Battery not recognised? Onyx may solve it

I recently bought a secondhand PowerBook, running 10.4.11, along with a replacement third-party battery.

However, the PowerBook wouldn't recognise the battery. As soon as I disconnected the power cable, it powered down.

I tried to reset the PMU, as a discussion on this boards suggested (http://support.apple.com/kb/HT1431) but that didn't help.

So, as a long-shot, I installed and ran the automated maintainence routines in Titanium's Software Onyx (http://www.titanium.free.fr/).

After the Powerbook restarted, it recognised the battery.

I don't know if this was a fluke, or whether Onyx has battery-fixing abilities, but it worked for me.