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Old 07-21-2009, 09:59 AM   #1
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1992 Dodge house battery not charging while vehicle running

I have an older Sportsmobile, it is a 1992 and the house battery recieves no charge while the van is running. I have all the wiring diagrams but admit that I am no expert. I have followed all the wires to see if the proper conectoins are made and it seems like everything is hooked up right. Any thoughts on where I should begin looking for the problem ? Thanks

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Old 07-21-2009, 01:16 PM   #2
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Re: 1992 Dodge house battery not charging while vehicle runn

Check to see if the house battery is connected to an isolator. Check voltage on both sides of the isolator. While the engine is running the voltage should be the same or close to the voltage at your starting battery usually around 14 volts. If it different by a large factor the isolator may have a bad connection or it might have failed. I assume you are not having problems with the starting system. If the isolator seems to be working then you can check it at the house battery.

Check voltage at the house battery (on the post and on the lug...it should be the same voltage as the alternator maybe a little less) with the vehicle running somewhere between 13.2 to 14.2 or in that area. If you get a different voltage at the lug compared to the terminal on the house battery, take off the battery cable, clean it up and put it back on. Recheck the voltage without the engine running then start it to see if the voltage comes up. There is a post stating corrosion is heavy at the separator...make sure it's clean and the connections look good.

That's where I would start. You could have more than one problem (such as poor connections elsewhere ) or an intermittent problem which is hard to diagnose. If you always are getting a good high 13-14 volt charge to the battery and the voltage drops below 12.2 when you shut down the engine for a while, the battery itself might be bad. Most RV repair centers have the good equipment to help you out.

Good Luck and post back what you find.

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Old 07-22-2009, 12:54 AM   #3
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Re: 1992 Dodge house battery not charging while vehicle running

Dave is right on with the Isolator, which is what the '92's had. Probably a Surepower model 1302. Very common for these to have corrosion at the terminals, or loose terminals also. You'll want to seriously consider going to a Battery Separator if the Isolator is bad, you may want to update to the Separator anyway.

I just re-read your post and noticed that it was the house battery that wasn't charging, you probably have a bad 50 amp auto-reset circuit breaker.To locate the circuit breaker, you'll want to first find the Isolator (about 3"x3"x7" with fins). Trace the large wire from the Alternator, it will connect to the center terminal on the Isolator. The outer terminals are for the house and starting batterys. Trace the wires on these outer terminals, one will go to a factory Dodge power distribution box, the other will connect to a small metal cased 50 amp Auto-reset circuit breaker, and then continue on to the house battery. This 50 amp Auto-reset circuit breaker would corrode internally and cause all types of problems. On later model SMB's with the Isolator (pre-Battery Separator models), the 50 amp circuit breaker was omitted from the system. You can either replace the circuit breaker, or bypass and omit it like the later models.

If you omit the circuit breaker, make sure you trace the wire all the way to the house battery to confirm it is not subject to any chaffing or shorting out. Add cable/wire loom as needed if you are concerned about any potential wear areas.

John K.
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Old 07-22-2009, 07:49 AM   #4
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Re: 1992 Dodge house battery not charging while vehicle running

Thank you guys for giving me some starting points, I was a bit overwhelmed by this system but I feel confident that I can figure out what is going on now. We are heading to the mountains for a few days and I will tackle this as soon as I return and post my progress.
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