50 Amp inverter

[WV Camper]

I have a 5500 watt generator ordered for our new 5th wheel but who knows when we'll ever see it. I was watching a video on a very expensive motorhome that talked about how the lithium batteries could run the whole unit, including AC for like 20 hours and that got me to thinking that maybe that would be better than a generator.

Does anyone know of an inverter that could be installed in the trailer that could do this?

Thanks,

[Mopar_Earl]

Where would you put all those batteries? What solar system size was used to recharge them? That's a lot of batteries. A 50amp 120/240 inverter would probably be very large as well.


Earl

[WV Camper]

That's what I'm trying to get a handle on. I think even with lithium the size and weight would be too much as I would need 6-8 batteries and a bank roll bigger than I have. I think the day will come when this will be feasible but it doesn't look like we're there yet

[Shackrat]

If AC is the goal, use a generator. Here’s why…

Too much focus is placed on how much power to get out a battery system when it should be on how to put it back in. For example, a 13,500 BTU AC unit draws around 1200 watts in continuous operation (forget startup surge for a moment).

Assuming no other loads, a single 100AH Lithium battery is rated for 1200 watt-hours (12v x 100 amps). That’ll run the AC for an hour then the battery is dead. A four battery bank of (400AH) will run it for 4 hours. For intermittent use, 4 batteries might be enough for some sporadic use for a day but that’s it.

There is still the dilemma of recharging. The same math works for charging too. Most 100AH batteries will charge at around 1/2 the max discharge rate or about 50AH (600 watt-hours), but I’ll set that aside for this example.

If you have a pair of 200 watt panels on the roof of your RV, assuming full sun, optimal angle (tilt, not flat mounted), you can expect a maximum of 400 watts. To fully change a single 100A battery it will take a full 3 hours of peak sunlight.

Using the 4 battery example, to fully charge that from depletion will take 12 hours, which is obviously impossible. You would need to double the amount of panels to (800W) get that replenishment time down to a more realistic 6 hours.

A 4 battery system with 800W of panels is easily a $4k investment not including the inverter. A decent inverter generator can be had for $1k. Unless you are camping in places where generators are not allowed, this option makes more sense. You may never recover the costs of a solar/lithium build.

[RayPayne]

You can get Victron inverters and chain four of them together to get 12,000 watts if you wanted (50A equivalent) but two would match your genset more closely. The issue is batteries. If your truck has dual alternators and you invest in a good high-current DC to DC converter for charging you may pull it off. But Jayco doesn’t make a trailer that even comes close to cargo carrying capacity of some of the higher end class a motorhomes. There isn’t enough roof space to get 6,000 watts (or more) of solar to keep up with the loads. Even with the lightest lithium batteries I’ve seen at around 30lbs for 100Ah, you’d need 100 batteries at 100Ah to run even 6,000 watts for 20 hours. That’s 3,000lbs of batteries. If you want to step up to full 50A service on inverters for 20 hours, you’re up to 6,000lbs.

Reality is almost nobody would use 50A at 100% for 20 hours. So try to use a calculator for power use (popular for solar sites) and work from there. If you want to use inverters and batteries, start with reducing your needs as low as possible first, rather than building up to the same as plugging into 50A service.

With two 3000 watt inverters I can run both ACs while I drive, but I’m pulling almost 4,000 watts from the dual high-output alternators on the truck while I drive. Using solar I get less than half that in full sun in ideal conditions. And solar isn’t all day long. Without using anything else, I could get maybe a few hours AC from solar, assuming a single AC in use only, and four 100Ah batteries.

My reason mostly for the inverters and batteries are because I’m in a seasonal park with 30A rather than 50A. It’s great to supplement and it lets me stay in an older park with so many trees I can’t see a neighbor in any direction. It lets me run the second AC, washer/dryer, etc. without worrying. It’s not a setup to run AC in place of a generator.

[WV Camper]

Great information!I’ll be waiting for the Onan generator.