Ford Starting /House Charging Question UPDATE Test

I am confused about start relay and charge relay, and start and run, and my apparently one solenoid. I will do some research to see if I can then understand the replies above. Also poke around with the voltmeter. T ! :)

Hi BFL13,

There are two relays.

In my E-450 the "house" solenoid is below the battery. It is fed from a 60 amp fuse in the "engine" fuse box. I replaced the fuse with a 40 amp automatic circuit breaker, after the 3rd one failed. I added a second charging path fed from the starter battery, also with a 40 amp automatic breaker.

Each path has its own 200 amp continuous duty solenoid to which I added switches to allow me to manually control the flow of power.

They are, unfortunately still controlled by the ignition switch. But I can do a sort of "poor man's" boost from the house batteries.

I added a trik-l-start to keep the "engine starting battery" charged from the solar panel.

Ford start relay has NOTHING TO DO WITH battery charging
Chassis or house
In your case, The charge relay is only wired to the "run" side of the ignition, and only active when the key is in the run position, it might even be tied to the fuel pump relay circuit and only active with engine running
On the start mode of the ignition it does not engage/activate
Or you would not have needed to use that long jumper cables

I only have the one solenoid by the engine battery on the passenger side.fender It has the starter and battery wires on one side via some sort of buss bar, and the house batteries on the other side via circuit breaker next to solenoid with the ignition wire in the middle.

I don't have a second solenoid that I know of. No batteries on the driver's side. House batts are back in the RV part.

I got all confused by that other thread, but got to wondering if with my set-up, just when that solenoid closed to put the house batts in parallel with the engine battery. If it is as soon as you turn the key, I wonder if that means the house batteries always assist in starting. Or does that solenoid only close after the engine cranks?

I gather that the ignition wire in the middle is what operates the solenoid?

Yours should be very similar to this one from another post.Drawing
Your chassis information should be very similar if you put Winnebago info like on this other post.

The starter relay and the relay that connects the house and engine batteries are 2 different solenoids. The engine battery is used to energize the starter when the key is turned. At some point after the engine is running, the other solenoid is energized so that the alternator can charge the house batteries. The same solenoid is used when the "battery boost" button is pressed to use the house batteries to start the engine. In some coaches, that solenoid will also provide a way for the converter to charge the engine battery while parked on shore power. That last configuration is not available on all coaches.

Ford starter is energized by the starter relay. Power to the starter control circuit and under dash fuse block comes off the large post on the relay. Ford uses fuse links adjacent to the relay to protect the wire. Ignition switch when turned to start position applies power to the coil.