Q: batery

I wouldn't attempt that.  http://www.macsales.com/ and http://www.welovemacs.com/ may have the right battery.

The chemistry does not get better after it is depleted

by adding electricity. A replacement battery, is a fair

bet to restore the computer and not toast the charger

or the computer you'd overcharge the dead battery in.

You may be able to get a copy of a similar battery at

some discount, but it may not have the microchip in

it that correctly controls the charge/recharge cycles;

another source for a quality battery would be 'OWC'

or macsales. These have a higher capacity, but are

not discount clones, & are from a reputable company.

Other product sources may provide suitable quality online.

OWC offers new batteries for iBook G4. (& other)

http://eshop.macsales.com/shop/Apple/Laptop/Batteries#ib

•iBook Repair guide - iFixit:

http://www.ifixit.com/Device/iBook

Hopefully this helps somewhat.

Good luck