12" rev. B PB battery "crashes"

You should try recalibrating your battery. Keep running your laptop until it forces itself to sleep. Just ignore the warning messages and keep on using it. Once the battery is completely empty, the laptop will sleep, then you need to charge the battery up completely. That may help. Here's an Apple article that talks about it:

http://docs.info.apple.com/article.html?artnum=86284

you could try resetting the pmu

try the recallibrating, but it seems to me your powerbook is fried... Had it happening with my 12 inch rev A also, would go to sleep at 30% left, really annoying but you learn to live with it.

Same here.

That started happening to me a while back as well. ( I have 12'' Rev A. though) I think it was about the 9 month mark as well. All of a sudden the computer would just crash. No warning, nothing. A very big problem if you ask me.

I tried re-calibrating the battery, and resetting the PMU, like other have suggested, but it never worked for me.

I checked out the Apple Forums, and the macrumors forums, and there were a surprising number of user who have the same problem. It was rather funny, on the Apple.com forums, the Apple people said it was perfectly normal for you computer to randomly go to sleep with less than 30% battery life. RIGHT. Several said they had gone to the Apple Store and were given new batteries.

I ended up buying a new battery, and it ended up fixing the problem. I think its a bunch of BS myself. A battery that won't even last a year. Diminished life I understand, but completely shutting off, unacceptable.

Good luck in your battle. I hope apple takes care of you.

It seems the notebook batteries found in the Powerbooks are very sensitive to how they are used.

To help keep your new battery in tip-top shape, take a read of this:

http://www.apple.com/batteries/