Cruiserdrew
On the way there
There have been a number of threads about solar power, battery charging and refrigerator power use so I thought I would post up my experience since I finally bought a folding panel this year, and used it extensively at the recent Rubithon event. At this year's event, I sat for 4 days at the mid point (Buck Island Lake) and then 3 days in Rubicon springs. This provided a chance to test if a 100 watt panel could keep up with my fridge, and keep the batteries charged.
Equipment:
Renogy 100 watt folding solar panel
Moringstar SunSaver 10 Charge controller
Costco Marine/Starting 100 amp-hour battery x2 - One isolated to start, the other for house loads
Engel MT45 refrigerator vintage 2003
Blue Sea SI-ACR 120 amp charging relay (0.175 amp draw when closed, ie "on"))
Weather:
Sunny-ideal power production conditions
Daytime 90F+
Nighttime 65F
Parked in full sun, but no direct sun on the fridge-all windows and tailgate open
Results:
Average Fridge daily power consumption: 11 amp-hours to 16 amp-hours (2.7 amps when running)
(in fairness not measured every day, only 3 of the days but this was the range)
Battery resting voltage 12.8 volts
Average House Battery voltage at dawn just before sun rise: 12.5 volts
9am-3pm Panel output - 5.7 amps (moved every 2 hours or so to face the sun)
Would make measurable power from 7am-5pm from 2 amps up to 5.7 amps
Generally by 11am the house battery was fully charged to 13volts-
-this would close the charging relay and top the engine battery too
The rest of the day, the batteries would float at 13.4 volts
Comments:
The Engel is much more efficient than I would have thought
I did not measure run times to get duty cycle but it's around 1:10 at night
During the day, the panel supplied all the power when the fridge was running
Batteries remained fully charged all day after hitting full charge each morning
Having a power meter is very helpful to see how much current is flowing and the power consumption of various loads.
So a 100watt panel can easily keep up with a standard 12volt refrigerator with room to spare. It was very helpful to have a permanently mounted dual voltmeter to monitor battery voltage and thus state of charge. Very happy with this set-up and frankly surprised at how well it kept up with the fridge and kept the batteries at 100%. This was a test run for a Baja trip and everything looks good to go.
There was some discussion in another thread if the MorningStar controllers would float the batteries-it does. You can watch the voltage step up to 14.4 for the absorb phase and drop to 13.4 to "float". @TrickyT wanted to post up data and this is what I got in real world conditions. Many thinks to him and @george_tlc for pushing me in this direction.
And one other thing-once parked at each spot, I did not restart the truck until I left, so the panel was supplying 100% of all power used.
Equipment:
Renogy 100 watt folding solar panel
Moringstar SunSaver 10 Charge controller
Costco Marine/Starting 100 amp-hour battery x2 - One isolated to start, the other for house loads
Engel MT45 refrigerator vintage 2003
Blue Sea SI-ACR 120 amp charging relay (0.175 amp draw when closed, ie "on"))
Weather:
Sunny-ideal power production conditions
Daytime 90F+
Nighttime 65F
Parked in full sun, but no direct sun on the fridge-all windows and tailgate open
Results:
Average Fridge daily power consumption: 11 amp-hours to 16 amp-hours (2.7 amps when running)
(in fairness not measured every day, only 3 of the days but this was the range)
Battery resting voltage 12.8 volts
Average House Battery voltage at dawn just before sun rise: 12.5 volts
9am-3pm Panel output - 5.7 amps (moved every 2 hours or so to face the sun)
Would make measurable power from 7am-5pm from 2 amps up to 5.7 amps
Generally by 11am the house battery was fully charged to 13volts-
-this would close the charging relay and top the engine battery too
The rest of the day, the batteries would float at 13.4 volts
Comments:
The Engel is much more efficient than I would have thought
I did not measure run times to get duty cycle but it's around 1:10 at night
During the day, the panel supplied all the power when the fridge was running
Batteries remained fully charged all day after hitting full charge each morning
Having a power meter is very helpful to see how much current is flowing and the power consumption of various loads.
So a 100watt panel can easily keep up with a standard 12volt refrigerator with room to spare. It was very helpful to have a permanently mounted dual voltmeter to monitor battery voltage and thus state of charge. Very happy with this set-up and frankly surprised at how well it kept up with the fridge and kept the batteries at 100%. This was a test run for a Baja trip and everything looks good to go.
There was some discussion in another thread if the MorningStar controllers would float the batteries-it does. You can watch the voltage step up to 14.4 for the absorb phase and drop to 13.4 to "float". @TrickyT wanted to post up data and this is what I got in real world conditions. Many thinks to him and @george_tlc for pushing me in this direction.
And one other thing-once parked at each spot, I did not restart the truck until I left, so the panel was supplying 100% of all power used.