I have an Samsung Galaxy S2 GT i9100. I have had it for quite a time, but today I noticed something strange:

First my battery had not been charging while I was sleeping: when I woke up I had only about 13% charge left. So I put the phone on the charger while I was making breakfeast.

When I came back to the phone some time later, it had nearly not charged at all: in fact the phone was using more battery then it was charging.

Why is my phone battery's charge dropping when I'm charging? I had this problem the whole day -- it won't charge more then 30%, then suddenly the battery level drops. How can this be solved?

  • 1
    Have you tried to completely shut down the phone, removing the battery for at least 30s, put it back into the phone, and charge it while the phone is still switched off? Might be it's just the display of the charge level (i.e. the "reporting process") which is "confused".
    – Izzy
    Commented Mar 10, 2013 at 22:42
  • Maybe you have a problem with the cable of the charger.
    – false
    Commented Mar 11, 2013 at 1:02
  • i think it was the cable... i used a sony ericson greenheart charger last night and my phone charged perfectly normal. and my battery has been nice to me the whole day so far :D Commented Mar 11, 2013 at 12:55
  • On S3, I use HTC cables after a couple of Samsung cables that all started to make problems after a few days.
    – false
    Commented Mar 11, 2013 at 13:00

4 Answers 4


Had exactly the same, did the same as you asking questions and hearing lots of different answers. My solution new battery, couple of quid on ebay.


This mostly starts when you upgrade your firmware. I believe the Jelly Bean upgrade is a big drain on the phone resources.

My way out? Throttle down the CPU speed (antutu or CPU-Z can do the job for you)


I have had a very similar problem a couple of times in the past with my Samsung tablet. It was always software-related, and never the cable or charger (I have two original Samsung chargers for that tablet, and both had the same problem, as did various cables. For me, it would not charge past 50%.

The first time, I let the battery discharge all the way until the tablet went into severe battery-saving mode, and I let it go as long as I could until I lost patience. I then charged it up, and it worked OK after that. It happened again, it seemed, a few months later. This time, I unplugged the charger,turned off the power, then plugged it back in and it charged OK.

Samsung phones are often picky about chargers. I've found that some will not work at all with my Samsung tablet, but will work with my LG G2 and my wife's iphone, while others work with it, with my LG, and with my wife's iphone. I never really figured out exactly why. But as with all chargers, sometimes they will work, but at only .5 amp if you don't have the right match, or a special charge-only cable. So, if you have such a charger, it might not be able to keep up with the discharge.

I worked in electronics repair, testing, and design for about 15 years, so I have a good understanding of the basics, and troubleshooting. People who suggest special short, thick, whatever cables are simply not very knowledgeable, or repeating misinformation from others who are just guessing out of partial knowledge. For the amount of current going through the cable, and the difference in resistance for different types of cable, the loss is negligible. The only time a cable will make a difference is if the connector is damaged, or it is wired in a nonstandard way internally. Of course, a cheap cable can have a wire break, but that has nothing to do with size of cable.

Also, if you're not careful, the connector on the phone can be damaged, or have foreign matter caught inside, or some obstruction keeping it from making a good connection. The micro-USB connection is not the most robust way of making a connection, which is probably why they are creating a new standard.


The cable does make a huge difference, so I'm glad that I read your new cable made it last for a day. In addition, once a week you want to do a full charge cycle. Completely waste the battery, [to the point where you can't boot] and charge it for 8 hours straight, off.

I find that shorter, thicker cables make the battery of the device last longer.

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