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  • Off grid controller

    Hi
    I have an off grid setup with 4 solar panels each panel is 240watt 8.52amps and 37.1volts witch I have connected in parallel
    so I would have 34.8 amps and 37.1 volts going to the controller

    I have a renogy 100amp mppt controller
    and my question is, at full sun my controller is sending an average of 70 amps to the batteries
    Is this correct

    thanks


  • #2
    What is the voltage of the batteries? If it is 12 or 14 volts it is less power than the theoretical of 34 Amps at 37 volts that could go into the controller in ideal conditions. . What is the actual voltage and current going to the controller?
    9 kW solar, 42kWh LFP storage. EV owner since 2012

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    • #3
      Hi
      I have 4 200 ah lithium batteries connected in 12 volt parallel
      is it normal for the controller to push out more amps than what’s going into it

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      • #4
        Originally posted by Sime View Post
        Hi

        is it normal for the controller to push out more amps than what’s going into it
        Amps and volts are just a means to the end game of Power.(Watts)

        Watts equals Volts times Amps
        That is what your charge controller is doing.by lowering volts to charge your batteries. The result is some loss of power but an increase in Amps.
        9 kW solar, 42kWh LFP storage. EV owner since 2012

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        • #5
          Calculate the WATTS going into your controller ( figure about 80% of the PV panel nameplate watts for noon, even less for off noon)
          decide what charging voltage you use for your batteries ( 13V when really low, 14V when nearly full ) with a genuine MPPT controller

          240w x 4 = 960w 80% = 768w as a rough guess, on a great day @ noon

          768w / 13.5V = 56.88A to the batteries. Are the batteries allowed to receive that much ?

          MPPT controllers work their magic by watts in = watts out ( minus a % or 2 for internal losses ) and they convert excess voltage to amps magically along the way.
          PWM controllers only control battery voltage, amps in = amps output to the battery, when the battery is full, the PWM shuts off the amps
          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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          • #6
            Hi mike
            the batteries have a max charge of 100 amps

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