Surfing around tonight, I came across an interesting website of a fellow who has really spent some time improving his motor home. An interesting addition he made was to put mineral oil into his batteries to lessen evaporation loss of water and to a lesser extent the bubbling out of sulfuric acid. I have never heard of this, but according to him, this has been done a lot on the past in certain places.

Has anyone else ever heard of this practice?

ADDED MINERAL OIL TO BATTERIES
I had read about the oil that they sell to add to your batteries to stop or minimize the corrosion around them. I did some research and it seems that Edison used oil in his original batteries that were used along the railroads. In fact, they say you can still find the bottles along the tracks some places. Anyway, I did some research on the stuff that is being sold today and found the patents for it. Turns out that it is primarily mineral oil with a few other additives, primarily for color. I made a call to a friend of mine who is a chemist to see if there would be any reaction between sulfuric acid and mineral oil. He said that not only is mineral oil just fine in a battery, HE had used it for just that many years ago while working as a mechanic in his Dad's truck shop. He said that it worked great to stop the corrosion and out-gassing so based on this information (and Edison's experience!) I added 4 ounces of USP grade Mineral Oil (intestinal lubricant!) to each cell in my 6 volt, deep cycle batteries. That amount seems to result in a blanket about 1/8 - 1/4 inch thick. If you take a cell cover off now while the batteries are charging, there are little tiny bubbles on the top of the oil. No more big popping bubbles to carry sulfuric acid out of the cells. We'll see how it works! I will report back in a few months.

April 2003 UPDATE:
It has now been over one year since I first added the mineral oil to the batteries. I have had to add a very small amount of water one time in that last year. I recently did a load test on the batteries and I cannot tell that there is any capacity loss at all in the last year. I don't believe that the addition of mineral oil has in any way harmed the batteries and it has certainly eliminated the corrosion that was occurring on the terminals. I will definitely use the oil in any deep cycle batteries I purchase in the future.

Here is the website I got this info from: http://users3.ev1.net/~crossstitch/UltrasportMods/Ultra...ods.html#CRASH%20BAR



------------------
Bill & Georgene Goodwin
92 Regency 36ft
300hp Cummins
Gillig Chassis

Works fine. I use it. I remember an old lady in our town who had a Baker electric car that used genuine Edison battery oil on top of the elecrolyte. It doesn't completely stop the outgassing, but there is less acid corrosion of terminals and hold downs. One caution: When you use a hydrometer, be sure to squeeze the bulb after the tip is submerged to eliminate the possibility of sucking in a little oil. The oil makes reading the float difficult.

Bill,
It was my guess that you would have knowledge of this accommodation for batteries. It makes sense to me, does it lessen the frequency of adding water to the batteries? Are there any negatives to this use of mineral oil in a battery? Do you use regular mineral oil of is there a commercial product that is better?

Bill

[This message has been edited by goodwinw (edited January 10, 2004).]

There is a commercial battery oil. I believe I saw it at CW a while back.

http://www.thermoilbatteries.com/faq.htm


http://www.survivalunlimited.com/thermoil.htm

There is also a whole battery that is a regular battery with oil floating on the electrolyte.

I have used regular mineral oil in my deep cycle batteries since the seventies, but it is possible that the anti-foaming additives in the commercial oil might be a bit better. With my soda slurry on the batteries and LPS3 on the metal parts, I have no corrosion problems. I have good solar and line chargers, so my batteries are charged gently anyway. So, I am unable to report any dramatic results. I have recommended oil to some of my rabid fisherman co-workers who really use their trolling batteries hard, and they report an improvement in battery top cleanliness and less electrolyte loss.

But I do believe the oil reduces the turbulence of the bubbling. It would be fun to have an old glass railroad batteries and charge it, one cell with mineral oil, one with Thermo Oil, and one with no oil.

Considering the cost of a pair of Trojan golf cart batts, I will probably spring for the ten dollars and buy the Thermo Oil next time. Their claims of anti-foaming additives and such like make sense.

All my vehicles have sealed AGM batteries for starting, so I can't report anything on them.



[This message has been edited by bill h (edited July 01, 2005).]

Bill, thanks for the links and the info. I think I might just give this stuff a try this spring when the Barth comes out of winter storage. Bill

Will the oil protect from freezing?
Went out to Barth today and found that power had been cut off, and since I had heat running, the batteries were very dead. Luckily I'm working on the battery tray and had two of the four golf car batteries disconnected. After I got power back on, I went to check out batteries and they were very, shall I say, 'plump', opened vent cap and top it was solid ice.
Guess I'll have a set of four new batteries shortly instead of the two I just got.






------------------

89 Barth Regal 32
Runs like a Deere
New Hampshire



[This message has been edited by Jack (edited January 10, 2004).]

No, the oil will just float on top of the electrolyte. The only thing that will prevent a cold battery from freezing is a full charge. That is, a high specific gravity reading on the hydrometer.

A fully charged battery will freeze at around -75F. A half-discharged battery, with a specific gravity of 1.190 will freeze at -10F. A battery at 75% discharge, with a sg of 1.155 will freeze at 15 deg F above zero.

It is a good idea to take your batteries inside for winter storage. That failing, be sure they are fully charged and then disconnect them to assure that no phantom drains will pull them down to where they will freeze.