280c startup trouble

[David Linker]

I am helping a friend with a 280c that he just got, which has not been 
used for a long time. It has 30 MB RAM, a PowerPort modem, and two 
batteries, one of which is an Apple type 3, and the other a BTI type 4.

It will not start up with the batteries in place. If I remove the 
battery and plug in the adapter, it starts up just fine. If I plug 
either battery in while it is running, it suddenly stops after a few 
seconds. I tried letting the batteries charge for an hour or two, but 
it would still not start with the batteries in.

Does this indicate that the batteries are the problem?

Thanks in advance.

David Linker