Why is my battery draining fast even when turned off?

[AC Question]

Fast draining battery even when turned off

Hi !

On my Koodo Mobile (CA) S3 (i747m), stock Android 4.4.2 , I got a problem of battery draining, even when the phone is turn completely off (shutdown). When I start it again, I see about 5% of loss per hour while it was off !

The problem seemed to appear suddenly after a road trip and my car charger. Do you think it could damage the motherboard ?

I tried to swap the battery with a good one (tested ok on another S3)
Make a factory reset and cache wipe
Update via Kies

The pb persist after all this...

 

[B. Diddy]

Re: Fast draining battery even when turned off

Welcome to Android Central! If you have an SD card inserted, unmount it in Settings>Storage, remove it, and reboot. A corrupt card can cause battery drain, although it shouldn't if the phone is completely off.

So the replacement battery exhibits the same behavior?

 

[rv03]

Re: Fast draining battery even when turned off

Hi, Thanks for your answer. No, I don't have any SDcard on it..

Yes, same behavior with another battery.

In battery manager, "Android System" seems to take a lot of energy.

 

[Rukbat]

Re: Fast draining battery even when turned off

In battery manager, "Android System" seems to take a lot of energy.

Not with the phone turned off. You have a hardware problem. Where? It could be a leaky bypass capacitor on the power line. Probably, though not definitely, something on the motherboard.

Could the charger have caused it? Not likely. Some capacitors just go. It doesn't happen very often these days (replacing power supply filter caps used to be a large part of the radio and TV repair business), but it does happen sometimes.

The only way to know what's wrong is to take it into a repair shop. (If you replace the motherboard yourself [without causing any other damage] and it still happens, you'll have wasted money, time and effort. Buying the test equipment to diagnose the problem correctly would cost a lot more than a new phone.

 

[rv03]

Re: Fast draining battery even when turned off

Thanks a lot !

I'll give a try for a repair shop recommended by Samsung, but they told me they won't be able to change the motherboard if it is necessary...

 

[apizz]

I have the exact same problem with my Sony Xperia SL. It was okay a week ago, then after a full charge lately, the battery suddenly drains so much in a matter of hours. Before this, a fully charge phone could easily last me for 2 -3 days. but now it could hardly make it for half a day. Worst is, even when its turned off, the battery still being drained. had it at 53% power before i turned it off, few hours later, it dropped to 35%. Something is eating my battery away..help pls T_T