Thor Forums

[Chance]

Originally Posted by scrubjaysnest

Our friends have 4 216 Ah batteries and still need to run the gen set for 5 hours every day. Based on the amp draw I measured that is pretty close to what Onan comes up with based on their example. The refrig draw via the inverter was ~ 17 amps. When the gen set was running the inverter/charger was putting out 60 amps. 60 amps would be about 720 watts of solar. Their 432 Ah battery bank would require a minimum of 500 watts of solar.

Running a 4,000 or 5,500 watt generator for hours to charge at 720 watts seems inefficient if that's the main load. If they were going to run generator anyway to run air conditioner then it seems more efficient.

To me it seems clear that if owners add extra batteries, they should also increase their converter capacity proportionally (or higher) to avoid running generator at very low loads for hours at a time. I would just make sure not to exceed battery charging rate.