Android tablet kiosk development

I am trying to develop a kiosk application on android. I am facing two challenges.

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1. Once the tablet getting off due to a battery drain. it is not turning on even after the battery reached 100% . is there a work around for this ? I have seen regarding editing some files in /system/init of Android after rooting. But I have not seen any file related to battery or charging. I am using 4.1 and higher

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2. I am experiencing a problem of battery draining. as it continuously keep display on, battery drains gradually even if the charger is connected.

Has anybody came across similar problems and find any solutions ?

Is there android devices available which , power on automatically after connecting wall charger ? Is there tablets that doesn't have battery and directly works from charger connection ?

Please provide your suggestions.

Update 1:

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As I am using kiosk operation, I have to keep the screen on every time. I am not experiencing a quick battery drain, it drains slowly even if the charger connected , like 1 percentage in 6-8 minutes, so it lasts approximately 10 hours with charger connected. Then once it gets switched off, it needs to be powered on manually ( not power on after battery drain is a normal behavior, but is there a work around for this ?).

Actually I am not expecting the battery to get drained on a charger connected. is that a normal behavior ?

Can I do anything from the software to prevent it ? When I analyzed most of the power is consumed by screen, then wifi, then comes the application. Both are switched on all the time. Any advises on this ???

Update 2:

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 android:permission="android.permission.BIND_DEVICE_ADMIN"

Update 4

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As my issue is considered. It is not an issue triggered by a particular event. I assume when connecting a charger android is loading the kernel and only showing a battery symbol, When we press on power button it boots up the kernel. Is there a way to bypass it ? Or is it depended on hardware or firmware ?

If it is dependent on android, Yes there is some hack we can do about it. Else it might be not possible. :(

A similar discussion is here but no definite answer android auto boot on external power

Answer

@aivknow tech

I did this on Samsung Galaxy Tab sm-t330nu

edit the lpm service entry in init.rc from

service lpm /system/bin/lpm
    class charger
    critical

to

service lpm /system/bin/reboot

    class charger
    critical

Result = from powered off state, plug in charger, battery icon displays briefly, then device reboots to normal operation.

to mod your device's service in your init.rc in the

on charger

section find that equivalent service.