Hello fellow Android enthusasts,

I recently bought a Nexus7 that I want to use for development. The thing is, every time I connect it to my USB, in order to test some apps on it, it starts charging. Now, i know that this is absolutely normal for every device, but I am also concerned that the constant charge/discharge cycles can shorten the life of the battery. What do I do?

Do I need to get concerned at all? I mean, if it reduces battery life with something like 1% per year, I am totally fine with it. Yet, if it is a significant drain, how can I prevent it from charging unless I am charging from a charger?


Charge/discharge cycles are mostly irrelevant for li-ion batteries. The main source of capacity loss is simply time. A li-ion battery sitting unused in storage will lose 15-20% of its capacity per year (see charts on page 4). Any minor losses from cycling is going to get drowned out by that.


I haven't heard about number of charge cycles affecting battery life. However...


dwelling in a full state-of-charge for an extended time can be more stressful than cycling.

Most Li-ions are charged to 4.20V/cell and every reduction of 0.10V/cell is said to double cycle life.

Keeping Li-ion battery in high state of charge will reduce it's lifetime. Some laptops have Battery care function (software) to limit maximum charge to 80%. It's recommended by them if you routinely run on AC.

On android there is some kernel modifications allowing you to limit maximum charge in similar fashion. (it's from 2011) http://forum.xda-developers.com/nexus-s/development/mod-battery-life-extender-blx-t1257497

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    Most of my devices' manuals set this extended period of time in full-charge to between a week to a month. I am pretty sure you can left the device plugged at full charge for several hours with no problem (all of us probably do that every night already). – Mindwin Sep 23 '14 at 18:57

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