LiFePo4 for RV and Cabin with Generator

[medic149]

We just purchased a 320 sqft off-grid cabin and plan on keeping our Jayco 29RLDS trailer on the site as well.

I've been researching a lot on solar and would like to go that route, but the lack of available sun light might be an issue. I will know more on this once I am at the camp in the spring.

I was wondering if I could use a Honda 2200i generator as part of my power system. Here is what I was thinking. Don't beat me up to bad if I am totally off base on this lol

1. Looking at 8500 watt-hours of usage a day between the cabin and trailer
2. Use 2 LiFePo4 12V 100 amp batteries
3. Inverter to power the trailer (trailer would think it was on shore line)
4. Run power from the inverter to the cabin for AC items
5. Run DC power from batteries to cabin for DC refrigerator
6. Use the generator to charge the batteries

Is this something that would actually work? Instead of running the generator all day, would like to use the batteries to power at night and most of the day.

Thanks in advance.

Andy

 

[snoobler]

Your batteries are woefully undersized. If you're using 8500Wh, you likely want that much in battery capacity. 2560Wh is way too thin. You likely won't make it through the night unless you use no power at all (no RV propane furnace blower).

FWIW, our 5th wheel is essentially powered by our "off grid shore power" via a 50A plug. All the equipment is in a shipping container. The 5th wheel alone uses 2.7kWh daily running the converter, 4 LED lights, a modem/router, Blink camera wifi module and LP detector. When we're there, it's easy to use over 8-9kWh, though we do run the water heater on electric for 2h/day (about 3kWh)

DC to AC to DC is only about 75% efficient, so anything 12V in the trailer will require notably more Wh than it uses. Your inverter will have a background draw of about 8W/kW of the inverter (4kW inverter uses 30W or so) just being on and providing 120VAC available to use even when not in use. Some have power saving features, but they entail needing to have no loads present, or loads that cycle on and off. A converter will be a constant load. Cheaper units tend to have higher idle consumption. For us, it's about 0.720kWh just having the inverter on.

Your inverter would need to be an inverter/charger with the generator attached to the inverter/charger. Thus, when you run the generator, it will charge the battery.

Lastly, running 12V long distances may incur notable voltage drop depending on the load.

 

[medic149]

Your batteries are woefully undersized. If you're using 8500Wh, you likely want that much in battery capacity. 2560Wh is way too thin. You likely won't make it through the night unless you use no power at all (no RV propane furnace blower).

FWIW, our 5th wheel is essentially powered by our "off grid shore power" via a 50A plug. All the equipment is in a shipping container. The 5th wheel alone uses 2.7kWh daily running the converter, 4 LED lights, a modem/router, Blink camera wifi module and LP detector. When we're there, it's easy to use over 8-9kWh, though we do run the water heater on electric for 2h/day (about 3kWh)

DC to AC to DC is only about 75% efficient, so anything 12V in the trailer will require notably more Wh than it uses. Your inverter will have a background draw of about 8W/kW of the inverter (4kW inverter uses 30W or so) just being on and providing 120VAC available to use even when not in use. Some have power saving features, but they entail needing to have no loads present, or loads that cycle on and off. A converter will be a constant load. Cheaper units tend to have higher idle consumption. For us, it's about 0.720kWh just having the inverter on.

Your inverter would need to be an inverter/charger with the generator attached to the inverter/charger. Thus, when you run the generator, it will charge the battery.

Lastly, running 12V long distances may incur notable voltage drop depending on the load.

I must have messed up my calculations. Looks like 5 batteries would be the minimum required then, I think.