Battery Apple Powerbook
Where can I get an Apple PowerBook G4 replacement battery online?
You can order those through Apple. But if you are looking to save a couple of dollars there are some other sources. You might consider Other World Computing at http://eshop.macsales.com/
or possibly Powerbook Medic at
http://www.powerbookmedic.com
Good Luck!
Apple PowerBook 3400c Running on Battery