Sent Using My Rooted Kindle Fire HD 7"
I have the same problem! My Kindle shuts down for no reason. When I try to power it up again, it shows the shimmering kindle logo shows, the screen flashes as though it is about to boot up but is simple switches off again.
The only way I can get it to boot is to plug it in to a power charger. When it finally boots, the battery is often 50 - 60% charged?
This often occurs when unlocking the screen.
Any suggestions as to why this happens, or what I can do to fix it would be most welcome
What roms are ou using? Do you have rooted devices? Did you tried monitor your apps for apps that might eat up your RAM?
If you have full battery problem might be in RAM and the shutting of is basically android mechanism for "fixing" the issue with full RAM. Look into your apps and see if you have any app that might be causing this. If there is anything suspicious try uninstalling the app and see if the reboot comes back.