I'm in the same boat with Wallstreet batteries, out of 3 I've received neither one of them worked (and that machine is a bit older than the pismo), even after trying Battery Reset... fortunately I was lucky enough to have a good battery for my Lombard (which also fits in the Pismo AFAIK)

Doesn't really matter to me though, although a battery (even one that lasts about 5 or so minutes) could be useful in certain situations like moving the computer to another room, or a short power outage, etc.