Needing Help with my 1kw array, and a 40 AMP MPPT at 24 Volts...

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DigitalSolar
DigitalSolar Registered Users Posts: 1 ✭
in Solar Beginners Corner #1
Good Evening!

I am still getting my feet wet and am looking for experienced advice. I have an Epever 40 AMP Tracer AN charge controller that says it can handle 1040 watts of solar in the manual. The conundrum I am in, is I can not figure out a way to configure it, no matter what I try to think of it ends up being over 100Volts ( charge controller max voltage)  5 in series 2 parallel  22.3 is the open voltage of these 100 watt panels, I have 10 of them. or I end up having 2 panels left out in the cold 4 in series 2 in parallel, only being able to use 8 out of the 10 panels because I would not want to have 2 sets of 4 in one string and a set of 2 in a third string right?

Any help would be GREATLY appreciated, if there is just no way to get 1000 watts of solar connected though a charge controller that says it will take 1040, I may end up having to buy a new controller I suppose, but I bought this one because it said it could handle 1040..

Thanks!
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    edited May 2021 #2
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    Yeah, got to plan ahead and work within the constraints of the charge controller. You could do 3 strings of 3 to maximum effect with what you have or search for a charge controller that will handle then 5 in series. Something like the Outback FM60 might be the cheapest I can think of that allows for 150 volt strings. Of course the other option is seeing if the Epever can be 'over paneled' and buy 2 more panels and do 3 strings of 4 panels...

    You could do 5 strings of 2 panels, but even if Epever did say that was okay, I would work with what boB Gudgel has said about needing 30% voltage above the VMP, to charge effectively.  boB and Robin did some of the early work building MPPT charge controller when they owned Outback and now with Midnite.


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    edited May 2021 #3
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    I went back and read you post. I assumed it was a 24 volt system. If you have a 12 volt system, 5 strings of 2 panels would be fine.

    My original 24 volt system, had 2 arrays of 5 strings of 2 - 200watt panels on 2 different charge controllers. You do need a combiner box for more than 2 strings.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited May 2021 #4
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    Photowhit said:
    I went back and read you post. I assumed it was a 24 volt system. If you have a 12 volt system, 5 strings of 2 panels would be fine.

    My original 24 volt system, had 2 arrays of 5 strings of 2 - 200watt panels on 2 different charge controllers. You do need a combiner box for more than 2 strings 
    With a 40A controller it must be a 24V nominal system 2 series 5 parrallel would be 44.6 VOC, about perfect and yes a combiner with overcurrent protection for each string. The real output would be somewhere around 75% of the rated output in most cases or something in the neighborhood of 32A in full perfectly aligned sun.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #5
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    mcgivor said:
    With a 40A controller it must be a 24V nominal system 2 series 5 parrallel would be 44.6 VOC, 
    I believe the desired voltage should be VMP above the charging voltage, NOT VOC. 
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,044 ✭✭✭✭✭
    #6
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    This might help with any over paneling worries.




    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • MichaelK
    MichaelK Registered Users Posts: 234 ✭✭✭
    #7
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    I think your best option will be to upgrade to a higher capacity controller.  Look at Epever'sTracer 5420 and 6420, their 50A and 60A controllers, respectively.  They make both 150, and 200V max versions.  I would pay a bit more to get the 200V model.  What I would do is first contact the seller you purchased from and ask if you can upgrade to a bigger model.

    If you can't return your controller to the seller with the option to buy an upgrade, then maybe you could sell it "new, open box" on Ebay.  Recoup a fraction of the price that will help pay for the upgraded controller.

    If you are really stuck with keeping this 40A controller, then just utilize 9 of the panels and wire them in a 3S3P configuration.  Keep in mind that with more than 2 parallel strings of panels, they must be fused/breakered for short-circuit protection.

    If you decide to buy 2 additional panels, you could wire them in a 3S4P configuration without much worry of overloading the controller.  Assuming you are not likely to ever see greater than 85% output, the math would be (1200W/26V charging) X 0.85 efficiency =39A.



    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
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