Running Your RV Refrigerator Down The Road

Welcome to another Todd’s Two-Minute Tech Tip Tuesday, brought to you by the National RV Training Academy, the largest hands-on RV training facility in America. Today’s question comes from “RVing with Bandit,” and it’s all about how to power your RV fridge without using propane while driving down the road. Let’s dive into the details and see if it’s possible to make your fridge run purely on battery power without running your generator.

The Question: Can You Power Your RV Fridge Using an Inverter Without Draining the Battery?

RVing with Bandit has a Class A RV equipped with:

• A 1,200-watt inverter.
• A 280 amp-hour lithium battery.
• A 30-amp DC to DC charger connected to the coach’s alternator.
• No additional solar power.

Bandit wants to avoid running the generator during long drives and is curious if the inverter can power the fridge for 6 to 10 hours on a drive, using only the lithium battery and the alternator’s charge.

Step 1: Is It a Good Idea to Use the Inverter for Your Fridge?

Yes! It’s perfectly fine to connect your inverter to your fridge. In fact, many RV manufacturers wire their inverters to power essential kitchen appliances, including the fridge. However, this does require some technical rewiring, which might need a qualified technician depending on your electrical skills. But the simple answer is, yes, you can run your fridge off the inverter.

Step 2: Will the DC-to-DC Charger Provide Enough Power?

Now, let’s look at the math to determine if your setup will work.

You have a 280 amp-hour lithium battery. In practice, you can probably use 250 amp-hours of that without fully draining the battery. If we multiply that by 12 volts, you’ll have roughly 3,000 watt-hours (250 x 12 = 3,000 watts). Let’s use 2,800 watts as a conservative estimate.

Next, we need to consider how much power your fridge will consume. Depending on the size and type of your fridge, power consumption can range from 300 to 500 watts. To be safe, let’s assume your fridge consumes the higher end of 500 watts per hour.

• 2,800 watts ÷ 500 watts/hour = 5 to 6 hours of runtime, assuming no other power sources or loads are present.

Step 3: Factoring in the DC-to-DC Charger

You also have a 30-amp DC-to-DC charger connected to your coach’s alternator. This charger will supply additional power to your lithium battery as you drive, helping to extend the runtime of your inverter.

• 30 amps x 12 volts = 360 watts per hour.

This means your charger will be adding 360 watts/hour to your battery. Assuming your fridge consumes 500 watts/hour, the charger will be covering about 70% of that, leaving your battery to provide the remaining 140 watts/hour.

With these numbers in mind, your battery should now last around 8 to 10 hours instead of just 5 to 6. However, keep in mind that other factors, like running the dash AC or other appliances, could reduce the power available from your alternator.

Step 4: Tips to Extend Your Fridge’s Cooling Time

Here’s a handy tip to help your fridge maintain its temperature for longer while reducing its power consumption. Place frozen items from your freezer into the fridge before starting your drive. This creates a thermal buffer, which helps the fridge stay cooler longer without the compressor kicking in as frequently.

Frozen meats or ice packs can absorb some of the heat inside the fridge, slowing down the warming process. This trick reduces the number of compressor cycles, giving your fridge more cooling power without consuming extra battery life.

Conclusion: Yes, You Can Power Your Fridge Using the Inverter!

To sum it all up:

• Yes, you can power your fridge using your inverter.
• Your 30-amp DC-to-DC charger should provide enough additional power to keep things running for 6 to 10 hours.
• Keep in mind other factors like alternator load from running your AC and other devices.
• Using frozen items in your fridge can help extend its cooling time during long drives.

As always, if you’re not comfortable doing the electrical work yourself, it’s best to consult with a qualified technician to ensure the wiring is done safely and efficiently.

Got more questions? Drop them in the comments below, and I’ll be happy to help you out in my next Tech Tip Tuesday. And don’t forget—if you appreciate all this free advice, go ahead and hit that subscribe button so you don’t miss out on future tips!

Stay safe, and happy RVing!