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BadLarry · 09-03-2014, 09:16 PM

Hello,
Im back with another question !

I just got a 1984 Shasta Class C built on a Chevy 1 ton can chassis. I believe this to have been made by Coachman.

Under the hood at the Battery, there are 2 Positive cables. When I got the MH the "Extra" cable was disconnected from the battery, I connected it and haven't noticed any changes. I decided to contact the previous owner and ask him what it was for, He told me that it connects to "House" battery to the front battery to charge it when the engine is running. While I haven't had the time as of yet to slide under and follow that cable, Wouldn't I find an isolator ? I looked around and I didn't see one. Wouldn't that also mean that I would be able to locate an "Emergency start" switch to bypass the isolator should the front battery go dead ?

Totally confused !!!!

Skip426 · 09-03-2014, 10:07 PM

Sounds like some one Jerry-rigged the system . It wouldn't have left the factory like that.
Chances are the dual battery isolator failed, and some one , removed it and left what you found.
Not , normal, not particularly safe.
Get out the volt meter and start testing, if the cable shows , house battery voltage when it's not hooked up, it should never have been left hanging.

EDIT: Most class C's don't have an emergency start set up, but there should be an isolator. Without seeing the cable , I'm thinking it's not heavy enough to supply starter voltage and amps.

BadLarry · 09-03-2014, 10:18 PM

Its a heavy cable, It has a nice "factory / oem " style clamp, not a replacement looking one. Where would the isolator be located ? Closer to the house battery ?

and thanks !!

r___r · 09-03-2014, 10:44 PM

Quote:

Originally Posted by BadLarry

at the Battery, there are 2 Positive cables. When I got the MH the "Extra" cable was disconnected from the battery, I connected it and haven't noticed any changes.

Wow, BadLarry, I think you dodged a potentially hazardous incident.

If there was a disconnected cable that looked as if it was used for power, and I had no knowledge of where the other end was (connected, or, just floating freely and exposed), I would have made the call to PO, or, physically traced the wire down confirming it's status before I connected it.

So now that you have talked to PO, if I were in your shoes, I would confirm its status that its secured and not floating freely.

Good luck to you,

Rich

BadLarry · 09-03-2014, 10:59 PM

Well, This was my theory on connecting it... IF it is connected to the house battery, there should be an isolator. With an Isolator installed, it would prevent the cable I found at the front from being live unless it was connected to the front battery. As far as the other end.. who knows at this point, I checked it ( at the front ) for V+... nothing. I also checked it for continuity to GND.... Nothing. Without a V+ or V- being present, I figured it had to be a supply cable. It fits the theory of an Isolator.. I just cant find it. Next time, Ill Disconnect the house batt and check the cable for V+ and V- , if its being fed from the front Batt, it should show V+.. Ill keep ya posted. Id assume at this point that the Isolator is hidden somewhere and I just haven't found it... Ill test the cable on house batt and If that doesn't give me any results, Ill just have to get my lazy butt under there and follow it :(

Skip426 · 09-03-2014, 11:13 PM

RV's of your vintage the isolator was usually in the alt. charge wire.
If the cable you have is battery cable size it might be something else, perhaps attached to a marine style battery selector switch hidden somewhere. Here's a picture of a typical dual battery isolator install; showing only the charge wiring.
In the picture the red handled switch, above the left battery , is a manual battery interconnect. ( Emergency start)

BadLarry · 09-03-2014, 11:37 PM

That makes more sense. If I disconnect the house batt, I still wouldn't get V+ on the cable unless the engine is running, regardless if the 2nd + cable is connected to the front batt.

the switch makes more sense for the 2nd cable at the front, as is didn't have any + or - as the switch is more than likely open.

I hope its just not a dead ended cable loose somewhere. There must be a Switch somewhere.. Time to get dirty I guess.

I planned on applying a coat of liquid roof and installing a new A/C gasket this weekend, weather permitting. I think it will be a good time then.

As a side note, there is a potential for rain this weekend... the day after I had planned on coating the roof. Think its still ok to do ? Will 24 hrs be enough time before it gets wet ?

Skip426 · 09-03-2014, 11:46 PM

Minimum dry times will be on the container.
Personally, the longer the better.

BadLarry · 09-03-2014, 11:52 PM

understood. I haven't picked it up yet, Ill read it over before I apply.

I just uploaded some pics.. I guess this is a test...

Michael_Locksmith's Library | Photobucket

BadLarry · 09-03-2014, 11:57 PM

What I meant to say was, the order of liquid roof came in and I haven't gone to pick it up yet.

wa8yxm · 09-04-2014, 10:48 AM

My rig has 3 positive cables on the chassis battery (Well it did, I made a mod so it's one now and a small terminal block nearby)

Steps, Engine and Battery control (The link to the house)

BadLarry · 09-07-2014, 10:49 PM

Is it possible that the generator would not charge the battery? Maybe it only charges when its plugged in? That doesn't make any sense, Why would someone design the converter that way. When the generator is running and I remove the Batt term.. the Gen dies..

What I get from that is the Gen is running off the battery and is not charging it: as it is not even able to run without a battery.

Skip426 · 09-08-2014, 01:13 AM

I'll have to check my gen set owners manual, but I believe the gen set I have powers the converter/charger with 110v and the C/C, then charges the battery. No 12v output from the gen set.
But I will double check.