Originally Posted by family wagon
I'm kind of chuckling to myself and hoping it's okay to tease a little bit.. we're getting all this concern about battery box air leaks from the guy who wants to leave the side emergency exit door wide open and work at a desk just inside it with the A/C running, and has enough A/C capacity to run a mobile freeze dry service.
(I guess the air leaks would present a problem when commissioning the vacuum part of the freeze dry operation!)
I do have something helpful to add, too. Batteries in a rack under the body might be relatively well-protected with just side shrouds clipped on after the batteries are loaded into their rack. There often isn't a great deal of protection provided to batteries living in the engine compartment after all. Yes there could accumulate "stuff" on the battery surface and provide a leakage path between the battery terminals, but I'd think that would really become noticeable only if the vehicle sat unused in storage with no charge source for a time. With regular use the leakage will probably be small compared to the demands of actual use.
Way more than I was going to suggest.
I was going to say build a battery compartment underside with an un-sealed access door and the venting will take care of its self.
My starting batteries are on a crude slide out but it works when needed.
My house batteries will be underside in a storage compartment and if I think I need more ventilation then I will drill holes in the entering air side add some copper screen and drill some holes in the leaving air side and cover with some screen.
You can over engineer anything and spend a lot of money and time creating what you want or you/we can use the older tried and true methods?
You don't want any battery good or bad off gassing in your breathable space?
Put them underneath and let natural ventilation help even if you want to add a louvre's to your design.
Batteries in use create heat even in cold weather.
Batteries setting dormant in cold weather do seem to lose charge faster but not if they are used daily.