Battery Isolation Switch Question

[Blue Sky]

My understanding of isolating the single 12vdc battery in my trailer, is that it will disconnect the 12v components in the trailer but the battery will still charge from whatever source it was charging from prior to being isolated. Is that correct?

I attached the 12v schematic for this trailer for reference. For those interested in "budgeting" their amp draw, the holding tank heaters draw the most by far. What was interesting to me is the power vent draws more (slightly) than the refridgerator.

[Morich]

I was hoping to see an actual schematic of one of the trailer groups as a way to better understand how they are wired but not seeing the good stuff on that info.
One of the big questions is what will be left on when the battery disconnect is used.
I would not assume ALL the load is disconnected if they do it the same as on their motorized group.
For safety and liability, I would not expect them to disconnect the safety things like CO and propane detectors or steps. If those were disconnected and you came back to an RV full of propane, it could be bad and I would not expect them to do that?

Without a real schematic showing where and how it is wired, we are left pretty much guessing.

[tinglett]

In my 2019 2108DS the battery cut-off will interrupt the positive 6 AWG 12v wire that connects to the converter/fuse panel.

If you are NOT on shore power, this means none of the circuits on that fuse panel have any power from the battery. Those are the devices in the table you posted. However, there do remain other things connected to the battery (look at all the wiring around a 12v junction box under the trailer tongue). In my rig, the battery is directly connected with a fused wire to the tongue jack. It is also connected through a 30A manual breaker to the slideout controller and motors. It's also connected with no fuse or breaker to the brake-a-way switch, and is connected to pin 4 (black) of the trailer connector. That last connection means the battery will charge via the trailer connector even with the battery cutoff switched off. Because this is all a common circuit, it also follows that the trailer connector will power these things, too. Remember that if you find your battery is flat and you want to run in the slide or run the jack. Hook up the trailer connector and give it power from your running tow vehicle!

If you ARE on shore power, the battery disconnect simply keeps the battery from charging from the converter. The converter will be powering the fuse panel circuits, while the battery is powering all the other stuff I listed previously.

Then why have a battery cut-off switch? Well, one reason is that the stuff that is connected directly to the battery shouldn't be a parasitic load. However, you'll find this isn't really true if you somehow leave your tongue jack light on .

Yours may be wired slightly different, but this is roughly the gist of it. I sure wish it was better organized. I've made plenty of changes to my own setup, including adding a circuit breaker right next to the battery that I can use to shut EVERYTHING off. I find that more useful and can't say when I last turned off the battery cut-off switch.

[tinglett]

Originally Posted by Morich

For safety and liability, I would not expect them to disconnect the safety things like CO and propane detectors or steps. If those were disconnected and you came back to an RV full of propane, it could be bad and I would not expect them to do that?

That's an interesting point! In my trailer, the CO detector is dead when the battery cut-off is off. Pretty stupid. On the other hand, they did do the brake-a-way right. There isn't even a fuse or breaker in that path.

[Morich]

Not looked at a trailer close enough to know anything about the last 20 years, so lots of guessing?
Is there a propane detector and does it have a small green light on the face? That is one of the clues that pointed me to knowing that it was still left powered on motorhomes.
I noticed mine when looking in after dark one night and seeing the little green glow!
Discussing it with others, the idea was that they do not want the RV to fill with gas and not have an alarm!

Would they consider it different in the trailer group? It would be nice if we could just look online for the differences in each one they build!

[SactoSteve]

I believe this is a FLX?
If so it does not operate quite how you suggest.
Start here, https://www.winnieowners.com/forums/...ml#post3929376

[Blue Sky]

Originally Posted by SactoSteve

I believe this is a FLX?
If so it does not operate quite how you suggest.
Start here, https://www.winnieowners.com/forums/...ml#post3929376

... not a FLX. Thanks, anyway.

