Venting flooded lead acid batteries

[AZJoe]

I have a battery box built into my camper and I want to keep the batteries plugged into a deep cycle chargers when not in use. I wanted to develop a system to vent hydrogen gas so it would not build up in an enclosed space. My solution was to have 4 vent ports, two high to vent out and two low to bring fresh air in.
I installed screens on all vents so I would not geto bugs nesting and covers to keep rain from getting in too. Onot the upper exaust ports I installed two small 12v fans hidden inside the ventsame to help pull air. I was originally going to set up a simple timer, but decided to build a small hydrogen sensor wired into a switch that can use thathe as a trigger or just vent on a planned timer.
I read that 4% concentration of hydrogen is dangerous and explosive. Has anyone else done anything like this and am I over thinking things.
When the fan is nothe on, the vents are still open.

[azdave]

I probably don't know much more than you about battery venting but hydrogen gas rises and if you have vents at the very top and bottom it seems like you already have what you need without running any fans. I'd worry that the fans on the upper vent would be an ignition source for any hydrogen that would be rising up there. I'm sure someone here can give a more definitive answer.

[Sunking]

All you need is a vent at the highest point.

FWIW assuming you have the Float Voltage set correctly, no gas is generated. For a battery to gas requires the voltage to be at or above GASSING VOLTAGE which is roughly 2.4 vpc or 14.4 volts which only occurs during the last part of Bulk and the Absorb stage. Float is well below that at 13.2 to 13.8 volts.