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Bought a new Fifth Wheel, want to go solar

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  • Bought a new Fifth Wheel, want to go solar

    Hey everyone, I’m been browsing around the forum and YouTube for some info on Solar and Rvs. We have full time camped in our Enclosed trailer that we built into a toy hauler for camping/hauling our toys there. I built a solar set up for the unit using 2x320 watt panels, 40 amp tracer and 2x 320 AH Trojan battery’s. The system has worked great for running our mini fridge 24/7, lights, phones anything we needed to power off our 1500 Pure sine watt inverter. I was super impressed how well the solar worked because all we do is boondock!

    Now we finally upgraded to a big fifthT wheel toy hauler, it has a built in Oman 5.5 generator, from what I read these are one of the best you can get for rvs. But even though we have it I didn’t want to listen to a generator before and don’t want to now. So the research I’ve done my only concern is the wiring into the trailer. I see you wire your system how you would normally. Panels to controller, controller to batteries , batteries to inverter, obvs fuses, breakers ect... But I see you have to tie the inverter into the rv ( auto switch/converter ) where all the breakers, fuses ect of the trailer are.

    Now I see there is some options In different inverters for rv that aren’t just your standard inverter. You’d run your cables off your batteries to this inverter and than you have 4 other parts to go into your rv section. I know some use normal inverter and wire it to one plug into the trailer, but we want our whole trailer to run off our batteries. I’ll probably put those 2x 320 amp batts back in our fifth wheel and add another set to go with them. Just want to be able to charge a phone in our bedroom or use any plug in the trailer!

    Just wondering if some people can chime in to how they wired their rvs and what parts they used. Thanks!

  • #2
    Before you get carried away with batteries, what are your loads going to be ? Will the 5th wheel nearly always be attached to the tow vehicle ?
    Put the batteries and inverter in the truck bed?
    Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A



    • #3
      We use the old "manual" transfer switch, its easy and fool proof. We strictly boondock and we just plug the normal shore power cable directly into the inverter 120V AC outlet. The camper is then fed with 120V AC from the inverter exactly like it would be if plugged into shore power or generator, all outlets are live. It is critical you disable the onboard 12V DC converter when you do this, otherwise you create a power draining loop. WE put the converter's 120V AC power supply on its own AC breaker in the panel which we use as a power switch for the converter, we switch it off when plugged into inverter. You also need to be aware of potential AC loads that will be too much for your inverter/battery setup to supply such as air conditioner or microwave or water heater on electric. Don't use those, or switch their AC breakers off as well. Switch refrigerator over to propane as well.
      I'm an RV camper, mine has 280 watts of solar


      • #4
        Originally posted by Mike90250 View Post
        Before you get carried away with batteries, what are your loads going to be ? Will the 5th wheel nearly always be attached to the tow vehicle ?
        Put the batteries and inverter in the truck bed?
        I already have 2x 320 AH V6 battery’s for my last build that I’m going to use. Looking to mostly run the plugs in the trailer for small electronics and hopefully run the fridge as that’s what I built my last set up was for. We have the built in generator for bigger loads too.

        not looking to build or Mount anything in the truck box. Want this to be contained to the trailer


        • #5
          Thanks for the reply! Everything you said makes perfect sense! There is a few good YouTube videos I’ve been watching explaining the solar system on an RV, not overly complicated but littles like switching the converter off I see a lot of people miss and it drains their battery’s!
          I would like to do an auto transfer switch and hard wire the inverter into the trailer, but I might just unplug/turn off the rv converter and plug into the inverter from the trailer to test and play with the system before hard wiring it


          • #6
            I am nearing the end on my RV build, my first real solar project.

            For some of the DC wiring, I am adding some DC charging ports and also a separate fuse box for them. Since I may upgrade to 24 VDC in the future, I am hooking some dual voltage accessories to this fuse box. I have the separate fuse box for some higher voltage DC items. These USB charging ports don't get their full potential unless they are 24 volts, but I will still need to keep the rest of the trailer on 12 VDC which it was designed for.

            I don't have the built in generator you do, so makes the wiring a bit easier. Mine is a 2.3 kw continuous inverter generator by Craftsman. I pull it out and turn it on and off for higher loads. At some point, I'd like to add a generator to run the A/C, but that will be with the next RV.


            • #7
              The goal would be we could run everything we need off of solar even our fridge would be nice. Our last solar build I ran a oversized mini fridge with freeze, and these trailer we opt for the single fridge as we don’t need a double, we only boondock, so I doubt this fridge takes much more power than that other one. Other than that it’s mostly charging phones, cameras, led lighting inside and outside. For the most part our power consumption is pretty min. We do have the generator for back up, most people are just telling me to run it, but it’s nice not having to listen to generator, spend money on the gas, ect...


              • #8
                I have a very similar system except I have 3 320-watt panels. I live almost fulltime in my RV off-grid on the Northern California coast (I'm a camp host at a campground) with 4 Trojan T105's wired for 12 volt (I should really redo them for 24 volt), which I think gives me a capacity of 450 amp hours or my preferred way of measuring is 5400 watt hours, and I almost never get low on power. I wish more campers here would install intelligent solar systems as you're doing! Too many people here rely on their generators, which are unbelievably noisy, stinky, hard on batteries, and because of quiet hours leave them in the dark after 9pm. So silly. So kudos to you sir.

                Reading this thread my only suggestion would be to consider adding more panels, since you have the room and they're dirt cheap. Or at least plan for their possible addition in the future. A great thing about over paneling is that, for one thing, since our panels are flat mounted (I'm assuming yours are) we lose ~15% of power off the top. And having extra panels means we're still getting significant charges on cloudy days. If you have the roof space, I'd recommend it, it's worked out great for me.

                That said there's a couple of considerations:

                - if you have more than two parallel panel banks (1 non series'd panel is a "bank", as is 2 or more series'd panels) you need to put fuses on each bank. Easily done I can post links if you need.

                - your charge controller needs to be able to handle the panel voltage. I used to have a Tracer and it was 100v, which wouldn't let me do 3 panels in series, so I wired my 3 panels in parallel with fuses. I've been really glad about that decision since I frequently have partial shade or a kayak covering one of my panels.

                - and of course your wiring needs to be beefy enough to handle the max power your panels might put out. I'm a big fan of overly fat wire since the primary issue with wire throws is the labor and penetrating the RV, not the expense of the wire itself. So I use 8 gauge.

                I'm subscribed to this thread, glad to chime in if you have any questions.

                Edited to add: one thing that strikes me is your fridge: if this is one of those propane/AC/DC fridges it might not use a compressor, and might use a bunch of power when running off electricity. You might want to test it's power consumption and duty cycle (how long it stays on). Long ago I rigged up a system to power my RV fridge once my batteries were fully charged, and it was a losing battle since that fridge was so inefficient when running off power. Since you mention successfully powering a fridge off solar in the past you might want to look into any differences between this fridge and your last.
                Last edited by Wrybread; Today, 04:00 AM.