What gauge wire?

[Keith_Haw]

I'm going to be adding a second solar panel and need to know what gauge wire I need for 2/140w panels on a 35' run.

Thanks
Keith

[time2roll]

#10 if fine, or kill it with #8.

[CA_Traveler]

deleted - sorry about that

[CA_Traveler]

Will your controller support a second panel?

[CA_Traveler]

deleted

[CA_Traveler]

Assuming you're connecting the panels in parallel, the distance is 35' one way and PWM controller then 10ga would give you a 1.5V drop plus the additional drop to the battery.

You might want to consider a combiner box and then 8 ga to the controller. You should get more information if you post all of the details like controller type, all existing wiring lengths and gauge and panel specs.

[CA_Traveler]

Assuming you're connecting the panels in parallel, the distance is 35' one way and PWM controller then 10ga would give you a 1.5V drop plus the additional drop to the battery.

You might want to consider a combiner box and then 8 ga to the controller. You should get more information if you post all of the details - controller type, panel specs and all involved wiring lengths and existing wire size.

[BFL13]

The "run" is the one-way distance? Panels in series 9a, 44V; in parallel 18a, 22v

This calculator uses the one-way distance so it is easy to use

http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=2.061&voltage=12&pha...