Asus A4 battery question

I've just bought a replacement battery for my old A400K laptop, as I'm giving it to my father to use now I have a new one.

I plugged it in, and switched the laptop on, and all looks fine: Full charge give 2 1/2 hours, which is about the same as the original.

However, I have noticed that the battery charging light only comes on when the laptop is powered up, and not when it's off. Leaving plugged in for a couple of hours (turned off) doesn't seem to charge the battery.

Any ideas what could cause this? Is the battery bad, or is there a bad connection on one of the 4 pins it connect to? If it's something simple, I'd rather not send it back, as I'll have to pay postage.

 

I suspect bad firmware, rather: the charging logic not working properly (not charging when the notebook is off).

But it could also be the hardware, of course.

Be aware that if it's not a hardware malfunction, any new battery (from same type/revision) that you get might be affected by the problem.

You could also try to update the BIOS to the latest version, although that should only have an effect when the computer is on, not when it's off...

But is it really necessary to worry about this? For instance with my usage pattern, I never keep the notebook plugged in when I'm not using it; which means it's always on when plugged in, and the battery charges like that. If your father isn't likely to need charging the battery with the computer off, maybe it's best to just leave it be.