HP-50g Backup Battery

[cdmackay]

and make sure you backup everything to SD card first

I use both the builtin ARCHIVE and ARCHIV for that.


There are BTMON and BATST utilities available; I think they only monitor the AAA batteries, but a voltage reading there would tell you whether they were OK: if they are, then the flag must be for the CR2032 backup.

Some people recommend changing one AAA cell at a time, not all four at once.

The Quick Start Guide says: "When the low battery annunciator appears, please change your AAA batteries", which implies that there's no annunciator for the backup battery. But I'm not sure that's right. However, the User's Guide says a screen message will appear when the backup battery is low, which seems to contradict that.