Alternator voltage problems

[jkpsr@usa.net]

I have a long, sad, story to relate. In Fall of 2007, we were on a caravan in Atlantic Canada, when I noticed my house batteries were not getting charged, then that my chassis batteries were also not getting charged, so I had my wife start the generator so we could get to somewhere to get repairs. I found a very well rated truck service facility in New Brunswick, who I called to warn them we were coming. I told them I had a 130 amp Leece Neville alternator, so they told me they could give me a 165 amp one at a good price, so I said to go ahead and get one ready for me. I discovered, later, that the new alternator was a Delco, not a Leece Neville. When we arrived they started to work on my coach, but they spent over four labor hours installing the part. The service manager was nice enough to eat some of these charges because he believed it should have taken one hour at most. We picked up out coach and proceeded to our campground, but we forgot to turn on the Boost switch so the chassis batteries would get charged. Some days later, when we were going to leave, we found that the chassis batteries were dead, so we turned on the generator for about a half-hour and tried again to start with success. My wife, who is the driver, noticed that the volt meters were reading zero, so we concluded that the service center had miswired the alternator, so we found a truck repair place outside of Boston, stayed the night and had them diagnose the problem. After spending another four hours of labor, they told me that they were getting the proper voltage on the generator side of the battery isolator, but low voltage on the other side, so I concluded that I would have to replace the isolator and we continued home, stopping to run the generator to keep the batteries charged from time to time. I ordered and received a new 200 amp isolator, and took my coach to a third service center, US Coach in Berlin, NJ, and had them replace the isolator, new batteries and a number of other unrelated things. Again, they had no end of problems getting things to work and even had to call Delco, who built the alternator, for help rewiring it correctly. They pronounced it good and we went on our way. We did notice, however, that the dash voltage meters were only reading 12 volts, but we experienced no trouble starting. We, however, have kept the coach on shore power for the last few months. I fear our problems are not behind us, because of the low voltage readings. My wife took the coach out a week ago and said the voltage read high at first, but dropped to 12 volts shortly afterwards. Is there any way I can get my Delco alternator to work properly, or will I have to buy a Leece Neville to finally repair my problem. Does anyone out there have a suggestion?

[tbutler]

We had alternator problems on a used coach we purchased eight years ago. We went to Cummins in San Diego and they weren't having any luck finding an alternator. I called Monaco and talked to the tech people who gave me the information needed to find the correct alternator. It turns out the previous owner had taken the motor home to a truck shop and they had put a regular truck alternator on the motor home and then wired it to make it work with the motor home. A regular alternator has just a single post for the hot wire. The correct one for our motor home was a dual post alternator. One post for the engine batteries and the other for the house batteries. I think this is still the case with our current motor home. You didn't say what make/model motor home you have or if it is gas or diesel. I would check with the manufacturer if you can and if not find a reputable dealer who can help you. Non-motor home service centers may not have the information or experience to handle the special case of a motor home.

[jkpsr@usa.net]

We have a 1996 Foretravel U270, but we have a battery isolator, which would indicate that only one circuit is there. I talked to Foretravel, who said that I should use a Leece Neville, bur gave me no explaination. Maybe I should contact Leece Neville. Thanks for your suggestion.

Jack

[tbutler]

One other thing to pass along. The reason give for our motor home using the Leece Neville was that their alternators produced a higher percentage of the rated amperage at running temperatures than the "other" alternator. I can't remember what the other generator was when this was given as a reason in 2002 when we had our work done. I know that the alternator that was in our rig was rated higher amperage than the Leece Neville but they specified the Leece Neville. Also, I noticed I wrote battery isolator when I meant to refer to the battery cut-off switch and a relay associated with that. Let us know what the resolution is when you finally find the problem.