Why does my kindle fire die when not being used?
When I am not using my kindle fire I have it in sleep mode. But occasionally it will die while in sleep mode. I go to use it and it tells me that it has died and needs to b charged. It has happened three times so far but it doesn't do it a lot.
Do you not use it for a very long time? Because battery always is used some even if the device is not on. Also leaving it in cold areas will make it run out faster.
In sleep mode it still uses up some battery. There's also some tips on optimizing battery life of the Kindle, see if it helps:
If there's battery problem (like your Kindle was not used for a long time, or whatever problem), you can see a discussion here on how to fix such kind of problem:
Hope that helps.