I posted details, and a source for the battery, over on the Powerbook G4 15” PRAM battery replacement page: PowerBook G4 Aluminum 15" 1-1.5 GHz PRAM Battery Replacement
It should be the same thing here.
SUCCESS! The 3.7V battery worked wonderfully, and has held a PRAM charge overnight twice now. Charges back up fine too; no leaking.
I purchased this one from eBay: https://www.ebay.com/itm/Cgl-3032-3-7-v-...
If you’re reading this in 2025, I’m sure that link will be dead — you’re looking for a 3.7V (NOT 3.0V) 3032 LIR (Lithium Ion Rechargeable) battery with solder tabs.
An update 3 weeks later — the cell above did NOT work. Battery stopped holding a charge and was leaking badly; I think this may be because the new cell was only 3.0V and the original was 3.7V, and possibly the charging circuit was overcharging it.
I have found a 3.7V cell on ebay, so I’m going to try that next.
For those that are trying to do this in 2021, when new replacement parts are basically unavailable — you can replace just the cell itself with a new unit — Panasonic actually still makes these 3032 rechargeable cells. The part is here: https://www.digikey.com/en/products/deta...
The new ones are a 3V cell; the Apple spec’d battery is 3.7V, but it seems to work fine. You’ll need basic soldering skills — take the old unit out, unwrap it from the kapton tape, unsolder the old one and solder in the new one. Make sure to use a hot iron and spend a minimal amount of time heating (not more than a second or so). You want to heat the terminal, but not the battery itself.
When I did this, my old Apple OEM battery was reading a 1.03V charge; the new one was a full 3.05 volts.