Why does my laptop power off a few moments after I plug in the charger

Hi ! I am new to this part of computing . I got a bunch macbook parts alongside a dead one as a project . Besides the motherboard i had in the laptop , i got 2 others in unknown condition . The one in the laptop prooved to have a dead gpu but was charging and running off of the charger fine . A bit of heat got the board temporairly functional but it wasn't long lived . The second one refused to power on under any condition but was able to charge the battery .

The third is where things got interesting . It seemed fine . Compared to the other somewhat functional board it refused to power on without the battery but that isn't the problem . It runs great on battery power until it its plugged in . In a few minutes tops it shuts down . Under mac os it recognises that its plugged in but the battery wont charge and the led on the magsafe plug doesnt light on green or orange . Looking closer at it i see a faint orange light pulsing . Any ideea what could be wrong?