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  • Please review my setup

    Hi all,

    Im currently putting together a solar setup for a small camper van conversion. We've calculated we'll need about 65 amp hours / day max.
    The setup thus far:

    Solar - Wansun 200w 12v mono
    (V) 18.9
    (A) 10.6
    15A
    OCV 22.68
    SCC 11.4

    Victron 75/15 MPPT Controller
    15A 12V
    max PV 220w
    max OCV 75v

    Lithium 100ah Batt.

    Victron 12v 375A Phoenix Inverter
    Cont power 300W
    Peak 700W
    DC low 10.9

    Im still learning how these elements interact but with my limited understanding, these numbers all seem to work.
    I'd really appreciate if anyone could shed some light upon this for me!

    Cheers

  • #2
    The 200w solar panel you list, would not need a MPPT controller. MPPT down converts high voltage PV strings, to battery voltage, saving expense in cables. In an RV, the distances are so short, and your system size small enough, MPPT is not needed. Generally over 300W, MPPT becomes useful.

    I would NOT suggest your first battery being a LiIon. I'd suggest instead, a pair of 6V golf cart batteries wired for 12V

    With a 200w panel, I would only expect 100w output, being flat on the roof, is a poor sun angle, and will have a reduced harvest. You will also have to park in full sun for 10 hours a day to meet your aH target, are you moving to the equator where you can get a good 6 hours ?

    Skip the aH calculations, instead convert things to watt hours. 12V x 65 = 780wh 100w from PV x 4 hours = 400wh harvest.
    battery 12V x 190aH = 2,280wH ( or 2.3kwH )

    You can use a smart battery isolator, to allow the vehicle engine to charge the house battery, and leverage that to make up for the losses of your small PV array, or add 2 more panels to your planned array. You could make a "sandwich board" to mount a panel onto and put the panel in the sun and run a cable to the charger.
    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


    • #3
      Originally posted by Mike90250 View Post
      I would NOT suggest your first battery being a LiIon. I'd suggest instead, a pair of 6V golf cart batteries wired for 12V

      With a 200w panel, I would only expect 100w output, being flat on the roof, is a poor sun angle, and will have a reduced harvest. You will also have to park in full sun for 10 hours a day to meet your aH target, are you moving to the equator where you can get a good 6 hours ?
      Thanks for your feedback!

      In regards to solar I could possibly increase to 2 panels and reach 300w to make the mppt worthwhile. I'd rather have opportunity to upgrade as well.
      We are slowly heading towards the equator, but will also have charge coming from the engine batt when possible. Also installing shore charge option.

      Do you suggest against LiIon for a beginner because im likely to kill it?
      My reasoning to go with that option was based on our space restrictions in the van, as well as the obvious power and life efficiency.

      Comment


      • #4
        My feeling is that until you learn with a solid, established tech like lead acid, it's best to learn one thing at a time. Learning with a "cheap set of $220" batteries, that may be stinky sometimes as they are charging hard, is a lot better than discovering the $2,500 Li-Ion battery is bulging and the BMS has a blinking red light.
        You need to first learn how to manage low power living, and when that is settled in a year or two, then switch to the pricey Li-Ion battery. Currently, there is no easy plug-n-play interaction between a battery and a charge controller and a inverter. you have to buy them as a "black box kit" all in one, and trust the box to do all the magic properly.
        Li-Ion batteries don't often have a problem but when they do, deadly toxic fumes are released. If they get to a point where they are burning, there is really no way to put them out, and all will be ruined. Hopefully, in another year, things will be much more settled and I'll feel better about them, but currently, they are "expert use only", IMHO.
        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
          Originally posted by Rummage View Post
          Hi all,

          Im currently putting together a solar setup for a small camper van conversion. We've calculated we'll need about 65 amp hours / day max.
          The setup thus far:

          Solar - Wansun 200w 12v mono
          (V) 18.9
          (A) 10.6
          15A
          OCV 22.68
          SCC 11.4

          Victron 75/15 MPPT Controller
          15A 12V
          max PV 220w
          max OCV 75v

          Lithium 100ah Batt.

          Victron 12v 375A Phoenix Inverter
          Cont power 300W
          Peak 700W
          DC low 10.9

          Im still learning how these elements interact but with my limited understanding, these numbers all seem to work.
          I'd really appreciate if anyone could shed some light upon this for me!

