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Solar overflow to run water heater?

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  • #16
    You first need to work out a decent match up between panel output and heater consumption.
    Otherwise the effort may only succeed in feeding some current through the heater, but burning
    up most of the available energy in the panels. Bruce Roe


    • #17
      Thanks ewarner, I'll look in to it.

      I do have additional side ports on the WH but there for output spigots, with all the tubes and annode inside I'm not sure if I could get a 2nd element in there but it's something to check in to.

      Did anybody know how many watts this EPever 3215BN outputs at the aux load port and when? The manual didn't tell me anything.

      I have 2 x 255w, 30V, 8.49A wired in series (see attached). How big of an element could I run with these panels off the aux port on this CC?


      Attached Files
      Last edited by Carv; 02-08-2019, 02:22 AM.


      • #18
        I run 2,000W 120V elements in my system. These are common and cheap, used in point of use water heaters under 10 gallon in the US. Half the voltage gives 1/4 the rated power, an exact match.


        • #19
          I believe my Morningstar can deliver up to the entire solar input to the load output if state of charge of the batteries warrant that (i.e. they're fully charged). The program logic is current comes in from panels and first priority is to the charging lines. Current is routed there until batteries reach the voltage setpoint, either in absorption or float charging state. Once setpoint is reached, PWM does it's duty cycle thing except that instead of just on/off to the charging lines it is switch between charging line/load line so that charging line voltage stays constant at the setpoint. When in float charging mode, very little current is directed to the charging lines and most of it would go through the load lines.
          I'm an RV camper, mine has 280 watts of solar


          • #20
            See also [U]t[B]his thread.[/B][/U]
            SunnyBoy 3000 US, 18 BP Solar 175B panels.


            • #21
              Thank you Inetdog, I read it and it sounds like everybody's trying to over complicate things I understand it better but I'm still a little lost.

              I think I need to do something like you have set up, but I'm not sure exactly what that is. From reading the other thread I believe you take 60V panels, send that PV through your unavailable CC and convert it to 60V AC which raises your water tempature not to 60F, but raises you're water temp by 60F, so from 50F to 110F?

              I checked my specs and my water heater does not have a 2nd port IIcould put a DC thermostat in to Although I might be able to put it in a extra incoming water port but it's 3/4 NPT so I don't think the 1" NPT DC element with thermostat will fit so I really don't think this is an option?

              This leaves me having to configure a way to use the existing AC element for heating the water. My current AC element is 120V 1650W. So how do I take the current PV output or my DC output and convert it to use with the AC element & thermostat?

              If I ran the existing element at 60V that would give me 412W which is enough to heat the water. I'm just not understanding how to go from what I have now to the AC element?

              I did see the techluck converter thing but it's pricy and from people on that thread have said it seems a like dangerous.

              I also saw the PMW CC set up to run a WH but that's as much as the MPPT CC have now