What WERE they thinking?

Morich · 02-04-2021, 09:23 AM

There is a post about a battery problem on a 2002 Adventurer which prompted me to look at the drawings for how things work on that specific model but I got to a real question!
Either I do not understand or they totally blew it on this drawing!
I was looking at how the start battery and coach batteries are tied together. It's pretty common for this to be done through the mode solenoid that we use to boost the start battery when it is weak or to charge the coach batteries from the alternator while we drive.
Start power on one side of the solenoid and coach on the other, so that is pretty simple. That matches what I see on the first picture, no problem!

But where I get a big question is what they show in the second picture!
What's gonna happen if you tie your incoming start battery directly to a ground stud?

theSane · 02-04-2021, 11:58 AM

That is the negative leg on the battery and the solenoid, not being an electrical expert, I do not see the issue.

Bones2003 · 02-04-2021, 12:18 PM

Hi Richard, good catch! Hard to believe that hasn't been changed after 18 years. I looked at the wiring diagrams for the other model Adventurers from 2002 and they show that wire going to an insulated stud as you would expect. Also the Wiring Installation diagram that is associated with the schematic you have shown has that mode solenoid wire going to an insulated stud not to a ground stud.

powercat_ras · 02-04-2021, 12:18 PM

Yes, Morich, it is a drafting error on that particular drawing, if you look at the drawings for other 2002 Adventurer models you'll see that the Red wire does not go to ground it goes to an isolated stud, not to the ground stud.

Morich · 02-04-2021, 03:11 PM

Quote:

Originally Posted by theSane

That is the negative leg on the battery and the solenoid, not being an electrical expert, I do not see the issue.

That's where things can get messy if we are not into the electronics thing!
What it shows is to connect the positive battery to ground! That is going to make a great big ball of fire and possibly blow up the battery!

Then to make it even more exciting if it was done this way and IF we did get the solenoid to work, we get more fun. When the solenoid operates, it connects the big posts on the right and left side together as that is what we want to happen. We expect the left side start battery to be connected to the coach batteries on the right side lug..

But if we follow the red wire up from the coach battery positive post and go down to the solenoid, the solenoid operated will then be connecting that positive battery post directly to the negative battery post.
That is where lots of folks get hurt if they use metal tools and happen to make contact between the two battery posts!

Two big rules to follow? One is to never let the positive go directly to ground and the second is to never put total trust in what you find on the internet, even if it is from a trusted group like the Winnebago drawings.
I think somebody once said, "Trust but verify"?

Wyatt · 02-04-2021, 09:06 PM

Quote:

Originally Posted by Morich

That's where things can get messy if we are not into the electronics thing!
What it shows is to connect the positive battery to ground! That is going to make a great big ball of fire and possibly blow up the battery!

Then to make it even more exciting if it was done this way and IF we did get the solenoid to work, we get more fun. When the solenoid operates, it connects the big posts on the right and left side together as that is what we want to happen. We expect the left side start battery to be connected to the coach batteries on the right side lug..

But if we follow the red wire up from the coach battery positive post and go down to the solenoid, the solenoid operated will then be connecting that positive battery post directly to the negative battery post.
That is where lots of folks get hurt if they use metal tools and happen to make contact between the two battery posts!

Two big rules to follow? One is to never let the positive go directly to ground and the second is to never put total trust in what you find on the internet, even if it is from a trusted group like the Winnebago drawings.
I think somebody once said, "Trust but verify"?

Good response, though I might say, “Verify then trust”...

Morich · 02-05-2021, 08:02 AM

Yes, there were a lot of things they had backwards!

NormD · 02-11-2021, 03:55 PM

When wired as shown you never have to worry that your engine will charge your batteries to too high a voltage. You also save fuel, since your engine will likely not run for long. A winning combination!

Morich · 02-11-2021, 04:38 PM

Doing more looking, it does show they just got their "wires crossed", maybe?

What they show for the 2002 Adventurer 32V at left but what I think they meant to do is at right. as shown for the 30 Y!

Reniram · 02-12-2021, 06:56 AM

So what is the purpose of the isolated stud?..Why not just eliminate the red wire on the battery solenoid...unless its in a handy place for testing by the tech when troubleshooting........

Morich · 02-12-2021, 01:01 PM

Quote:

Originally Posted by Reniram

So what is the purpose of the isolated stud?..Why not just eliminate the red wire on the battery solenoid...unless its in a handy place for testing by the tech when troubleshooting........

One of the small 'mysteries" of how Winnebago goes about some points on their drawings is that they seem to leave off some terribly important info, almost as if they are setting a situation where the folks who read the drawing will KNOW the tricks but the novice DIY may totally miss that important clue to see how things work.

One of my first confusion points when looking at the mode solenoid is a perfect example as on this drawing. I knew the mode solenoid was meant to connect the start and coach batteries together at different times like when we want to boost the start or to charge the coach when driving. That means the two have to have connections to the mode solenoid, so we can see the coach connection to the solenoid, but the only other start battery connection goes up to the breakers. Say what? Do you want charge voltage from one battery to another going through a breaker? NO!

So where is the connection to the start battery from the solenoid? They DO NOT show it but it is the isolated stud!!! A look on the RV will find a big old battery cable on each side of the solenoid. That combined with finding this bit of really good info way down on sheet two of this drawing info:
https://www.winnebago.com/Files/File...l_callouts.pdf

Let me get the real picture of the start going to the isolated stud and a cable with purple marking going to the solenoid left side!!!!

So does it make it easy to understand the mode solenoid, if we accept that there is start battery on the left side and coach battery on the right side, and we know that the left and right are connected when the solenoid operates?

Looking at the 30Y drawing (correct one!) above, the control voltage from the dash area comes down to the solenoid on the 14 gauge yellow wire, through the coil inside the solenoid and in this solenoid they connect that coil to the metal mounting screw where there is also a wire FM going back up to the dash to complete the circuit (circle?) to make it work! That coil is a magnet that moves the contacts to connect left and right sides together!

But they leave off the connection to the isolated stud we need to know to make sense of the drawing! The isolated stud is the connection to start battery and we need that info.