Problem with HP 25

[AndiGer]

You JUST see the battery low indication!

From the Owner's Manual (download at https://literature.hpcalc.org/items/654 if you don't have it):

Low Power
When you are operating from battery power in RUN mode, all
decimal points except the true one light to warn you that you
have a minimum of 1 minute of operating time left.
6 0.2. . . . .. 23 Low Power Display
^
True Decimal Point

Andi