Dual battery switch and battery wiring.

[John.0]

I have recently acquired a 79 Brave that is setup with one battery and the dash wiring is an absolute mess.
I have the schematics for the battery compartment so hopefully will be able to get that sorted but the dual battery and condition switches are broken and need replaced.I'm not confident that they are wired properly and would like to get them right before hooking up the other batteries.

I attached a photo showing them.The like colored wires on the dual switch appear to be white in the middle and grey on the right,the black wire piggybacks off of the dual switch to the condition switch.I have the coach and chassis wiring schematics but am unable to find anything for the dash(which I need badly)If anybody can let me know if the current switch wiring is correct I would appreciate it also if I could be pointed to some dash schematics that would be amazing.

John.

[John.0]

I spoke with a fellow at Winnebago and he explained the switch wiring to me.I'm sure it's nothing new to most of you on here but I didn't find exactly what I was looking for when I searched so here is whit I got from him.

What he told me is that the DUAL and MOM position do the exact same thing (send 12 volts to the solenoid connecting the batteries) with the exception that DUAL only does it when the key is on.So the switch wiring is   the left connection +12v always on from coach batteries,center to solenoid and right to ignition on +12v from chassis battery.

I've read on here how leaving DUAL on while parked will drain the chassis battery but how is that even  possible if the chassis battery is disconnected with the ignition off.

John.

[Rickf1985]

Maybe it has to do with the later vs. older years? My newer 89 will drain all the batteries if I leave it in dual no matter the ignition position. It stays connected as long as the switch is on. Momentary is just that, on-off.

[John.0]

I guess yours must be setup different or I'm just missing something on mine.But as far as I can tell on mine with the ignition off and the switch in DUAL there is no way power is being sent to the solenoid to connect the batteries.

[DaveVA78Chieftain]

But as far as I can tell on mine with the ignition off and the switch in DUAL there is no way power is being sent to the solenoid to connect the batteries.

That is the way it is supposed to work to prevent draining the chassis battery while boondocking (Dual B+ source = chassis battery).

In MOM B+ source = coach battery.  You are using MOM because the chassis battery has been drained so the source to has to be the coach battery.

[John.0]

I understand how it works.What I don't understand is why people like Rickf1985 have problems with the chassis battery draining if they leave the dual switch on but with the ignition off.It doesn't make sense that Winnebago would change to that.

[Rickf1985]

It could have been a PO modification, I have never really looked into it because I never leave it on except when I am driving to charge the batteries.

[bluebird]

]Awful easy to  forget to turn it off and run your batteries down. Not hard to change it back to only hot when key is on. You may just have to move the wire on the fuse panel.

[Rickf1985]

I agree, I believe the switch has been changed somewhere along the line since there was a note in the owners manual about a change in the position and the switch position does not work as it is labeled. I look at it this way, It would take a week to run all the batteries down to a point where I could not start the vehicle or generator. That would have to be without me checking the voltage for several days which I do on a daily basis. I camped off 15 years in a slide in pick up camper with one battery and I am quit well versed on battery conservation so I use very little power. That being the case if I ever did manage to run all of the batteries down I am never so far off road I could not call AAA for a jump. Or just get someone nearby to give me a jump if even just to get the generator started.

[HamRad Mobile]

Good morning; 

This comment may be getting into the area of "off topic" according to some, but it is related to the subject at hand, and it will influence the health of the engine starting battery: 

I am making the assumption that the DUAL-OFF-MOM switch is in the normal OFF position for most of my discussion. 

While there are some solar panels on the roof of the motor home that are used to keep the coach or house batteries charged while parked, and to operate the interior LED lights and some other lower load devices, there is also a 32 Watt solar panel on the passenger side of the dash that is plugged into the engine starting battery through a small voltage regulator or charge controller.  It can provide up to just under 2 Amperes to the engine starting battery, and it keeps the battery charged while parked.  While I have the 32 Watt panel that is in that service here, a 10 Watt to 20 Watt or so solar panel would do fine in this application.   Anything to help keep the engine starting battery happy will be appreciated if the AAA tow truck is going to be some distance and time away from you. 

There are many things you can do to be self-sufficient with your motor home and then be able to help others when needed.  By having the dual solar panel charging systems for both of the batteries, I can either go to the MOM position for engine starting if the chassis battery is down, or I can start the engine and go to the DUAL position to charge the coach or house batteries with the alternator if the rooftop solar panel system has not been able to keep up with the load on the coach batteries.  And there is still the Onan AC generator that will power the "12 VDC Power Supply" with "Smart Charging" capability in the motor home that can also recharge the batteries.  So far, I have not needed to use these functions, even when the motor home has sat over the winter.  The solar panels have kept the batteries happy, and it does not take too much in the way of solar panels to do that. 

Enjoy; 

Ralph 
Latté Land, Washington