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  • Suggestions for second season in RV

    We bought a large, old but new-to-me RV a year ago. Put new Trojan batteries in it (6 x 6V). The batteries are in a block of 4 on the driver's side and 2 on the passenger's side - which is factory, but I have read that the differences in cable length make it less than ideal but would be really difficult to change. It's all rigged for 12V and used to start the diesel engine as well as run the RV part. It never had any solar till last year when I got it and decided I didn't want to use the generator all the time. I put 2 265 Suniva panels on it and a Morningstar 45A mppt controller. It only worked as I hoped (charged by mid-day) a few times. Since the panels don't tilt, they aren't getting ideal sun. Then the stupidest and most expensive mistake was assuming the panels would keep things good through the winter. They got covered up with snow, batteries trickled off to nothing and froze.
    So what would you do? Thinking the batteries were the right ones, so I'll suck it up and replace them with new standard Trojans. I can easily fit one more of the panels. With some ingernuityengineering I could fit 2 more. Either way, I would need another controller. Same one- Morningstar mppt 45?

    I know I don't have my consumption figures here but can confirm that if I start out mid-day with full charge, I never run out before morning. I have a 2000W inverter and run an Avanti apartment size fridge and one or two 12v fans and occasionally an LCD tv. Water pump kicks on now and then and LED bulbs throughout. It's not too much for the six batteries if I can get them charged back up each day.
    Thanks in advance for any suggestions moving forward!

  • #2
    More panels is always better in my book. Panels shaded by vents or antennas are nearly useless too. in the winter, disconnect ALL loads, switch the inverter off, and even snow covered panels should maintain (not recharge, but simply maintain) the batteries, unless the engine computer draws power and depletes them
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister

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    • #3
      A 12v system with 2x265w=530w, 530w/12v=44a, so your 45a controller is near it's peak before clipping with just those 2 panels.
      If your only adding one more panel to it for 795w, I would probably go ahead and stick with a 45a controller just realizing it will clip (probably around 600w).
      If your adding 2 more panels, I would use a bigger controller or 2 separate controllers. I would go this route if you have the space.
      Flat panels are never ideal in any area that sees any snow. I would recommend fitting those 4 panels up there tilted about 15 degrees to each side with a peak in the middle, with the left side panels on one controller and the right side panels on a different controller. Then you can pull snow off them with a long handle from each side of the rv.

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      • #4
        spring for the extra bucks and get the morningstar MPPT 60. It has a web interface, if you have a laptop or wi-fi and any browser, you can view the solar status.
        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

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

        Comment


        • #5
          Any thoughts on a Victron vs. Morningstar mppt?

          Comment


          • #6
            Originally posted by Larjarvee View Post
            Any thoughts on a Victron vs. Morningstar mppt?
            I have Morningstar & Midnight Classic, I prefer the Mornigstar. no experience with Victron CC. you would be pretty much on your own
            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

            solar: http://tinyurl.com/LMR-Solar
            gen: http://tinyurl.com/LMR-Lister

            Comment


            • #7
              The numbers on your system actually seem fairly well balanced to me and you're not complaining about not having enough power. So I would suggest only dealing with the issue of winter at this time. How about getting a smaller 3rd panel and a charge controller matched to it and mount it in such a fashion that it will not get buried in snow. Say on the south facing side when it's parked for the winter. That would keep you're batteries charged up for the winter when you're not using it.

              WWW

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              • #8
                I think SupraLance makes a good point; With a non-tilting RV install you generally over-panel but never see rated wattage. So slightly under-sizing the controller may not have any practical drawback. Do still size the wires/breakers for the rated values though ; ) Our roof is slanted about 10 degrees and I've never seen more than ~80% rated wattage come out of the array even in summertime. If yours are dead flat you'll see a little less.

                It's already been mentioned but RV roofs are terrible about shading. So many things up there! It would be worth making several trips to the roof over the course of a day and really studying where those shadows fall before you locate any new panels -- the current ones may even need shifting. Remember antennas that raise and vent lids that open. You need zero shading.

                An alternative to more panels on the roof is "ground deploy". We personally don't prefer that approach but it seems very popular with other RVers, especially those with lots of shading issues on the roof!

                If your batteries drained down to dead over winter but you had everything "off" then you've got some phantom loads -- not uncommon at all even in quality rigs. The manufacturers are frankly just assuming constant shore power. The fancier your rig the more likely you're bleeding electrons. If you're feeling patient, try chasing down those current leaks with a multimeter. Not only will it let you rest more easily while the rig is stored, but it will probably prevent that wasted energy while you're boondocking and every amp counts.

                Can't go wrong with Trojans but some of the best advice i ever got was to not buy expensive batteries for your first set. Well, it's too late for that advice...but perhaps also your second set doesn't need to be Trojans? Lower-priced deep cycle batteries will perform just fine -- they just won't last as long. Lead acid batteries are pretty tough but not invincible - and chronic under-charging is a relatively quick way to kill them. This is a personal decision, no right or wrong - just think about priorities and how long you're planning to use the system for.

                - Jerud
                ------------------------------------------------------------
                1220W array / 1000Ah LFP house bank
                MidniteSolar Classic, Magnum MS2812
                ME-RC, Trimetric, and JLD404
                2001 Fleetwood Prowler 5th wheel 25 foot, self-rebuilt
                Full-time 100% electric boondocking (no propane, no genny) since 2015
                www.livesmallridefree.com

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                • #9


                  i had a question please, i am working on a project about sizing PV system grid-tied , in my project i have to design the system the way that the inverter should shutdown the PV modules when there is a excess of electricity , because in our country it s not allowed to sell the surplus to the grid. at the same time, in bad conditions of the PV system, we need to take electricity from the grid. HELP plz !
                  Last edited by Mike90250; 03-05-2018, 01:43 PM. Reason: delinked embedded URL

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                  • #10
                    [QUOTE=zamboni;n372285

                    If your batteries drained down to dead over winter but you had everything "off" then you've got some phantom loads -- not uncommon at all even in quality rigs. The manufacturers are frankly just assuming constant shore power. The fancier your rig the more likely you're bleeding electrons. If you're feeling patient, try chasing down those current leaks with a multimeter. Not only will it let you rest more easily while the rig is stored, but it will probably prevent that wasted energy while you're boondocking and every amp counts.


                    - Jerud





                    Look for things like Co2 and smoke detectors and digital clocks. I have been able to pull the fuses in the power panel, leaving the door open with the fuses sitting the door so that they can be replaced when you hit the road.




                    2.2kw Suntech mono, Classic 200, NEW Trace SW4024

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