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Will my charge controller work with this set up? Series or parallel?

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  • Will my charge controller work with this set up? Series or parallel?

    I have 5x 100 watt solar panels - 5.62 amps, 17.8 Volts
    3x 100 ah lithium batteries
    2000 Watt inverter/charger
    150/35 mppt solar charge controller

    This set up is for a travel trailer roof.

    My original plan was 4x panels wired 2s2p and to tilt the panels. However, I decided to add an extra panel and not tilt the panels. I guess I can't do 2 in series then the other 2 in series...run those two as two groups and just add the 5th panel in parallel?

    So 5x 100 watt panels horizontal on the roof.

    The charge controller is only 35 amp, but the manual says it can work with 500 watts of solar, which I doubt I will be getting with all of them flat on the roof. I like to be safe, though.

    I can arrange 5 panels on the roof so that when parked with the door/awning side of the trailer facing the southern sky there will be no shade on them (assuming no trees, etc.). I can add a 6th panel, but it may have a little shade when parked in this position from a TV antenna or AC unit.

    I think I may have bought too small of a charge controller....with regards to amps...I'm not sure. I doubt even with 6 panels I'll be bringing in more than 35 amps.



  • #2
    With only 5.62 amps, 17.8 Volts you cannot use a MPPT controller, You should use a PWM which does not need to down-convert the PV voltage. MPPT would likely need closer to 28-30V to reliably activate and charge the batteries. Look for the specs on your model and see if 17.8V would work. This voltage will decrease nearly a volt when the panels are all hot & toasty on the roof
    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
      With only 5.62 amps, 17.8 Volts you cannot use a MPPT controller, You should use a PWM which does not need to down-convert the PV voltage. MPPT would likely need closer to 28-30V to reliably activate and charge the batteries. Look for the specs on your model and see if 17.8V would work. This voltage will decrease nearly a volt when the panels are all hot & toasty on the roof
      Looks like it needs Vbat +5V to start and Vbat +1 to run.

      https://www.victronenergy.com/upload...-150-35-EN.pdf

      I guess I could use 6 panels and wire in parallel series groups 2s3p. That would cover my Vbat +5V, but would potentially ruin my my CC with too much current 600W / 12V = 50 amps which is a lot higher than the 35 amps the CC can handle.

      I'd be reluctant to just assume that my panels will only produce 80% of their rated power.....or less, given that they will always be horizontal.... and just roll with the 35 amp CC.

      So I guess my options are:

      1. Wire the 5 panels in parallel and hope the CC will work with Vbat (I'm hoping here Vbat means 12V and not the actual 13.4 or whatever the batteries hold) +5V.

      2. Exchange my CC for the 100/50 and go with 6 panels wired in 2s3p

      3. Return one of my panels and just run 4 panels in 2s2p. My concern with this option would be not generating enough power to charge my 300 ah battery bank
      Last edited by Skwidward; 04-20-2019, 06:32 AM.

      Comment


      • #4
        I suspect that 6 panels 2s3p would be your best option. Many MPPT controllers can be slightly overpaneled and be fine. With un-aimed panels, you are not likely to overload the controller

        > I'd be reluctant to just assume that my panels will only produce 80% of their rated power

        That's the standard de-rating for real life, no reason you should assume your panels are an exception. Flat on the roof, it's going to be even less. An no more parking in the shade, they are solar panels, not shade panels.
        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

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