XPERIA U - battery dropping while charging

[DariaPahlavi]

My battery is dropping to 15% then when I put it on charge, it's still dropping. The phone has died on me 4 times already today. What do I do? I've taken the battery out, but still nothing. I need to charge my phone to go out, how do I fix this please?

No matter where I charge it, the charge symbol is showing but the % is going down rather than up. doesn't make sense. 

help would be appreciated. thanks. 

[Uliwooly]

How are you charging your battery? (Wall charger or through a computer) 

[DariaPahlavi]

Wall charger. 

[Uliwooly]

Repair your phone with SUS if that doesn't work then take it to a Sony repair center

Update Service (SUS)

http://www.sonymobile.com/gb/tools/update-service/

http://www-support-downloads.sonymobile.com/Software%20Downloads/Update_Service_Setup-2.11.12.5.exe

PC Companion (PCC)

Bridge (for Mac)

Alternatives on How to backup Xperias

http://talk.sonymobile.com/thread/36355

[DariaPahlavi]

can't use SUS because it needs at least 50% charge to update. i can't charge. 

[Uliwooly]

ok try this 

Press and hold power & volume up for 5 seconds > connect the phone to the wall charger > press and hold power & volume up > let it charge for 1 or 2 hours 

also, are you using Sony's charger and/or usb cable? or some other brand?

[Fahim715]

Try this
Take out your battery and wait for 30 second
Then put it back into your phone and charge it without booting the phone
Wait at least 20-30 minutes then try boot the phone

[DariaPahlavi]

I tried using the SUS and rebooted the phone and reinstalled the software. Still slow, battery still doing the same thing. I tried the volume up power thing, no change.