Galaxy s3 (LTE) slow charging (very weird behaviour) topic

My S3 is charging slow.
Unless I plug in and unplug every 5 minutes.
Basically I downloaded the galaxy current monitoring app and whenever I plug my max current is 1000ma but it starts to drop until it reaches 0. I have tried different chargers and cables and some don't even get me to 1000ma.

I don't think its a problem with my USB port since it starts well and it drops.

Could it be my battery?

[Q] Xperia Z Strange Behaviour with Battery connected topic

Hi XDA community, i open this thread for know if anyone have a similar issue.
When i connect the USB charger to my Xperia Z, nothing appear, no led and no vibration, seems totally dead, this occur with an original wall charger or with a PC-USB connection, but just when i disconnect the battery of the phone with the USB cable connected to USB PC or wall charger, the red led blink 2 times and become blue if i press immediatly vol+ or become green if i press immediately vol-, obviously immediately after battery disconnection.
With the battery connected no signs of life, seems that if the battery is connected the USB connection refuse to activate, but the strange thing is that without battery i'm able anyway to flash any firmware without problem, but after a correct flashing without error no signs of life and no boot.
I think there something wrong with the battery management, but the battery works 100% because i tested with other phone and work, and i tried to use other working battery but always same problem.
Anyone have this issue or know something about it?