enough about baseball gloves to be impressed with top of the line gloves from Wilson, Rawlings and Mizuno. The web sites of these 3 glove makers do a good job of describing which gloves apply to which positions.

    These high end gloves tend to list for $300 to $600 but can often be had for less than half the MSRP on eBay.

  82. I ordered a CC16 charger, but got a CC55E charger. Is there already experience with the CC55C or shall I rather try to get the ordered CC16? Thanks.

  83. Stefan – I am not familiar with CC16. The CC55 is the newest Panasonic charger but according to Jim (scroll about 10 messages back) it charges at a high rate with not so great heat dissipation because of its compact size. It will not destroy batteries, but the heat , over time, will reduce battery capacity and longevity.

    If you decide to keep it, be sure to always use it with at least 3 batteries inserted. With 1 or 2 batteries it charges at an even higher rate, generating even more heat.

  84. Stefan – My preliminary Panasonic BQ-CC55 tests showed battery temperatures that were 8 – 12 degrees (C) higher than the Fujitsu FCT-344 Ni-MH battery charger when charging four 2000mAh low self discharge (LSD) batteries. The CC55’s 38.1 — 42.7 — 43.1 — 40.8 degree (C) temperatures are not dangerously high, but these temperatures are not optimal over a five to ten year LSD battery lifespan. Charging only one of two AA batteries will use a charging rate that is probably in the 1400mA range for each battery instead of of its lower (and cooler) 750mA rate for each battery when charging four batteries at a time.

    The CC55 battery charging rate when using AAA batteries is 275mA and this should be fine when charging 1, 2, 3 or 4 AAA batteries at a time.

    The only drawback that I see with the CC16 charger is that for maximum battery capacity when charging, the CC16 requires an additional two hour top off charge to fully charge batteries. The CC17 battery charger takes about seven hours to fully charge four AA batteries. If you are using older 2000mA batteries that are usable but past their prime, the CC17 charger is better than newer compact chargers from Panasonic, Fujitsu and most other charger manufacturers.

    An excellent but very technical review for the CC16 charger is at

    This picture from the review shows results with four AA batteries where the blue line shows increasing current that is stored in the battery and the black line shows the battery temperature during the charging process.

    This is the reviewer’s conclusion for the CC16 charger:

    “The charger is very good at filling the eneloop batteries. The two hour top off charge helps filling batteries if the charge terminates slightly early. No trickle charge is an advantage for LSD cells.
    I would have preferred a lower charge current for more time, instead of the high current pulses, the pulses may give problems with some old cells.

    I believe this is a good NiMH charger.”


    I will be doing additional in-depth temperature testing with the BQ-CC17, BQ-CC55 and Fujitsu FCT-344 chargers this week. Tests will include two AA batteries, four AA batteries along with two and four 950mA AAA High Capacity batteries.

  85. Hi! Thanks for all the great info. What about cold weather use? As a photographer my camera bag and equipment are often out in very cold temperatures for extended periods. Very often my speedlights fail to perform if i havent prewarmed the batteries, and even then only work for a short while. Any suggestions? Thanks!

  86. Mark – I have no experience personally in cold temperatures but there’s a discussion of cold temperatures for Eneloops at CandlePowerForums:

    The bottom line seems to be that Eneloops will do well at typical winter temperatures in U.S. (down to around -10 to -20 Celsius) but for better performance and/or lower temperatures, Lithium batteries are the way to go. Lithium batteries are much more expensive so if you think you won’t be going below -20 Celsius, then low self discharge batteries are the best way to go.

  87. Hi, There
    Thanks for the volumes of info on batteries/chargers/history
    A quick question is what charger is a good one when talking about volume charging?
    8, 12, 16 batteries at a time?
    Tenergy’s comes to mind, but are there others that would be ok too?
    Kids have a lot of batteries for R/C stuff and games.

