Battery Box Corrosion
Dear RV Doctor:
First, thank you for your very informative seminars. I attended three in Perry and was pleased every time. We were unable to take our motorhome to the convention, so we stayed off premises. When we returned home, I was eager to use some of your advice. When I opened my battery compartment, I discovered that I have a corrosion problem. I need to clean some metal and then paint it. Do you know of a paint for metal that will stand up to battery acid? I had a similar problem with the battery box in my airplane. I used a product made by Randolph Aircraft Products. Aircraft Spruce & Specialty Co. sells it for $17.50 per quart. They also recommend first priming with an epoxy, which costs $48.35 a quart for the base and $21.75 per pint for the catalyst. It is generally applied with a brush or roller to any metal area that may be exposed to leaking battery acid. I just wondered if you knew of a cheaper way to go.
Bob Hummell, F350558
Leesburg, Florida
Thanks for your kind words, Bob.
My opinion is if the battery bank and the compartment are kept clean and dry, and the charging and discharging rates do not exceed the battery bank specifications, it’s not necessary to have a special coating to guard against the acid. I’d start by using a wire brush on the box to eliminate the corrosion and then paint it with a rust-resistant paint. Try it for a season and see how it goes before using the fancy stuff. If you do this once each year as part of annual maintenance, I would think you could forgo the extra expense.
I’m sure the Randolph asphaltic coating would be superb, too; perhaps just not necessary. I’ve not tested the Randolph product. Evidently it has worked for you in the past with your airplane. If your coach is prone to overcharging or the creation of acid vapors that can quickly deteriorate the box, I’d imagine the Randolph product will do the trick.
Refrigerator Operation
Dear RV Doctor:
This has me concerned. It happened once in March 2016 at the “campground” during the FMCA convention in Perry, Georgia, on a 30-amp site with a 50-amp 2005 Itasca motorhome. My refrigerator warmed up inside and switched over to propane with the message “LO AC.” For about an hour and a half, I could not get the refrigerator to run off shore power. It would run only on propane, and even then, the interior temperature warmed to 54 degrees. After about an hour and a half, I put it back on AC, and it operated normally. The problem has not reoccurred since. Any idea what happened, or why? My personal theory is that we had a “brownout” in the campground. And why wouldn’t it hold the cold when running propane?
Morris Devereaux, F448748
Roswell, Georgia
Were you plugged into the grid at Perry or on one of the generators? In either case, it sounds like you suffered from a lower-than-normal voltage situation that eventually dropped out altogether. By the time the refrigerator realized it and switched over to propane, the box had already warmed to some degree. We had a couple of hot days there.
Absorption refrigerators do require annual maintenance to set the pressure and clean the orifice and the burner/flue, etc. If you haven’t had that performed lately, that’s where I would start. The fact that it would not cool back down on propane could indicate improper propane delivery line pressure or a regulator problem. The problem would have been exacerbated if the sun stayed on that side of the motorhome during the hottest portion of the day.
I agree that the refrigerator either suffered a brownout or a low-voltage situation, but even that should not cause an issue with the refrigerator’s propane operation. I’m thinking it’s a separate issue and probably easily rectified by a simple clean-and-service procedure.
Oil In The Battery?
Dear RV Doctor:
A couple of years ago a friend of mine said he read on an online forum that adding mineral oil to each cell of the batteries will extend the battery life. Have you ever heard of this before? I sure enjoyed the two seminars I attended at the FMCA convention in Perry!
Alvin Mitchell, F429297
Eastpoint, Florida
I’m not sure I’m convinced that adding mineral oil to just any old battery will actually extend its life, but ThermOil batteries of old and their current additives apparently do provide a layer of oil to help contain the recombinant gases associated with battery charging and discharging. At one time, more than a few RV manufacturers installed ThermOil batteries right at the factory. However, I’m not sure I would recommend the addition of oil for just any battery unless you get approval from that particular battery maker.
For some interesting reading, check out www.thermoil.com. One small disclaimer: I have not tested or evaluated the ThermOil additives.
Perplexing Multiplexing
Dear RV Doctor:
My 40-foot Alpine Coach motorhome is equipped with Vansco Multiplex Modules. The indicator lamps do not light. I want to remove the plugs on each unit and swap them to see whether one will light, but I can’t figure out how to unplug them. I’ve disconnected the plastic clip, but I can’t pull it out. I’ve checked the voltage on the incoming wire plug, and there are two lines that each measure 12 volts. Can you please advise me?
Llonald Mixell, F385148
Vero Beach, Florida
The most common problem associated with multiplugs is maintaining a good, clean, tight connection. In some cases, the wires may not be making good contact in the opposite side of the plug. Your problem also could be a fuse.
Looking at the photos you supplied, it appears that once the clip is removed, the plug should just pull straight out. I hesitate to recommend prying on the plug, but it just may be a tight fit that requires an extra nudge to break loose. If you’re comfortable, and you’re sure there is nothing securing it further, you might try to carefully pry it a bit to loosen it. It also may be necessary to remove the cover to gain access to the fuses, relays, or other components for more in-depth troubleshooting.
Remember, clean, dry, and tight is important for all connections, including those wires inside the multiplug. I’ve sent you the Vansco system service manual. Let me know how this turns out.