I recently got a MakeSkyBlue 60A MPPT charge controller, and it specifies that the maximum wire size it can accept for both the input and output is 9 AWG. I'm planning to connect three Trina 250W panels (Voc: 37.6V, Isc: 8.85A) in parallel because I can't use series connection due to voltage limitations from the controller. I found that for a 12V system, running at 60A with a 20ft distance, I should actually be using 4 AWG wire from the controller to the battery. Can anyone explain the best way to increase the wire size coming from this controller? Or if there's something I'm overlooking, I'd love to learn more!
2 Answers
Unfortunately, you can't really change the wire gauge from the charge controller since it's fixed. A common workaround is to consider switching to a higher battery voltage. If you double the battery voltage, you cut the current in half, which effectively reduces the wire size needed. That's why a lot of people opt for 24V or 48V systems.
Check the specifications carefully, as the correct data can change the situation. 9 AWG copper wire, if used properly, can handle approximately 47.5 amps according to US electrical code. It’s worth verifying how much current your charge controller actually delivers to a 12V system. If it's pushing that much, it might be time to reevaluate your setup.