I put a 1/16" piece of abs plastic over the bottom steel slats of the battery compartment and drilled 1 1/2" holes along one side and siliconed screen on the bottom side of the holes.
My my front compartment door has a vent in it from the factory so it is venting up from the bottom holes through the door vent.
The plastic bottom also stopped the narrow Trojans from falling sideways in the big gaps of the slats.
It's funny this thread popped up because I was just at the dealer looking at the large gaggle of 2017 NorthPoints and Pinnacles that my dealer has. I was checking out the new improved battery compartment that Jayco has put in the 2017's. I'm a little ticked that someone at Jayco even thought of putting in the compartment we have in the 2016's. It can hold six batteries, sure, but you can't ever check the water. Also you can't use 6- 6volts because they are too tall with shelf installed.
I had to cut out my shelf to get my 2 6 volts in. It's REALLY hard to check the water.
Now I want 2 more 6volts and I have no where to put them, because that compartment is useless.
But wait! Have a look at the 2017 battery compartment. That's better.
I guess they fired the genius that came up with the 2016 design.
I'll post a picture of the new style later.
Back to my first thought above.
When I was driving out of the dealers lot I noticed that none of the 10 Pinnacles, 1 Designer, or 10 NorthPoints (all build dates after mine) have the vent in the door for venting the battery compartment. I guess they ditched that idea after the first month of production back in 2105.
Here's a picture of what I did. It's hard to tell in the picture what's going on.
The front batteries cover half the hole because of poor measurements. The back hole isn't covered.