Charging the coach battery

deltamaster wrote:
I have a 2004 Four Winds Fun Mover Class "C" built on a Ford E-450 cutaway van chassis.

Recently I have noticed that it appears the coach battery is not charging when the chassis engine is running.

I have checked the circuit and found there is a cable from the engine battery that goes to a relay. Then the cable goes to the coach battery.

The relay activation circuit is energized in two ways. One is through the emergency start switch on the dash which energizes the relay. The other goes through a small electronic control and then to the ignition circuit for when the key is in the "on" position.

When the emergency start switch is depressed the power from the engine battery is sent to the coach battery and back so that power is shared between the two batteries.

When the ignition switch is turned on I can hear the relay click on but there is no power on the coach battery side of the relay. It is not until the engine is started that power is present on the coach battery side of the relay.

Problem is that with the engine running it seems there is still insufficient power sent to the coach battery. The lights are dimer unless the emergency start switch is depressed.

Does anyone here have any information on how this circuit operates and give me some information on what might be the problem.

The relay looks like the ones used in golf carts that are open when not energized but closed when they are energized to allow current through them. My experience with them is that they are either open or closed and either supply all power or none.

Are these systems different in some way?