Why is my phone battery dying so fast?

[AC Question]

So... I have a Samsung Galaxy S3 Neo, as I said my battery is draining so fast and I don't think its even charging properly. I charge it at night but when I wake up it is something like 75-80%. Also it won't charge with the original charger. Now I'm charging it with a Sony one I think which has a smaller amper thing (0.75mA while the original was 1mA). Now this wouldn't be a problem to me if it was actually that, but if I play a 3 minute youtube video it drains it like 7%, and when it gets really low (like 20, 15%) it drains SUPER fast, like (15 - 13 - 9 - 4 - 1 - dead). Oh yeah also when it's charging and I unplug it, the battery goes down, and if I keep doing that, it does it until its dead. I think that is about it, I tried using another battery, doesn't work, and I even changed the charging port thing, I don't know what it's called, charging regulator something... and it kept doing that. Please please help, any fixes? :/

 

[Rukbat]

1. I suspect a bad charger, but you're not charging the battery enough. Get a Samsung charger. Samsung Micro-USB 2A Travel Charger - Android Wall Chargers - ShopAndroid is US$13.

2. NEVER let the battery drain down past 40%. Never do that to ANY lithium battery.

3. If the charger Output current is less than the phone is using internally (run Ampere to see how much it's using), it will discharge even if it's connected to the charger.

 

[Laura Knotek]

Have you taken it to a repair shop to have them look at it? It sounds like there are hardware problems that only repair technicians would be able to diagnose.

 

[MrPhF]

Yeah, they told me that it was the battery/ charging regulator thing, and they changed it, but it didn't work ...

 

[MrPhF]

Hmmm... now that you mention that, I think I remember using a friends charger (a Samsung one) and it worked.
I mean one day my original charger was acting a bit weird and sometimes it was charging and sometimes no, so I gave it to my sister (she has a Samsung Galaxy S3) and it worked for her perfectly, and she's still using it today (any ideas why it's working for her, and not for me?), so I used one of her friends charger and it worked for me like a regular charger... I mean I'm going to get a new Samsung charger just so I can try it, but yeah just wanted to let you know!

 

[akakpaws]

I had this problem. In addition the phone was taking forever to charge it never did charge fully. I discovered that the charging port tab was deformed from years of use and was shorting out. The solution was to carefully insert a 90° Usb mini adapter into the slot and then plug the charger cable into the adapter instead of directly into the phone. It has been working fine ever since. The trick is to get the adapter inserted carefully without shorting out that connector tab. Once that’s done the phone will work fine. Hope this helps.