Batteries

[davejay]

hey,
Happy 4th to all, especially you vets.
Can someone tell me how to set up my batteries. My two 12 volt house batteries positive lead goes where?
My motor battery pos goes to the block on the frame. But, there's that little cut off switch that does something.
Do the positive leads from the house batteries tie into the positive lead of the motor battery, or are the batteries seperate.

Hey, I got my seats in, look great. I got them in what they call ranger black. It looks like black ostrich, kinda. Pretty cool.

Second question. My compresser does not come on when I turn ign on. Should it? If I touch the ground less to the plate the soliniod, air switch and the high pressure switch is on then the compresser will run to the point of where the switch will turn it off. Is that normal? Thanks DJ

[uncle_bob]

Hi

First off, it would help a lot if you changed your info to reflect what sort of RV you have.

Pretty much *all* battery negatives go eventually to the chassis. The only exception would be wiring up 6V batteries. With multiple 12V batteries, both negatives strap together and head to the chassis. If you have two house batteries, both positives tie together. They never / ever connect to the chassis ( unless you like smoke and fire).

Those are the basics. Past that, it matters very much just what sort of RV you have. Since this is a MH section, one would guess a MH, but .... which one ....

Bob

[Magnet18]

1, what kind of rv
2, a picture is worth a million words
3, house and engine batteries are usually separate with a switch on the dash to bridge them in case the engine one dies
4, what compressor? Air ride? AC?
5, your last paragraph is kinda scrambled and hard to understand
6, seats are cool... Why are you talking about them in the middle of a battery thread?

[Bill M.]

“My motor battery pos goes to the block or frame”

Are you sure that is correct? I would think the negative would be grounded to the block and frame. I personally have never seen a positive ground system.

I would think the engine system is separate from the house system. You should have a buss bar and a fuse panel somewhere for the house 12 volt system.

[OTRA15]

Originally Posted by davejay

. . .
Thanks DJ

Could you please fill in some of the missing details? You could also add info to your user ID to the left, as uncle bob suggested, so that folks can give better advice.

Thanks,

Peter

[bkahler]

Originally Posted by Bill M.

“My motor battery pos goes to the block or frame”

Are you sure that is correct? I would think the negative would be grounded to the block and frame. I personally have never seen a positive ground system.

I would think the engine system is separate from the house system. You should have a buss bar and a fuse panel somewhere for the house 12 volt system.

Bill, you must be a youngster! My 51 dodge pickup is 6-volt positive ground and my 63 TR4 is/was 12-volt positive ground

Sorry, couldn't resist

Brad

[bobmiller1]

I am going to leave this thread alone, Regards, Bob

[Kota]

The convention became negative ground and that’s what your coach is. GM won over Ford’s positive ground many years ago. Positive ground has some advantages. Ever had bad ground issues? From a corrosion standpoint positive earth would be choice. They say spark plugs even perform better with the electrons going the other direction.

Just a little fun with science.

[Magnet18]

Originally Posted by Kota

The convention became negative ground and that’s what your coach is. GM won over Ford’s positive ground many years ago. Positive ground has some advantages. Ever had bad ground issues? From a corrosion standpoint positive earth would be choice. They say spark plugs even perform better with the electrons going the other direction.

Just a little fun with science.

Nifty, maybe I'll go reverse mine

[uncle_bob]

Hi

..... ummmm ..... errrrr ..... spark plugs are driven off of a spark coil. It's a flyback transformer driven by a switch. The output is an AC waveform. The spark plug hasn't a clue if the signal started off as positive or negative ground ...

=====

If you still have a landline telephone, that is a positive ground system.

Bob

[davejay]

Hey,
Ok, I got a 325 classic 1985. With 5420 miles on it.
The pos lead off the motor battery goes to the red block on the frame. The neg lead goes to the frame. Got it.
There is a switch behind the battery's in the compartment. What does it connect to. There's two leads coming off of it. I think, one goes to the two 12 volt house battery's where does the other connect to. There is another block on the back of the compartment next to that round switch. It too has two leads coming off of it .
I'm thinking, the red lead coming off the red block on the frame, goes right to the motor battery.
Somehow the house battery's are connected to this whole setup. That is my question. How do I hook up the house battery's. Pos lead goes to.... What.
Signed..... Frustrated DJ

[davejay]

