Interesting that it is 2 batteries, and I see the 3 wires. I could bet there's a heat/over charging sensor in there.
Only permanent solution is to get the PRAM into a flash EEPROM which is not a viable solution without total ROM rewrite. Rechargeable watch batteries would be your best bet, which would only last about 10 or so years.
Another solution have a get of rechargeable PRAM Battery and in case that fails, have a floppy boot up the system and load in a saved PRAM into memory and then reboot. There is a program called "TechTools" by MicroMat (their current version is for Intel/OSX, but search the net for the older versions for 68K and System 6/7/8; Hint: Macgarden, and pay what shareware fees applies). This way if the PRAM battery dies and the information lost, you can reload it from the floppy and reboot. Though it takes a few extra steps, it saves a lot of headaches down the line. BTW - while the 540c (or any laptop as a matter of fact) is plugged in but off, the powerpac takes over of keeping the PRAM alive. Though keeping a powerbook plugged in may not be an option 24/7, it could be a saving grace for a while.
Only permanent solution is to get the PRAM into a flash EEPROM which is not a viable solution without total ROM rewrite. Rechargeable watch batteries would be your best bet, which would only last about 10 or so years.
Another solution have a get of rechargeable PRAM Battery and in case that fails, have a floppy boot up the system and load in a saved PRAM into memory and then reboot. There is a program called "TechTools" by MicroMat (their current version is for Intel/OSX, but search the net for the older versions for 68K and System 6/7/8; Hint: Macgarden, and pay what shareware fees applies). This way if the PRAM battery dies and the information lost, you can reload it from the floppy and reboot. Though it takes a few extra steps, it saves a lot of headaches down the line. BTW - while the 540c (or any laptop as a matter of fact) is plugged in but off, the powerpac takes over of keeping the PRAM alive. Though keeping a powerbook plugged in may not be an option 24/7, it could be a saving grace for a while.