I have a LG Optimus S Android on Gingerbread (The one on the cheaper side with least specs for an Android).

I have found that when I use the USB charger connected to my computer, at times instead of charging my phone, the battery gets drained. (Also I perceive that the battery gets drained faster than normal phone usage at such times)

While I have a fix which is to restart my Android phone. Could someone explain why such thing happens?

2 Answers 2


Now your typical wall charger on a smart phone provides 1A of charging current. The USB 2.0 on a computer will only supply a max of 500mA, that is half as much. So if your screen is on and you are using the phone then it is drawing more power than it is taking in since the screen is the largest drain on the battery, therefore the battery will drain while charging on a USB connected to the computer.

  • Actually the thing that I forgot to mention is the device is in standby the whole time, I hardly use the device and most of the times I disable sync (Another battery drainer) as well.
    – veepsk
    May 30, 2013 at 17:43
  • @veepsk That it is a bit odd... I could understand charging slower in that case but discharging...? Is your battery dying? How old is the battery?
    – TronicZomB
    May 30, 2013 at 17:45
  • The battery is 1 Year 6 Months old. Maybe that might be the reason, but when I charge my battery using wall charger, it seems to charge just fine.
    – veepsk
    May 30, 2013 at 18:23
  • Seems rather early to be dying... Is that a 4G phone? And if so is the 4G antenna on? That could draw some power away...
    – TronicZomB
    May 30, 2013 at 18:27
  • 1
    No it is a 3G phone. I was stunned when this happened the first time but I have seen this occurrence couple of times and I don't exactly know what is the reason I believe that might be some bug with Gingerbread for that version because it seems to get fixed when I reboot the phone.
    – veepsk
    May 30, 2013 at 19:19

Could very well be a wakelock. I hate to sound like a broken record on these types of questions, but if it's not a hardware problem, it's probably an app or service that's preventing your phone from conserving power like it should.


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