After a pretty long charge, the battery took a good 20AH+ in and was sitting at a much happier voltage, it also ran a much larger number of pump cycles before hitting low voltage warning. I disconnected the battery and charged it with a lab power supply, while measuring things with a WattsUP meter. No matter how I tried to explain that I see no meaningful charging ever happening, the tech just kept insisting on his line. The answer that came back was – “you need a new battery”. All this sounded like a system that is not charging correctly. And finally I remembered that in the two or three years of owing the system I’ve never had to add water to the battery, even though the manual warned that it should be done pretty regularly, based on low water indicator. Too low for any kind of charging to actually occur. A nice discharger so to speak!īattery voltage was suspicious as well- at most it was sitting at 12V while always charging. It was actually taking more energy out of the battery than putting into it. The charge current was very small, and about on the order of discharge current. Looking at the current, it would go into the battery for a bit, then out of it! Upon a bit more thinking, I realized that this is how the unit tests for battery’s presence and relative health. First thing I noticed was that the battery is charged in a pulse fashion- the charger turns on for a bit, then turns off.

That sounded weird after the system just sitting there charging all the time, so I started digging in. During one of such tests I noticed that with the pump turning on, I’d also get a low battery alarm.

I’d test it occasionally by pressing the test button or moving the floats and the pump would kick in.

For the first year or two the system sat there blinking happily.

Watchdog battery