24V inverter + 24 volt flooded battery bank. Solar for pop up trailer

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  • popupheaven
    Junior Member
    • Jun 2021
    • 2

    24V inverter + 24 volt flooded battery bank. Solar for pop up trailer

    Goal to not use a generator.
    System components bought on instinct not facts. I bought my panels at santan near phoenix and the rep told me people always say they should have bought more.


    4 x CSUN 250W Snail Trail Solar Panel
    Rated Power: 250W
    Open circuit voltage (VOC): 37.3 V
    Max power voltage (VMP): 30.1 V
    Short circuit current (ISC): 8.78 A
    Max power current: 8.31 A

    EPEVER MPPT Charge Controller 40A 12V / 24V Auto, Solar Charge Controller 150V PV Negative Grounded Solar Regulator for Gel Sealed Flooded Battery(Tracer 4215BN)

    with mt50

    AIMS Power PWRI150024S Pure Sine Power Inverter, 1500W Continuous Power, 3000W Surge Peak Power, 24V ,,,, aims had a very low draw at idle.

    batteries x 2 = 24 volts
    • Brand: Crown Battery
    • Voltage: 12
    • Format: BCI Group 27M
    • Lead Acid Type: Deep Cycle
    • Capacity: 95AH
    • Cold Cranking Amps: 625
    • Reserve Capacity Minutes: 160
    Wire size all 6 awg . short runs
    150 amp vicrtron fuse to inverter , all panels have fuses 15 amp .
    battery temp sensor taped to 1 battery top. is there a better way epoxy ?
    wiring off of the input side of the charge controller from array.
    I want to be able to plug and play different configurations voltages etc.
    Y splitter added so I can choose configuration at controller.
    4 panels 1 roof mounted on pop up trailer basically as a backup truly a standby.
    The other 3 as to be positioned for optimal performance.
    Or if necessary 4th panel is utilized.
    States and times of year Southern Oregon forests summer.
    Arizona winters.
    Load is the key here so my realistic expectations are to.
    Run pc and 65 inch tv for 5 hours per day. about 200 watts per hour.
    Maybe run a small fan off inverter low watts draw.
    If the panels sustain other loads friends nearby that would be great of course all dependent.
    The pop up has a shore power 110 v input to a 12 volt convertor.
    If my batteries are charged for the expected load I could plug in the 110 shore connector
    to my 24 volt invertor that will charge the 12 volt prius battery that replaced a heavy 12 volt deep cycle .
    So that is converting 110v energy from the 24v invertor to supply power to the 12 volt interior led lights seems like a waste
    of power conversion to me. Or maybe the existing system is ok as a backup.
    Low power draw not expecting to run a fridge microwave emitter or possibly a low power coffee maker.


    Suggestions on configurations of the available panels series parallel etc. would be appreciated.




















  • chrisski
    Solar Fanatic
    • May 2020
    • 547

    #2
    You have the start of a plan, but could be good to read the stickies, especially on the batteries. So mauch can be learned from those in helping you build a safe, realistic system.
    =======================================
    What is the max charge amperage of your batteries?

    Mine is C/8, which if your batteries have the same rate, yours is about 11 amps at 24 volts. Your four panels and charge controller can push way more than that, so that could fry the batteries if the CC pushes the 34 amps at 24 volts your 1000 watt panels are capable of. In fact to stay within limits, only a panel should be hooked to prevent going over an 11 amp limit. You need to look at your battery spec sheet to find out.

    I think a 1500 watt inverter is too big for your wiring. I would only use 6 AWG for a limit of 55 amps. That means the inverter might be limited to around 600 watts before ampacity become a problem.

    You state you want 1000 watt hours of power a day (200 watts * 5 hours). If that truly is your limit, your two batteries give you 1100 watts without going below 50% which kills them quickly.

    Comment

    • Mike90250
      Moderator
      • May 2009
      • 16020

      #3
      > 4 x CSUN 250W Snail Trail Solar Panel
      I hope you got a good discount price on the used panels. Good panels don't have snail trails. New panels don't have snail trails. Used panels can have snail trails and still be good for a while.

      Check into what PV voltage your charge controller needs, to recharge a 24V battery. Your VMP: 30.1 V is uncomfortably close to the battery charging top end, and the fancy MPPT circuits may not work, until you feed the controller 40V. 2 panels in series would work, but you still have to watch the battery recharge amp limits
      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

      • popupheaven
        Junior Member
        • Jun 2021
        • 2

        #4
        What is the max charge amperage of your batteries?
        = do not know searched and hit a brick wall.

        Mine is C/8, which if your batteries have the same rate, yours is about 11 amps at 24 volts. Your four panels and charge controller can push way more than that, so that could fry the batteries if the CC pushes the 34 amps at 24 volts your 1000 watt panels are capable of.
        = there is a setting for amp hours in the controller. the default was 200 amp hours I changed it to 180. I will need to do some testing run the bank down then change the amp hour rating to see the difference in amps going to batteries.

        I think a 1500 watt inverter is too big for your wiring.
        = I have learned to always buy much larger invertors so they have good headroom and over spec start up current if I run something like a high amp circular saw sawzall. Also the larger invertor has more heat sink area so the fan comes on less. I do not need to or want to run high watt things. But if I do I can always feel the wires for heat and with 24 volts compared to 12 there should be less resistance = heat?


        You state you want 1000 watt hours of power a day (200 watts * 5 hours). If that truly is your limit, your two batteries give you 1100 watts without going below 50% which kills them quickly.
        = I tested today 2 panels in series at about 150 watts draw for 4 hours and there was plenty of volts left over and that was with the panels disconnected from cc. I have a 12 volt 1500 watt inverter in my prius so If I ever want to switch to a (smart generator = prius) to my 12 volt inverter I can.

        4 x CSUN 250W Snail Trail Solar Panel
        = there is minimal snail or almost zero and I paid $60 each. I chose these because they are mono and might be better on cloudy days?


        Check into what PV voltage your charge controller needs, to recharge a 24V battery.
        = no specifications in the manual.
        Your VMP: 30.1 V is uncomfortably close to the battery charging top end, and the fancy MPPT circuits may not work, until you feed the controller 40V. 2 panels in series would work,
        = there was no warning anywhere in the manual.
        but you still have to watch the battery recharge amp limits.
        = and that is where the parameter of battery amp hours should reveal by me testing the settings with good sun, change from 180 amps to 25 amp hours.
        Im guessing the cc uses the amp hour parameter to set a max amp charge output. The manual says nothing about that and there is no warning.
        The meter on the mt50 reads low compared to a meter on the battery post weird. the inverter and the cc both have low battery warnings and cut offs.
        The manual doesnt go too deep about everything but ill try the computer download and see if there are any additional info.
        thanks for the help

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