solar panel wiring, and fuse
- Thread starter JimJimmy
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chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
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https://www.calculator.net/voltage-...it=feet&eres=48&x=87&y=23&ctype=necDEpends on how far this run is. First look at the ampacity of the wire:
I would go with at least 6 AWG, but then I’d shoot for a 3% or less voltage lass, so may need to be thicker. I use this voltage calculator:
www.calculator.net
You left off the panel voltage, but I-used 18 volts. With 6 AWG, you could run this 12’ after combined and reach 3% voltage drop.
I would go with at least 6 AWG, but then I’d shoot for a 3% or less voltage lass, so may need to be thicker. I use this voltage calculator:
Voltage Drop Calculator
This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.
www.calculator.net
You left off the panel voltage, but I-used 18 volts. With 6 AWG, you could run this 12’ after combined and reach 3% voltage drop.
The panels have a Voc of 22.3V. The SCC can handle 150V. The 6 current panels in series is 133.8V and will get to 150V at -13ºC/9ºF.
So the current 6 panels in series is OK as long as they don't get any colder than -13ºC/9ºF. 8 of these panels can't be put in series on that one controller.
If your 6 current panels are in series why do you want to put them all in parallel when you add 2 more? 4S2P would be a much simpler solution. That would allow you keep the existing 10AWG wires and you wouldn't need a combiner box or fuses. Just a pair of MC4 Y connectors to connect the two series strings together.
I currently have a total of 6 100w panels wired in series to a 60a controller with a max of 150v. I want 8 panels, 8 panels in parallel will keep me under 150v. what I am asking is what size fuse do I need inline from the panels to the controller?
and the answer is 50.
8 x 5.86 equals 50.
But you have other options. If you go with 8P then you need a combiner box and 8 fuses, one for each panel. Then you need the 50A (really 60A) fuse for the whole combination and you need at least 6AWG wire to handle the 47A. The existing 10AWG is far too small.
If you wire the panels in 4S2P then you can keep the 10AWG wire and you don't need a combiner box or any additional fuses.
If you wire the panels in 4S2P then you can keep the 10AWG wire and you don't need a combiner box or any additional fuses.
That would imply 2S4P. You can do that. And you would need 6AWG to the controller and the fuse as you state. But in post #3 you stated you didn't want new wires. You wanted to use the existing 10AWG.
I'm suggesting 4S2P. Wire 4 panels in series. Wire another 4 in series. Put those two strings in parallel. Join with Y connectors. Keep the 10AWG all the way to the controller and avoid the need for the extra fuse.
It just seems strange to go from 6 panels all in series to 8 panels mostly in parallel. But either approach works.
that is what I am going with. 4 panels in series x 2 sets of 4 panels in series, 2 sets of 4 in parallel.
approximately 4 panels in series are 80volts, 6 amps x 2, in parallel is 80 vol, 12 amps.
all 8 100w panels making electricity, no need for anything more than a inline 15amp fuse.
thank you for all your help.
