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Solask · 02-02-2014, 05:56 PM

Got My class a winnebago out of storage to prepare for a trip south. Been very cold here in Indiana. After running gennie for about and hour, running fridge and furnace, I thought I would peek at my two 12 volt house batteries. Cells are covered but the fluid looks like brown slime! What is this?

palehorse89 · 02-02-2014, 07:35 PM

How long have you had this Coach?, my guess is that there is mineral oil in the cells.

Solask · 02-02-2014, 07:41 PM

Quote:

Originally Posted by palehorse89

How long have you had this Coach?, my guess is that there is mineral oil in the cells.

Thanks Palehorse, I've had the MH 3 years. Don't know how old the batteries are. How would mineral oil get into the battery and is it a problem?

dennis45 · 02-02-2014, 07:43 PM

Quote:

Originally Posted by palehorse89

How long have you had this Coach?, my guess is that there is mineral oil in the cells.

Mineral oil is clear.

palehorse89 · 02-02-2014, 07:47 PM

Quote:

Originally Posted by Rkh

Thanks Palehorse, I've had the MH 3 years. Don't know how old the batteries are. How would mineral oil get into the battery and is it a problem?

Have you just added water over those 3 years to them? I am guessing that is what you are seeing......Mineral oil is put into wet cell batteries to reduce the water evaporation and boiling of acid gases to reduce the mess on the top of the batteries. If I was you I would take a clean piece of wood of sorts to dip into a cell and examine it to see if you can tell what it is you are seeing. Here is some reading on the mineral oil https://www.google.com/search?q=mine...earch=irv2.com

dennis45 · 02-02-2014, 07:51 PM

Quote:

Originally Posted by Rkh

Thanks Palehorse, I've had the MH 3 years. Don't know how old the batteries are. How would mineral oil get into the battery and is it a problem?

It is common to add mineral oil to keep the batteries from off gassing Hydrogen Gas during the charging process. It reduces the amount of battery maintenance required such as reducing the amount of Distilled water required and preventing the terminal connections from corroding.
If the fluid is brown, I suspect someone may have added normal Motor Oil instead of pure Mineral Oil which is clear.
Not sure what you can do at this point other than making sure the level in the cells is maintained.

spinn · 02-02-2014, 08:15 PM

Just to clarify, the batteries will still off gas hydrogen (or the battery would never charge) but the bubbles of electrolyte that usually accompany the hydrogen bubble is stripped off by the mineral oil. The net net is that you loose significantly less electrolyte, so need to add less water and there is usually much less corrosion off the area around the battery.

Solask · 02-02-2014, 08:22 PM

Wow, I had no idea about the use of mineral oil in batteries. Last year, I noticed that the cells were pretty low and added distilled water to the correct levels. Batteries performed fine all last year. So, am I hearing that the batteries aren't necessarily shot? I hit the road tomorrow so I guess I'll know so enough.