Pokemon Ruby, Sapphire, and Emerald only use the battery to power the onboard clock, the saves are on flash. If you look at the PCB you can see the flash chip on the left, it’s the one that’s not under the battery.
It’s safe to replace the battery, but since the RTC will be starting from 0 again you won’t see time based events happen until it catches up to the time stored in the save. If you’re not planning on starting a new game or fixing the save file using a cart reader and save editor (alternatively a DS with GBA slot and a flash cart) there’s no point in replacing the battery.
Update: Now I’ve replaced the battery in Pokemon sapphire. Luckily since it uses flash memory my 25 year old save file is intact.
Wait… can you confirm that these things don’t use volatile memory for game saves?
Pokemon Ruby, Sapphire, and Emerald only use the battery to power the onboard clock, the saves are on flash. If you look at the PCB you can see the flash chip on the left, it’s the one that’s not under the battery.
It’s safe to replace the battery, but since the RTC will be starting from 0 again you won’t see time based events happen until it catches up to the time stored in the save. If you’re not planning on starting a new game or fixing the save file using a cart reader and save editor (alternatively a DS with GBA slot and a flash cart) there’s no point in replacing the battery.
Edit: Fixed typos
Thanks, that cleared things up.
The only thing I can tell you is my save survived the battery replacement, which tells me it’s flash and not SRAM.
Did the same on my Ruby half a year ago. Fun times.