How Many Watts can a 20-60 amp PWM Charge Controller Handle?

The following calculator will tell you how many watts of solar you can have with your 20, 30, 40, or even 60 Amp PWM solar charge controller.

We will use the following formula to know the amount of watts a PWM charge controller can handle.

Charging current * Charging battery voltage = Max Solar power input (Watts)

Charing current: the current written on your charge controller
Charging battery voltage: for a lead acid battery, this is 12.6V for a 12V battery. For a 24V battery, this is 25.2V. For a LiFePO4 battery, this is 14V for a 12V battery and 28V for a 24V battery.

You can also oversize your solar charge controller for those cold sunny days. Your solar panels can produce more power than they are rated for.

A 20A PWM charge controller with a 12V battery can handle 250W of solar. If you have a 24V battery, the PWM charge controller can handle double that, 500W.

A 30A PWM charge controller with a 12V battery can handle 378W of solar. If you have a 24V battery, the PWM charge controller can handle double that, 756W.

A 40A PWM charge controller with a 12V battery can handle 504W of solar. If you have a 24V battery, the PWM charge controller can handle double that, 1008W.

A 60A PWM charge controller with a 12V battery can handle 756W of solar. If you have a 24V battery, the PWM charge controller can handle double that, 1512W.

Off-Grid Solar Power Simplified

Seeing there was a high demand for a simplified guide to off-grid solar power, I decided to write a book about it.

I guarantee this guide will save you $100s on buying the right components by having a good design and sizing.

You can get the book for a reasonable price on amazon

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I’m an off-grid enthusiast. I created this website to give clear and straight-to-the-point advice about solar power. I’m also the author of the book ‘Off-grid solar power simplified‘. Read more about me on my about page, check out my Youtube channel, or send me a message.