Imagine my surprise when I opened my battery compartment a couple weeks ago to check the water level in the batteries. I saw a mess of white in what is supposed to be a black battery compartment:
Look at the corrosion at the base of the batteries.
The paint is just peeling off with the corrosion lifting it up.
So much corrosion that the acid has leaked out and dripped on to the mounting point for the pneumatic opener.
Though there is evident of acid reaction on the top of the batteries, on the hold down straps, the battery terminals are clean with no sign of corrosion. I had removed the two "house" batteries in November and cleaned the compartment, the posts, the hold down straps and the bolts. Now I have a mess. From November until I discovered the mess, we have put on about 3K miles and spent about 12 nights out.
This is after the batteries were removed. As you can see, just about all of the floor of the cabinet is affected.
After the compartment has been wire brushed and washed with baking soda and water. The surface was then wiped down with denatured alcohol, and then primed with a rust control/converting primer. After 24 hours it was given two coats of Truck Bed Liner coating. I debated between that and Vehicle Under Coating which has a rubber product in it. The Truck Bed Liner coating should be harder and I plan to put something between the batteries and the floor of the battery compartment. This is how it looks.
My initial thought was a low fiberglass tray, like you use in a restaurant. Finding one that is 36"x19" is proving to be a problem - maybe a "big boy" restaurant. May be a Tupperware or Sterilite or Rubbermaid container. Something that will "contain" any future acid spill. I thought about just some rubber between the batteries and the floor of the compartment, but that would still allow it to contact the floor of the compartment and possibly cause a problem in the future.
Tray problem solved - Google can be your friend. Termed "Fast Food Trays" they come in a couple different sizes. 10x14, 12x16 and 14x18, most made of plastic. On-line these will set you back about $4 each. Then there is shipping. I was lucky, one of the local restaurant supply stores had some used fiberglass 14x18 trays for $2.50 each. I just had to drive "across town" to get them. Seems like a perfect solution.
With a little paint, and holes drilled for the battery anchor points, this is how it came out.
The anchor bolts go through the fiberglass tray and through the floor of the battery compartment. A washer on the top of the tray and a washer on the bottom side of the floor. I used a ny-lock nut on the bottom, and standard nut on the top side. Then we have a washer and a lock washer under the nuts that are on the battery clamps.
It took a little while, but now I hope that it will just be washing the dirt out of the compartment with a hose at every outing. There is plenty of ventilation in this compartment, with the winds we have had, this was a layer of dust on the compartment floor you could have done a painting in.