If anyone has had a problem with their battery corroding the frame, here’s some possible solutions.

How to beat “The Fuzz” - Forest River Forums

 

Lets think about what causes all this corrosion in the box?


I have never had that happen before myself. Only around the terminals. But not on a TT or 5er. In the truck or the car only.

 

Anode/Cathode process (electrical) + moisture = chemical reaction causing the metal to corrode. The battery strap in my truck did the same thing. All batteries emit a small amount of energy that helps this process along.

I figured insulating the battery itself from anything metal by using the rubber mat would help, and creating the air space under the battery will help condensation to evaporate and vent instead of sitting on the hardware, which is now stainless steel and coated with insulating varnish. The textured finish of the bed liner on the mounting plate should create air space between the box and the fame to help with moisture evaporation also. The dealer told me that the unit doesn’t ship with a battery, and that they install the battery when it arrives. I could have made this a warranty issue, but if they can’t do it right the first time, why would they do it right the second time? Terminals are clean as can be and I plan on putting some of that terminal goo on there to keep it that way.

*EDIT* The battery is strong and healthy and anything electrical in the TT work just fine. The only thing that has blown is fuse 91 on the truck, the tailer battery charging circuit. Hopefully doing all this work to isolate the trailer battery will prevent this from happening because the Jcase fuses are a pain to find, I had to go to the dealer to find them.

 

Correct. Units don't come with a battery. It is put in just before purchase.


In automotive applications the battery is not fully enclosed so I think you can get away with a metal tray.


TT/5er are closed.


Although most 5ers have a vent built into the lid of the box. I think that helps.


On a TT the box is right against the frame and non vented usually.

 

The lid on the box is vented, it’s just that the battery was sitting directly on the non-stainless hardware and against the bottom of the box so the moisture had nowhere to go. It’s easy enough to take the battery out between trips so that’s what I might start doing.

 

Personally, I would switch to AGM type batteries and the problem will go away. The problem stems from a combination of two factors. One is the shaking and bouncing that occurs when the trailer is being towed, and the other is the battery gassing while charging. In that enclosed box the gasses settle and condense. AGM batteries have no free liquid so they don't slosh and their gas production is only a small fraction of that of a flooded cell battery. They cost about twice as much as a conventional battery but also last much longer. They are great in automobiles where high under hood temps. cause excess discharge also. They are available in starting and deep cycle type.

 

Good insight, thanks!

 

I just realized that I may have said something a bit vague. With regard to high under hood temps. causing excess discharge I meant gas/liquid discharge. Several years ago I had a Tahoe that discharged so much that it ate up the washer bottle, pumps and hoses because this assembly was located right under the battery. After proper neutralization, priming, painting and parts replacement the AGM seemed like a bargain (and solved the problem). If you stick with wet batteries, a cheap and easy preventative measure is to lay down a nice bed of baking soda - maybe 1/8" or so - in the box before setting the batteries in. Sprinkling some around the terminals also helps because it neutralizes the acid before it gets to the metal.

 

A long time ago when I worked in a shop, we used to use RTV to seal the battery/case at the terminals to prevent the out gassing from around the terminals where all the corrosion starts. We also used a undercoating spray to seal the battery box, and then sometimes used a rubber mat on top. overfilling the battery is also a problem in some cases as it will let the fluid seep or leak out the vent in the caps.

I also went to the red top batteries to not have to worry anymore about corrosion. I alaso put agms in my motorcycles, big difference.

 

A couple of comments to this thread. The battery boxes on my RV have holes that drain any liquids to the ground. I have never seen anything that makes me think that liquids are draining.


I have AGM batteries in the truck and will never consider anything else again. When the batteries in the RV act like they are failing, AGMs will go in there as well.


My Ford dealership, where I have all my servicing done, offered me an anti-corrosion treatment for the battery connections, that they guaranteed for life, for $30. I took the deal. Now they clean the terminals if they start to corrode (which after a year they have not) and every time I take the truck in for an oil change, they clean everything up again whether it needs it or not. I asked if they would do that for the RV and they said yes, all I had to do was bring it to the dealership.

 

This last year I replaced my battery in the 5er with a AGM from tractor trailer supply. Excellent battery. I will have to look it up.


Excide is what I think it is.

 

If you are getting excess corrosion you may want to check the output voltage of your converter after the battery is fully charged, if it's over 13.8 it will cause the batteries to gas.

11.5 years ago when our trailer was new I installed two Optima Blue Tops and they are still going strong and the original cables still look like new. I had them out for the first time last year to clean and paint the rollout tray, it rusted from salt air not battery acid.

Denny

 

Thanks to all that replied. While I'm sure I have the corrosion under control, I'm leaning towards getting a dry type battery. It's kind of exciting really, all the shock proof deep cycle BS I see in the Optima commercials finally applies to me. I might check out a blue top this week because I have more marine stores around me than RV stores. Dual purpose group 30ish for an RV I assume?

 

If you do go with a Optima I would spend the extra money and go with the D31M, it has the most AH at 75. The ones I have are D31M but are only rated at 55 AH because they changed them in the last 11 years. If you go with AGM batteries they have a lower full charge voltage that is around 13.2 and when they discharge they hold their voltage longer but when they die it happens fast but they charge faster than wet cells.

Denny

 

Odds are good you got USA made ones, which you can't get any more.
High/early failure rates are prevalent with the now made in Mexico ones.