When shore power is not charging your house batteries, it can put a real drain on your camping experience. So, what should you do if you experience battery drain and shore power is not keeping your battery system charged? The solution is usually fairly simple and can be checked while at the campsite.
The most common reasons that shore power is not charging house batteries is a weak battery connection, the battery disconnect switch being turned off, or bad battery life.
This post will run you through the 3 steps quick steps to troubleshoot the issue, including:
- Inspecting the battery terminal
- Checking the battery disconnect switch
- How to quickly test the battery life
Whether you have an RV, travel trailer, or camper, these simple steps will guide you through getting the battery power you need and staying charged.
Table of Contents
As we dive into the steps, let’s first review how shore power should work properly to keep your batteries charged.
Shore Power
When you are connected to shore power, your house batteries should be charging. When all is working correctly, your shore power provides 120v ac power. This ac power is used for your camper receptacles to plug in any household appliance like a coffee maker.
This works very similarly to your house where you have ac voltage coming in by wires to an electrical panel. That electrical panel has circuit breakers that distribute the power throughout the house.
However, your RV is different because it also has many appliances and lights that use dc power from a battery to operate. And your RV is designed to convert that ac power to dc power so your batteries are always fully charged.
Visit my post on what runs on a battery in your travel trailer if you want to see the complete list of appliances and devices that need this battery power.
Converter
A converter is basically an RV battery charger. You will need an RV converter to change ac power to dc power. The good news is that all RVs and campers come with one, and it is usually seamless to charge your house batteries as long as you are plugged into shore power.
Your RV converter is basically a battery charger. Very similar to the battery chargers you see at the hardware or auto part store, where you plug in one end into a house receptacle, and the other end has two jumper cable ends connected directly to the battery. If you took a multimeter to those jumper cable ends, you would get a dc voltage reading anywhere from 13 to 14 volts. Even though your battery is 12 volts, the higher voltage difference gives the battery a charge.
Now, let’s use the simple concept of the battery charger to help troubleshoot why you are not getting your RV battery charged. For example, what would happen if you didn’t connect one of the jumper cables to the battery terminal? The battery wouldn’t charge…right? That’s because both the positive and negative battery posts need to be connected for the voltage to reach the battery. Or, another example is, what if you plugged in and connected everything just right, but there was a break in one of the wires? I think we can agree that it would not charge.
Your camper battery is no different in what it needs to charge properly. It needs to be plugged into ac power, with no breaks in the line, and a good connection to the battery. Any issue with those steps will cause the battery not to charge even though it is plugged into shore power.
Troubleshoot
Now that we have simplified the battery charging system let’s examine why your shore power is not charging your house batteries.
Battery Connection
The number one reason that a camper battery does not charge is a bad battery connection. Without a good connection, that voltage from the converter doesn’t reach the battery to charge it.
Here are a few steps you can do to check the battery connection:
Step 1: Clean the Battery Terminal
With the chemical process and sulfation of the battery, you can get corrosion on the battery terminal. If the corrosion is bad enough, it cause a gap between that metal connection you need for the voltage to flow.
If you notice any corrosion, disconnect the battery cables from the battery and clean the terminals with a wire brush or sandpaper. You want a bright, shiny metal surface on the battery terminal and cable connection.
Step 2: Check Battery Disconnect Switch
Next, check your battery disconnect switch. This battery switch is usually provided in new RVs and allows you to easily disconnect the battery when not in use to avoid unwanted battery drain. It acts as a battery isolator to separate the battery connection from the RV. Kind of like an inline fuse or breaker that disconnects the wire every time you turn the switch. And if you forget that the switch is in the off position, it is like a blown fuse, and you will not get a connection to charge the battery.
Sometimes, and this has happened to me a couple of times, the switch was turned off while connected to shore power. In those cases, what happened was that I turned on my disconnect switch, and everything was ok!
Also, please take a look at the disconnect switch itself. Sometimes these have issues and need to be repaired themselves. If you suspect a bad battery switch, visit my post on battery disconnect switch problems. There we go more in-depth on diagnosing the issues with a battery disconnect switch.
Battery
The second most common reason for house batteries not charging is the battery itself. A camper battery is usually a Deep Cycle battery. This is because, unlike a starter battery to start an engine that is designed to give just a burst of power, the deep cycle battery is designed to give consistent and deep power until it drains completely down. Whether you have a traditional lead acid or AGM battery, it is still considered a deep-cycle battery. Even the new lighter lithium battery is still a deep cycle battery.
And deep cycle batteries (like all batteries) have a battery life. Here is a quick snapshot of what you can expect on battery life by type of battery.
Deep Cycle Battery Life
- Lead Acid Battery – 3 to 4 years
- AGM Battery – 5 to 7 years
- Lithium Battery – up to 10 years
As you can see, there is a range. And depending on your battery, it may be as simple as a dead battery and need a new one. Here is a quick step on how to check your battery.
Step 3: Battery Test
The easiest way to test your battery is to remove it from your camper and charge it on a separate battery charger you know works. Make all of your connections and let that battery charge for at least 24 hours.
After 24 hours, disconnect from your battery charger and let the battery sit for an hour. This allows the charge to settle so you get a more accurate reading. If you have a multimeter, check your voltage. You should get a battery voltage reading anywhere from 12.5 to 13 volts. If not, then the battery may be dead.
If you don’t have a multimeter, reconnect the battery to your RV and see if the battery is functioning as fully charged. The water pump and lights should work great if the battery is fully charged.
If you are still not getting a good charge, you can always take it to an auto store for testing. They usually offer free testing (hoping you will buy a battery from them). Their testing is better than just a multimeter because they load the battery to see how it behaves, giving you a more accurate reading of its condition. If the battery is dead, replace it with a new one and see if that helps your shore power.
Final Thoughts
Shore power is vital for keeping RV house batteries charged. It provides 120v AC power to the camper receptacles, while a converter ensures the batteries are fully charged by converting AC power to DC power. Troubleshooting issues with the RV battery charger not working involves checking for a good battery connection and inspecting the battery’s condition. Corrosion on the battery terminal or a faulty disconnect switch can disrupt the charging process, and if the battery itself cannot hold a charge, it may need replacement.
Tony is an avid camper and RV traveler. He fell in love with camping on his first RV trip with his wife over 25 years ago. Tony loves sharing lessons learned and tips about RV maintenance and safe traveling.