          Cheers
          Need more info on how long driving is & how long stays are. If you drive for say 4hrs and stay camped for one night you might get by, but long camp stays require a serious solar setup.

          Best advice is to fit the biggest battery & carry the most solar you can possibly fit before your setup becomes comprimised.
          I would do it so there is 3days of reserve capacity. Mobile setups are completley different to offgrid and the wattage & AH numbers mean nothing really, offgrid size for winter Watthours, have alot of space and powerful gennys to fight the clouds.

          What I know from experince is any solar panel roof mounted setup is mostly useless in all but high sunhour + small cloud areas.
          Most times they serve only to float/maintain the starter battery. Fools say just park in the sun...Face the sun...nevver works in the real world!

          I automativcally de-rate a panel by 25-30%, this takes into account the losses in real world like in a lower lattitude area you loss a fair chunk of peak current
          at midday as suns rays dont strike earth direct from the tilt, also in higher regions the temp of the panel will be very high and lower the wattage.

          Just go the victron mppt, smartsolar model builtin phone monitoring. They are easy to use and decent quality.

          200W is ridiculously undersized for 100AH of lithuim or AGM.even flooded should require 250W.
          Solar sizing doens't work while mobile as you could have all kinds of sunhours, may be in an
          an area with 7hours of sun, but the mountains block half...Clouds for days on end & no genny!
          You are going to need portable panels and I would look at 3x 200-250W glass & alloy in parallel feeding the single mppt, cheap and weatherproof. Fuse each one.
          Roof panels are good to still have but most times portable is what does the work. size the wireing for no more than 3% V drop.

          If you have one large portable panel only, you will have to move it every hour or so as the sun moves, having many panels means you can
          spread them out and collect a good chunk of solar over the day.


          The big advantage of lithium (lifepo4) is no absorption phase, no matter how big ya panels are, you need a minimum amount of sunhours to get a lead battery charged.
          Flooded you will never have enough sunhours and will be cycling them in the 50-85% range I bet, and flooded should be de-rated by 15% capacity as they takes ages to get their rated capacity.
          Size your panels to produce .25-.35C on a lithium battery and your system works well & reliable. As long as you know the basics of wireing up chargers and batteries, no reason why you can't go lithium. The dropins are fool proof (short circuit protected, low volt/high volt cutoff, and can come with a decent built in bluetooth soc gauge). Still use a catastrophic fuse on postive terminal and fuse all other wireing. Add a low volatge/high voltage cutout if you want, and size charger output wireing for no more than 1% V drop. As long as your charger allows to set absorb & float voltage and has an end amps to float style absorb timer with no over absorbing, equalization your fine.


          I charge mine perfectly fine with off the shelf gear now, victron mppt & sterling pro charge AC shore charger.
          If you go the sterling it has a broken absorb timer. set to power supply mode (bc) and use custom setting with absorb 14-14.1V, float 13.5V. May have to use
          13.6v & 13.5V for long stays on shore power. not much a problem. sterling appers to be one tough robust unit.


          edit: forgot to add, when overpaneling dont go over .5-.6C charge current for the lithium battery to keep it safe, just incase you have all the panels in the midday sun. victron mppt can set the charge rate so handy feature. also it's absorb timer will best be left to 30mins max.
          Last edited by Jman; 01-28-2020, 10:33 AM.

          Comment


          • #6
            as a motorcoach owner and traveler of many, many thousands of miles and off-grid overnights and stays, I wouldn't spend so much money up-front on a 'system' you have little experience with yet - you may find that you've spent a lot of money on something that rarely gives you the effect you are looking for.
            A simple set of two 6v GC2 deep-charge golf cart batteries, in series, will give you the 12v output.
            The simple solar panel(s) and a PWM controller will provide some of the battery charging you are looking for, when the sun is available, especially directly overhead, for several hours, if you are not parked in the shade.

            Overnight is really what most folks are trying to 'get thru' with solar, and yet solar is of little value during that time, UNLESS you have the battery storage to hold those amps the solar provides during the day. FLA batteries are very capable of providing you what you want, and yet are very economical...and to 'learn' with these, versus sinking the money into Lithium - an expensive proposition.
            Likely, you'll need a generator anyway, as most folks do, even those with substantial solar setups, so you'll be having this to charge your battery bank on days when the sun is not available, or you are parked when the sun is not optimal, and for those long overnights after a rainy day.

