12VoltInstalls
life passes by too quickly to not live in freedom
I feel dumb posting this but I am perplexed after trying a couple online calculators. I’m helping a local/neighbor install a 6548, two server-rack 5kWh batteries, and twelve roof-mounted 300W panels.
The solar panel cabling will have ‘losses’ and that’s ok. Initially used a calculator that said ~5% for 10AWG thhn and I was ok with that for the one-way 130+ feet.
Yesterday I tried another calculator that someone posted her for education/entertainment value. It said 8ga was required at 20% loss. What? Another site said 9.x%. So I thought I’d look it up here. But apparently others have had confusion, too.
So here are the specs on the 300MS panels:
I will be running three 4S strings to a combiner box, which will output one 4S string (~130V, ~9.25A, ~160VOC) and one 4S2P (~130V, ~19A, ~160VOC). I was planning 8ga but 10ga seemed fine for the amps and the footprinthero calculator “approved” the 4S run.
With the 250VOC limit on the 6548 6S won’t work in Vermont.
What gives with these calculators? I used them to bolster confidence and verify my plan but the later-found disparity lowered my confidence.
I can buy 8ga thhn but that’s another $300+.
Or I could run the 4S2P with 2 pairs of 10ga I suppose.
Or is 10ga fine (being that I’m fine with the loss- initially was going with ten 300W panels but the 12-unit pallet was attractively priced versus singles x ten. So “free” watts to save on wire was my idea). I could always do 5S2P and ‘save’ the two as spares.
Thank you for thinking about my dumb cabling question.
I have not retried “footprint hero” fwiw
The solar panel cabling will have ‘losses’ and that’s ok. Initially used a calculator that said ~5% for 10AWG thhn and I was ok with that for the one-way 130+ feet.
Yesterday I tried another calculator that someone posted her for education/entertainment value. It said 8ga was required at 20% loss. What? Another site said 9.x%. So I thought I’d look it up here. But apparently others have had confusion, too.
So here are the specs on the 300MS panels:
I will be running three 4S strings to a combiner box, which will output one 4S string (~130V, ~9.25A, ~160VOC) and one 4S2P (~130V, ~19A, ~160VOC). I was planning 8ga but 10ga seemed fine for the amps and the footprinthero calculator “approved” the 4S run.
With the 250VOC limit on the 6548 6S won’t work in Vermont.
What gives with these calculators? I used them to bolster confidence and verify my plan but the later-found disparity lowered my confidence.
I can buy 8ga thhn but that’s another $300+.
Or I could run the 4S2P with 2 pairs of 10ga I suppose.
Or is 10ga fine (being that I’m fine with the loss- initially was going with ten 300W panels but the 12-unit pallet was attractively priced versus singles x ten. So “free” watts to save on wire was my idea). I could always do 5S2P and ‘save’ the two as spares.
Thank you for thinking about my dumb cabling question.
I have not retried “footprint hero” fwiw