    Thank, Douglas

  88. Douglas – I have never used a charger with more than 4 bays. If you always have 8 extra unused batteries, then you can simply use them right away when needed, then recharge batteries 4 at a time over next 2-3 days.

    That being said, there is a great 8 bay maha charger. I’m not a fan of tenergy chargers based on reviews I’ve read though I personally have not ever used one.

  89. Douglas – MahaEnergy is the company that makes and sells PowerEx batteries and chargers. For about $40 their MH-C800S 8-bay model looks to be an excellent smart charger that allows you to use a rapid (fast) or a soft (slower) charge rates where the soft charge is ideal for longer battery life. Note: the default charging rate uses the faster charge rate. There is also a battery conditioning setting that can help restore older batteries.

    This charger comes with a 3 year warranty and Maha support is reported to be excellent. You can download a pdf copy of the user manual from the Maha site.

    Check it out at the Maha website:

    I did a quick search for a Tenergy 8-bay charger and the first one that I found was a slow, 8 – 10 hour charger that wasn’t a smart charger.

  90. For anyone considering buying Amazon Basics – in my 2017 update post (coming a month or two from now), I’ll be dropping my recommendation for Amazon Basics batteries. While other brands have been gradually improving for years, Amazon Basics have not improved. Furthermore, some Amazon Basics batteries are sourced form China (the black ones). Given that most people will use their LSD batteries for a decade or more, it makes sense to buy higher quality batteries.

    Leading brands such as Eneloop are of much higher quality – they will last slightly longer before needing to be recharged, they will retain charge for longer when idle, and the maximum capacity decline will occur much more slowly over the years.

  91. Hi Joe, thank you for brilliant easy to understand articles.

    Just wondering, have you reviewed the 2017 Ikea Ladda 2450mAh batteries or charger ?

    Would love to hear your thoughts on the new Ikea Ladda’s.

  92. Hi Chee – glad you find some of my articles useful. Unfortunately, I can’t comment on the Ladda batteries or charger as I know nothing about them.

  93. My Panasonic BQ-CC16 Smart & Quick charger (bundled with 4x AA Pro) does not accept any other NiMH rechargeable battery other than Eneloop (Sanyo & Panasonic, both regular and XX/Pro) brand – no way, the charger green leds are blinking with Duracell, Sanyo (2300 mAh non-eneloop), Tronic (Lidl brand) etc. AAs and AAAs, so I have to charge non-eneloops with big & bulky (but decent) Ansmann Energy 16 charger.
    The surprise is BQ-CC16 accepts and gladly charges 10-15 years old Sanyo 1000 mAh NiCd AA cells (thats unbelieveable how excellent these Sanyo nickel-cadmium cells are until now).

  94. Interesting article thanks – will look for the updates.

    Thought worth mentioning – your link director seems to re-direct to the wrong product sometimes – at least for me – I’m based in the UK. Have seen US/UK amazon redirects do this before.

    e.g. link to:
    “High Capacity AA LSD (Low Self-Discharge) NiMH batteries:
    Panasonic Eneloop Pro 4 Pack AA NiMH Rechargable Batteries”

    Actually sends met to Amazon UK product B00KM4CICM aka BK-3MCCEC4BE – the white 1900mAh Eneloops with box

  95. Thanks for the feedback, Daf – really appreciate it. Up until a couple weeks ago I had all Amazon links going to U.S. but I’ve been experimenting with Amazon’s new automatic link redirection feature for UK and Canada.

    Good to hear that it is attempting to do something for someone based in U.K. But obviously disappointing that it’s not redirecting to the same product. Eneloop has slightly different product codes for the Europe market than North American market, so my guess is that the slight product code difference is what is throwing off whatever the Amazon Algorithm is.

    Not sure if there’s much I can do about it, other than turn the feature off altogether. At this point the jury is still out as to whether this Amazon redirect feature makes sense for FilterJoe.

