Reducing Battery Compartment Ventilation Area

[OldForester]

I have debated about reducing the size of the vent area on the top of the battery compartment on our '06 since I replaced the wet cell batteries with Lifeline AGMs about 3 years ago. Just don't see the need for the huge hole in the top of the compartment that drives a lot of dust and road grit into the battery compartment from the engine area. Figure it would keep me from dusting the battery compartment as often as i do to keep it looking new.

I have seen a couple Alpines where the owners have reduced the size of this vent opening after they replace their wet cell batteries, but don't remember the size they felt comfortable reducing the hole. I don't have the coach near me right now but I think the hole is about 8" x 16". It also seems to me the ones I have seen reduced are down to about 3" x 5" or so.

I'm down to a small list of to-do's on the coach and wondered, those of you who have reduced the area with some sheet metal/screen, or those of you who have some electrical background -- how small do you think this vent hole could go to without any problems, with AGM house batteries and sealed engine batteries?

[takepride]

I closed my ventilation down a bit by adding a battery shelf forward of the tray and outboard of the jack. I plan to close it even more, leaving just the 1" - 1.5" outboard of the tray (between tray and door). AGM batteries can be housed in un-ventilated areas, subject to decent temperature maintenance.

[EngineerMike]

OF- go for it. Dale Gerstel taped his practically shut after AGM'ing it, even tho starter batt's remained "maintenance free" type. This is on my 2Do list also.

[OldForester]

EM--

Thanks,

I'm going to take it down to nothing more than maybe a 3"x3" square hole with mesh in it when I get time and see how it works.

[EngineerMike]

You can tape most of it shut at seams using aluminum duct sealing tape available @ HD, if you clean the painted surfaces well.
There are some round holes on the floor of the AGM battery tray; you can put your batteries on a white plastic mudflap (~$10 at your local truck supply joint) trimmed to size (24 x 30 IIRC). There is a somewhat wide vertical seam at the back-rear corner just above the tray you may not have noticed due to batteries in the way. There is a horizontal seam against the frame at back of HWH jack black box. And the toughest part to seal is the U-shaped cutout on top of HWH black box for the hydraulic hose connection due to odd size. I don't recall the front & rear vertical closures on the 06 just inside the compartment lid; on mine those are a bent rubber strip which works pretty well as is. On a friend's 06-34, he had a maybe 8"x10" hole at rear-back-top that connected into engine; he made a hinged plywood cover to limit dust & spray coming from engine.