Buying a new battery for powerbook g4 alu

[MattMK45]

If I bought a brand new battery for my powerbook (this one's on it's last legs; 40 minutes tops!) how much battery life on average would I get?

 

[GoCubsGo]

3-4 hours I'd imagine.
It will vary. What were the battery specs when you bought the machine new?
Do you have Bluetooth and wifi on? What about screen brightness and running apps? It'll vary ... that's about the best anyone can say.

 

[MattMK45]

Those specs are very promising seeing as I only get like 40 mins tops as I said. I didn't buy it new, I actually bought second hand about nearly 2 months ago, maybe its just not an official apple battery?