            As much as many of us RVrs like the idea of solar, and some have spent tons of money to 'prove' the concept, the reality is that most anyone in these situations will continue to need the generator and other forms of power.

            '14 Palazzo 33.3 diesel coach
            100w solar, PWM controller, 4 - 6v GC2 battery bank, 6k Onan diesel onboard generator, 2000w Magnum Inverter, AGS
            100,000 plus miles over 5 years across all the continental U.S. states, Alaska, and most of Canada

            Comment


            • #7
              Originally posted by NCmountainsOffgrid View Post
              as a motorcoach owner and traveler of many, many thousands of miles and off-grid overnights and stays, I wouldn't spend so much money up-front on a 'system' you have little experience with yet - you may find that you've spent a lot of money on something that rarely gives you the effect you are looking for.
              A simple set of two 6v GC2 deep-charge golf cart batteries, in series, will give you the 12v output.
              The simple solar panel(s) and a PWM controller will provide some of the battery charging you are looking for, when the sun is available, especially directly overhead, for several hours, if you are not parked in the shade.

              Overnight is really what most folks are trying to 'get thru' with solar, and yet solar is of little value during that time, UNLESS you have the battery storage to hold those amps the solar provides during the day. FLA batteries are very capable of providing you what you want, and yet are very economical...and to 'learn' with these, versus sinking the money into Lithium - an expensive proposition.
              Likely, you'll need a generator anyway, as most folks do, even those with substantial solar setups, so you'll be having this to charge your battery bank on days when the sun is not available, or you are parked when the sun is not optimal, and for those long overnights after a rainy day.

              As much as many of us RVrs like the idea of solar, and some have spent tons of money to 'prove' the concept, the reality is that most anyone in these situations will continue to need the generator and other forms of power.

              '14 Palazzo 33.3 diesel coach
              100w solar, PWM controller, 4 - 6v GC2 battery bank, 6k Onan diesel onboard generator, 2000w Magnum Inverter, AGS
              100,000 plus miles over 5 years across all the continental U.S. states, Alaska, and most of Canada
              FWIW, I think it's a pleasure to read a post from someone with real life experience relating to the thread and common sense to go with it. Thanx for the sanity break.

              A thought question: Would PV be as popular with RV'ers if silent and vibration free ICE powered generators were available ?

              Comment


              • #8
                It's safe to assume that generators are not the power source of choice for most, nowadays anyway, as they see them as big unwieldy fuel consuming and noise generating engines. The reality is, though, that most onboard generators are not nearly as 'loud' as most people seem to complain about - it's usually the neighboring RVr with a standard 'contractor' generator set outside, away from their own RV, that brings out the generator naysayers.
                Vibration, yes, there's an engine running and that will generally have some effect on the RV, yet it's also really not the 'problem' that some may fear. Those with generators under their end of the RV, such as under the bed area, certainly have more to be aware of, though. Those of us with generators up front, as far from the bedroom as possible, tend to not be so concerned.
                I've often found the generator restrictions at some places laughable, as they 'restrict' the usage times for generators, yet have no restrictions for the extremely LOUD and obnoxious Harleys and Turbo Diesel Trucks which can run rampant in some parks, no matter the hour. Screaming kids and folks laughing and talking loudly around their 'campfire' all night also have little restrictions. Oh well, so much for the 'quiet' camping environment... even WITHOUT my generator.

                Yes, the factories are aware of the 'pushback' with generators, in today's 'solar' environment, and some have even take the steps to build some 'generator free' solar/battery only powered coaches - even if just a prototype. Thor built their largest motorcoach, the Tuscany, with a huge LITHIUM battery bank in the front compartment, where a generator normally sits, and it includes THREE very large inverters, along with a good amount of solar on the roof, of course, and an additional oversized ALTERNATOR, just for charging while traveling.
                I would love to take a trip or two across country with this new unit in order to 'test' the validity of these new ideas - I'll be the 'guinea pig', if they wish(I WISH!)...

                Comment


                • #9
                  Originally posted by Rummage View Post


                  We are slowly heading towards the equator............

                  You should probably take an electrician with in case you have trouble. I volunteer

                  Comment

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