T460s weird power issues

[sona1111]

Hi all, got a t460s, won't power on if the BIOS battery is plugged in. If I take the BIOS battery out the cmos datetime error comes up and then it boots normally and everything works fine.

A second more critical issue is that neither battery seems to work. There is no power at all unless it is plugged in. I tried taking out each of the internal batteries in turn and neither is detected by the operating system. Any idea what might be the cause of these weird problems?

Thanks for reading!