  96. Due to a site issue, the following comment got deleted. So I’m manually returning it here:

    Oliver 9/23/17

    I have used the Maha and the LaCrosse, and the latter has one benefit:
    it charges batteries in the cycle mode till they don’t gain in capacity, the Maha will continue to cycle until the number of cycles is done, even if you ran 10 cycles without any gain of capacity…

  97. Hello everyone!,

    I just found this awesome blog and I would really appreciate your advice.
    I´m a professional electronic engineer and personally, I´m tired of buying crappy chargers, some have features others don´t but mostly they don´t do what I want.
    I have tons of batteries, some old some brand new, eneloops, sanyo old ones, etc etc etc.
    I would like your personal opinion since I´m willing to build from scratch a flexible charger that could eventually do whatever I want.
    Long story short:
    I find most of the chargers to charge my batteries too fast (very high current) or trickle for too long or even use timers for charging without caring for anything else.
    Some time ago I managed to test (oscilloscope in hand and quite more tools of course) quite a few chargers (mines and from friends) and had an awful feeling of not getting what I wanted.
    Since I´d like as a small personal satisfaction project build my own charger I´d like your expert opinion.
    -Would you like to have different charging rates (selectable) let´s say (100-1000mA) completely configurable?
    -Would you like the charger to select to do a trickle charge or not?
    -In case of trickle charging, would you like to have a configurable timer for this (let´s say 30 mins to 3 hours selectable in steps of 30 minutes?)
    -Would you like step charging or continue charge?
    -Would you like the charger to analyze the capacity left in your batteries?
    -Would you like to have a ultra slow reconditioning charge for completely depleted batteries?
    -Would you like to have an LCD display?
    -Would you prefer to be small or big? How compact?
    -How many batteries would you prefer to charge individually? maybe 4?
    -How do you think is more practical to configure the charger? buttons? touch screen? cellphone app? What would you prefer?
    -If you could buy something like that, would you pay for it?. For some reason (not my case) most people just buy a charger and don´t have second thoughts. They charge the batteries and that´s it. But for some of us this is not good enough. This is why I´d like to see if this small project would be appealing for you too.

    Sorry if that felt like an intensive interrogatory, I´d really appreciate your comments

    Thank you all for this excellent post!.
    Best regards,


  98. Luis,

    I tend to personally be in that category you mention of “people who just buy a charger and don’t have second thoughts.” Because of that, I think BQ-CC17 is already close to the perfect charger, though I suppose it would be nice if it could also accept a USB input from a laptop or USB battery backup (or such a device combined with solar panel) for when you’re not near an electrical outlet.

    However, Jim tends to get more excited about high end features on chargers so let’s see if he give you more of the kind of answer you’re looking for, for the type of user that would desire more features and control.

  99. Just one further thought for you Luis – a private question I get more frequently than any other is whether I can recommend a charger that works best when away from an normal electrical outlet or car. In other words – what are the solar options? I have never felt really solid about any of my recommendations. A real innovation would be a charger that can accept a USB input, because then it becomes easy to use an USB battery pack, which in turn can be charged from a solar panel.

  100. Luis – here is Jim’s reply:


    You asked for it…. now you’ve got it.

    The Opus BT-C2000 (rev: 2.2) analyzing charger is now my every day charger and my 7 year old Maha Powerex MH-C9000 charger is now in semi retirement.

    search using: mc3000 charger thread for more information in web forums
    note: you can dowload the MC3000 user manual from their website
    Check out the CPF MC3000 thread which has a little over 5000 posts!!

