There are three major reasons to keep your iPhone plugged in. Here they are, followed by product recommendations if you need more charging options:
Save Time (No More Battery Management)
iPhone batteries typically last 2-6 hours under moderate to heavy use when most services are turned on (location, Bluetooth, WiFi, 3G, etc.). Yes, I know there’s plenty of ways to extend battery life by turning off unneeded services, keeping brightness to a minimum, turning off push, etc. But if you keep your phone fully charged when not in use, you won’t need to spend so much time and attention managing your battery.
Prolong Battery Lifespan for Heavy Users
Apple describes ways to prolong iPhone battery life and lifespan. However, Apple neglects to mention that frequently recharging an iPhone after shallow use can potentially increase battery lifespan. According to Battery University and the book Batteries in a Portable World (page 198), “[for Lithium-ion batteries], the smaller the depth of discharge, the longer the battery will last. If at all possible, avoid frequent full discharges and charge more often between uses.” So keeping your iPhone plugged in most of the time will have the side benefit of prolonging battery lifespan because the phone will rarely experience full discharge.
Note for light use: For optimal lifespan, Lithium-ion batteries need to be used. The above advice assumes moderate to heavy use throughout each day. If you’re not using your iPhone for days at a time or you use it just a few minutes per day, then only charge it back up once every couple days, as discussed in ars technica’s the best way to use a Li-ion battery.
Reduce 3G Data Usage
The most obscure reason for keeping your iPhone plugged in is also the inspiration for this post: My usage rate increased by about 100MB last month. I finally figured out it was because I was no longer leaving my iPhone plugged into a charger as much.
Why is 3G data use higher when an iPhone is not plugged in? Because WiFi turns off while 3G stays on when an iPhone is in standby. This is done automatically in iOS 5 to conserve battery life. While in standby, 3G data gets used for syncs, push email, etc. You can stop this by going into settings/network and turning cellular data off when not needed. But why take on yet another phone maintenance task? If you leave your iPhone plugged in, WiFi stays on, so 3G data is not used.
Plug iPhones into . . . What?
As every iPhone owner knows, you can charge your iPhone from a computer’s USB port using the included cable or from an electrical outlet with the included plug. But if you’re going to keep your phone plugged in most of the time, you want it to be convenient. If you’re like me, that means one charger upstairs, one charger downstairs, one at my office, and one for my car.
For me the car charger was an easy choice: Kensington 2-port Charger. It can handle any Apple device, including an iPad at 2A and it can also charge other USB devices out of the second port at 500 mA.
For home and office, you can buy additional high quality Apple plugs, if you don’t mind paying top dollar. There are also many low cost, low quality knock offs. I avoid both of these options.
I prefer the versatile Rosewill 4-port USB charger RUC-6180. I have one at home and one in my office, for less than the cost of a single plug from Apple. It’s 2 Amps so it can also charge tablets and e-readers. As you can see in the picture, I always leave 3 different types of USB connectors plugged in: Apple USB to Dock Connector, micro USB, and mini USB.
My particular Rosewill model has a quirk: in order to get the iPhone to charge, I have to plug it in first, before other devices. The other thing not to like is the ugly cord mess, which may inspire you to hide the cords behind desks or other furniture. Alternatively, you can spend more to get more aesthetically pleasing charging stations from iHome.
It’s possible to keep your iPhone plugged in more often without buying additional charging stations. But if your noticing that you’re only charging your iPhone at night, it’s worth buying more chargers. Conveniently located chargers will makes it easier for you to keep your iPhone plugged in more often.
Combine a great pocket computer with a limited battery, and you’ll frequently run down the battery. Countless articles describe ways to get more out of your battery by turning battery draining services off, dimming the display, and other tricks. In my opinion, following all this advice is distracting and time consuming.
A key smartphone benefit is the convenience of having a computer available at all times. Add a battery maintenance chore and you’ve lost some of that convenience. Leaving your iPhone plugged in while you’re at home, driving, or at your office is a lot more convenient than managing battery life.