Unhappy [Q] Xperia neo V battery problem

Hi everyone
I have an Xperia Neo V with official CM 9.1 and I have problem with battery stats and charging.
When I plug the charger the battery won't charge (on lock screen says "charging" but in settings at battery status says "discharging"), i need to use an external charger to charge the battery (I have 2 batteries)...
Only when I reboot the phone shows my actual battery percent (max 90 percent) and stays to that percent till the battery is fully discharged and phone shuts down.
What should I do? Please, I need help
This problem persists since I was on stock ICS from Sony, with no root and locked bootloader... so I pretend that the custom rom I installed is not the problem:-??

P.S.:Sorry for my bad english:|