I started up my lathe fanuc 21t control Alarm 307 absolute battery down. I had a spare changed the battery cleared alarm.
I started my sharp mini mill fanuc oi mate control I get the same alarm 307 absolute battery down.

I just used both of these machines yesterday what are the odds of both batterys going out at the same time on 2 different machines.

Ive been runing them with a rotery phase converter for years no problems all 3 legs are within 3 volts could this be some kind of power problem to cause this or just bad luck. Both batterys have the same voltage 4.33 volts.
Thanks
Tim