So, I measured the battery capacity. I figured that since I use all of them in series in my application the most interesting measurement would be to discharge them in series. First I charged them up in parallell to about 1,4V.

I screwed up the measurement, I discharged the batteries through 421,7 Ohms, but measured voltage over a 384 Ohm resistor, so voltage is a bit off.

Anyway, the batteries showed a not-so-impressive capacity of about 10mAh. I think its only one battery that is really bad. After the measurement I measured individual cells and all but one had 1,2 - 1,3 Volts. One battery had 1,0 V.

The graph below shows the discharge. Discharge current is about 20mA (depending on the voltage). When I reached 6V the accumulated capacity was 11,0mAh.

Still, if my system draws 0,1uA the batteries would last 100h minus the capacity used for opening and closing the valve. I only need 4-6 hours or so since night time in sweden is very short during the summer. I think I will stick them back in and see what happens. If I see resets in the logfile I can always change them later.