chassis alternator not charging coach batteries

On our coach that solenoid is activated by the ignition switch OR the aux start switch - just like you are talking about doing. As long as the alternator will provide the additional current, I see no reason not to. Are you sure your's isn't supposed to be doing that already? On our coach we have replaced that solenoid several times. The main indication of failure is the loss of house battery charging from the alternator.

This sounds like a failure of the Intel brain box that controls the large solenoid the connects the two systems.

TomandCandy wrote:
after trying to find the connection between the engine batteries and coach batteries I thought what if I hooked up a wire to the emergency start solenoid to the ignition the key? whats your thoughts this is on a 1996 coachman catalina spartan chassis with the cummins engine called spartan they were no help waiting on coachman return thanks for any idea info Tom

there will be a 12V solenoid or relay somewhere that's key activated
in the mean time just run a + wire from coach to chassis batterys

+ means positive post to positive post
simple and effective

Tom,

Very likely your "emergency start solenoid" is NOT, repeat NOT a constant duty solenoid.

Suggest you determine whether you have a SOLENOID-BASED or DIODE-BASED battery isolator.

Then we can give you diagnostic and "work around" help.

Tom/Barb wrote:
This sounds like a failure of the Intel brain box that controls the large solenoid the connects the two systems.

More likely the solenoid itself.
I've had them go bad on the last 2 RVs I've had.
The last one called it a "battery isolator" relay.

wolfe10 wrote:
Tom,

Very likely your "emergency start solenoid" is NOT, repeat NOT a constant duty solenoid.

Suggest you determine whether you have a SOLENOID-BASED or DIODE-BASED battery isolator.

Then we can give you diagnostic and "work around" help.

Thats the problem I can't find it so not sure but the emergency solenoid is a Cole Hersee 12 v grounded continous duty 80 amp Tom

Follow the large-gauge wire from the alternator B+ terminal. It WILL lead to your isolator.