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[Chance]

Originally Posted by Chateau_Nomad

Got the two 100Ah LiFePO4 batteries and 3k inverter installed and working. Did a few DC amp draw tests with clamp meter directly on battery cable:

Inverter draws 3.7 amps idle
Uses .1 amp on power saver

Refrigerator draws 29 amp (-3.7)*
Microwave 120 amps (-3.7)
Water Heater 120 Amps (-3.7)
Portable heater 131 amps (-3.7)
A/C uses 180 amps DC current (-3.7)
*Readings include inverter amps

Furnace blower minimal

Just ordered two MaxxAir Deluxe fans. They're supposed to be ultra low amp draw. Will test after install for proof.

Based on this, I would require something like 12kWh to run the A/C overnight.

Your air conditioning data seems unusually high, even if you have the optional 15,000 BTU/hr unit; which I assume you do. In any case, if running it overnight when there is no sun and temperatures are much more favorable, A/C power requirement will be much lower when compressor is operating, and duty cycle will be much lower as well. You may need 12 kWh for say an 8-hour night, but I doubt it would be that much.

Just finished helping with design and installation of a similar upgrade, but with greater lithium capacity and two smaller air conditioners. Motorhome is roughly same size as your 24F. While taking initial data, it is obvious that each A/C power requirement will vary significantly depending on temperatures. In evening with inside and outside temps in the low 80s they only pull around 8 Amps each, or just under 1,000 Watts. However, if turning A/Cs on when inside and outside temps are both 90 F or higher can easily lead to current in 12 A range, or 50% higher.

Just mentioning this to make everyone aware that running A/C overnight from batteries isn’t that impossible or cost prohibitive any more. This is particularly the case when the motorhome has a segregated bedroom area with its own small and efficient air conditioner. Unfortunately, your 24F’s open floor plan requires cooling the entire MH for the most part.