Community Forums

ClarkBowen · 07-06-2008, 05:58 PM

I recently noticed that battery acid was eating the paint below the house batteries on our 2007 36'. I washed it off and made a mental note to attend to it when we got the Alpine back from Cummins Coach Care (replacing the wardrobe slide hydraulic lines and pushing the slide back in).
It had been at Cummins for 3 - 4 weeks and when I got it back the white fluffy material that you find on the positive pole of batteries was on the compartment floor and eating the paint off of the diagonal support between the house batteries.
We have the automatic battery filling system and it will empty the one gallon resevoir in a short time even though the battery indicators on top of the cells look like they are at the top. There isn't any water on the ground after the battery fill system has sucked down a gallon and deposited it God knows where. Anybody know what is going on?

ClarkBowen · 07-06-2008, 05:58 PM

I recently noticed that battery acid was eating the paint below the house batteries on our 2007 36'. I washed it off and made a mental note to attend to it when we got the Alpine back from Cummins Coach Care (replacing the wardrobe slide hydraulic lines and pushing the slide back in).
It had been at Cummins for 3 - 4 weeks and when I got it back the white fluffy material that you find on the positive pole of batteries was on the compartment floor and eating the paint off of the diagonal support between the house batteries.
We have the automatic battery filling system and it will empty the one gallon resevoir in a short time even though the battery indicators on top of the cells look like they are at the top. There isn't any water on the ground after the battery fill system has sucked down a gallon and deposited it God knows where. Anybody know what is going on?

OldForester · 07-06-2008, 07:31 PM

Clark,

I have the same problem. I have found that by using battery cleaner to clean the fluffy corrosion off and battery terminal protector after cleaning the fluffy corrosion off, it works fairly well. I have had the same brace between the house batteries, where the battery hold down strap contacts it, corrode a number of times. But the cleaner/protector step minimizes it, and I have to re-do it about every six months.

One thing I have found helpful is to minimize the water in cleaning the battery compartment because it tends to spread the acidic liquid venting from the batteries.

Instead of washing, I dust the batteries and the compartment regularly with a swiffer duster. We first dust the inside of the coach with the swiffer, then I use it to dust the batteries and wipe out the excess venting before disposing. If I see some corrosion I'll clean that and carefully flush only that area with water, dry it off, and put on the battery terminal protector. Seems to work fairly well.

I got both the battery terminal cleaner and protector at an auto parts store; just matched the same brand. I think NAPA works best, but mine came from Kragen.

Algoma · 07-07-2008, 04:19 AM

Sounds like the fill system is overfilling the batteries and they may be being overcharged. Mine started doing this when the batteries were getting to the end of their lives. My solution was to replace the batteries with SLA (AGM) types. No filling problems now.

hrhuggie · 07-07-2008, 10:20 AM

Clark,
you dont mention if you leave the "fill" lever to your automatic battery filling system on or off. I too have had difficulties with the ongoing corrosion in the battery compartment and as Old Forester says, clean and protect works well.

I have only gone through large amounts of water in the resevoir in a short period of time when I left the fill lever in the "on" position and then I have a lot more off gassing through the battery vents which contributes to the corrosion problem. I now regularly open the fill valve and stand and wait for the resevoir to stop lowering then re close the valve. Far fewer problems and use a lot less water

Hope this helps

ClarkBowen · 07-07-2008, 07:05 PM

The more I think about it and view your comments, the more I think the battery fill system is the culprit. I like the idea of the sealed batteries but I want to get some more life out of these year old ones first. While I do leave the battery fill system off, I must have left it on for quite some time for a gallon of water to disappear down it. Guess I'll watch it much more carefully like Hugh and Cyndi do.
Thanks for your help.

Clark

Algoma · 07-09-2008, 05:26 AM

Clark,
The point I was trying to make earlier was this. The corrosion you see is due to sulfuric acid being emitted from the breather in the battery top. This is due to gassing inside the battery which occurs when the battery is being overcharged. If the acid has been diluted too much by all that water that was added the battery will not reach full charge and the charging system will keep pumping amps into it trying to reach full charge. Check the specific gravity of the electrolyte and if it is not around 1.3 then you may have to have a specialist top it up or replace it.

ClarkBowen · 07-09-2008, 03:02 PM

Thanks John...

The entire battery/charging system understanding seems to elude me. Guess I'm used to putting in an Optima and driving without a thought off all the activities going on under the hood. It is much more technical than I realized. Could this have been caused by the battery fill system overfilling the batteries? I wasn't aware it could do that.
If I get a hydrometer and check each filler, what would I have to do to increase the ones that are too low? - Or is this a tech job?

Clark

Algoma · 07-09-2008, 04:37 PM

Hi Clark,
The normal rule is that if any one of the cells has a low S.G. then you replace the whole battery. That one bad cell is dragging the battery voltage down and causing the overcharging problem. Hopefully all the cells have the same S.G. and they are just a little low. At this point you need a specialist who can tell you how much acid to add to bring the S.G. up to spec. If you are really lucky the S.G. may be OK and you just have overfilled cells. In this case acid may be being forced out of the caps due to expansion and all you have to do is lower the electrolyte level using a syringe to suck out the excess. Hope this helps.