Anything special I should know about using these panels?

Rkg76
Rkg76 Solar Expert Posts: 35 ✭✭
in Solar Beginners Corner #1
Hey All,

I have 10 200 watt panels (may not use them all) with the following specs....

Vmp 28.9V
Imp 6.93A
Voc 36.2V
Isc 7.68A

Anything special I would need to know about using these in a 24V offgrid system, besides having to use a MPPT charge controller likely?

Thanks
Russ
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #2
    Re: Anything special I should know about using these panels?

    If you have 3 or more parallel strings of panels, each string should have an ~15 amp fuse/breaker per string--usually in a "combiner box" (keep a shorted panel string from being fed power from the other 2 or more parallel strings). See the panel specs. for series fuse rating.

    You need to pick the MPPT charge controller. Very roughly, the "most efficient" Vmp-array voltage is ~2x battery bank voltage.

    Need to know the maximum Vpanel input voltage for your MPPT controller, and the minimum sunny morning temperature for your location (sub freezing panels, Voc-cold can rise enough to over voltage the charge controller if you have enough panels in series (and/or the Vpanel input voltage is on the low side for the MPPT controller).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Anything special I should know about using these panels?

    With Vmp of 28.9 you should have two in series for each string of the array. This will give you an array of:

    Vmp 57.8
    Imp 34.65 (fuse/breaker on each string)
    Voc max in Winnie of 94.12

    With a 2kW array on a 24 Volt system you could produce over 64 Amps so you should pick either a MidNite Classic 150 or Outback FM80.
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  • Rkg76
    Rkg76 Solar Expert Posts: 35 ✭✭
    #4
    Re: Anything special I should know about using these panels?

    Great...thanks...do you recommend one of those CC's over the other?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
    Re: Anything special I should know about using these panels?
    Rkg76 wrote: »
    Great...thanks...do you recommend one of those CC's over the other?

    Not really. The MidNite is "top of the line" but the Outback is slightly cheaper. :D
    Classic 150 $610 http://www.solar-electric.com/mnclassic.html
    FM80 $565 http://www.solar-electric.com/oufl80sochco.html
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