If your RV or camper battery is not charging when plugged into shore power, there are several troubleshooting steps you can take before calling in an expensive professional.
In fact, the culprit is, more often than not, a blown fuse or corrosion on your battery connections.
But, sometimes, it can be more than that.
So, let’s take a quick walk through each troubleshooting step to get your camper battery charging again.
Troubleshooting House Batteries Not Charging
If shore power is not charging your house batteries but is providing power to your RV, then we can take a step-by-step approach to find the root cause, starting with the most obvious…
Is Your RV Converter Designed to Charge House Batteries?
First things first, and this may seem obvious to some, but does your camper or travel trailer battery charge when plugged in? In other words, is your converter designed to automatically charge the house batteries when plugged into shore power?
Most likely, it is. However, some older campers have converters that were not designed to charge batteries. And since every motorhome is different, you will need to refer to your owner’s manual for information specific to your vehicle. There might even be an owner’s manual for your converter.
If you don’t have your owner’s manual, contact your RV dealership or visit your RV manufacturer’s website to get a new copy.
All the troubleshooting in the world won’t help if your RV converter was not designed to charge your house batteries when plugged in, so this is step one. Once you’re certain it was designed for this purpose, we can move on.
Check the Wiring and Fuses
Important: Ensure your RV is unplugged from the 120v power source before continuing.
Locate your RV converter and do a visible check of all the wires coming out of the device. Look for any wires that are:
- Loose or damaged
- Melted or discolored
- Bare wires touching each other
If applicable, tighten any loose connections and/or replace any damaged wires and check if your RV batteries are charging again.
While we inspect the wires, look for any inline fuses that may have blown and, if applicable, replace them.
Tip: When replacing fuses, be sure to use the same amp fuse, as a higher amp fuse could cause overheating and a potential fire in your RV.
You’ll also want to check the wiring and fuses connecting to your RV batteries. Are any of these wires frayed, loose, discolored, or touching each other? Are there any blown inline fuses? If so, replace as necessary.
In complicated RV electrical systems, a wiring diagram may come in handy (though they can be hard, if not impossible, to find). Check to see if your owner’s manual or manufacturer website has one available.
If all the wiring and fuses check out, we can move on.
Check the Batteries for Corrosion
Next, we will want to check the battery terminals for noticeable corrosion and if the battery cables are tightly attached to the battery posts.
In my experience, this is one of the main reasons that house batteries stop charging when plugged in.
Of course, you’ll want to tighten any loose connections and clean off visible corrosion.
To clean corroded battery connections:
- Create a thick paste mixing two tablespoons of baking soda with two tablespoons of water.
- Disconnect the power and ground wires from the battery terminals.
- Scrub the terminals and wire connections using a wire brush and paste, removing the corrosion.
- Wipe the terminals clean with a paper towel
- Reconnect the power and ground wires to their respective battery terminal, ensuring a tight connection.
If your RV battery still won’t charge, we can move on.
Check the Breakers
Locate your RV’s fuse and breaker box. This panel is usually in the same compartment as your power converter.
You should notice breakers on the panel, similar to the breakers you have at home. Those breakers are for your RV’s 120-volt system. Check the breakers to see if any are tripped by physically touching them to ensure they’re in the proper position.
Tip: Refer to your owner’s manual or look for markings near the breakers themselves that identify what each circuit breaker is for.
In that same area, you may also notice your RV’s fuse box (they will look like the fuses in a car). Check these fuses to see if any are blown. If you find any burnt fuses, replace them and check if your RV batteries start charging again when plugged in.
If all the breakers are in the “on” position and fuses are good, we can move on to the next step.
Check the Battery Disconnect Switch
Many RV’s and 5th wheels come with a battery disconnect switch located somewhere in the vehicle itself. Check that this switch is in the “on” position.
You may have to again refer to your owner’s manual to check if your vehicle has a battery disconnect switch and where it’s located if it does.
Check the Battery Condition
Next, we want to make sure the problem isn’t with the battery itself. It could be that your RV’s charging system is working fine, but the battery won’t hold a charge.
Checking your RV battery is simple:
- Hook a battery charger up to your battery to charge it up. If you’re out on the road with no access to a battery charger, you may be able to use your RV or tow vehicle alternator to charge it (if your RV is set up to do that). See How to Charge an RV Battery From Vehicle While Driving for more information.
- Use the battery disconnect switch mentioned above to disconnect it from the system, basically isolating the batteries from the electrical system.
- Wait a few hours and then check the battery’s charge using a digital multimeter or voltage meter.
If the battery’s charge is noticeably draining in that short amount of time, you may have a bad battery. Replace the deep-cycle battery and test your RV charging system again.
If your battery checks out, then that leaves us with one final troubleshooting step.
Check the Converter
First, check if your power converter is indeed producing 13+ dc volts. You can do this by measuring the voltage at the battery while plugged into shore power.
- Using your voltage meter, you should see around 13.5 volts at the battery.
- Disconnect your RV from shore power and measure the battery again. This time you should see the voltage drop.
This quick test will tell you if your converter is working properly.
If it’s not, then you could be facing a cooling fan issue in the converter, a defective thermal sensor, a bad circuit board, etc.
It is not recommended that you open or tamper with the converter unless you are an RV Technician. Instead, take your vehicle to a certified RV technician and have the problem fixed.