Redarc MPPT + battery charger

cptdondocptdondo Solar Expert Posts: 72 ✭✭✭
I found this nice unit that fits everything I need.

Except that the MPPT controller is spec'd at 9-32V.  I'm struggling to find panels that add up to 600W that are reasonably priced that are within that range.  I want to use a couple of these: but they're spec'd at 
  • Vmp: 33.32 Volts
  • Voc: 40.13 Volts
Just over the Redarc's limits.  Any suggestions on matching panels? Or will the Redarc handle those panels?  I've sent an email off to Redarc but no response yet. 


  • EstragonEstragon Registered Users Posts: 3,717 ✭✭✭✭✭
    With that voltage range you're pretty much stuck with 12v nominal panels, something like 4-5 of these in parallel:

    With VOC of 40v, the ones you linked would be way over for the controller.   Peak voltage tends to happen in the early morning before the sun warms the panels, so it's Voc that's the limiting factor, not Vmp.

    12v panels tend to cost more/watt, but can be used with cheaper pwm controllers.  Bigger panels are less $/watt, but tend to need more expensive mppt controllers.
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • cptdondocptdondo Solar Expert Posts: 72 ✭✭✭
    Thanks for the explanation.  I’m still strugging with mating the pieces parts together.  I have an existing 170W Zamp panel but Zamp wants nearly $600 for a second one.  I think I’ll stay with the single Zamp panel and then beef up the solar and batteries in the other bank.
  • BB.BB. Super Moderators, Administrators Posts: 29,208 admin
    As long as the Vmp of your "12 volt" panels are in the range of Vmp~17.5 to ~19 Volts STD (standard test conditions), any "12 volt" panel will work (in parallel).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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