I just recently found this website and I want to tell you I am impressed. Very informative !!
I am a expediter. I basically spend hours and hours, sometimes weeks out on the road at a time.
I have a 2500 watt power inverter and I am getting ready to buy 2 6v golf cart battery and am considering buying a 120 watt solar panel from e-bay.
What I am trying to do is power my electric heater which is 1200 watt’s. Gasoline is too expensive to let the van run and propane is no different. I want to wake up alive and this is the safest way to go as far as I know.
Do you have any other suggestion’s or any past articles on safely heating my van?
If you check my last thousand replies you will find I keep telling people its not cost effective to power any electric heating device with solar electricity. For example using the numbers you give, your 1200 watt electric heater would run about 1 hour before totally discharging your 2 gold cart batteries, then it would take your single 120 watt solar module about 2 or 3 days to re-charge the batteries before you could again run the heater.
A 6-volt deep cycle battery stores about 1 kWh of power before totally discharged, which damages any battery. Two would gave you the same amount of power by safely discharging only to 50% discharged. You will get about 3 hours of full sun during winter days in most parts of the US due to the low sun angles and shorter days. Also a typical solar module will only put about 70 to 80% of its nameplate rating into the battery charge. 120 watts X 80% / 3 hrs/day = 288 watt-hrs per day, which requires 4 days to produce 1200 watts, and your heater requires this much power every hour it operates, so it will only run 1 hour before it uses up 4 days of solar charge.
Better buy electric socks and gloves!