How To Troubleshoot RV Batteries and Trailer Lights

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An RV without a battery is…well, it’s still an RV, but with fewer amenities than you’d want. RV batteries keep your unit’s electrical features functioning properly, so it’s important to keep your battery in optimal condition.

So let’s highlight a few ways to safely ensure your battery is operating at capacity, from troubleshooting to charging. 

Where is Your RV Battery?

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Depending on your RV type, your battery (or batteries) will be located in different areas. Here’s a quick breakdown of general locations, but remember this may vary slightly for different makes and models: 

On RVs: Inside the engine compartment, not to be confused with your engine battery.  Motorized RVs usually have two batteries (an engine battery and a house, or coach, battery). Consult your owner’s manual to differentiate the two.  On Travel Trailers and Small Campers: On the tongue near the propane cylinders.   On Fifth Wheels: In a battery compartment accessible by opening a door on the side or front of the unit.

How to Test your RV Battery

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If certain electrical systems on your RV aren’t functioning as expected, you’ll need to check your battery’s voltage. To do this, you’ll need a volt meter, and you’ll need to switch it to the Volts DC setting. 

Touch the meter’s red lead to the battery’s positive terminal and touch the black lead to the negative terminal. The meter’s display will read the battery’s current voltage. You want a reading over 12 volts and if the reading is below that, consider recharging or replacing your RV battery.

How to Test your RV’s Charging System

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If your battery is healthy but you’re still experiencing electrical issues, your next step is to test your charging system. In this case, we’re referring to your breaker panel as your charging system. 

To test it, you’ll need to start by removing the screws holding the panel cover in place. Remove the cover and set it aside. Using your volt meter, touch the black lead to the circuit board’s ground wire (which is either white, black, or green). 

Then, touch your red lead to the system’s positive cable. Once again, you should get a reading above 12 volts. If you do not, start by checking for blown fuses. Then verify that your 120-volt AC breaker for your converter hasn’t tripped and your coach’s 120-volt AC power is working properly. 

From there, your system may require further inspection by a trained RV service technician.

Tips for Keeping RV Batteries Charged

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When you aren’t using your RV, it’s important to keep your batteries fully charged. You have a couple options on this front: 

Plug your RV into 30 or 50-amp shore power once a month for about eight hours. When fully charged, disconnect the battery, remove it, and store it in a cool, dry place like your garage.  For extended storage, test and charge your batteries monthly. Clean battery terminals before storing, as well as periodically while in use. 

For lead acid batteries only, maintain the water level approximately ½” above the lead plates. Use only distilled water when refilling. 

Keeping your batteries charged is also something to think about when you’re in the middle of a camping trip. This is less of a concern if you’re plugged into shore power at luxury RV resorts, but it’s essential for those interested in boondocking or camping with minimal services. 

Here are a few tips to help you keep RV batteries charged while camping: 

Mount solar panels on your RV’s roof or set up portable panels when stationary.  Get a portable generator to run large appliances and recharge house batteries (if your RV doesn’t have a built-in generator) Use battery-powered or solar-powered lanterns and headlamps to minimize battery use. Consider switching to lithium-ion batteries for a longer-lasting and faster-charging power source. Minimize furnace usage by wearing extra layers or adding a few new camping blankets to your RV.  Connect the 7-pin cord and run your tow vehicle. It’s not the most efficient method but will recharge coach batteries in an emergency. 

Read more tips on how to conserve and create power when boondocking. 

Testing your Trailer’s Signal Lights

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It’s vital to test your trailer’s signal lights before hitting the road. You’ll need a spotter to do this easily, so this might be a good time to study the basics of guiding an RV. 

The first step to testing your signal lights is ensuring your 7-pin connector is securely attached to your tow vehicle’s electrical outlet. If it is and you’re experiencing issues with your lights, testing the 7-pin plug is your next step. 

Each pin in this plug is responsible for a different electrical aspect of your trailer. Here’s a quick graphic to explain: 

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And here’s the written breakdown, moving in a clockwise direction: 

Top right = battery power Middle right = Right turn signal and brake lights Bottom right = Brakes Bottom left = Ground Middle left = Left turn signal and brake lights Top left = Tail and running lights Middle pin = Reverse lights

These pins can be tested by setting your volt meter to volts DC, placing the black lead on the ground pin, and then placing the positive lead on the pin you want to test. If you’re having sweeping issues with your trailer’s signal lights, this test can help you hone in on which pins are holding a charge and which may need repair. 

Depending on your tow vehicle and 7-pin connector compatibility, you may need an adapter to ensure proper signal light functionality. 

Explore Camping World’s full selection of electrical connections to find what you need. 

A Note on Battery Safety

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Testing your RV batteries is certainly one of the RV maintenance tasks you can do yourself. But it should be cautiously approached, and you should be confident you know how to do so safely. 

If you’re uncomfortable performing any of these tests, your local Camping World Supercenter can help. Check out our state directory to find the location nearest you.  

If you need to replace your battery, learn more about RV, truck, and boat batteries to ensure you get a battery that’s right for your RV. 

Do you have any other tips for troubleshooting your RV batteries and lights? Share with your fellow readers in the comments below!