Large load power to 5er from tow vehicle

[Vapors56]

I'm looking for a way to power an ac unit in my 5th wheel while traveling. I could use a generator but I have dual 220 amp alternators on my tow vehicle which should be ample to supply one ac unit. Big inverter in the truck bed? If an inverter, what does it get wired to in the trailer? How do you waterproof your connections? Something else?

PLEASE don't give me a lecture about how it's unsafe to ride in a 5th wheel. I already know that. It's for the cats. They can't ride in the tow vehicle with the dogs. They're going with us in the tow vehicle whether any of you like it or not. I'm looking for advice on electricity - not judgment of my choices. Thank you.

[AnotherMike]

Delivering that kind of wattage at 12v DC would require welding-cable size conductors, if not even bigger than that.

Delivering it at 120 volts AC would make the wire size reasonable...

I'd locate the inverter close to the battery under the hood, and run a length of #8 to a set of waterproof breakaway connectors back by the hitch.

But nothing comes to mind... Something made for a boat? What high power marine environment device would require a breakaway connector that could be acquired and repurposed?
I'd have to do some research...
Maybe something made for shore power on a commercial fishing boat?

You'd plug the shore power cord into that breakaway cable. Then everything inside the 5th would "think" it was still on shore power.

Yes I read that you have dual 220 amp alternators in the tow vehicle.
But honestly it might be easier to just mount a Honda 2kw generator on the tongue and plug the shore power cord into a dogbone plugged into the genny...

Mike

[DavidEM]

As an expansion on Mike's suggestion above:

You need a waterproof place to put the inverter close to the truck's batteries. Maybe a truck box in the front of the bed? Then run big cable, 2/0 from your truck's alternator to the inverter. Then use #8 2C+G to wire AC from the inverter to the back of the truck. Use marine 30A twist lock connectors at the inverter and at the back of the truck. Plug the 5th wheel's shore power cord into the 30A connector using an adapter.

It won't be breakaway but it will break away when necessary.

David

[YC1]

Would the new F150 do the job? Just trying to think out of the box. I know a 5th wheel can be quite heavy.

Installing an inverter that size would be a very big job as suggested. Doable of course. Heat in any enclosure would need to be addressed but the AC cord might be able to reside inside the enclosure for protection from the weather and allow plenty of air circulation.

The specs for the battery cables will be given for any inverter.

In addition I would find a remote thermometer to monitor inside temps of course. I actually use one to monitor fridge temps in one compartment to maintain medicine between a very narrow range.

I use a wi-fi temp monitor when parked of course and it can tell me the temps from anywhere.

[MtCamper]

It sure would help to know what TV and trailer you have. Maybe you could add them to your signature? Anyway by far the cheapest and easiest is to use a generator. My trailer came generator ready. Meaning there is a wire run from the front generator compartment to a female plug in where the shore power enters. It was easy to run a 30 amp cord from the generator in my truck bed to a plugin wired to the generator ready wire in the RV front storage compartment. I'm not sure how your plan to run your alternators at full output for an extended time would affect them. My thought is it wouldn't be good.

[Palmeris]

Use the batteries and invertor in 5ver to run the AC, use a DC to DC charger to have truck alternator charge the batteries. run appropriate size cables, use waterprrof anderson connectors

[Old-Biscuit]

I added an additional 50A Receptacle on front of 5vr under the overhang
Generator in Truck bed with a 50A Plug on gen cable (30A jumpered)

Plug in gen power cord.....run gen/run 5vr A/C
Nice and cool when we stop for lunch, set up at CG in summer time
Exercises the gen too

[kdauto]

Thinking outside the box here, but exactly how far are you driving with the cat(s) in the trailer and in what kind of weather conditions?

Cats and dogs are pretty resilient. They don't necessarily need full trailer cooling, but they do need a livable, breathable area they can rest in. Not sure how much rest they will get in a 5th wheel, but since you don't want to hear about it, I'll leave that for another discussion.

My answer? Build a cheap swamp cooler. There are loads of videos on Youtube and such. Get a small lunch cooler, install a small fan, like a computer fan or two, they will only draw a few watts. Depending on what you buy, you can run it from the trailer's 12V battery(ies), or a small auxiliary battery/power pack. You can plumb the exhaust out through a flexible and bendable hose. Just fill the cooler with ice, get an inlet hole and it'll push out decent cold air for the kitties.

Cooling the entire RV is energy intensive and can get complicated. Your small swamp cooler can be built for under 40-50$ and used anywhere. It'll be a LOT cheaper than running the A/C unit on the trailer roof.

[xc-mark]

install a good pure sine wave inverter , Victron energy 3000 watt is the one in my 5th wheel. It has a auto transfer switch that take the 50 amp RV cord power and disconnects the utility side and power the entire trailer off the inverter. You need around 150~190 amp at 13.6 volts DC to run one roof AC unit so its NOT pratical to run off a truck 12 volt system , you just dont have that kind of constant current ( it will burn out the truck wiring and alternators).

Next get a 2000 watt inverter generator ,preferably a Honda or Yamaha , connect that to the trailer incoming power. You set up the inverter to only accept 9 to 50 amps max from the generator so your not killing your battery's and it will charge the coach battery when it is able to cycle off the AC units. Any time the AC draws more then the 9 amps the inverter helps supply power from the battery so its adding not 100% on one or the other. If its a hot day and you run out of gas the battery will keep the inverter going for a little while (depends on battery bank size.) My 500 amp hour battery bank will run the 15K AC unit for about 2.5 hour with no other power being added to the DC system. You can also install a Victron Orian DC to Dc charger to the RV. they have several different sized units , I have the 18 amp Orian smart version. I get a full 18 amps at 14.4 volts into my RV battery regardless of the voltage at the trailer plug , before installing the Orian I was only getting about 5 amps at 13.2 volts (not enough to charge battery). I have 2000 watts of roof mounted solar , 2 - solar DC charger (Victron) and a Battleborn Lithium heated battery bank , a Victron Cerbo and touch screen that gives you all the data you ever want . I will be adding some more battery's soon for more off grid run time. So Yes it can be done but this isn't a project your wallet is going to like and on a scale of 1~5 as a DIY , its a 4.5.

[twinboat]

Set up 400 AH of batteries ( 4, 6 volt GC2s ) and a 3000 watt PSW inverter in a box, in the bed of the truck.

Run 2/0 battery cables to the engine compartment and 12 gauge 120 volt power cord to the 5er.

[SGhost]

That swamp cooler idea is worth exploring. Remember, the simpler the solution the less the possibility it will fail. Stick some dry ice in there, plumb it properly with a mini fan, and include some trailer ventilation and you should be good to go.

[wolfe10]

Originally Posted by Palmeris

Use the batteries and invertor in 5ver to run the AC, use a DC to DC charger to have truck alternator charge the batteries. run appropriate size cables, use waterprrof anderson connectors

NO. Running the power from TV to 5th wheel as 12 VDC would require HUGE gauge cables.


As others have said, battery bank and inverter in the TV and connect that to 5th wheel shore power cord with waterproof cords.

[Dave Pelletier]

I think running a gennie is the only realistic solution to having the AC running whilst travelling....at least for any period of time

Dave

[kdauto]

Originally Posted by Dave Pelletier

I think running a gennie is the only realistic solution to having the AC running whilst travelling....at least for any period of time

Dave

Yeah, but it sounds ridiculous doesn't it? Run a big truck, sucks fuel. Add a big generator (more fuel), more noise, more wiring to be mindful of and a bunch of other surprises.

Gee whiz, I'd crack a few vents and/or windows, and if need be a swamp cooler.