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Extending Battery Life

So you have a smartphone or laptop that you've owned for a year or two and the battery seems to lose charge very quickly.  However, some batteries in a friend's identical device seems to have lasted for years longer!  So what's the deal?

The deal is that modern devices use lithium-ion batteries, and it is very easy to mistakenly misuse a lithium-ion battery. 

What?  A misuse a battery?  How does THAT happen?

The common killer of lithium-ion batteries is heat.  Heat just sucks the life out of a lithium-ion battery, and they never, ever recover.  My goal for battery care is to always avoid unreasonable heat.  So here's the short list of the rules I follow for long battery life:
  • Never leave a device in a car.  Cars interiors can get very hot.  If I leave my device in the car even once for 15 minutes, where the temperature can get over 120 °F, I have forever stolen some life out of my battery's soul.
  • Never leave a device in the hot sun.  This is really a variation of the above statement.
  • Never use cheap, generic chargers.  A cheap charger can send poor quality power to a device, and then the device needs to smooth out and reduce that voltage to something it can safely use.  All that voltage smoothing results in substantial heat - which, as we now know, kills batteries. 
  • Never use "fast chargers".  Fast chargers inject more energy into a device over less time, resulting in more heat and more stress on the battery.  It's best to use a normal charger, and avoid speed-charging.
  • If a device feels hot, restart it.   Bad software can spin out of control, resulting in a lot of internal heat production.  A restart terminates all software and gives it a chance to behave normally.  And make sure the device's software is up-to-date.  Up-to-date software is less likely spin out of control and heat up a device.
  • Never let a battery completely discharge.  Once a lithium battery is allowed to sit for months without a charge, it might not be recharge-able.  I never store a device with very low charge, and I never let a device sit for several months without charging it up.
Other myths to debunk:

I think the following silly ideas come from the age of the NiCad batteries of the 1970s.
  • Do not purposefully "drain" or "calibrate" a battery.  Doing so simply weakens the battery.
  • Do not worry about "overcharging" a battery.  All modern devices have a managed charging system.  These systems are necessary to protect the battery and to prevent event leaks, fires, and explosions. Attempting to trick the charging system will only reduce battery life.
Buying a replacement battery

It can be hard to buy a replacement battery.  First-party manufacturers (like Samsung, Apple, Dell, etc) all charge quite a lot for a battery.  But the battery they sell you has a real warranty and will certainly be of higher quality.

Third party suppliers generally sell batteries without a warranty.  Some might claim they offer a warranty, but most don't provide any mechanism to make a warranty claim.   That's no warranty.  Furthermore,  some of these 3rd party batteries can be ill-fitting, low-powered, and can have very short useful lives.  But they are very inexpensive, often one quarter of the price of a manufacturer's battery.

I almost always buy 3rd party batteries on Amazon.  Here are the 3rd party battery purchases that I have been happy with.  Of course, double-check your model number before buying anything!

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