Need to repaint the battery box in our Winnebago Sightseer. Plan to use POR15. Was wondering if I could put something else down there to protect acid from rusting the bottom like aluminum or plexiglass. Recently switched over to a multistage converter so that should help some.
Well Sir, battery acid is ugly stuff. It just about eats everything that's metal, no matter what kind of metal. Batteries are a pain. Some are worse and some are not too bad. Trying to keep ahead of the great "corrosion" attack is sometimes a tad overwhelming. One of the main problems is, when you clean a set of batteries, and or a battery tray and they/it has an extreme amount of corrosion on them/it, all that washes off to the driveway/street etc and makes a huge mess and, most likely A SERIOUS STAIN.
Now, in my opinion, here's the ultimate remedy. "UHMW" or "HDPE" are both high impact, ultra strong and super durable plastics. UHMW stands for Ultra High Molecular Weight and , HDPE stands for High Density Polyethylene. If you look on the bottom of just about every plastic container in the world, you'll see the recycle triangle and, the letters HDPE. That plastic can take any abuse you want to throw at it.
UHMW is the same thing only a few grades higher in both durability and cost. You can obtain HDPE at any plastics supply outlet. In fact, an easy way to get some and you don't even realize it is, stop in at your local restaurant supply or K-mart or Wall Mart and pick up a white plastic cutting board, yep, HDPE.
What I'm getting at is, trying to line that battery box to the point where it is sealed against corrosion is almost impossible unless, you can do it in such a manor that you have an HDPE box made. Yep, HDPE can be WELDED!!!!!!! It's a form of "plastic welding". Now then, you'll have the ultimate insurance against damage of you metal battery tray.
In fact, I don't know how much you know about boats but, about 95% of them have battery "boxes" that are of HDPE plastic and, they completely encompass the batteries with only the holes for the battery cables to pass through.
Scott and Karla SDFD RETIRED
2004 Itasca Horizon, 36GD Slate Blue 330 CAT
2011 GMC Sierra 1500 Ext Cab 4x4 Toad 2008 Caliente Red LVL II GL 1800 Goldwing KI60ND