Rouge MPPT charge control question

Crystal
Crystal Solar Expert Posts: 128 ✭✭✭
in Solar Beginners Corner #1
I was researching the Rouge MPPT charge control and studied the manual.
I was looking at Table 4.4.1 in the manual and I see that PV volts are 34.8Vmp.
We will have two Evergreen ES-A-210 panels, each panel has 18.3Vmp. So the two panels will make 36.6 Vmp.
Will this be too much for the Rouge charge control?
Or am I looking at this in the wrong way?
These panels will be wired in series to create 24 volts and then down-convert to 12 volt into the battery bank.
Any advice would be greatly appreciated.

Thank you!
Crystal
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Comments

  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #2
    Re: Rouge MPPT charge control question

    I think you would be under the 60 volt limit but can you give is the Voc of the panels and where you are located how cold will they be in the winter?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,639 admin
    #3
    Re: Rouge MPPT charge control question

    The maximum input solar voltage, open circuit, is 60 volts (from pdf manual).

    If you assume a 0F minimum temperature, then Voc cold max = 51.65 volts maximum (for two panels in series).

    Assume a nice hot day of 95F and 63F rise due to solar heating (158F total), the Vmp min hot = 30.2 volts

    Vmp min is a bit on the low side [for a 24 volt battery bank/fine for a 12 volt bank--fixed BB]--but should work OK (may need to equalize batteries on a cooler day).

    Marc/Lorelec will be better able to address the details next time his is here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,639 admin
    #4
    Re: Rouge MPPT charge control question

    Sorry, I made one mistake---The Vmp=30 volts is no problem for a 12 volt battery bank... It is only a mild issue for very hot weather and a 24 volt battery bank (especially if equalizing).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #5
    Re: Rouge MPPT charge control question

    Section 4.3 last sentence says " The absolute maximum input voltage for the mpt 3024 is 75 volts. Above this will void the warrantee."

    Hope this helps.

    Tony

    PS The Rogue manual is one of the best manuals out there that I have seen. It explains in "simple detail" if that isn't an oxymoron, how, what, where nearly everything you ever needed to know about charge controllers.

    T
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: Rouge MPPT charge control question

    voc of each pv is 22.8v. 2 in series is 45.6v and should be well below any of the max specs of the rogue for voltage. after conversion you could see around 23a give or take.
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  • Crystal
    Crystal Solar Expert Posts: 128 ✭✭✭
    #7
    Re: Rouge MPPT charge control question

    Thanks so much for the helpful info. I am going to go ahead and order the Rouge MPPT as well as the panels. The rest of the system is just about figured out.
    Just trying to figure where and how to mount onto our south-facing wall. We have limited space due to windows, however, we are considering mounting them horizontally. This shouldn't be a problem from some of the images I've seen. Also, we may construct our own mounts with hinges...like Tony suggested awhile back. We are still working on this mounting design.
    I'm getting excited to get all the components together and see how it works!

    Thanks a bunch!!!
    Crystal
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  • lorelec
    lorelec Solar Expert Posts: 200 ✭✭
    #8
    Re: Rouge MPPT charge control question

    Looks like y'all beat me to it, so I don't really have anything to add, except to comment on the 75v max rating -- beyond that point the controller will be damaged, since the FETs and auxiliary supply inside are rated for that voltage. 60v was chosen as the usable limit because it should accomodate nearly all "24v" arrays after taking Voc into consideration, and leaves a little headroom to spare. The controller will actually shut down if the PV ever goes above 60v. Just keep in mind that there's nothing there to limit the input voltage to less than 75v...only your choice of PV.

    Marc
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #9
    Re: Rouge MPPT charge control question

    Horizontal or vertical, the PV doesn't care. Consider a large strap or tee hinge(s). I have several of mine simple hinges on the top, and an prop stick of the the right length for different seasons. You need to be careful with the prop stick so that it doesn't undully stress the panel.

    Tony

    PS. I think you will be very happy with the Rogue controller.
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  • Crystal
    Crystal Solar Expert Posts: 128 ✭✭✭
    #10
    Re: Rouge MPPT charge control question

    Tony,
    Thanks for the tip.
    Do you have a custom built wooden frame to attach the hinges? Or do they attach directly to the panel frame? Would building a frame be necessary, or would if be just extra weight to lift while adjusting? I believe that it would not be too difficult to construct if a frame is recommened.

    -Crystal
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #11
    Re: Rouge MPPT charge control question

    I have just bolted the hinges directly to the panel frames. I think that any extra frame would just add to the weight. The ones that I have hinged are small 55 watt Siemens panels, but I also have a couple of BP 63 watts hinged on other sites as well.

    I think the most important thing is not to stress the panel (twist).

    Tony
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