31L wiring logic?

[blw2]

can anyone explain the wiring schematic in my coach.
I'm trying to wrap my head around how they wired the charge system, and as best I can find the documentation on it or a schematic is non-existant.

The emergency start switch on the dash board seems to activate a momentary relay that connects the house battery system to the chassis.
If this system isn't engaged, does the engine charge the house batteries at all?

Also, why did they install a switch that activates a relay for the battery disconnect? Seems like a disconnect switch, similar to a marine switch or industrial disconnect would give a much more positive and reliable means to switch OFF....

.... and with this disconnect switch in the "store" mode, is the battery still going to receive a charge from either source (genny, converter, or engine?)?

[FW28z]

The engine does not charge the house battery. The emergency start switch is simply for starting the engine off the house battery if your engine battery is dead.

When the battery disconnect switch is off for the house batteries, they will not charge.

Marine switches can potentially cost more, and by using a remote relay, the RV manufacturer can use shorter battery cable (which is also expensive). I think it is all just a matter of cost.

You could force the engine alternator to charge the house batteries if you installed a combiner, such as the Blue Sea (marine) 7610 Voltage Activated Relay (ACR). I have wired these into boats before.

These devices sense when the engine is running by monitoring for a higher output voltage (when the alternator is producing voltage). When it senses that, it closes the switch.

So you could wire such a switch across the emergency engine start relay.

Then, when the engine is running, the Blue Sea ACR would sense the alternator voltage and automatically close - charging the house batteries. And when the engine stops, the ACR would automatically open, isolating the house and engine batteries.

However, this means you may potentially be trying to simultaneously charge three batteries (engine plus two house batteries) as well as run the engine - and the alternator might not produce enough current to do all of that.

But the Blue Sea switch does have a remote shut off so you could defeat it's action if you wish.

[DavisK]

Originally Posted by FW28z

However, this means you may potentially be trying to simultaneously charge three batteries (engine plus two house batteries) as well as run the engine - and the alternator might not produce enough current to do all of that.

Any alternator would be capable of charging 3 batteries, it would just be slower with an alternator with a lower output. My Silverado has 2 batteries, and when I'm towing my 5th wheel, it is keeping all of the batteries (truck and camper) charged and powering the inverter in the camper. It has only one 125 amp alternator.

[blw2]

Does anyone know the delay or logic used to set how long this relay is engaged before disconnecting the two systems?

[FW28z]

If you are referring to the emergency start switch - it is a momentary switch - that is, it is engaged only as long as you hold it in the emergency position.

So basically, to start your rig using the house batteries, you hold down the switch, start the engine, then let go of the switch.

There will be a few mSec after you let go of the switch before the relay breaks contact, but nothing significant.

If you want to couple the two systems for longer term - and for charging, etc. then look into the Blue Sea ACR systems that are put on boats. Some of the systems are designed for battery charging only, and some work as an engine start (i.e. they have heavy duty contacts).

[blw2]

OK, thanks....
but that doesn't seem quite right. I used it a couple times now to "jump start" my generator.....
House battery too week to turn over genny
walk to the front press the switch (not hold it in, just press and release)
walk back to the genny control panel
and it turns over like it's connected to a good battery....

Actually as I'm thinking about it, I believe that both times I did this, I started the chassis engine before pressing the e-start switch.....
....Perhaps contrary to what I thought earlier, the engine does in fact charge the house battery????

I sure do wish they published a schmatic of how they built it!

[FW28z]

All I can say is how it works with my coach. Thor has been known to change things from year to year, and even for the same year.

I did get some "schematics" from Thor, but they are not very detailed - they basically show the location of the devices and a few other pertinents, but not how things are wired.

[blw2]

and I understand and completely appreciate that! You have been a huge help to me. I'm just scratching my head trying to understand....

We're heading out this weekend & I'll be crawling through, under, and around this thing trying to fix all the little things the factory "missed", and at the same time trying to understand this thing!

I'm really shocked at the huge number of silly little things that the factory swung and missed on.... and that the dealer didn't even try to catch and correct.... doors that don't meet their latches, things loose or out of adjustment, shotty little annoyances really, nothing too major so far... but I've been busy trying to figure out if each thing is a problem, or just me not understanding something.

[sandaj]

blw2 and all; I echo LOUDLY the shoddy workmanship and non existent quality control from Thor. This is our first motor home. There may be more in the future, but Thor will not be in consideration. Right or wrong, when I spend this much money, I expect more than Thor delivered.

sandaj