How To Charge 12V Battery With 24V Solar Panel

Can you charge a 12V battery using a 24V solar panel?

Yes, you can!

The concern doesn’t rely on the voltage; it’s the current that the solar panels can provide.

This short article will talk about the 3 simple ways to charge a 12V battery using a 24V solar panel.

Let’s jump into it!

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Try These 3 Methods

Method #1: Solar Charge Controller

The most appropriate way of charging a 12V battery using a 24V solar panel is with a solar charge controller. All you do is connect one end of the controller to the 12V battery and then connect the other end to the 24V solar panel.

The charge controller monitors the battery using pulse width modulation (PWM). This will help regulate the voltage so that the voltage doesn’t cross the safety limit of the battery. You can leave this setup connected forever, and no damage will be done to the battery.

Method #2: Direct Connection

Directly connecting a solar panel to a battery is more of a DIY method, as it can be bad for the battery due to overcharging. All batteries have a specific Amp-hour rating—usually 20 to 100 hours.

For example, suppose you have a 300 Amp-hour battery. In that case, it can supply a continuous current flow of 30 Amps for 10 hours, 15 Amps for 20 hours, 60 Amps for 5 hours, or however you would like to set it up—as long as the current multiplied by the hours is equal to the Amp-hour rating on the battery.

Method #3: MPPT

A maximum power point tracker (MPPT) is an auto-adjusting DC-to-DC converter that runs the PV module at an optimal power level, down-converts the Voltage, and finally, charges the 12V battery.

For example, if you have a 200-Watt module. The Voltage at maximum power should be around 36 Volts, and the maximum current would be around:

200 Watts / 36 Volts = 5.56 Amps

If you wire that module to a 12V battery, it will charge that battery at around 8.3 Amps and pull that Voltage down to what the battery can handle. For example, if the battery is pulled up to 14.7 Volts, you will charge at:

14.7 Volts x 5.56 Amps = 81.7 Watts

This means that you have just lost about 60% of your initial power. That’s where MPPT controllers kick in. MPPTs are great for retaining power from all of the energy that will be lost because the module is constant current, and you’re doing the work at too low of a Voltage.

Learn to size your MPPT controller

Ying Xu

Graduated from the University of Kansas with an Aerospace Engineering degree & served 4 years as an US Air Force officer. Experienced with basic survival skills, weapon system security,  technical disaster recovery, and system troubleshooting

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