Battery help, please!

[Pfhjr5205]

Hey, guys. I own 2 class A motorhomes. I’m trying to sell them. However, it seems as though some homeless drug addicts have take over the motorhomes where they are parked. They also stole all of the batteries. I’m trying to buy replacement batteries to get them started but I’m not sure how many i need and should they be top or side terminal. I’ll include a photo to you can see. In the photo, you’ll see 4 battery cables. If you can help, I’d be amazingly grateful. I’ll also include a photo of the motorhome. The property owner where they are parked decided to be a smart ass and PAINT the word ‘TOW’ on the side of the motorhome, just so you’ll understand why it says TOW on it. In fact, lol if anyone knows how to get paint off of it, I’d be more appreciative.

 

[Morich]

First big point to rebuilding is getting good info on exactly which models you have as many Rv come listed as a specific year but the chassis is a year older. They buy stripped chassis and it make take a year before they get the RV built on top?
One place to find reliable info is a sticker found somewhere near the drivers seat with all kinds of good dope on what you have. This is important when you get into auto parts like brakes. etc.
It also allows us to look up the wiring drawings and parts to spot what was there when built.

For a general "guess" I might expect to find two batteries tied together to double the amp hours to use for the coach items like lights inside and fans, etc for the RV. Then there is likely to be a second battery just for the starting and truck/car things.
If you have a winnebago RV and post up which, we can often get drawings to show which cables should go back where to make it much easier.

Parts:
https://catalog3d.winnebagoind.com/menu/Parts.htm

Wiring:
https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/Wiring.htm

 

[Pfhjr5205]

Richard, thank you very much for that important information, I had no idea. I’ll gather all of the correct info and post it immediately. I think I recall it only having 2 batteries under the Step. With 4 cables hanging loose, might it possibly also mean that there are only 2 batteries? And, you know, what else through me off was that 2 cables look like They go to top terminals and 2 look like they go to side terminals.

 

[Pfhjr5205]

Ok, I got it. It is a 93 Chevy Winnebago Vectra Model has a 454 engine. I’m still trying to figure out if it’s an M-33RQ or an M-37RW. I saw the owners manual online and it’s showing 2 batteries on the compartment below the step.

 

[Morich]

Okay, the parts drawing list may help as they show a floorplan on first page.
Might be easy to spot which matches what you have?

This is the battery layout for the 33 foot and might guess the same for larger?
No side posts shown so I think they have been changed?? One thing that says they are not the OEM is that red and black cables are never supposed to be on the same post like these. Red positive, black negative!

I marked the negative cables as black, the positive for start as blue and the coach positive as red. The big bus bar for all grounds is likely on the frame right behind the battery rack out of sight! Good place for dirt and corrosion where you can't see it or reach it!

Click the drawing to get better view?

 

[Pfhjr369]

Ok, Richard, thank you for that. And based on trust diagram, there seems to be 3 batteries And not 2?

Also, you drew ‘NOT’ on one of my photos. Are you saying that the way that the cables are connected is incorrect?

 

[creativepart]

Assuming you have 3-batteries under that step it would be safe to assume that one is your chassis (starter) battery for the engine and the other two are your House batteries to run 12v items within the house portion of your RV.

Richard above mentions the two separate battery banks as "Start" and "Coach." Which is totally correct, but commonly called Chassis and House.

 

[Morich]

Ok, Richard, thank you for that. And based on trust diagram, there seems to be 3 batteries And not 2?

Also, you drew ‘NOT’ on one of my photos. Are you saying that the way that the cables are connected is incorrect?

Well the question is how we want to deal with repairs as most folks do like to keep the black cables on the negative of the battery and the red cables on the positive. So seeing a set of both black and red on the same post says one is wrong!

Not saying things won't work like that as the cables arepretty well color blind but it does open up a chance for others who come along to get in lots of trouble if they assume the black cable is the ground.

Like in your case if you were trained to think the black goes on the negative and the red goes on the positive posts and don't see you are putting a direct short on the battery!
Since side terminals are rare (never?) on Rv, it looks like somebody went with easy rather than right and just used whatever cables they had to fit whatever battery they had.

That could lead to all kinds of reasons the RV have wound up being close to scrapping? If you were the folks trying to get it going and the first thing you did was blow up a battery , that might make a guy get way far away!

My guess might be that they used some form of deep cycle battery like one would find on a fishing boat that has a form of deepcycle that is a combo of starting the engine and running a trolling motor. Those will work for RV coach lighting, etc. but they are not as good as a true deep cycle. The difference is that a true deep cycle will let you get a lot more hours of use out of them without damage to the batteries than the combo which has to be built different for the use to start things.

It's kind of a theory thing as the starting part needs lots of energy quick, while the long term use for RV needs a slower energy use over a much longer time.

What I think you need is looking at the drawing, there is a "isolated stud" marked and that is just a bolt set in the wall but insulated so that it is a contact point for the positive cables but not actually making contact with the metal of the wall.

So looking at that drawing there should be red (positive) cables going from the start battery positive post to that stud, then other cables going forward to the start, one to a relay and one to a mode solenoid.

Then on two deep cycle batteries for best use for the coach (inside RV?) stuff, there should be cables tying the negative of each battery to the other battery and then to the ground bus bar on the frame.
Then there should be a red cable from one coach battery positive to the other coach battery positive and then one going to the second big lug of the mode solenoid.

That solenoid may be behind a panel of breaker and there may be a label to locate it. But if you know what a starter solenoid used to look like on older cars, it looks like that or this is one type that uses four wires while other types use three wires. Big lug left and right side is where the battery cables go.

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