Battery compatibility between Al and Ti Powerbooks?

the two batteries have the same form factor but does anyone know if the new ones are backwards compatible?
Micko wrote on :

Reply to (mosborne) over at fastmail.fm

My PowerBook G4 667 has been getting progressively sicker since I had a big stack on my pushbike whilst carrying the laptop in a backpack. Result - right hinge damaged (possibly the "invertor board" I was told) so video still displayed but no backlight hence the screen was normally unreadable - I could still use with an external monitor however. (The cost of repairs was prohibitive as the entire screen assembly must be bought as a single part from Apple, >$1000).

After a few months I began experiencing a problem with the battery/power supply. The laptop would not always power up when I pressed the power key, and it would immediately power down when I plugged in the power adaptor. I got it to work a couple of times after I removed the battery and then replaced it. It now doesn't power up at all, with or without the battery in. If I plug the power adaptor the light displays green and then orange as it would when charging, but the battery doesn't appear to charge properly (if I push the button underneath the battery it flashes the first light out of four).

I thought that the original battery was cactus so bought a new one, although I think might have accidentally got one designed for the new Aluminium models as it has a different part number (M8544G/B, although not a genuine Apple battery, versus my original which is M8511). I still can't get the damned thing to work - hence the topic of my post, the two batteries have the same form factor but does anyone know if the new ones are backwards compatible?

The other possibility is that there is a short circuit or something with the power adaptor - I tried using an iBook adaptor with the old battery in, that didn't seem to work, but didn't try it with the new battery, and no longer have ready access to any other powerbooks or ibooks.

Any ideas are welcome, I am reluctant to spend very much money on this Powerbook as I am eyeing a new 15 inch Aluminium. I am in Melbourne (Point Cook) if anyone is interested.

Thanks, Michael