[tinglett]

Attached is a diagram I drew up for my 2019 2108DS. I am willing to bet yours is nearly identical except what is in the dotted box labeled "Junction Box," and perhaps a little bit about how solar is connected in. Newer models have moved around some of the components under the tongue of the trailer, so I'm not sure what remains inside that galvanized box, and what is outside.

In the diagram you can see where the cutoff breaks the circuit. Note that this diagram is an "external" wiring diagram. I drew a box for the "Fuse Panel" but don't have all the circuits drawn out that hang off that panel. Someday .

[tinglett]

Hmm...I realize I need to make a v4 of this diagram. I was looking at my trailer hookup cable the other day and noticed the wire gauges were not all 12ga. I believe I originally sketched it that way as some Winnebago document declared it.

I need to go measure, but I believe the hookup cable wires are 14 AWG, but the blue brake wire is 12 AWG, and the black and white are 10 AWG. These sizes make sense to me, though I wish black/white were heavier. Maybe there are also other corrections I should make?

[vascout]

This is great.


Just one clarification, these draws for like the water pump and the Puck lights etc. are operating draws while devices are being used. Correct? If boondocking non use of these items would save the batteries.



I need to shut things off like the TV antenna boost when not in use.

[Blue Sky]

Originally Posted by tinglett

Attached is a diagram I drew up for my 2019 2108DS. I am willing to bet yours is nearly identical except what is in the dotted box labeled "Junction Box," and perhaps a little bit about how solar is connected in. Newer models have moved around some of the components under the tongue of the trailer, so I'm not sure what remains inside that galvanized box, and what is outside.

In the diagram you can see where the cutoff breaks the circuit. Note that this diagram is an "external" wiring diagram. I drew a box for the "Fuse Panel" but don't have all the circuits drawn out that hang off that panel. Someday .

I downloaded v03, thank you. The 2108 TB is a small and uncomplicated trailer. Once our weather cools down a little I'm going out and trace wires. I'll use a meter, continuity tester, and/or test light with the converter powered and off. Thanks again.

[bigb]

Originally Posted by Morich

Would they consider it different in the trailer group? It would be nice if we could just look online for the differences in each one they build!

My propane alarm shuts off with the battery switch but so does the propane supply solenoid since I have an ASME tank, so no risk of propane flowing with battery switch off. On a trailer or other RV with a manual propane valve I can see where it would be best to have the propane alarm on with the battery switch off. Of course it wouldn't work once the battery died but by that time the leaking propane would probably be empty anyway.

[Morich]

Knowing how each RV is set up and wired is hard because it is done so many different ways.
When the safety part got my attention was when the stove got turned on and we did not know it.
A lady had gone in to get a sweater for setting out and as she came by the stove, the sweater caught on the knob but she did not think much about it and went outside! That left the knob turned on and gas flowing so that the RV was soon getting filled with lots of propane and the alarm went off.
Knowing what propane smelled like, we were able to get by without major damage but if we had not known what the smell meant and the alarm was not working we could have easily blown the whole thing sky high!

So the alarm can be great but it also has the potential to run the batteries down if it is on the upstream side of the cutoff. Different RV will have it different places, so we need to check what WE have, not what the next guy might have?

One of the problems with the RV built after 2010 is that we no longer get the good drawings to spot where the alarms are wired.

This is one example of a chassis battery cutoff on a pre 2010 model that shows how there are things upstream of the disconnect which stay on even when we have the disconnect off!

Click to get a better view!


We have 12VDC on the isolated stud from the chassis battery going to the disconnect relay and much of the RV items are on the right side of that relay and will be cut off when the relay is open.
But at the same time we have wire KKG that is on the left side and not cut off with the relay which goes up to a small buss bar to feed things left powered---even with the disconnect open or closed!
Figuring out how OUR specific RV is wired can help us figure out why our battery goes dead when we store it!

