Battery Disconnect

[psomers]

Large wire short run is important AC or DC.

[wecker1]

Just got my brand new 3791 back from the Service center. The frame was holding a 12.73V charge, power was flowing through the battery disconnect switch in the front compartment when in the off position, and, the Lippert levelers were not working properly, said the unit was level when it wasn't. The service center diagnosed the problem as incorrect wiring of the disconnect switch from the factory. Glad they were able to confirm my suspicions but now I think I may have to replace the batteries as they will only hold a 1/3 charge when viewing the control panel inside the unit.

[ACFD139]

3791 RD...Does anyone know if I can attach a 3rd battery in series with my 2 on board batteries. I was told that it is possible and would provide a longer charge.

[twindman]

Maybe in parellel (sp?) but not series. But highly recommended to match batteries. i.e. get 2 (or 3) identical batteries. The output will be whatever the lowest voltage battery carries.

[scottz]

Originally Posted by ACFD139

3791 RD...Does anyone know if I can attach a 3rd battery in series with my 2 on board batteries. I was told that it is possible and would provide a longer charge.

Yes you can, but as twindman pointed out, it is parallel, not series. (Series would give you 24, 36, 48 or some other multiple of 12; not good!) Reference attached drawing. You can hook your positive load cable to terminal 1, 2, or 3; no difference, all 3 are electrically the same point. Hook your negative cable to terminal 4, 5 or 6.

My unit came with one battery. I removed that and replaces with three AGM batteries. I also welded in some angle iron supports so weight of three batteries is not resting on the bottom of the compartment.

If you are not comfortable with electricity, get someone who is to help you.

[beeje]

Most of the battery wiring diagrams I have seen tell you to hook up the + wire to one end of the bank of batteries and the - wire to the other end. I do not really know why, but they say do not connect them in the middle of the run if you know what I'm saying.

[scottz]

Anywhere on the red bus is electrically the same as any other point on the red bus. Same for the black bus. The resistance of the batteries determines which way the electrons flow; doesn't matter where the cable is physically attached. The only other variable is the resistance of the cables between the batteries. I use 2.0 cables. It might be possible to set up an experiment in a lab to prove one case or the other, but I think the difference is too small to measure.

[CaptnJohn]

Originally Posted by carl n susan

The MOC is the best, if not the only, source of knowledge for all things Montana. Anything you likely need to know is here and that can't be said for any other RV forum that I am aware of.

You can ask Keystone for wiring and plumbing diagrams but all you will get is the response "they don't exist". This has been tried numerous times over the years with no success. Do a Search on "wiring diagram" and experience the frustration others have felt.

Having seen the plumbing and wiring in several units I agree with Keystone, diagrams do not exist. Possibly there is a 1st year engineering student that draws up diagrams to assure it will work, then they are locked in a hidden vault somewhere in Peru where the donkey transporting them dies. Safe to say no one on the work floor has seen them.

[scottz]

Originally Posted by CaptnJohn

Having seen the plumbing and wiring in several units I agree with Keystone, diagrams do not exist. Possibly there is a 1st year engineering student that draws up diagrams to assure it will work, then they are locked in a hidden vault somewhere in Peru where the donkey transporting them dies. Safe to say no one on the work floor has seen them.

I just wish it was not true.

[RoadRunnerTR21]

Not to interfere with hcolvin's thread on power outage, his situation got me to thinking. What is the correct configuration for the battery cut off switches when in storage but hooked up to shore power? Right now I have the disconnect in the front battery compartment connected, the disconnect in the convenience center is off. The rig is parked in my garage and hooked to shore power. Is that the correct storage configuration?

[CaptnJohn]

If connected to power batteries are being maintained and should be on/available. All disconnects off. Just check battery water level monthly.

[RoadRunnerTR21]

Thanks Captnjohn. I will make sure both disconnects are in the off position and check the water level monthly.

[scottz]

Originally Posted by RoadRunnerTR21

the disconnect in the convenience center is off. The rig is parked in my garage and hooked to shore power. Is that the correct storage configuration?

By "off", do you mean the batteries are disconnected? My unit is always connected to shore power while in storage. I leave the batteries connected and let the converter do it's job of maintaining the batteries.

[RoadRunnerTR21]

Yes, by "off" I mean the connect/disconnect switch in the battery compartment is now turned to disconnected and the convenience center switch is set to disconnect based on how I read Captnjohn's response. If that's not correct can you give me the correct configuration settings that you use? The manuals provided are as worthless as teats on a bull.

[scottz]

If you are connected to shore power, why disconnect the batteries? The converter will maintain them properly and you are always good to go. If I did not have shore power available, I would disconnect the batteries to keep the parasitic loads from killing them.

I'm not sure there is a "correct" configuration, but that is how I do it. Someone else will probably have a different opinion.

[RoadRunnerTR21]

Ok thanks. I'll go back out and change it back. What about the convenience center switch? What setting should it be in when connected to shore power?

[scottz]

How do you like the 3121RL? That is the same as our 2017 3160RL except the kitchen is on the opposite side.

[scottz]

Originally Posted by RoadRunnerTR21

Ok thanks. I'll go back out and change it back. What about the convenience center switch? What setting should it be in when connected to shore power?

My unit only has one disconnect; in the convenience center. In any case, I would leave the batteries connected (all switches if you have more than one) if shore power is hooked up.

The only time I disconnect the batteries is for maintenance or if the unit will be sitting for a while without shore power.

Be aware that the convenience center disconnect does not disconnect all loads. There are a couple loads that get power without going through the convenience center disconnect switch. Maybe that is why you have an additional disconnect in the battery compartment; perhaps Keystone upgraded.

[RoadRunnerTR21]

So far so good. It has everything we wanted and then some. We bought a new SOB in 2003 and they have come a long way in the amenities since then. Where are you up in CO? I've got a BIL in Littleton and a FIL in Highlands Rach. We have also spent most of a summer a few years back west of Evergreen. I love playing golf up there.

[scottz]

Originally Posted by RoadRunnerTR21

The manuals provided are as worthless as teats on a bull.

Manuals?? Where the heck did you get a manual? Didn't know Keystone had such a thing!