« on: November 30, 2011, 10:44:53 am »
I have a new 2012 2350 (Ford) on which I had a 120 watt solar panel installed by the factory during construction. The standard coach batteries are 2 deep-discharge type 27 lead-acid 12 volt batteries wired in parallel.
My concern is that either I'm not getting full output from the solar array or there is a phantom load draining the batteries. The maximum output I've ever recorded from the array is 12-14 volts (bright, cool, sunny day) at approx 1.4 amps. While that will just barely restore the battery to its bulk capacity (13.6 volts), by the next morning the batteries are back down to about 11 volts. This seems excessive. I have unplugged every outlet, turned off every appliance, and shut off the inverter, but there is still considerable (or is it?) voltage reduction on the batteries each night.
My previous coach (2007 Roadtrek) had an 80 watt array and kept the coach batteries fully charged all the time. I expected the same or better peformance with a 120 watt array. I don't know if a 2 - 2.5 volt drop in the coach batteries each night is normal (it doesn't seem so). I also don't know if 12-14 volts max output from the solar array on a sunny day is normal (seems it should be more).
Any advice would be appreciated. Phantom load? Insufficient solar output? Both?