Hey Bob,
Thanks for reserving comment. I'm looking for help, not a bunch of commentary as to the ways of pos vs neg systems. And if any of you guys have read any of my posts, I think you'd get a pretty good idea, that I know quite a bit about these things. I've owned 4 motor homes to date. So please, if you want to be cute, save it for someone else. DJ

[Kota]

Originally Posted by uncle_bob

Hi

..... ummmm ..... errrrr ..... spark plugs are driven off of a spark coil. It's a flyback transformer driven by a switch. The output is an AC waveform. The spark plug hasn't a clue if the signal started off as positive or negative ground ... [emoji4]

=====

If you still have a landline telephone, that is a positive ground system.

Bob

The ignition coil is charged by a DC current which builds up a magnetic field. When the charging current to the primary coil is switched off by the points opening after the dwell cycle, the field collapses inducing aa high voltage in the secondary coil which the creates the spark. Although it does ring out a bit, the main component is DC. Electrode positive and engine block negative.

If you have ever welded with DC there’s a big difference in electrode positive vs electrode negative as far as heat transfer goes.

https://www.autoserviceprofessional....lly-use?Page=4

I can answer your questions with enough detail to visualize your connections and switches. Pictures would help.

I’ll shut up now.

[uncle_bob]

Originally Posted by Kota

The ignition coil is charged by a DC current which builds up a magnetic field. When the charging current to the primary coil is switched off by the points opening after the dwell cycle, the field collapses inducing aa high voltage in the secondary coil which the creates the spark. Although it does ring out a bit, the main component is DC. Electrode positive and engine block negative.

If you have ever welded with DC there’s a big difference in electrode positive vs electrode negative as far as heat transfer goes.

https://www.autoserviceprofessional....lly-use?Page=4

I can answer your questions with enough detail to visualize your connections and switches. Pictures would help.

I’ll shut up now.

Hi

I can see how you would be confused if you are looking at the plots on that site. They show the primary ( rather than the secondary ) voltage on the coil. Transformers don't move DC from primary to secondary .... They move AC.

Why show primary voltage? It's much lower and much easier to measure. Getting onto the secondary is not what you would do while running diagnostics.

Bob

[Boom Sounds]

No fighting on the dance floor chaps.

Check section H
https://www.airstream.com/wp-content...ream-MH-OM.pdf

[Kota]

If your coach matches the manual, the page H-2 shows all the a aux start solenoid. (5). When wire 8 is energized via the Aux start switch, all batteries are tied together for the purpose of starting the engine only if more cranking power is needed if the engine battery is low for whatever reason. So per the diagram all batteries ground wires are tied together and connect to the frame. (15)

The coach batteries are tied in parallel feed the coach through (7) an 80 amp breaker then the kill switch (4). The junction block (12) distributes the engine battery power.

[davejay]

Well, Kota and uncle bob,
I'll let you two discuss the finer points of DC current. Neither of you answered my question, about where the positive cables coming off the the house battery's go to. So, I open this discussion to the more mechanical type.
Gotta love engineers.
Anybody got any practical advice to help me solve this dilemma? DJ

[davejay]

Kota,
I just read your post. My apologies sir. That does help me. But my question is , if all the battery's are tied together, what happens if you run them down, say on a long weekend. Are you then stuck, because you don't have any juice to start it. I don't like electrical stuff.
I don't know if my manual is complete. I'll look into it, and see the schematic.
Thanks DJ

[Magnet18]

Originally Posted by Boom Sounds

No fighting on the dance floor chaps.

Check section H
https://www.airstream.com/wp-content...ream-MH-OM.pdf

There's the good answer

See attached, I don't know if this is the same as your 325, but it answers your question about the batteries wired together.

The 2 house batteries are together, the engine start battery is separate, for exactly the reason you said
The start assist solenoid is for in case the engine battery dies but the house batteries are still good, you can switch it with a button on the dash

[Boom Sounds]

Originally Posted by davejay

Kota,

I just read your post. My apologies sir. That does help me. But my question is , if all the battery's are tied together, what happens if you run them down, say on a long weekend. Are you then stuck, because you don't have any juice to start it. I don't like electrical stuff.

I don't know if my manual is complete. I'll look into it, and see the schematic.

Thanks DJ

Did you look at the link I sent you? I think that should set out everything you need to know.