No announcement yet.

12v / 24v charge controller + inverter quandry...

  • Filter
  • Time
  • Show
Clear All
new posts

  • 12v / 24v charge controller + inverter quandry...

    Living in Madagascar for the past 12 years, I recently (naively!) purchased equipment based on a local retail store manager's recommendations, but now (having done lots more internet research, see that I have a problem, given that I have two 150Ah 12 volt batteries, but two 24 volt 230 watt microcrystalline solar panels, a 2000 watt 12 volt inverter, and a 50 amp charge controller expecting an input voltage of 16-20 volts.

    It appears in retrospect, I should have been told to buy a 24v inverter and 24v charge controller. Given that my budget limitations won't currently allow that, can I still make this system work without losing too much power with a 24v to 12v transformer?

    Is it essential to change the charge controller to 24v or is there any other way of still charging the (serial connected) 24v (double) battery bank, and yet still draw off only 12v direct to the 2000w inverter from my current system?

    All suggestions welcome.

    Colin Radford
    HELP Mg.

  • #2
    Hi Colin - Welcome to Solar Panel Talk!

    Mike, Sunking or another member who can best reply to you should be along before long.

    Again - Welcome,


    • #3

      Hi Russ!

      Thanks for your prompt reply and welcome! Our world really is small in the internet age!

      While waiting on the experts to respond, I just thought of another related question...

      If there were no other options with my current system components (basically a 12v system with a pair of 24 volt panels) would it be a) advisable or b) more (or less) efficient to use a 24v to 12v transformer between the PV panels and the charge controller, or use the same transformer between the (24v serial) battery bank and the 2000w inverter?

      Again, TIA

      Colin Radford
      HELP Mg.


      • #4
        using a ordinary PWM charge controller, you are throwing away 50% of your PV wattage. You need a MPPT charge controller to downconvert the 24V PV to 12V battery, and the good models run 90-95% efficient. 460W @ 15V = 30A so a small controller will not be suitable.
        I would suggest the
        Morningstar Tristar MPPT 45A
        Rogue 30A

        or one of the BlueSky controllers

        Xantrax and outback also make reliable MPPT units, but they are larger than you need.

        Beware of "sales" on ebay, many are NOT actually MPPT or have such a poor implementation that you are better off without 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