    Check out the UltraSmart information at:

    UltraSmart Charger
    UltraSmart Charger Kickstarter Project (open-source)
    UltraSmart Charger with Inflection Termination
    It looks like inflection termination is better than -dV and 0dV termination.
    Also check out

    • provide internal resistance results as a separate test option
    • charging C and D cell NiMH batteries using an included adapter if necessary
    • Charging Current range 200 ~ 3000 mA minimum for C and D cells
    • Discharge Current range 100 ~ 1000 mA (maybe higher for C and D cells)
    • Max. Charging Capacity 20,000 mAh (20 Ah) minimum
    • illuminated LCD backlight with selectable on/off/20 second on options
    • selected options for top off and trickle charge rates (default for both settings is NONE)
    • option to select continuous current (CC) charging if it’s possible with proper charging termination
    • option to select primary, secondary and tertiary termination types
    • include 2 reasonably quiet internal cooling fans to lower the charger’s electronics
    • save detailed run time voltage and temperature results for each battery in CSV format and include software to create result graphs
    • provide a break-in option the follows the IEC 61951-2 section7.5_Endurance initial 0.10C charge / 0.25C discharge / 0.10C charge procedure
    • the MH-C9000 provides a break-in test (without graphs or database results) but it takes 40 – 45 hours for the test to complete
    • let users select how many times they want to run an extended charge/discharge cycle test, in most cases up to 5 cycles should be enough
    • provide 10 – 20 or more stored charging and discharging charging profiles
      saved profiles can be created and stored on the charger, a computer and/or cell phones
    • the charger can be controlled from a computer and/or cell phone via wireless and usb connections
      provide firmware updates to fix minor bugs and/or add new features
    • if possible, separate the charger’s electronics from the battery bays for optimal thermal management
    • size is wide enough to have at least 1/4 inch of ventilation space between each of the four AA charging bays
    • optional buzzer and/or flashing indicator when each battery’s cycle completes or if overheating is detected
    • multiple programmable profiles that can be downloaded from a computer to the charger
    • logging statistics that can be viewed on your computer in real time or saved to your computer
    • able to charge power banks and/or cell phones while batteries are being charged or discharged
    • 5mm OD, 2.1mm ID with center positive jack for the power supply input
      balance battery charging profiles might be useful for some consumers
    • default safe mode defaults on startup so that non technical family members can safely charge batteries
      The model name for your analyzing charger should start with CF which stands for Control Freak.
      A $14.95 retail price would be great, but I’d be willing to pay $50.00 for all of the above features.

    re: solar power
    search using:

    • solar power battery charger
    • portable solar power bank battery charger
    • site: solar charger
      Woods Walker appears to be the most knowledgeable solar power member at CPF.

    My consulting fee is 25 cents per byte, including spaces 🙂

  101. Thanks for posting here, Marco. That would account for some of the disappointing experiences people have had with Amazon Basics pre-charged (LSD) batteries in recent years.

  102. Hi Joe,

    I recently pick up a BQ-CC75 charger, and have added it to my collection of Eneloop chargers.
    I also have a ’55’ (which I’m not going to use, I can wait for a slower/healthier charge), and also have a ’17’.
    I see that the older ’17’ is well-regarded: is the ’75’ the same as a ’17’ but with a usb charger added?
    I haven’t seen any reviews and want to use the best charger that I have.
    Thanks for all the effort you put into this site.

  103. Hi Charles – I too bought a BQ-CC75 recently as part of a Costco pack but I haven’t tested it. From what I’ve read, it is as you say – apart from addition of USB charger, it’s identical to the BQ-CC17 which has tested very well by myself and many other battery enthusiasts. I need to spend some time testing the BQ-CC75 to see if it does indeed perform identically to the BQ-CC17.

  104. This thread is pretty long in the tooth but I need to know if my BT-C2400 is defective or what. Quick test on AAA NiMh batts produces inconsistent results. Random batteries in random slots will report 400+ mΩ while others report anything from 70-120 mΩ.

    I moved the same batteries into other slots and got more random results. I am exchanging the unit with Amazon but I wonder if it’s just this particular unit or a symptom of the design. Any thoughts?

  105. Hi Ben – Jim has done all the testing on Opus models, not me, and he stopped responding to FilterJoe comments a year or two ago. But it sure does sound defective on the face of it.

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