Can a truck inverter charge your RV batteries? Many modern pickup trucks now include a built-in 120-volt inverter in the bed, leading many RV owners to wonder whether they can use that power to charge their RV batteries while driving.
In this edition of Todd’s Two Minute Tech Tip Tuesday, Todd answers that question and explains why, although it’s an interesting idea, it may not be the safest or most practical solution.
The Idea Behind Using Your Truck’s Inverter
Many newer trucks include a factory-installed inverter that provides 120-volt AC power through an outlet in the truck bed.
The thought process is simple:
- The truck’s alternator supplies power.
- The inverter converts that power into 120-volt AC.
- The RV’s converter could then convert that power back into 12-volt DC to charge the batteries.
While the concept sounds reasonable, Todd points out several important considerations before attempting something like this.
Safety Comes First
One of the biggest concerns is safely delivering 120-volt AC power from the truck to the trailer while traveling down the road.
Todd explains that traditional connections between a tow vehicle and an RV are designed to carry 12-volt DC power, not 120-volt AC power.
Creating a removable connection that safely carries household voltage while driving introduces additional safety concerns that should not be overlooked.
Is It Worth the Effort?
Can a truck inverter charge RV batteries?
Even if the wiring challenges could be solved, Todd questions whether the added complexity is worthwhile.
Many RV converters are not isolated for this type of setup, meaning additional equipment or modifications could be required before the system would function as intended.
As Todd puts it:
“I don’t know that the juice is worth the squeeze.”
Better Ways to Charge Your RV Batteries
Instead of relying on the truck’s inverter, Todd recommends alternatives that are better suited for charging RV batteries.
If your RV is equipped with an onboard generator, running the generator while traveling can allow the converter to properly charge the batteries.
Another option is installing a DC-to-DC charger in the trailer. Combined with upgraded wiring and an appropriate connector between the truck and trailer, this approach is designed specifically for charging batteries while towing.
A Second Viewer Question: Why Are Only Some RV Systems Working?
Todd also answers a troubleshooting question from an RV owner experiencing an unusual electrical issue.
Some 12-volt systems—including the slide, stairs, and landing gear—had stopped working, while other components continued operating normally.
The RV owner had already inspected the converter’s fuses, but the problem remained.
Understanding Reverse Polarity Fuses
Todd explains that the fuses located on many RV converters are reverse polarity fuses.
These fuses are designed to protect the converter if the battery cables are accidentally connected backward during installation.
If those fuses are intact, the problem likely lies elsewhere.
Check the Converter Output
Rather than assuming the converter has failed, Todd recommends verifying its output with a multimeter.
With the RV connected to shore power:
- Place the multimeter on DC volts.
- Measure the converter’s output terminals.
- A properly operating converter should produce about 13 volts.
- Then check the battery voltage for comparison.
If the converter is not producing approximately 13 volts while connected to shore power, additional troubleshooting will be necessary.
Start With the Basics
Electrical problems can sometimes appear complicated, but Todd encourages RV owners to start with the fundamentals.
Check:
- The converter breaker
- Converter output voltage
- Battery voltage
- Overall charging system
Working through these basic tests can help narrow down the source of the problem before replacing expensive components.
Learn RV Electrical Systems Hands-On
Questions like these are exactly the type of real-world troubleshooting discussed during classes at the National RV Training Academy (NRVTA).
Whether you’re maintaining your own RV or looking to better understand RV electrical systems, hands-on training can give you the confidence to diagnose problems safely and correctly.
Final Thoughts
Using your truck’s built-in inverter to charge your RV batteries is certainly an interesting idea, but according to Todd, it isn’t the safest or most practical solution.
Purpose-built charging methods, such as an onboard generator or a DC-to-DC charger, are generally better suited for keeping your RV batteries charged while traveling.
When troubleshooting electrical issues, always begin with the basics, verify voltages, and work through the system methodically.
Sometimes the simplest tests provide the biggest answers.