Community Forums

Goofaroo · 04-26-2014, 11:37 AM

I bought a 95 Rexhall Aerbus last fall and have been doing some maintenance on it. Everything has worked fine when plugged into shore power. The house batteries have been dead and the generator leaked oil so bad it was unusable. Now I have repaired the generator and replaced the house batteries with new AGM units. The generator now fires right up and everything works fine under 110 power from the generator. With the generator running, the battery disconnect panel glows red for the house batteries. However, if I switch off the generator, I can not get the house batteries to engage and give me 12V power to run the lights, etc.

I'm sure I'm doing something wrong but what?

Also, while I'm asking....... The in-dash stereo only works with the key in the ignition and in the accessory (or on) position. Is that normal or should I be able to use it from the house batteries? Can I just count on it not discharging the chassis battery as long as I am plugged in or running the genset? Should I just leave it off and use a alternate music source?

BFlinn181 · 04-26-2014, 11:44 AM

Sounds like your battery isolator relay is not making a connection or is turned off. Usually near entrance door, the switch disconnects house batteries when storing RV. Check to see if LP sensor, electric entry steps, etc. are also not working, usually they bypass the battery shut off and continue to operate even when isolator is off. Check ground connections, a common issue. When you locate the battery isolation relay, you can temporarily bypass by hooking both large gauge wires to the same post on relay.
Many RV radios have a switch on dashboard to switch power from ignition control to house battery control. My switch is identified by a musical note.

"007" · 04-26-2014, 11:50 AM

You always need your battery disconnect switch on when ever using your coach so your converter can charge your batteries while plugged in or the alternator when your driving your coach.
Here is a link that will explain how things work in your coach 120 and battery systems.
When you shut off your GEN is your shore line plugged in?
Battery cut off for house batteries needs to be on to supply 12v from house batteries to your lights and control units of appliances.

Goofaroo · 04-26-2014, 12:04 PM

Quote:

Sounds like your battery isolator relay is not making a connection or is turned off. Usually near entrance door, the switch disconnects house batteries when storing RV. Check to see if LP sensor, electric entry steps, etc. are also not working, usually they bypass the battery shut off and continue to operate even when isolator is off. Check ground connections, a common issue. When you locate the battery isolation relay, you can temporarily bypass by hooking both large gauge wires to the same post on relay.

There is a battery disconnect panel right in the entry. I can turn the chassis battery off or on, but I get a "click" from the electric panel under the hood when I try to turn on the house batteries with no results. If I turn off the chassis battery, nothing works including the steps. It sounds like I need to bypass the relay and see if it fires up. Thanks for the tip.

What does it mean that the house battery light comes on when I am running the genset?

Quote:

Many RV radios have a switch on dashboard to switch power from ignition control to house battery control. My switch is identified by a musical note.

I don't seem to have that feature.

Old Bounder · 04-26-2014, 01:21 PM

Quote:

You always need your battery disconnect switch on when ever using your coach so your converter can charge your batteries while plugged in or the alternator when your driving your coach.

The house battery disconnect (batteries ON) does not have to be on for the alternator to charge the house batteries.

BFlinn181 · 04-26-2014, 01:39 PM

Quote:

Originally Posted by loulong

The house battery disconnect (batteries ON) does not have to be on for the alternator to charge the house batteries.

Maybe not for charging, but any other house function requires the 12 v power. I believe 007 was trying to suggest that some seem to think the disconnect switches should be shut off while living in the coach. They are usually for STORAGE only.

wa8yxm · 04-26-2014, 03:05 PM

I agree the battery isolator is not working this may be due to:
BAD SOLENOID
Tripped Circuit Breaker
Bad connnection
Bad switch
Blown 5 amp fuse in the battery control center.

And the ever popular "Other". But those are the biggies.

ON MY RV, when it was less than a year old the blasted rocker switch failed .. Worked fine for "OFF" (STORE) but for ON (Use) no joy.

