I use two PX625 1.5v batteries and a silicone wrist band. I've got details & a photo at:
https://submini-l.groups.io/g/main/topic/76041714
I assume this approach can be used for the other cameras that use the PX30 battery.
https://submini-l.groups.io/g/main/topic/76041714
I assume this approach can be used for the other cameras that use the PX30 battery.