So, I bought a HiLetgo set of 5.
Tried one of them - it worked right away!
Measured the battery voltage before installing - 3.3V
Finally, the problem is really solved.
I guess these things just don't last long.
Max S.
RPI 4 B (4Gb) with SMate
Askar FRA400, TPO RC6, Nikon D5500 full spectrum (with IDAS clip-in filter).
ASI2600MC Pro
ZWO ASI120MM Mini on ZWO 30F4
ZWO ASI224MC-S on Orion 50 mm f/3.2
ZWO EAF x 2
SW AZ-GTi
SW HEQ5
RST-135