Battery charging

With all of the smartphones, tablets and laptops around, most people have a device with a battery and have heard advice from other people on how to get the most out that battery.  The main thing I've heard is that you should let your battery drain all the way and then charge it back up to increase the battery life.  Curious if this was true I set out on a journey through the internet.

I found a bit of conflicting information and learned a few things about the different types of batteries, though I'm nowhere near an expert now.  Basically there are a few main types of batteries used.  The older ones are NiCd (nickel cadmium) and NiMH (nickel-metal hydride).  They aren't very widely used anymore because of environmental concerns surrounding their disposal.  Apparently with these types of batteries it is a good idea to completely discharge and then recharge them to ensure maximum capacity.  They're also said to have a "memory effect" that can result from not following this procedure.

Newer Lithium-Ion or Lithium-Polymer batteries are commonly found in smartphones and the latest electronic devices.  These don't suffer from the memory effect and the batteries can be shaped to different sizes allowing flexibility in the design of the devices they'll power.  From the Apple website on batteries they say that "you can recharge a lithium-ion polymer battery whenever convenient, without requiring a full charge or discharge cycle."  Although on their iPhone battery page they say "Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down)."  It can also be important to calibrate your battery to make sure that any battery stats that are reported are correct.

Other sources seem to support the occasional full discharge and recharge every so often.  Apparently it's also not necessarily a good idea to keep your phone plugged in all the time as it can stress the battery.  Extreme temperatures (hot or cold) are also bad, pretty obvious.