From PowerBook G3, 3400, 5300, 190: Battery Interchangeability (

In order for the PowerBook 3400 to be able to charge the PowerBook G3
battery, M4895, you will need to upgrade to Mac OS 8.1. The Mac OS 8.1
update includes the necessary software that will allow the PowerBook 3400
to recognize and charge PowerBook G3 batteries. If you are using Mac OS
8.0 (or older), you will not be able to charge the battery.

Does Linux support charging a PB G3 battery in a PB 3400?

Mvh. / Kind regards
Henrik Farre