Battery Life? What does this mean and what can I do about it?

The term "battery life" has two different meanings, and control of "battery life" has two different outcomes depending on the meaning.  To the point, the two meaning of battery life are:

1. How long does a battery charge last when not being charged (device not plugged in)?
2. How long does a battery last before it has to be replaced because it no longer holds charge for a reasonable amount of time when the device is not plugged in?

The conflict is:  if you optimize for battery charge life your battery will probably not last as long before you have to buy a new one.  Conversely, if you optimize for length of time before you have to replace the battery, the battery won't last as long between charges.  To distinguish between the two kinds of battery life, I'll call the second kind "battery health."

Why the conflict:  In short, because if you want the battery to last longer before you need a new one, you shouldn't charge the battery to 100%. 

I'll provide some details about the operating system controls for Windows here.  You can do a search for the terms "Extending battery life" and the name of your device or operating system to learn what controls are available for your device to gain some control over how long your battery will last between charges. 

Extending battery life between charges

With that out of the way, there are ways to make a battery last longer between charges.  The controls you have available are pretty much functionally the same between different kinds of devices, but the user interfaces and the number of controls you have available vary by device, by the operating system, and by any extra application you might install to control this kind of battery life.

Windows:  This article explains the operating system controls available:  https://support.microsoft.com/en-us/help/20443/windows-10-battery-saving-tips

Android:  Read this article:  https://www.androidauthority.com/android-battery-saver-tips-tricks-189882/.

Extending battery health

Windows:  There is one control in Windows whose purpose is to maximize battery health:  "Battery Life Extender."  It controls whether or not the battery will be charged to 80% or 100%.  Battery designers say that charging to 80% will extend the life of your lithium battery.  For details on the Windows control see:  https://answers.microsoft.com/en-us/windows/forum/all/why-does-my-laptop-only-charge-up-to-80-and-not/916ea22c-9e36-4b69-a5ef-f91495de4fda.  If you use your laptop mostly plugged in and don't use it on battery for more than 4-5 hours at a time, then you can set this control to 80%.  If you are traveling and you can't be sure how long you will be able to go until the next charge, then set Battery Life Extender to 100%.

Android:  Rather than getting into the details of the operating system controls for battery health, download the app AccuBattery.  It has more tools than you could ever want to monitor the health of your battery.  I haven't found a way to automatically control the maximum charge on a locked Android phone, which is what most people have.  Manually, you can watch the charge and not charge to 100% and occasionally discharge to depletion. 

PS:  If you wish to add the Apple appropriate information, please feel free to use the comment feature of this blog.