Would Century N70 Deep Cycle batteries...

Even though the Swan could hardly be considered air tight or draft proof, flooded batteries such as these must be vented to atmosphere, not just to the van interior.
You could enclose them in a sealed box and have a hole in the base and a second hole in the side up high and ducted to outside to allow cross ventilation, but it must be sealed from the inside of the van.
Or you could have the second hole also in the bottom and preferably diagonally opposite the intake hole with a brushless fan drawing air out of the box.
Don't have it drawing air into the box as you need to create a negative pressure in the box so that seals don't leak.
Hydrogen is lighter than air, so you need the fan to draw it off the top. A short piece of duct either on top of the fan, or under it to raise its height to that of the top of the batteries will suffice.
The fan can run continuously, or you can fit a simple voltage comparator that turns the fan on only at voltages where gassing is going to occur.
This keeps it a bit quieter at night.

Putting batteries under a bed...regardless of the type is shoddy in my opinion....though plenty of manufacturers seem to do it.

Putting flooded screw top batteries under a bed is asking for trouble.

There was a caravan explosion, documented with pictures in this very forum not long ago.
It was the considered opinion that what you are proposing is exactly what was the cause.

Fitting ANY battery without good ventlation is not clever, fitting a non sealed battery without good ventilation is just asking for trouble big time.

Sealed batteries will release small amounts of explosive gasses and corrosive fumes under certain circumstances, non sealed batteries will produce considerable amounts of explosive gasses and corrosive fumes every time and the whole time they are on charge

As for the idea of a hole here and a hole there.

Use "Bantam's fart test".....if you where to fart in the place where you propose fitting these batteries, how long will the smell linger.....that is how long explosive gasses will linger.


Adequate ventilation means a lot more than most people thnk.

IF you must fit batteries in places like under the bed, you need to make pretty danm sure that it is one of the better sealed batteries, and that the rest of your system is right on.

BTW, there is no such thing as a totally sealed battery, they will all vent some gass and some corrosive fumes under certain circumstances...plenty of people will try and tell you otherwise.

cheers

Thanks Brian/The Bantam

I guess you guys have confirmed what I suspected, both in terms of the suitability of the Century N70T in this scenario, and the scepticism I have towards even "sealed" batteries.

So, here is the inevitable follow up question:

Am I better to use:

"sealed" batteries, such as a Ritar or Ultimate etc

OR

one of those batteries with a hole on the top of each side designed to have a "hose" plugged in to one side and a bung into the other, the idea being the hose can then be run externally to the camper for venting purposes. I've seen these once at an Exide outlet and they sell the "kit" comprising the hose and bung.

Obviously the first option seems like the easier one, but maybe the second option is a much better alternative for this type of camper? (Though I'm not sure whether a hose connected to a battery in this manner would open up some sort of unintended consequence down the track, e.g. ants or something else travelling "up" the hose etc).

What are your thoughts?

Much appreciate your help.

Thousands of caravans have their batteries (AGM’s or Gel cells) situated under beds and seats in caravans without special venting. Wouldn’t advise this with a flooded battery.