battery venting?

[bevans6]

Not to steal the thread on battery slides, but what do you do for battery venting?  My house batteries are in the front bay, currently not in anything special.  I'm thinking of getting a big plastic box for them, probably a marine battery box, do you vent them up, down, sideways or all three?  do the fumes rise or fall?

Thanks, Brian

[Sean]

It's hydrogen gas, just like in the Hindenburg.  It rises, and explodes if it finds an ignition source.

If you have flooded batteries, the compartment needs to be vented at both the top and bottom, and needs to be sealed off from the coach interior and any bays where spark-producing equipment might be present (pumps, inverters, furnaces, water heaters, etc.).

-Sean
http://OurOdyssey.BlogSpot.com

[bevans6]

That is exactly what I thought.  My question came from commercial battery boxes that seem to vent sideways - in and out around the middle, which seemed wrong to me.

Easy to fix, though.

Brian

[Brian Diehl]

My box is not perfectly sealed.  However, I vent it out the top and have a brushless DC motor fan turned on by the inverter/charger during charging to help force air through the battery box.  The fan is at the bottom of the box and  the vent at the top of the box is routed over to the coach battery compartment.  This compartment is vented to the atmosphere at the top by the manufacturer.

[muddog16]

My Prevost had circulation fans in the overhead baggage rack on both sides, I saved one of these for the battery compartment to vent and circulate the gas!

[bevans6]

Isn't using an electric motor with brushes (at least the circulation fans I've seen have brushes) to vent explosive fumes kind of contraindicated?  I do see special brushless fans intended for such venting though.

Brian

[BG6]

It's hydrogen gas, just like in the Hindenburg.  It rises, and explodes if it finds an ignition source.

If you have flooded batteries, the compartment needs to be vented at both the top and bottom, and needs to be sealed off from the coach interior and any bays where spark-producing equipment might be present (pumps, inverters, furnaces, water heaters, etc.).

I'm going to add CIRCUIT BREAKERS to this list!!!  Don't put your breaker box and batteries in the same airspace.  If you are putting your house batteries in a cargo bay, the best thing is to put them in a big plastic box (nonconductive and impregnable) and run a couple of lengths of  vacuum cleaner hose to the vents.

If you are simply putting in a partition between the batteries and the rest of the bay, seal it with silicone.  It's also a good idea to yank the weatherstripping on that side -- you really really really want every last bit of airflow that you can get.

THIS INCLUDES ALL PASSTHROUGHS TO THE LIVING AREAS.  Many coaches, such as my 96A3, have small holes from the cargo bays to the cabin, which are closed off with little metal discs intended to stop drafts.  These holes MUST be sealed.

Hydrogen is the smallest atom in the Table.  It can impregnate any absorbent material, sneak into any space, and in any electrical device can ruin your whole day.

And you can't smell it.  No odor.  Your first hint of a problem may be impossible to ignore.

The best venting for a battery bay is passive -- such as the little cup vents you see on speedboats.  The top one should be as far up as possible and face forward, to break up any pools of H2 that might build up at the top of the bay.

This is especially important for your house batteries!  They produce FAR more H2 than your coach batteries, because you are cycling them more deeply.

[Tim Strommen]

...I vent it out the top and have a brushless DC motor fan turned on by the inverter/charger during charging...

Isn't using an electric motor with brushes (at least the circulation fans I've seen have brushes) to vent explosive fumes kind of contraindicated?  I do see special brushless fans intended for such venting though.

Correct - a brushed motor is not the one you want to use.  A brushless motor will not have to transfer power to the rotor - as the rotor features permanent magnets (the stator has three or more phases that get sequenced from a small microprocessor).

You can use a "special" battery vent fan or you can get any one of a variety of "el-cheapo" PC case fans for a few bucks that will do the same job...  And at the PC case-fan price you can keep several spares (and get them anywhere).

Also on the topic of battery gas control with flooded cells - consider "hydrocaps" (catalyst wet-cell plugs).

-T

[cody]

I keep my batteries in a wooden tray directly under the inverter but thats ok cause the hot water heater is next to it by the LP tanks but thats ok cause my doors don't really fit very tightly, I need the air movement around the cracks of the door to cool the breaker box. (backing away slowly now) lol