RV Generator Repair: Fixing an Overcharged Generator

  • 1-3 hours
  • Beginner
  • 10-25
What You'll Need
Electrical wire
Wire nuts or electrical tape
What You'll Need
Electrical wire
Wire nuts or electrical tape

If you have batteries that are overcharging in your RV, a generator repair may be needed to correct the problem. Overcharging batteries used in your RV shortens their life and can cause them to lose power when you need them most. Troubleshooting a generator that is overcharging batteries can take some patience, but this how-to guide will walk you through the process of correcting common generator problems that lead to battery overcharging.

Step 1 - Check Charging Voltage of Battery

Use the multimeter to check the charging voltage of the battery. While the generator is running and charging the battery, place the leads of your multimeter on the terminals of the battery. The voltage of the battery when being charged should be between 12 and 13.5 volts and never be more than 13.8 volts. If the voltage is higher than this, than the generator is definitely overcharging the battery.

Step 2 - Check Generator Fuse Connections

When troubleshooting your generator, the first thing you should check are the fuse connections. If your generator has an in-line fuse, check the filament in the fuse to make sure it's not broken or worn. Also, if the generator has a dedicated fuse in the fuse panel box, check that fuse as well. If there are any corroded or broken filaments in the fuses, replace them as needed.

Step 3 - Check Generator for Loose Wiring and Connections

Open the wiring service panel for the generator and look for any loose wiring or connections. Inspect all of the connections carefully and look for any frayed or broken wiring. If you do find broken wiring, you can use a pair of wire cutters and wire strippers to clean up the wiring, and then use wire nuts to make the connections and ensure that their properly shielded.

Step 4 - Locate and Adjust Potentiometer

Many generators come equipped with a potentiometer that allows you to adjust the voltage level that is applied when charging a battery. A potentiometer is simply a dial that is used to adjust current. So, if your generator comes equipped with a potentiometer, try turning the potentiometer dial back or counterclockwise slightly, and then check the charging voltage on the battery again.

Step 5 - Check Battery Levels

Another common cause of overcharging in an RV generator is caused by low electrolyte or water levels in the batteries themselves. Therefore, you should frequently check the water levels in the batteries to ensure that they are not too low. If water is needed, fill the battery with water until it reaches the fill line.

Step 6 - Clean Battery Terminals

Take a wire brush and clean battery terminals that are charged with the RV generator. Sometimes, corrosion and rust may cause improper connections that can cause spikes in voltage used to charge the battery. Therefore, cleaning the terminals occasionally may help to solve overcharging problems.

Step 7 - Check Battery Voltage

Once you have performed the above steps, check the charging voltage on the battery again with the multimeter. If the generator is still overcharging the battery, you may want to consider taking your vehicle into a certified service center to have the generator looked at.