There are companies who build custom battery packs &/or open up sealed factory assembled ones
and depending on what the product is, could replenish the rechargeable cells within them. You'd
have to ask a technician or customer service representative at such businesses if they could rebuild
an Apple portable computer battery case with new replacement batteries.
Some electronics supply shops have staff who can repair products, replace rechargeable cells,
and the like. Even in smaller cities. Figuring that many products have rechargeable battery packs
the places to inquire may be more than one may think.
There is a 'used' battery with one year warranty, listed in iFixit site, $99. aluminum for G4 PBook:
https://www.ifixit.com/Store/Mac/G4-Aluminum-12-Inch-Battery/IF153-019-1
A question that may come up with an actual re-fitting of the Apple computer battery with a replacement
li-ion or other appropriate cell, would be IF the original battery's circuit that helps control the charge and
that communicates with the power management unit, would need to be re-set somehow, as part of this.
While the iBook G4/G3 portables still have a source for battery replacement via OWC & newertech
it would seem other than the plastic vs aluminum case, and shape, the contents did not differ all that
much between the last G4 iBook 12-inch models and the last G4 12-inch PowerBook models. With
larger display sizes, processor differences, and power demanding options, this could vary the specs.
The power adapters were very similar, so that aspect of hardware unity is shared. Not sure if the
power cells from an iBook G4 1.33/1.42 would work in the battery case for a PowerBook G4 1.5
Perhaps a call to OWC macsales could help locate another supplier, or a rebuilder of G4 PowerBook cells. 😐
