Solar Panels: What Size of Charge Controller Do I Need?

Find out which charge controller size you need for your solar panel system.

Solar Panels Jeremy Bezanger / Unsplash

Last Updated: September 10, 2021

Written by Brandon Jones

Charge Controller Size

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Below is a table showing which size of charge controller you should get based on the power rating and the number of solar panels in your array.

For example, if you have two solar panels creating up to 250 watts of power, you should get a charge controller capable of handling at least 20 amps.

Charge Controller Size
Charge ControllerMax PowerNumber of Panels
20 amp 250 watt 2
40 amp 300 watt 3
40 amp 450 watt 4
60 amp 600 watt 6

To help buy new solar equipment, check out the Recommended Solar Equipment (TR) section below.

Learn more about setting up a solar panel system in my Simple Solar Panel System - Setup & Equipment Guide (TR).

Answers to Your Other Solar Panel System Questions

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Be sure to check out the articles in our solar panel series to help answer your other questions:

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Here's our list of recommended equipment for the most common solar power systems.

Charge Controllers

Charge controllers are used to regulate the voltage and current coming from the solar panels to prevent overcharging your battery.

Power Inverters

Power inverters are used for converting the battery's power (DC - direct current) into electricity used for powering your devices (AC - alternating current). Power inverters have an outlet on the device.

Batteries

Batteries are used for storing the energy produced by your solar panels. The battery is wired between your power inverter and the charge controller. Never connect your power inverter and the charge controller directly without a battery between the two.

100W Solar Panel

Solar panels are made of many solar cells (photovoltaic cells), most often made from crystalline silicon. These cells take in energy from the sun's rays, converted through the semiconductor, creating an electric field that transfers voltage and current. Solar panels connect to the charge controller to regulate the voltage and current produced by the panel.

Solar Power System Cables

Fuses

Fuses protect the wiring and devices from overcurrent. Fuses usually go on the closest point of the positive connection from your battery to the power inverter. You can also put fuses elsewhere in your system for protection, like an MC4 fuse for going between your solar panel and charge controller. You can find MC4 Fuses on Amazon (affiliate link).

Branch Connectors

Branch connectors are for merging the cables coming from multiple solar panels to your charge controller.