Are Engine and House Batteries Connected?

I'm sure it can vary from mfr, but on ours solenoids connect two together under certain conditions. One allows engine alternator to charge house battery while driving. The other is the emergency boost moment switch if cranking battery is low and needs jumping from house battery. If plugged in and converter is charging house battery, it does not connect/charge cranking battery.

I think I've listed those right...

Many have a relay that connects the two batteries together to charge the house batteries while chassis engine is running. Many use the same relay as the aux start.
Make and model of MH would help.

On ours, the house battery is charged by shore power, the generator, and the chassis alternator. The engine battery is only charged by the chassis alternator.

This heat can kill a battery REAL fast. Traveling in 100% plus heat we've had to add water every other day!

My thought would be a bad relay. I am no expert however. Let us know what you figure out please.

Mine did that turned out to be the house circuit breaker.

Also had to run a new trigger wire to the alt. That's
after I replaced the alt. But now I have a 150A alt.

Hi,

You may have a bad ground. Finding it may not be easy. Check where the dash electrical system fastens to the ground.

If your engine battery was 6 volts or so and now a replacement shows 14 volts with the engine running, my vote is for a loose battery connection. It could be loose at the combiner solenoid or at the battery terminal. When you replaced the battery you tightened those connections but did you follow those heavy wires and tighten anywhere they are connected???

The boost switch, if connected to the engine battery, would not close due to low voltage. If you get into a situation like that again, you can often just use one jumper cable between the positives to get things going.

I meant to say my unit is a 2010 Itasca Cambria 30C.

Also, just measured the voltage after a night of no charge, and the engine battery was 14.3, and house 13.8. I would have thought both would be lower than that.

I will do some tracing of the wiring to see what I might find.

BTW, the engine battery was 7 years old! Something told me to replace it before the trip because my hi-tech charger wouldn't go into de-sulfate mode on it's own. It's one of those maintainer chargers that switches to de-sulfate after charging is complete. I actually think the battery shorted out in a place or two due to age, heat, and the gawd awful bumpy roads in Colorado, at least where I was driving.

The battery boost/charge relay is a high failure item.

Note that the steps and the slide outs are powered by the chassis battery. Logic here is that if you can start it, they want you to be able to retract everything. If they were off the house batteries, you might have run them dead, but still be able to start vehicle and drive away with stuff extended.

I suspect your 2010 Itasca Cambria 30C has many of the same components and wiring logic that my '07 View has. There are two relays, one is a black one with two fused in holders made into it. It is the house battery relay. It stays in whatever position it was driven to by the solenoid, even if you disconnect the batteries, it will stay in its last position, it does not have a normally open or close position.

The other relay is a silver cylinder with two large terminals and one small one. This is the high failure boost/charge relay. Every time you start the engine, and the alternator begins to put out voltage, this relay is automatically closed, to allow the vehicles alternator to charge the house batteries. When the alternator voltage drops off (as in shutting down the engine) it opens back up (spring loaded to open). If you use the boost switch (and the house battery switch has to be on for this to happen), you are manually operating this same solenoid to connect the house batteries to the chassis battery to boost a weak chassis battery and keep you from being stranded.

My View has about 19K miles on it, and the boost/charge relay was receiving control power to the small terminal, everything else was normal, and it was simply not passing current thru its contacts. It would neither boost nor charge, but from all outward appearances (till I took a volt meter to it) it was working. I replaced it with a nearly identical Cole-Hersee 24213 200 amp relay. The major difference is two small terminals rather than one. The old relay had the solenoid windings grounded internally, while the Cole-Hersee has to have a separate ground wire run from one of the terminals to a good ground, most likely one of the solenoid mounting bolts.

Everything is fine now, and when I start the motor, I see 14.1 volts on the HOUSE batteries AND the CHASSIS battery, and if I disconnect the chassis battery ground, turn on the house battery switch by the door, and hit the boost switch, I get house battery voltage at the positive chassis terminal (when measured to a chassis ground). This proves the solenoid is working properly.

https://www.amazon.com/gp/product/B005K2429I/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

Charles

Thanks Charles. Looking at the wiring diagram, it appears these two solenoids are inside a two handled "Battery Mode Solenoid and Relays" box. I will check into it.

Very good info.