Question Acer Aspire ES1-531 motherboard button

[Saltedm8]

Hey, I have an Acer Aspire ES1-531 that I'm refurbishing, I've been having trouble with the battery, but I found an odd button on the right of the motherboard that when pressed, makes the orange charging light work and it actually starts charging.. is this button a pressure button to make sure you don't try charging it without the keypad etc on?

I also seem to have a secondary problem that when I insert the battery (I tried one that has 30% charge) as soon as I disconnect it from the power cable, the laptop has no power despite obviously knowing the battery is there and it being detected.