Chassis Battery Gauge issues

[dukenrock]

I just replaced all of my batteries in my 2002 American Eagle. 2-Chassis and 4-House. The gauge on the dash showing the chassis battery never gets over 13V and while running down the road, it will at random drop down well below 11V. I have to hit the AUX start button on the dash to get the voltage back up over 12.5 or so, then at random it will fall below 11V again. Also, after being plugged into 50A shore power for 2 days this week, the chassis batteries showed around 11V when I turned the ignition on. Not sure what is going on here......

[Gary RVRoamer]

I think you have two separate problems.

When driving the chassis batteries should be charged direct from the alternator. I would suspect your alternator is failing. A bad diode would give that sort of symptom.

When on shore power, there is a charge controller that monitors the state of charge and closes a relay as required to direct charging to the chassis batteries. The basic logic is that the chassis batteries must be below a voltage threshold and the house batteries above a certain threshold for this to happen. It could be the charge thresholds aren't being reached for some reason (unlikley with new batteries) or the charge controller is malfunctioning. On my '04, the controller is an Intellitec BCC device and a component failed on its circuit board, preventing charging of the chassis batteries. I think your '02 has a different type of controller, but the failure could be similar.

You could bypass the shore power charging problem by adding a Xantrex Echo Charge or a Trik-L-Charge. Either device will keep the chassis batteries charged while on shore power or generator.

[RJay]

Just to add to what Gary wrote, you might want to check the voltage regulator, it too could be bad. On some alternators the voltage regulator is in the alternator.

[dukenrock]

Gary,

Thanks for the quick reply. This has been driving me crazy! I suspected the alternator until I realized that the shore power wasn't charging it either, but now your explanation makes sense. I'll start with the alternator first and see where that takes me. This brings me to another question...

Should I tackle the alternator myself? (Haven;t looked at what it will take to pull it out) I recently had a starter go bad. If I recall, Cummins wanted $1,200.00 to fix it. I pulled it out myself and had it repaired for under $100.00. I can take the alternator to the same shop if it's as easy as the starter was.

[dukenrock]

Thanks RJay.. will do.

Originally Posted by RJay

Just to add to what Gary wrote, you might want to check the voltage regulator, it too could be bad. On some alternators the voltage regulator is in the alternator.