If you're dealing with a dead house battery in your RV, you’re not alone. This week, Todd addresses a common question about charging the house batteries while driving. Let's dive into the issue and explore some potential solutions.
The Problem
A user recently experienced a dead house battery—specifically a 230-amp hour lithium battery—after arriving at a campsite. To get their generator running, they had to jump it using the cab (starter) battery. Here's the catch: The manufacturer advised them that the alternator does not charge the house batteries, but others on Facebook said otherwise.
Can Your Alternator Charge the House Batteries?
In most motorhomes, the alternator does charge the house batteries while you drive. Typically, manufacturers use one of two mechanisms to enable this:
- A Solenoid – Operates by key activation, allowing current to flow from the alternator to the batteries.
- Battery Isolation Manager (BIM) – Acts as a relay that manages charging between the starter and house batteries.
While this OEM claims the alternator doesn’t charge the house batteries in this model, many owners report otherwise. If your alternator isn’t charging the house battery while driving, there may be a disconnect between the coach and starter batteries.
What to Check
1. Relay or Solenoid
- If your alternator is supposed to charge the house battery, the problem may lie in a faulty relay or solenoid. Ensure the solenoid is positioned correctly to allow power flow.
2. Blown Fuse
- Locate the fuse that connects the starter battery to the house batteries. A blown fuse could interrupt the charging process. Look for the red wires coming off your coach battery's positive terminal. One of those wires should connect to your starter battery, passing through a fuse or relay. If the fuse is blown, replacing it may solve the issue.
3. Corroded Connections
- Check the wiring for any signs of corrosion. A corroded wire could be preventing the alternator from charging your house battery. Ensure all connections are clean and secure.
Next Steps
If troubleshooting isn’t your forte, or if you’d rather not follow the wires yourself, it might be best to get a qualified RV technician to take a look. They can inspect for blown fuses, malfunctioning solenoids, or corroded connections to ensure your house battery charges as it should while driving. Visit www.rvtaa.org/locate to find one near you.