Battery charging, but when unplugged, laptop not working (Alienware 13 R2)

Hello,

problem with my Alienware R2 13 - I replaced motherboard (bought refurbished one from parts & people) and now the battery is not working. It is visible, charging (it took her almost 3 weeks to get her to 100%) but when i unplug the charger, laptop turns off automatically.

Bios is updated, battery health - performing normally, AC adapter 130W

I did the DELL test (when you press Fn while turning on laptop), battery health is 96%.

I also run the 60 sec test (powercfg will enable a trace for 60 seconds)..

So I really don't get where is the issue... is it the battery or my new board?

Unfortunately i don't have anyone with this kind of laptop to borrow his battery and do diagnosis.. :(