Removed power (pull said fuse) cycle 50-100 times, restore fuse and it works.. For 8 years now.

Old Bounder · 04-26-2014, 04:36 PM

Quote:

Originally Posted by BFlinn181

Sounds like your battery isolator relay is not making a connection or is turned off. Usually near entrance door, the switch disconnects house batteries when storing RV. Check to see if LP sensor, electric entry steps, etc. are also not working, usually they bypass the battery shut off and continue to operate even when isolator is off. Check ground connections, a common issue. When you locate the battery isolation relay, you can temporarily bypass by hooking both large gauge wires to the same post on relay.
Many RV radios have a switch on dashboard to switch power from ignition control to house battery control. My switch is identified by a musical note.

You are confusing (and/or misusing) the term "Battery Isolator". You are describing the function and control of the "Battery Disconnect solenoid" and calling it the "Battery Isolator", which is a totally different solenoid with a totally different function.

The OP does appear to have a problem with the "Battery Disconnect Solenoid" or possibly blown fuses, or tripped DC circuit breaker, that are preventing his house batteries from feeding his DC distribution system.

BTW - Hooking both large wires together on the same large terminal of the "Isolation Relay" will only connect the chassis and house batteries together and DEFEAT the purpose of an isolator all together. There are better ways to determine if the Disconnect Solenoid is good or bad, than moving large battery cables.

Goofaroo · 04-26-2014, 06:49 PM

You guys have given me some things to look into. It sounds like I have a problem so now I can start poking around. Initially, I thought maybe I was just doing something wrong. This has been quite a puzzle.

Goofaroo · 04-26-2014, 06:51 PM

Quote:

BTW - Hooking both large wires together on the same large terminal of the "Isolation Relay" will only connect the chassis and house batteries together and DEFEAT the purpose of an isolator all together. There are better ways to determine if the Disconnect Solenoid is good or bad, than moving large battery cables.

Such as?

Old Bounder · 04-26-2014, 07:58 PM

Quote:

Originally Posted by Goofaroo

Such as?

First you would need to have, and know how to use, a DC multimeter.

You would need to know the difference between an Isolator/aux start relay and a Disconnect relay.

You would need to know if the converter is charging the house batteries when plugged to 120vac. or generator.

What happens at the disconnect panel if you switch the house batteries OFF and ON while the generator is running?
What voltage do you have on the house battery Positive post while gen is running? What voltage there with gen OFF?

Goofaroo · 04-26-2014, 09:42 PM

I'll find out tomorrow and report back.

Nuclear · 04-26-2014, 10:27 PM

Interesting post...I'm hoping you guys can provide some insight on my post "how do you troubleshoot an inverter" as I too am having similar problems. If I had a good schematic of the wiring, it would be much easier to narrow down the fault.

Goofaroo · 04-27-2014, 11:13 AM

Went to my storage unit and here is what I found:

Chassis engine off and key in the off position: House batteries read 12.48V. Fire up the generator and let it get warmed up and now the light on the disconnect panel glows red but will not turn off. Still 12.48V at the batteries so apparently not charging?

Generator off and chassis engine running: Battery disconnect switch allows me to turn the house batteries on or off. With the house batteries switched on I now have full 12 volt power to the house. Chassis battery can not be turned off until ignition is turned off and then it can be manually turned off. The house batteries can still not be switched on unless the ignition is on.

I am not hooked to shore power at this time.

Any ideas? I checked a fuse on the house battery disconnect solenoid and I inspected all other fuses. It also had a couple of breakers with a test/reset button which I pushed and nothing happened. Everything in the control box is very tidy and clean.

There is a momentary switch on the dash next to the generator start switch. I assume that this momentary switch is to allow me to use the house batteries to assist in starting the engine if the coach battery is weak. It seems to do nothing and there is a solenoid (or relay?) in the fuse compartment for that switch. However, I am not sure if I checked that with the ignition switched to on.