MPPT Charge controller with 30.9V panels

Buchanan111
Buchanan111 Registered Users Posts: 1 ✭
in Solar Beginners Corner #1
Hi All,

I'm just trying to get my head around what i think i already know.... Controller is just an example i haven't settled on this yet!

I would like to run a a panel with rated voltage of 30.9V to a Charge controller for a battery. The charge controller has MPPT and lists the following specifications.

Specifications

  • Max Rated Charging Current: 30 amps
  • Max Rated Load current: 30 amps
  • Maximum Solar Input Power: 390 Watts @ 12V - 780 Watts @ 24 Volts
  • Self consumption: 10mA 24V
  • System voltage: 12 DC / 24V DC Auto-set
  • Work temperature: -35° to +55°
  • Battery Types: Gel, Sealed, Flooded
  • Max Solar input Voltage: 120 Volts DC
  • Temperature compensation: -5mV/°C/cell
  • Control mode: 1 x Load Control Output

I think if i have MPPT and my solar input voltage (from series panels) is less than 120V all is good? Link to controller 
https://www.sunshinesolar.co.uk/prodshow/MPPT_Solar_Regulator_Controller_30A_12V_24V/EMPPT3.html

Your help in providing a sanity check will be gratefully recieved (it's been a long day :) )

Jamie
 
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Comments

  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    Unless it can limit the output, you should not send enough wattage to it to produce more than 30 amps. It specifies 390 watts. So no more than 390 watts input, The maximum voltage would need to be calculated from the VOC (open circuit voltage) x the number of panels in your string, and then adjusted based on your lowest temperature. Voltage can be high than the voc rated when below freezing.

    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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  • MichaelK
    MichaelK Registered Users Posts: 236 ✭✭✭
    #3
    I'll take a guess and say that your panel is standard grid-tie panel designed for rooftop use with a wattage in the 250-275 range.  A mmpt controller would take those 30.9VDC at maybe 8-8.5amps and transform it down to the charging voltage for a 12V battery at 14.4 volts and ~17-19 amps.  That might work just fine with that controller if it is what it says it is.  Just to let you know, the outer shell of that controller looks suspicously like cheap Chinese PWM controllers that they've slapped a MPPT label onto.  Look into the weight of that controller.  If it's only 500 grams or so, I've study it very carefully.  If it's 4-5kg, it's more likely to be real.
    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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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #4
      Just to let you know, the outer shell of that controller looks suspicously like cheap Chinese PWM controllers that they've slapped a MPPT label onto.  Look into the weight of that controller.  If it's only 500 grams or so, I've study it very carefully.  If it's 4-5kg, it's more likely to be real.
    It is the real thing. I would recommend getting the optional remote lcd readout if you haven't already gotten it.

    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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