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Simpliest solar set up to back up battery

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  • Simpliest solar set up to back up battery

    I'm looking to install myself a solar set up for my battery as i am going camping and like to be safe with my battery.

    I am planning not to use my 12v lights that much, only at night for this summer season if im having a night without candles. I am using propane for my oven/burner this summer and will not be using my fridge but instead trying a clay made evaporating fridge to keep my food cool rather than cold even though it has 12v option i don't think my budget could afford it.

    this is just a basic set up to keep my battery alive this summer with minimal use, lights when possible.

    What would your set up be?

    Currently i have my one car battery connected to my camper Battery that goes to my 12v lights with a fuse. Then a have a seperate 120v circuit that runs the fridge, outlets, and also lights that goes out to an extension cord but that will not be used.

    ideally when I'm ready i want to be totally offgrid and be able to rely on my 120v sources by solar too but for now i just want to integrate or update my 12v system with solar with the simpliestset up.

    300 dollar budget is what id like to keep it around. I noticed pwm controllers to be super cheap. Even 100w panels.

    Last edited by millandr; 02-15-2017, 10:11 PM.

  • #2
    Is this camping inside an RV or a tent ?
    How many days 2, 5, 17 ?
    A 100w solar panel will essentially do nothing to keep a fridge running over a weekend. 500W of panels and a MPPT controller, and a couple of batteries, and then we can talk about a fridge.

    If you want lighting and a charger for a laptop and cell phone, a 100w panel may work - but only if you can get well aimed into full sun between 9am - 4pm (will need at least 2 aiming adjustments over the day)
    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
      Perhaps i should resimplify my post. I just want a basic set up to keep my battery alive for the lights that run off my current 12v circuit. I was just describing my camper. This is a slide in camper. The12v is powered by my truck battery along with another 12v outside of my camper.

      but to elloborate.. Perhaps its wiser to buy for the future. Buy a powerful mppt controller with just one 100w panel since i don't need that kind of energy right now. Keeping me under 400. And as vicky said, i was looking into portable chargers for my phone.

      I'm making a clay non electric fridge this summer instead of my 3 way fridge.
      Last edited by millandr; 02-16-2017, 02:06 AM.


      • #4
        The basic idea of starting small and then going bigger usually means you throw out all of the equipment (CC, battery & possibly panel) and purchase all new (and bigger) equipment.

        The 100w panel is more than likely easy to reuse but at almost twice the cost of the bigger panel wattage, you would have to ask the question, is it smart to spend a lot of money for multiple small wattage panels instead of going with a large one to begin with?


        • #5
          A 100 watt panel will do fine with a single 12V deep cycle battery with your described usage. I would keep your truck battery out of this setup as a rule of thumb, you don't want to be depleting the starting battery on your only way home from wherever you are. Change your camper's 12V lights to LEDs which use far less power than incandescent. They are cheap on ebay. If you do run your 3way fridge on propane, it will still draw roughly 1A continuously from 12V DC. So keep that in mind, that's around 24 Ah per day and will deplete a battery in a couple days even if nothing else is used. There are usually some phantom loads as well such as propane detectors and clocks, so don't think that not using the fridge or lights means the battery won't be still be discharging. And forget about the 120V AC side of your fridge when off grid, that's a 300 watt load (~30A from the battery via an inverter) and a waste of battery. Stick with propane which as I said is about a 1A load directly from the battery.
          I'm an RV camper, mine has 280 watts of solar


          • #6
            I was unaware that the 3way fridge draws from from the 12v dc. I'm away from my camper at the moment so I'm away from my manuals as well. I'll take note of that.

            I'm going to buy the 100w + 30apmw kit


            do you think its necessary to put a inline 15a fuse you each side of the controller?


            • #7
              My camper fridge is a two-way, propane or 120 volt AC, and it says right on its sticker rating of 1 amp DC or 300 watt AC. I have never used a three way, but if it uses electronics at all, which I'm sure it does, then I assume it also requires a continuous power source which is provided by 12 volt DC.
              As far as needing a fuse on each side of the charge controller, you certainly need one between the controller and Battery. Between the panels and controller isn't really necessary to protect anything, but it can be handy to have some type of interrupt device there for conveniently removing panel input to the controller.
              Buying a pre-built kit is often an overpriced way to do it, but that kit doesn't look too expensive. I don't know any online vendors serving Canada, but you can often use one to build your own system for less than a comparable kit costs.

              I know I mentioned earlier that 100 watts would work fine with one battery, it is certainly on the lower edge of bare minimum. In a smaller system, you want more wattage per storage ratio because you have much less of a storage buffer to get through the cloudy times. Can you afford to add another panel to the system from the start? A 30A controller gives you way more capacity than a single 100 watt panel. But I guess you said you have a long term plan to add more wattage later, which is something I would recommend.
              Last edited by ewarnerusa; 02-17-2017, 10:26 AM. Reason: suggest more wattage.
              I'm an RV camper, mine has 280 watts of solar


              • #8
                My wife has a 2006 PleasureWay RV, it has a single 12v Deep cycle battery for the cabin use. I bought a Renology 100 watt suitcase solar panel, it keeps the battery charged when we are out on the desert camping. Runs the propane fridge 24/7, the roof vent in the late after noon, the furnace in the morning and her c-pap machine all night, plus marginal use of the interior LED lighting. if the sun is bright we are usually fully recharged by early afternoon.

                I installed a Renol0gy 100 watt panel on the roof of my van and it runs a small furnace all night, roof vent on warm days, recharge my laptop(12v aftermarket charger) phone, kindle and interior LED lights and am fully recharged by early afternoon, temps are in the 20's at night.

                I'm a happy camper


                • #9
                  AWS: How long has your battery lasted so far?


                  • #10
                    I goy everything installed last sept. So far six months with nearly daily use. These are sealed lead acid batteries for a power scooter/wheel chair and my controller has a special setting for SLA batteries. If it is sunny it goes into float mode just after noon.