# 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.

PWM solar watts
W

Recommended max solar input voltage

To maximize PWM efficiency, use the following guideline:

• 12V battery: max 19V input voltage
• 24V battery: max 36V input voltage

### Calculating the power a Charge controller can handle

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.

### How many watts can a 20 amp solar charge controller handle?

• 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.

### How many watts can a 30 amp PWM charge controller handle?

• 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.

### How many watts can a 40 amp PWM charge controller handle?

• 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.

### How many watts can a 60 amp PWM charge controller handle?

• 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.
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