Hello barabbas.
If your battery is a 'Sealed' one, then the Oxygen and Hydrogen emissions will be minimal.
Even if not, the levels will be low, UNLESS you have a High Charge Rate, and/or a cell or some cells are defective. This will cause more 'gassing'.
Generally though, sufficient ventilation will be obtained naturally.
DO NOT HAVE NAKED FLAMES IN THE VICINITY!
Maybe someone has already been through this, and can give a definitive answer?
Hope this helps.
Kind regards James
------------- In the beginning there was darkness.
Then I bought a tent.
I'm not destitute, I'm just poor.
It should be fine, most car's ventilation systems run through the back, weather they have a separate boot compartment or not.
Gassing is not such a problem with modern batteries, but they all have a vent on them, & for this reason I would strongly suggest using a battery box, these will contain all the battery acid in the highly unlikely event of a cell splitting, they also make supporting the battery easier IMO, you just strap the battery box in & put the battery inside it. You cut small bits out of the lid for the wires to go through (these wires should also be fused somewhere along the line, but whoever fits your split charge set-up should do this).
I will have a quick search for battery boxes on ebay for you & post a link up shortly.
There's a few battery boxes here & some other crap that came up on my search, it's pretty evident what's what though, you can also buy them from boat chandlers (their main use is on boats) & some caravan/camper shops. good luck.
I have a BMW ,and the battery is fixed to the floor under the rear seat,so I can't see it being dangerous as long as you bolt it down efficiently preferably in a battery box.
------------- Corpogreen esq
dead horse
and
donkey buyer
corpogreen makes a good point - I have known quite a few vehicles that have such an arrangement.
As has been said, sealed batteries are inherently more safe in this regard, but hydrogen and oxygen together is highly explosive. A friend of mine (who as a fellow engineer should have known better) had been charging a spare car battery in his garage and then decided to test some bulbs he'd found by flashing them across the battery terminals with a length of wire. He remembers hearing a bang and then waking up on the garage floor with a bump on his head and a perforated eardrum. The battery had split apart and sulphuric acid was all over his clothes (luckily missing his eyes).
My friend's experience was with an older-style battery that had been fast charging, but nevertheless gasses can build up in enclosed areas.
------------- Please do not adjust your mind... there is a fault in reality