Oregon WMR300 and battery on external sensor.

[Cameron D]

This is just a bit of information for other WMR300 owners who might also come across this issue.  There is (I hope) no problem to solve, although there is a question for other WMR300  owners - can you see the battery status for the external sensor unit?

The external sensors of my system have been on the roof for about 6 years with no problem apart from cleaning out the rain gauge occasionally after the filters mysteriously disappear.

Recently it stopped transmitting, so I had a look - battery (AA Ni-MH) was showing 1.3V but the test points on the PCB were showing about 0.5V, so I gave a slight clean by rotating the battery and it sprang back to life.

For a few days.

I then started getting dropouts starting almost precisely at 16:35 each evening, for 5 nights out of 6.  But then, after about 30 to 60 minutes it would spontaneously start up again and work as normal all night.

This is not the behaviour I would expect from a degrading battery - it drops out after a day of charging, but happily provides power all night.

I plugged in the windows software to see if it gave me better information.

I gave the contacts a more thorough clean, and the battery terminals and pcb test points both reported the same voltage (about 1.3V).

I then noticed the sudden appearance of the  battery status indicator on the PC and also on the console (but only after I select the "today" portion of the screen).  The PC showed (judging by the icon) the battery was 25%, while the console seemed to show it was flat. Then the battery status disappeared and I could not get it back.

I replaced it with a recently fully charged eneloop and, after a few minutes, it showed the same battery status levels that it had before - i.e. nearly flat.  After an hour charging in full sunlight I brought it  back inside the house and  the cell terminals and pcb test point both registered 1.45V.

I have not since then seen any battery status indication on the console or the windows software.  It seems to only report it just after being powered on again. That might go some way to explain why I could never identify the signal in the USB data stream.

But why does it show most problems when it should be at its highest charge level but no problem  after powering the system all night?  I can only guess it is somehow getting confused as it tries to transition from solar power to battery power.