Yes sir! They are 2032's, and I would like to go back with something even bigger so we don't have to cross this bridge again for a good long time.
FYI, there is no way I would even chance replacing these cells without an extensive plan, including repowering the board before removal. I just cannot chance losing the software. I have seen some guys jumper/solder to the battery legs with a new battery, then cut the old one out but that will prove to be a problem in this circuit due to the space constraint.
I am curious, purely based on experiences, is it unlikely that there are two discrete backup circuits, and the circuit was actually designed to chew on one battery before switching to the other? Can you explain how this might work so I know what to look for in the circuit?
Also, regarding the voltage on the batts, on a 2032, what would new voltage be? I would assume it should be higher than 3V? I cannot remember if lithiums tend to hold full voltage until depleted, then drop like a rock? If I can determine the 3V batt will hold things for a while, I might side step the repair until I really have time to do this. I am a little busy with other projects right now.