Wiring Solar Charge Controllers in Parallel

What happens if you have a solar charge controller that is only big enough for the solar panels you’ve got – maybe one panel and a small charge controller or a whole array that’s maxed out – and you want to add more solar panels?

Well, all you need to do is wire a second charge controller in parallel in your DC load center, with each output of the charge controller going into the DC breaker box, or load panel. If both charge controllers are turned on, what’s happening is each charge controller is managing independently, sending it’s own current into the battery. So when both are turned on, you are getting the sum of the two because when you wire in parallel, amps increase, and the volts stay the same.

There are some charge controllers that will even allow you to connect the two charge controllers together and get even more advanced communication between them. In this particular demonstration, we are not doing that, and they’re still working together, doubling the current by having both charge controllers on and going in parallel to the battery.


About Author

Amy Beaudet
Amy Beaudet was in the solar industry at the altE Store from 2007 until her untimely passing in 2021. She was a sales rep, instructor, and an all-around solar evangelist, sharing her passion for solar around the world. When whe wasn't at work, she enjoyed sailing and skiing - but odds were good she was still talking about solar on the boat or on the slopes. See more of Amy Beaudet's blog posts.