So then, what is the point of the battery boxes in the first place, if not to protect the batteries from rain, fallout, dust, ozone, wash water, etc? My battery boxes on my trailers were mounted outside in similar boxes, but without the top vents. They didn't have a problem with water in the boxes, and I never had to deal with putting holes in the bottom to drain out the acid formed by the mixture of the water with the effluent of charging and hydrogen outgassing. Sounds from here as if it would be better to deal with keeping the water out in the first place, no?
2006 Jayco Seneca 34SS
2006 Jeep Wrangler Unlimited Rubicon Toad