[tinglett]

I have to say that when I first got my trailer I was puzzled when I switched off the battery disconnect and that didn't switch off everything. That puzzle, along with the fact that I wanted to switch over to lithium, and along with my disappointment that Winnebago only has diagrams for motor homes, made me decide to trace down my wires and draw up a schematic for myself. Through feedback I've found the diagram generally matches other micro minnies, which is good and also makes sense as there is little reason for Winnebago to design a zillion ways to do the same thing. Of course there are tweaks, and then there are crazy changes like the FLX which I assume is very different.

Winnebago does give out technical drawings for those who ask, but for the wiring diagrams as Blue Sky posted to start this thread, the drawing is more a compilation of maximum loads to justify wire gauges, fuse choices, and charger capacity than it is a guide for how the wires are laid out or how you might conserve power for boondocking.

To be fair, your house doesn't usually come with such a wiring diagram either. I recall once tracking down where the heck our doorbell transformer was, and I only found it when I flipped off the last breaker through process of elimination. It was attached to the furnace in a sneaky spot under the power switch! And we built that house!


BTW, my wiring diagram is drawn up as an SVG in inkscape if anyone wants the source to tweak to match subtle changes in their model or mods they've made. I just need to figure out how to get it to folks. The forum software doesn't want to upload it. Perhaps I can bury it as an attachment inside the pdf or doc, but I haven't tried that yet.

[Morich]

For posting, is it possible to put it in another program like "paint" or adobe and that would then let you save it as jpeg, etc which then would post on forums?

The more often I learn something, the more often I find I don't know enough!
I am way behind the curve on most computer use!

[SheCas]

Originally Posted by Blue Sky

My understanding of isolating the single 12vdc battery in my trailer, is that it will disconnect the 12v components in the trailer but the battery will still charge from whatever source it was charging from prior to being isolated. Is that correct?

I attached the 12v schematic for this trailer for reference. For those interested in "budgeting" their amp draw, the holding tank heaters draw the most by far. What was interesting to me is the power vent draws more (slightly) than the refridgerator.

Hello. Thank you for posting the wiring schematic. Can you tell me what source you used to find this info. WE are new campers and purchased a 2020 2108DS and I need this info. Any help you could supply is greatly appreciated.

[bigb]

For future reference a battery isolation switch is typically automatic and isolates the battery from the tow vehicle or MH charging system when the engine is turned off to prevent you from discharging the engine battery while camping.

The switch being referred to in this thread is actually called a Battery Disconnect Switch aka Salesman Switch and it is a manual switch that de-energizes a latching relay to disconnect the camper battery from camper loads.

[Morich]

A possible workaround for posting as a picture on the forum?
If using Winn10, you may have a really poor "improvement" they have made.
I had a "snip and sketch app which was my goto for lots of cut and paste but that stopped working with one of the constant updates.

I finally found they have now added a really lame snip tool in Winn10.
Maybe it would fit for your use?

Try getting past the cute trick of working the keyboard as the person designing it seems to have different hands than mine??
"windows key, shift and S" all at same time may bring screen which lets you choose shape of snip, outline what you want saved and it is put on your clipboard!
You can then open something like "paint and move it there to mark up, mod, etc and save as jpeg. The jpeg can then be posted as any other picture might!

Maybe it works? Maybe not! We don't get instructions for "simple" things like a computer, right?

[Blue Sky]

Originally Posted by SheCas

Hello. Thank you for posting the wiring schematic. Can you tell me what source you used to find this info. WE are new campers and purchased a 2020 2108DS and I need this info. Any help you could supply is greatly appreciated.

... as requested. The following list of schematics was provided by Winnebago CS. Although they are illustrated as pdf files, they are not links. (It's a screenshot from my file directory.)

As tinglett mentions above, the schematics don't always provide the exact feature(s) you are looking for, but they are a great help to any project.

If you decide to request schematics, have your VIN ready for the CS rep - one size does not fit all.

[tinglett]

They also have front, doorside, and roadside wall diagrams which show the layout of the walls. I also got a floorplan and roof assembly diagram. I'd call all these as "interesting" rather than essential. When you ask for them there is an agreement you will not share them. For these I was exchanging with email [email protected], but that was a few years ago.