Community Forums

skyviewman · 03-24-2012, 04:38 PM

I want to add mineral oil to my batteries. First of all do you add it to the chassis batteries as well as the house batteries. I understand from reading on this site that I should add 4 oz. to each cell. How much water should there be over the top of the plates in each cell before I add the oil? After adding the oil how far from the top of the cap should the oil be. I want to make sure that after I have added the oil I have a reference point so I know if and when I should add water if needed.
thanks

Midniteoyl · 03-24-2012, 04:44 PM

4 oz seems like a lot.. I thought it was 1/8-1/4 per cell?

GaryKD · 03-24-2012, 05:44 PM

Hi skyviewman,
The rule of thumb I know is:
2 oz per cell for a 12 VDC battery
4 oz per cell for a 6 VDC battery

I have not seen a flooded chassis battery in over a decade. I have AGM coach batteries. I did add mineral oil to my coach batteries, when they were flooded technology but that was many years ago. From what I remember, I took out all the water above the plates. There was still a bit of water covering the plates. Then added the mineral oil. Then added some distilled water to each cell to bring the water level to the bottom of the fill hole.

Mineral oil will float on top of the distilled water in the battery.

steelheadbluesman · 03-24-2012, 05:55 PM

Oil in flooded batteries? New to me.... What does it do?

BFlinn181 · 03-24-2012, 06:09 PM

Quote:

Originally Posted by steelheadbluesman

Oil in flooded batteries? New to me.... What does it do?

It slows down the evaporation of water from the batteries. You don't have to fill as often.

Rick Long · 03-24-2012, 06:24 PM

Unless your batteries are constipated

, don't put the oil in them.

denochs · 03-24-2012, 06:36 PM

Mineral oil also slows down the oxidization/corrosion (what ever you call it) and helps them last longer. Do your homework. But, what GaryKD said sounds about right.

In fact, if you buy a can of that spray solution that prevents corrosion, the main ingredient in most to of them is mineral oil.

Dave

steelheadbluesman · 03-24-2012, 06:56 PM

Thanks, guys, I appreciate the answer. Guess I'll try it.

RJay · 03-24-2012, 07:03 PM

4 oz. of oil in a 6 volt battery will provide about 1/8" layer of oil on top of the electrolyte. When the battery is properly serviced there is about 1/2" electrolyte below the oil to the plates allowing a hydrometer to get below the oil layer for an accurate specific gravity check.

stuhly · 03-24-2012, 07:28 PM

I put 2 oz in my 4 six volt batteries 11/2 years ago. Have yet to add water and we use the MH a lot. Have not had to clean corrosion at all. Only problem I see is it hard on the rubber gaskets. Just go to battery shop and get some more gaskets off trade in batteries.

Fred1609 · 03-24-2012, 07:33 PM

This is great information. It makes perfect sense but I would have never thought of it. Thanks for sharing this.

KIX · 03-24-2012, 07:39 PM

Golf carts use multiple six volt battery banks and are recharged more frequently than most motorhomes. I put mineral oil in my GC batteries several years ago. I'm a believer.

One of the effects of off-gassing during heavy charging is corrosion of nearby metals. That corrosion is drastically reduced when mineral oil is floated on top of the electrolyte.
YMMV

steelheadbluesman · 03-24-2012, 09:19 PM

My batts seem to need watering about every couple months. BUT, every once in a while I get there a little late -- and I can see the top of the plates

So, (now that I've ratted myself out), the question is: What happens if this oil gets on the plates? Any harm done? Do I need to change my sinful ways?

RJay · 03-24-2012, 10:17 PM

Quote:

Originally Posted by steelheadbluesman

My batts seem to need watering about every couple months. BUT, every once in a while I get there a little late -- and I can see the top of the plates

So, (now that I've ratted myself out), the question is: What happens if this oil gets on the plates? Any harm done? Do I need to change my sinful ways?

If your battery plates are exposed to air, the plates will oxidize and no longer receive a charge. If the oil touches the battery plates the oil will cover the exposed plates. Since oil is lighter than water, when the battery is serviced most of the oil will float to the top of the electrolyte. Surface tension between the oil and plates will not allow all the oil to immediately release from the plates. Since the dielectric strength of the oil is approximately 5 times that of air, it's not likely the oil covered portion of the plate will receive a charge. However, since the oil stops oxidation of the plates the plates aren't permanently damage as when they are oxidized. It's possible that vibration and equalizing the battery may release enough oil that the plates will once again receive a charge.

The major benefit is if you check your batteries every couple of months it's not likely your water level will ever be to the point where you will have to worry about damaged plates.