Should I use an MPPT or PWM Charge Controller?

“I bought a 20 or 24V solar panel and want to use it to charge my 12V battery. What do I need to do?”


A question that we get all the time! The answer is…

You need an MPPT charge controller to reduce the voltage down to the right voltage, about 14V, to charge the battery, but also increase the current on the output. If you use a PWM charge controller, because watts (or power) equals volts times amps, if you drop the volts down to the right voltage for your battery bank, the volts are going to drop, the amps are going to say the same, and you’re going to lose about half of the power.

With an MPPT charge controller, it will drop the volts, but raise the amps, so you’re going to get more of that power from that solar panel to your battery.

altE’s Solar Queen demonstrates…


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.



    Very informative website


      I am an Electrical Engineer, working in TATA STEEL Ltd.(INDIA)
      I am interested to build up solar power project for domestic utility.

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