Combiner Box Setup and Recommendations


New Member
Sep 16, 2021
Hey all, new here and looking for some advice on using a combiner box for my PV array to an All-in-one Solar Charger/Inverter.

Some insight into the current set up I've got..

3500w All-in-one with max 4400w solar input (manual recommended to use 4 AWG into solar input) - 150V max, 145V recommended
x8 405w (3240W total) 49.8VoC panels for this config:
3240W / 100V = 32.4A in 2s4p

x6 are currently set up as 2s3p (99.6V ~25 max amps just using those 3 to 1 wires, no combiner box) running over a 10 AWG ~100 feet from my barn to my garage.
x2 aren't currently hooked up since I don't feel comfortable going past 25A on 10AWG over 100ft. This being my current wire for the 100ft run -

* Going strictly by the VoC, it looks possible to put my current setup into 3s (49.8VoC x3 = 149.4VoC), but after reading around it sounded like on really cold mornings the VoC isn't the cap that it could be, and that it could go even higher? Granted I live in the South East of US, so cold isn't often a concern. But, if you factor in the voltage drop over 100ft, that may be enough to say it should be safe no matter what for 3s? Thoughts?

The options I'm seeing are either to
1.) Set up a combiner box right at my barn and do short small wire runs (x4 12+AWG temco 20ft, each carrying 8A at 100V) from the PV array on the barn roof to the barn interior. Then a long run (x1 8AWG temco 100ft, carrying 32.4A at 100V) from the combiner box at the barn to the garage.
2.) Set up a combiner box right at my garage and do long small wires runs (x4 12+AWG temco 100ft, each carrying 8A at 100V) from the PV array on the barn roof to the garage, then use recommended inverter's recommended 4AWG (x1 4AWG 5ft, carrying 32.4A at 100V) for the short run. This seems to be the most expandable for the future if I got more for my solar array?

Which would be recommended or other suggestions? Thanks all
Last edited: