How to Solar Power a 12V Fridge

In this tutorial, I’ll show you step by step how to solar power a 12V fridge.

In fact, these are the exact steps I used to create my own solar powered mini fridge.

The good news is solar powering a fridge isn’t too hard. I’ll cover all the parts you need, as well as some tips on what size solar panel, battery, and charge controller to get.

Let’s get started.

Parts & Tools

Note: The parts linked above are sized for a 12V solar array of 400 watts or less. Feel free to copy this parts list as is or use the tips in the sizing sections below to pick your own.

Step 1: Understand the Wiring Diagram

Here’s the wiring diagram I’ll be using to solar power my fridge:

And here are the main things to understand about it:

  • Power the fridge off the 12V battery. You can’t power a 12V fridge directly with a solar panel. Instead, you need to store the solar energy in a 12V battery and power the fridge off of that.
  • Connect the battery and solar panel to a solar charge controller. You’ll damage your battery if you connect your solar panel directly to it. The battery needs to be connected to the solar panel via a solar charge controller, which regulates the voltage and current output by your solar panels to safely charge the battery.
  • Protect your setup with a fuse between each connection. Safety best practices are to place a fuse on the positive wires between the battery and charge controller, and between the battery and the fridge. In some cases, you may also need to place inline solar fuses between the solar panels and charge controller. Refer to this video for guidance on whether or not you need to place fuses there.
  • Make sure all your equipment is rated for 12 volts. If you follow this wiring diagram, make sure you’re using a 12V fridge, 12V battery, and 12V solar panel. Your charge controller should also be compatible with 12V systems.
  • If you’re using a PWM charge controller with multiple solar panels, wire the solar panels in parallel. Wiring solar panels in parallel sums their currents while keeping the voltage the same. Parallel wiring is what I recommend when using a PWM charge controller. If you’re using an MPPT charge controller, I’d recommend wiring your solar panels in series.

With all that out of the way, it’s time to start building.

Step 2: Connect the Charge Controller & 12V Socket to the Battery

Connect the positive battery cable and fuse cable to the ANL fuse. Use a wrench or ratchet to tighten the bolts.

Now we’re ready to connect the charge controller and 12V socket to the battery.

Locate the battery terminals on the charge controller. They’ll usually be labeled with a battery icon or the word “BAT” or “BATT.”

On my charge controller, the positive battery terminal is labelled “BAT+” and the negative battery terminal is labeled “BAT-.”

Connect the positive battery cable to the charge controller’s positive battery terminal, and the negative battery cable to the charge controller’s negative battery terminal. For most charge controllers, you need a screwdriver to do this. Open the correct charge controller terminal with your screwdriver, insert the stripped end of your battery cable, then screw the terminal shut.

At this point, your battery cables are properly fused and your charge controller is now ready to be connected to your battery. We’ll connect both the charge controller and 12V socket to the battery at the same time.

Connect the positive battery cable and positive 12V socket wire to the positive battery terminal.

Connect the negative battery cable and negative 12V socket wire to the negative battery terminal. There may be a small spark when you touch the battery cable to the terminal. This is normal.

Your charge controller is now connected to your battery, so it should power on.

Confirm that your charge controller is now powered on. If it has a screen, the screen will turn on and start displaying system specs such as battery voltage. If it doesn’t have a screen, it should have LED indicators that light up or start flashing.

Select your battery type on your charge controller following the instructions in the controller’s manual. I’m using a lithium iron phosphate (LiFePO4) battery, so I selected that option on my controller.

Your charge controller and battery are now properly connected! Here’s what my setup looked like at this point:

Step 3: Connect the 12V Fridge to the Battery

Connect the fridge’s 12V power cord. In case you’re wondering, I’m using the BougeRV 12V 30 Quart Portable Fridge.

Plug the fridge into the 12V socket that you connected to the battery.

Confirm that your fridge is now powered on. This means your fridge is now successfully connected to your battery.

Here’s what my setup looked like at this point:

All we have left to do now is connect the solar panel.

Step 4: Connect the Solar Panel to the Charge Controller

Locate the solar terminals on your charge controller. They’ll usually be labeled with a solar panel icon or the word “PV.” (PV stands for photovoltaic module, which is another term for a solar panel.)

On my charge controller, the positive solar terminal is labeled “PV+” and the negative solar terminal is labeled “PV-.”

Cover your solar panel(s) with a towel, or flip them face down to reduce the risk of electrical shock.

If you’re using multiple solar panels, wire your solar panels in parallel using branch connectors. For this tutorial, I’m using only one panel. But here’s what it’d look like if you were to wire 2 panels in parallel.

Connect the positive and negative solar panel cables to the solar adapter cables. Once you do, make sure the exposed wire ends don’t touch.

Connect the positive solar cable to the positive solar terminal on the charge controller. Connect the negative solar cable to the negative solar terminal on the charge controller. Once again, use your screwdriver to do this.

Uncover or flip over solar panel and place it outside in direct sunlight. My deck had a lot of shade because of nearby trees, but I found a spot that was mostly sunny.

Confirm that the solar panel is now charging the battery. If your charge controller has a screen, it may indicate charging is happening with a battery charging icon. If not, navigate to the PV current screen and you should see a positive number. If your charge controller doesn’t have a screen, it should somehow indicate charging with its LED lights.

I went to the PV current screen to confirm. It showed a current of 0.6 amps. That means my solar panel is charging my battery at a rate of 0.6 amps. (The current is low for a 100 watt solar panel due to the shading on my panel.)

That’s it! You now you have a solar powered 12V fridge. The solar panel safely charges the battery via the charge controller. And the 12V fridge runs directly off the 12V battery.

Here’s a picture of my final setup:

How Many Solar Panels Do I Need to Run a 12V Fridge?

Most people will need 200 to 400 watts of solar panels to run a 12V mini fridge.

To build a solar array of this size, it’d be easiest to buy either two to four 100W 12V solar panels or one to two 200W 12V solar panels.

You connect multiple solar panels together by wiring them in series or parallel. I recommend parallel wiring if using a PWM charge controller and series wiring if using an MPPT charge controller.

What Size Battery Do I Need to Run a 12V Fridge?

A battery bank with 100-200 amp hours of usable capacity is a good size for running most small 12V fridges. (This is assuming you’re using your battery bank to power your fridge only.)

That size should give most people 2-4 days of runtime off the battery bank alone. Combined with a properly sized solar array, it should be enough to run your 12V fridge for 24 hours a day.

If using lithium batteries, get one to two 100Ah 12V LiFePO4 batteries or one 200Ah 12V LiFePO4 battery. In general, I recommend using lithium batteries in DIY solar power systems.

If using lead acid batteries, get two to four 100Ah 12V lead acid batteries or one to two 200Ah 12V lead acid batteries. A lead acid battery bank needs to have double the amp hours because lead acid batteries have only 50% usable capacity.

For this project, I recommend connecting multiple batteries together by wiring them in parallel. This keeps your battery bank voltage at 12 volts while expanding its amp hour capacity.

Note: There are a lot of variables at play here which may affect the right battery size for your setup. 12V fridges vary greatly in how much power they use based on their size, insulation, and whether or not they have a freezer compartment. Factors like ambient temperature and how often you open the fridge also affect power usage. If you find your battery bank dying often, that’s a good sign you should expand it.

What Size Charge Controller Do I Need?

Two popular 30A PWM charge controllers

For most people, a 30A PWM charge controller — such as the Renogy Wanderer 30A or Renogy Adventurer 30A — is a good pick if you just need to solar power a 12V fridge using the setup in this tutorial.

30A charge controllers are usually rated to handle up to 400 watts of solar power when installed in 12V systems. If your solar array is larger than 400 watts or you’d rather connect your solar panels in series, I’d recommend an MPPT charge controller.

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Alex Beale
Alex Beale
Hi, I'm Alex. I’m a DIY solar power enthusiast on a journey to learn how to solar power anything. Footprint Hero is where I’m sharing what I learn – as well as the (many) mistakes I’m making along the way.