Need advice on setting up Solar for my 5th wheel



  • OzzJimOzzJim Solar Expert Posts: 37
    Re: Need advice on setting up Solar for my 5th wheel

    Thanks! That sounds great, I will contact them and ask.
    As always, appreciate your help.
  • ReedReed Solar Expert Posts: 55 ✭✭
    Re: Need advice on setting up Solar for my 5th wheel

    New to this forum. Read entire thread and learned a few things.

    We have been utilizing solar for seven years of full-time RV'ing (Alaska, Newfoundland, Keys/Everglades, Yucatan/Belize) and have found solar to be invaluable.
    Current system is six x 235 W panels ganged in two series of 3 each so that voltage goes to controller at around 90V (TriStar MPPT-45). This goes to LFP battery bank (Manzanita) at 48V nominal (56.7V absorb and 54.6V float and about 9.5 kW-hours. Power goes to 5th wheel electrical system through Magnum 4.0 kW PSW inverter. Son designed and fabricated system (he has been in business/home solar for 23 years and just completed panels and low voltage wiring for 1.8 megawatt system). This makes us basically solar autonomous. Son trialed system running micro-wave and air conditioning (Dometic power hog 15,000 BTU) and it drew around 3 kW for half an hour.
    Noted that moderator Caraboocoot had design for a 48V system based on 8 x 6V batteries in series.
    We could put another 700 W of solar and another 4.4 kW-hours of LFP but see no reason to do such. 2100 W would run the a/c under full solar insolation conditions.
    Generally run Dometic refrigerator (a real power hog best run on propane) on AC during day, and at night if weather report shows it will be a sunny day. This generally starts the day at -3 kW-hours deficit.
    This does not permit full time air conditioning but we have run 3.5 hours several times as combination of solar and battery bank. Generally, we just run the a/c in late afternoon for an hour or so (2 kW-hours of battery) to get interior temperature down to below 85 F or so. We have had eight 12 V outlets placed about the 5th wheel for various purposes and using 12V fans which use little power after that. If the OP did emplace 1700 W of solar, then he could run air conditioning on solar through battery bank/inverter for much of mid-day without depleting battery bank.
    Disagree that "excess" solar is a problem. We have gotten reasonable power in overcast and rain (200 to 300 W) and around 100 W with 8" of snow. We even got some power in Olympic Rain Forest (about 50 W which did little than take care of the day's "phantom" draws).
    Someone on another forum made cardboard cutouts of different panel sizes and used them wandering about roof to see what might fit.
    One thing that our son has done with our system is to emplace 1500 W of battery charger in the battery bay. This permits charging from impure/dirty line power such as we have found in Mexico (burned out a micro-wave in Baja and another in Yucatan - German couple burned out all 110 V systems and had to have 5th wheel rebuilt - which they now have permanently fixed in a palapa). This permits dumping 50 amp cabling (darned heavy and clumsy) and charging with merely a 15 amp power cord. We generally boondock and avoid RV parks but sometimes they are necessary.
    Finally, there is supposedly a 48V DC a/c that takes only 750 W to run. Have written the firm for further information but have received nothing back as yet. Such as system would work well with our battery bank. I noted that there was a diagram for an 8 x 6V battery system in series in one of the moderators' posts.
    Reed and Elaine
  • SolarPoweredSolarPowered Solar Expert Posts: 626 ✭✭✭
    Re: Need advice on setting up Solar for my 5th wheel

    Personally if its an RV application and the panels are laying flat on the RV from season to season I prefer higher output positive tolerance panels.

    1) Solar world sunmodule 275 IMO is the best panel. Can withstand 150MPH+ hail storms so the panel can handle some heavy abuse, especially if the panel gets snagged by a tree branch, hail, or if you need to even walk on them to maintenance and clean them. If the panel is laying flat 0 tilt should yield around 230~235WP in summer which is right about where you would want to be at for charging, winter it will yield much lower, low amps, but high voltage, so its to be expected around 145~150WP in the winter.
    2) Suniva 270 is also a good choice, but the panels don't go through the rigorous test conditions that solar world puts their modules through and are typically .04 per watt cheaper than the solar worlds.

    For peace of mind I have only been purchasing the solar world panels, being a contractor I need a panel that can withstand heavy conditions.
    Both panels are excellent choices being mono crystalline with postie power tolerances so if you are MPPT per string you know the bare minimum voltage will be from name plate or better.

    Here is there video on the test conditions.

    I use to be a big fan of canadian solar, but I don't believe the glass or or the frames will handle portable abuse like the suniva, or solar world frames do, I've also noticed that canadian solar uses alot more AR coating on the panels so in teh long run it might go through more wear and tear and depriciation faster, also their 260MM and 270MM series panels are more expensive than the solar worlds, and the conversion efficiency between solar world and canadian solar are the same.
  • kellylippkellylipp Registered Users Posts: 21 ✭✭
    Re: Need advice on setting up Solar for my 5th wheel

    Just saw the original post. I've got a blog on WordPress that has a complete design for a fifth wheel that might be interesting to you. Here is the link:


  • OzzJimOzzJim Solar Expert Posts: 37
    Re: Need advice on setting up Solar for my 5th wheel

    Thanks to all who took the time to help and give input. After many sleepless nights and a big pile of printed material in my Solar pile, I put in an order to NAWS, Dan hooked me up with my care package.
    I have 3 Solar World 315 Watt Mono Panels in my shop, a Midnight Solar MPPT 96 amp 150 volt controller, Stainless brackets, a Midnight Solar Big Baby Box, breakers, Wire, connectors and a lightning/surge module.
    This should keep me busy for a bit.
    I am pulling my absorption reefer and installing a nice 10cu ft 120 volt residential mechanical system.
    If I need more charging, I can fall back on my twinned Honda 2000i's But I think I will be Ok.
    Thanks again. Kelley, I will be contacting you to chat, Might just run into you on the road.
  • scrubjaysnestscrubjaysnest Solar Expert Posts: 175 ✭✭✭
    Re: Need advice on setting up Solar for my 5th wheel

    An interesting thread. Ozz seems to have a greater need for power then we do. But then we have no TV, microwave or any other high wattage item. A small 400 watt inverter to charge what we can't directly off the 12 volt system.
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