I have a WS-2902C, and installed in in late November. Not even mid-Feb and the battries are showing they need replacement. This is in SoCal, so not like we had a brutal winter.
Is this normal for this device? I thought the solar panel was supposed to provide enough power when the sun is out, and expected the batteries to last longer.
I installed a WS-2000 in December, which uses the same Osprey outdoor sensor array. I used Energizer Ultimate Lithium AAs in the Osprey station and the 4 outdoor sensors I got. Those batteries do better in the cold (we've been down to 0F this year). I'm still hoping for at least 6 months. So far I've kept the outdoor array cleared of snow; at least, I've cleaned it off the next morning after the snow stops.
The Ambient API (local or remote) only reports 2 values for battery: OK or Replace. I'm guessing OK is mapped to 100%. It just doesn't mean the batteries are at 100%.
It depends on the driver. In mine I report 75% when it comes back as the OK value (and 0% when it is to be replaced), because you really do not know and 100% seems too definitive. Some methods actually report the battery voltage so those have finer reporting.