Combiner box moutning Question.

offgridcabin2015 Registered Users Posts: 88 ✭✭
Hello Experts. 

I will be adding 6 Q cells. So just so you caN visualize this i'll try to explain. Making a ground mount.  2000 watts to one Charge controller (outback flex 80) i'm a 24v system.
So my question is after wiring them up 2 panel pairs in series / so that's 4 panel to one CC. 

My idea is to mount the combiner boxes ( 2) under the ground mount arrrays and run the 4 wires. ( 2 wires left over from each CC)  (about 50 feet max) back to cabin.I want to run the 4 wires back to cabin. Doees that make sense?
As i'm not wiring in high voltage (to expensive for me). 

Would that be okies / acceptable?


  • BB.
    BB. Super Moderators, Administrators Posts: 33,500 admin
    Can you give a link to the Q Cell panel specs?

    Are you looking to install 4x or 6x YYYWatt panels?

    One or two FM80's?

    Do you want to add more panels/circuits to the array later (i.e., pull enough copper cable to support future expansion)?

    More or less--I would be looking possibly at 3x in series and 2x parallel?
    • 400 watt panels * 6 = 2,400 Watts
    • 2,400 Watts * 0.77 panel+controller deratings * 1/29.0 volts charging = 63 Amps typical best case charging current
    Have to look at minimum temperature for your cabin's location (North of Ontario Canada?) to see if your panel will work with 145/150 VDC max input voltage.

    If you can do 3s x 2p array, you don't really need a combiner box (no fuses/breakers needed)....

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • offgridcabin2015
    offgridcabin2015 Registered Users Posts: 88 ✭✭
    edited May 2022 #3
    Thanks bill for chiming in. 

    link for specs on Q cell . i have  6 of these. already bought 15amp breakers to wire two panel in series. 
    out back like volts rather than amp / so no need to wire in paraell.. Let the MPPT. DO it's magic.


    i have 24v system and 2 flexmax 80 charge controllers . so i can only wire up  4000 watts in totaal. i have 2 -six leg combiner boxes.

    When you say find out the MIN temperature. it get as cold as -40 here in winter.

    i do have 6000 watts in total solar but when i have funds i'll buy another Charge controller / will be Midnite solar. so yes will be wanting to expand down the road too.

    Just rather than running all wires to cabin can't i just have go to combiner box under the panels then the excess 4 wires run back to cabin? 
    saving on wire?  the distance is 50 feet max.