using house battery

[littlejohn]

I have a 1990 Ford Fleetwood Jamboree. I don't understand why I have to turn the ignition to the on position to get power to the house. My other RV had a switch that you used to isolate power. Previous owner never returns my calls. I am still new to this rig.

 

[Gary RV_Wizard]

That means your house battery isn't connected or is flat dead. When you turn the key on, the engine 12v power activates and apparent;ly is your only source of 12v power to the "house" part. Does the RV have a house battery disconnect switch? Is it Off or On?

 

[littlejohn]

No, I can't find a switch to save my life. When I turn the ignition to the on position you hear an audible click and then you get power to the RV but not without the key turned on.
I have two batteries hooked up in parallel. The vehicle and house battery. They both have a charge but nothing until I turn the key to ON.

 

[John From Detroit]

The switch may be just inside the door (in the step well) on the dash or on a control panel, it may be marked AUX or USE/STORE, But there is a switch..

This assumes... of course.. that you HAVE a house battery (it was not removed) and that it is properly connected,,, This means all connections are good.

There may also be a fuse or circuit breaker(s) in the line to said house battery.

An Automotive Test Lamp (Most Auto Stores or Depratments) can be real handy.. Starting at the battery (touch tip to one terminal and clip to the other) if you have a bright light good, if dark, problem found.

Now move the clip to the chassis, and test again,  then move out along the positive wire till light turns to dark

If you move the clip.. Re-test last known good point to insure you have a good ground.

 

[Dvan]

No, I can't find a switch to save my life. When I turn the ignition to the on position you hear an audible click and then you get power to the RV but not without the key turned on.
I have two batteries hooked up in parallel. The vehicle and house battery. They both have a charge but nothing until I turn the key to ON.

Did you say your house and chassis battery are wired in parallel, or did I read that wrong?

 

[2kGeorgieBoy]

I would suggest that the first thing you do is take both batteries out and have them load tested. No sense to spend time troubleshooting when one of the batteries is bad. If they are good or if they are bad and are replaced and the problem still persists, then proceed with the troubleshooting. While a test light is good, they really need to be load tested so you know what you're starting with.

 

[littlejohn]

Yes, I was told earlier in the post that my batteries are wired in parallel giving 12V and twice the amps. They both power the house. The previous owner did not tell me all the expensive repairs this RV was in need of and figures I will harass him so he won't accept my calls. I can't get him to answer any questions I have. SADLY! I never asked about the disconnect because I thought it would be in plain site when looked for. NEVER ASSUME!

 

[Alfa38User]

A physical examination of the wiring around and on those batteries is needed to confirm or deny what they are. Before disconnecting anything, take a picture of the wiring involved to help when reconnecting and perhaps make a little diagram. Look for loose and orphan wires in the area too. A chassis battery should be found close by too. A chassis or engine battery is seldom wired in parallel with another battery as there is usually no need. The exception might be for big diesel engines where multiple batteries may be provided.

A pair of batteries truly wired in parallel would be for house batteries although many RV's may have only one house battery initially. I would suspect some playing around with the wiring and battery arrangement if you do find two chassis batteries in parallel and perhaps dead or missing house batteries. The symptom of requiring the key to power the house as you describe point to this. On a class C RV the disconnect switch is possibly among the many switches on the lower dash and may not be well labeled.

House batteries can often be skillfully hidden in places like a box under the RV stairs.

 

[Gary RV_Wizard]

I beg to differ. It is normal for the house and chassis batteries to be wired in parallel, but they are separated by an isolator device of some kind and they get connected only when the ignition is on (which implies the engine alternator is running).  Every motorhome I've ever seen has house and chassis systems in parallel, with an isolator of some type.

It is entirely possible that this 1990 Jamboree has an isolator diode device rather than an isolation relay, and I suppose it is possible it has no battery disconnect. Systems were often much simpler back then...

I also don't think a load test is important at this stage of analysis. If the house battery is showing reasonable voltage, even just 12.1 or so volts, it should come online and power lights. The battery may be in poor condition, but it should still work for simple things like lighting.

The key concern here is how the house battery is physically wired to the house power distribution panel. Clearly house battery power isn't making it into the wiring, so it is necessary to trace the path from house battery to the house 12v distribution (fuse) panel. There may be a fuse or breaker or relay in the path, or there may simply be a broken or corroded wire connection. Also look for the point where the chassis and house battery wiring come together, probably at some sort of isolator device. You know the wiring is OK beyond that point because the chassis battery power gets through. The problem will be in between this junction and the house battery.

Some photos of the batteries and associated cabling would be a big help in diagnosis.

 

[Alfa38User]

Gary

You are obviously correct, but for me, I don't consider the systems to be in parallel unless 1: the engine is running and the relay sets it up, or 2: that little 'booster' switch is operated, again those relays in play or 3: I can see those heavy cables connecting one battery to another. With diode  isolation they are 'sort of' in parallel but.... My point is the system simply has to be examined and the various components identified as engine battery vs house batteries and go from there.... With everything just sitting, I consider them as 2 separate 12V systems.

 

[Gary RV_Wizard]

The previous owner did not tell me all the expensive repairs this RV was in need of and figures I will harass him so he won't accept my calls.

Well, it is a 26 year old vehicle and a 26 year old house!  Too bad you didn't come here for advice before buying - we could have told you that nearly all old RVs are money-pits as well as a non-stop repair & upgrade project.

 

[littlejohn]

Actually Gary, I am very happy with this rig. Low miles and the interior is in wonderful shape and the price was right. By the way, I did visit this forum and read about others fixing up older units. We all aren't rich!

 

[Gary RV_Wizard]

It's not a question of rich vs poor; it is one of expectations.  I am merely suggesting that have to expect more than a few minor repairs with any old vehicle or house. You did your "due diligence" and then bought the RV. As long as the seller responded truthfully to your questions prior to the sale and did not lie about anything, he really doesn't owe you anything more.

If my opinion is offensive, it is not intentional. Just trying to be realistic.

 

[Frankedj]

we could have told you that nearly all old RVs are money-pits as well as a non-stop repair & upgrade project.

If you upgrade to the heaviest duty stuff it will empty your wallet even faster.

I have to say that learning and doing in an older RV is kind of nice. While technology might have changed over the years you can still learn the basics about how things are done in an RV if you have never worked on the systems before.

My House batteries(three flooded 12v in parallel) were dead and unhooked. They can be charged through the alternator, generator or from the 30A hookup with the convertor. They have a remote store/use switch and a solenoid to disconnect them. I am replacing them with six 6v AGM and adding in a 2,000 watt inverter. Seven parts plus all new battery cables... about 5 grand including shipping. Money pit, yes, but for things that can move with me when I upgrade to a newer RV.

Before I am done I will be spending considerably more for all of the parts & new tires than I paid for the RV itself. This one is all about learning the systems, parts and construction. I spent a year reading here before I bought anything.

 

[oldme]

This may help understand the system.
The left is "ckickable" for different selections:
http://www.metrotrekkers.org/utility/electrical.htm