Charging a 24V Battery with 20V Solar Panel & PWM Charge Controller

We have done previous demos, showing the difference between a 20V (60 cell) and a 24V (72 cell) solar panel. What we want to show today is some real world usage of it; trying to use either of them to charge a 24V deep cycle battery bank.

A lot of people will call and say they’ve got a 60 cell solar panel and want to charge a 24 volt battery bank with it. Is this possible? Because when measuring it, they are getting say 38-39 volts out of it open circuit voltage, so shouldn’t that be plenty to charge a 24 volt battery bank? The problem is…heat. When it gets hot out, the voltage output of solar panels drops pretty dramatically.

See what happens when our Solar Queen attempts to charge a 24V battery with a 20V solar panel on a hot, summer day. And see how that compares to doing the same, using a 24V solar panel.

Can I charge a 24V battery with a 20V Solar Panel?

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.