Wire Size & fuses for solar install
I have 4 140 Watt 12v panels connected in parallel on the roof. I took the guy at Solar Blvd's advice and bought #10 AWG wire for the run to the controller. Controller is a Mornigstar TS-45 PWM. It is...
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Now I understand why nobody ever heard of Solar Bvld installation consultants :)...
You have 17 vmp, 8.4isc*4= 33.6 isc.
There are many voltage drop calculators, results are usually the same.
Calculator says that AWG 10 will result in 13% V-drop. This is too much for PWM.
AWG 8 will get you 15.4V at the controller, so #8 is the bare minimum that you should use. Buy 80ft roll of MC4 AWG 8, and cut it in half (you need MC4 plugs at the panels and bare ends at the controller). Or 100ft roll, if you are not sure that it's precisely 35ft distance. Then with #6 cable to battery you will still get over 15V if each Pos and Neg cable to battery is shorter than 6ft. Run the calculator yourself.
You should've bought MPPT 45. Then with AWG 10 you would lose 13% of daily AH haul (more likely just a few % because conditions are not perfect all the day). But high voltage drop wouldn't affect the charging voltage at the battery.
PS: I hope that whoever you talked to at Solar Blvd, did not suggest to use AWG 10 from controller to battery. Because if they did, tell the management to fire this m.oron.
You have 17 vmp, 8.4isc*4= 33.6 isc.
There are many voltage drop calculators, results are usually the same.
Calculator says that AWG 10 will result in 13% V-drop. This is too much for PWM.
AWG 8 will get you 15.4V at the controller, so #8 is the bare minimum that you should use. Buy 80ft roll of MC4 AWG 8, and cut it in half (you need MC4 plugs at the panels and bare ends at the controller). Or 100ft roll, if you are not sure that it's precisely 35ft distance. Then with #6 cable to battery you will still get over 15V if each Pos and Neg cable to battery is shorter than 6ft. Run the calculator yourself.
You should've bought MPPT 45. Then with AWG 10 you would lose 13% of daily AH haul (more likely just a few % because conditions are not perfect all the day). But high voltage drop wouldn't affect the charging voltage at the battery.
PS: I hope that whoever you talked to at Solar Blvd, did not suggest to use AWG 10 from controller to battery. Because if they did, tell the management to fire this m.oron.
