Battery Bank venting recommendations

[Gary LaBombard]

I am in the process of fabricating new baggage compartment doors, I need to consider the following information I am requesting before making the final design.
 
I plan to have a good sized battery bank for inverter / solar power use, I do not know of the size  of battery bank as yet, this is too far down the road in my conversion design and thoughts. The design for the air  ventilation for the battery storage compartment is needed now so that I can plan the air flow design of ventilation through my baggage doors as I plan to do if the batteries should be vented from over the top of the batteries.   The batteries will be totaly enclosed in their own compartment for safety in my design. What I am asking here is does the fumes of the battery rise or fall?  should my battery bank be vented from top of the batteries coming from the sides of my new door design or should I design a vent through the floor?? 

If the ventilation is through the side of baggage door or through the floor, how much open area is recommended for good air flow, I plan to ventilate the battery bank compartment from one side of bus to the other for  through ventilation if you do not recommended  venting through the floor.

Thanks ahead of time.
Gary

[FloridaCliff]

Gary,

I have been looking at this recently for myself.

My plan is to put louvers, forward on one side and reverse on the other, to pull air through while underway.

Thsi design is very consistant with what I have seen it boats and buses to vent compartments.

This should also create a draft effect while sitting still if you have any air moving at all.

I would also put a 1" drain in the floor incase something spills or leaks.  You could use a tailpipe piece like on a sink with the flange

end recessed into the floor to allow easy flow.  This will also alllow you to wash off your batterys with a hose.

A good practice to get into since they will collect dust and other contaminents on the upper surface.

If only I lived in NJ, I here theres a guy up there with some pretty cool metal brakes in his shop.

Cliff

[Gary LaBombard]

Cliff,
Thanks for the input, I am sitting here now looking for some tips before starting out for the day.  I am assuming that the ventilation  path you recommend should be mounted as high or higher than the top of the battery bank??  Also thanks for the insight of the drain in the floor.  Any more ideas on this, share them with me if you don't mind.   My metal brake is sheet metal clamped between two  pieces of 1 1/2" angle iron and bent with a mallet.
Thanks again,
Gary

[Dreamscape]

I just did a google search on battery venting.

One article said to vent the compartment at the highest point so the hydrogen gases can escape.

Hope this helps in some way.

I just learned something.  Thanks for the question.

Paul

[JackConrad]

Hydrogen gas is lighter than air and very explosive. Remember the Hindenburg? The OEM battery compartment on our MC-8 had small slots in the door skin near the top of the door and louvers in the floor. The louver openings face the rear of the bus. This was probably done to prevent water, dirt, etc. from getting in the compartment when the bus was moving and may have created a low pressure (Suction) to help keep gases from building up in the compartemnt. Hope this helps, Jack

[Dreamscape]

Maybe a good source of information on venting and what is used.

http://www.newenglandsolar.com/catalog_pages/catalog54.htm

Paul

[Dallas]

Gary,

I wonder how well, puting one set of vents low and one set high would work. Then whether the hydrogen gas is lighter than air would make no difference, there would be positive flow in either direction.
This might come in handy if the outside ambient temperature is warmer than the air inside the bay. As warm air is pulled in the upper vent, it would force the cold air, and along with it, the hydrogen out the lower vent.

If the situation is reversed, the natural tendency for the gas to rise would make the upper vent the escape route.

Just thinking off the top of my keyboard!

God luck and post what you have done!

Dallas

[Gary LaBombard]

To all that have posted in reply, thanks, I also know now the importance of considering this information from the web site posted above by Dreamscape.  Now the web site apparently is designed for one battery and I am unclear now also if perhaps this area they have used, 2'" in and 3"out for the ventilation is sufficient for large battery banks??  This final question is not necessary to have anwered today but a thought I hope that more experienced bus nuts can shed light on.  Does the size of the battery bank make a difference for ventilation considertion?  I do not necessarly want a huge opening though my bagage doors on both sides of my baggage compartment but I will do what is recommended from recommendations and experience of others.

Lots of food for thought here today, direction of air flow, (One vent forward and one aft through doors), (One higher vent and one lower vent on the opposit side),  (Size of air intake and Exhaust),  good grief, this was supposed to be easy but I love to just use experience to help decide.

Thanks for all the input, good grief you knock me out.

Gary

[JackConrad]

Gary,
   Another option is to used sealed batteries, I think these are AGM, or if using lead/acid batteries use HydroCaps on the batteries. either option elenimates the need for venting.  Jack

[FloridaCliff]

Gary,

One more thing.

If you use AGM's for your house bank you hardly need any ventilation.

My 10 battery sealed AGM bank looks great 1 1/2 years after install, no corroision from any battery breathing/venting.

All connections look like the day I installed them.

I am still venting the compartment though, as its not a perfect world.

Just another thought.

Cliff

[Gary LaBombard]

There I go, now another hurdle, ventless batteries to consider, more thought needed today, will just do the framing for outside of door, I believe just for back up sake, I will still install maybe the 2" diameter vent in and 3" vent out just for safety sake and eliminate any bad situations that could accientally occur, (Battery Burst etc.) I have no idea what could happen but as you all know at the extent of my conversion now I will use overkill  in my design I am sure but my Grandaughter will have one heck of a coach her papa made for her.

I have to go to work now, thanks for the input, good information now considered by many I am sure.
Gary

[DrivingMissLazy]

Gary, a couple of sites you might want to review. Lots of battery information.

http://www.marine-electronics.net/techarticle/battery_faq/b_faq.htm#6

http://www.batterytender.com/connecting.php

http://www.uuhome.de/william.darden//


Remember, there are no batteries that do not require ventilation. They all have a pressure relief valve to relieve pressure in case the charge rate gets too high. Unfortunately the only way you find something out like this is when the charger circuit voltage gets too high and the battery starts gassing. Then if you have anything in the compartment that could cause a spark, BOOM!
I like Dallas's suggestion best and also I would recommend you seal the compartment in the middle so that nothing but batteries are in that compartment. The other half of the compartment could then be used for storage or whatever.
Richard

[Nick Badame Refrig/ACC]

Hi Gary,

This link also gives you lot's of battery info..

http://www.marine-electronics.net/techarticle/battery_faq/b_faq.htm#6

Nick-

[TomC]

The nice thing about AGM (Absorbed Glass Mat) sealed batteries is that they don't gas, are rated for airplane travel (like on a wheelchair for instance), and can be mounted in any position with upside down not preferred.  Think how much more room you could have by mounting the batteries on end?  I saw a production sportfisher yacht with big Cats, and the 2-8D starting batteries for each engine were mounted on a shelf just under the floor on their sides.  Opens up many possibilities.  Even though the AGM (like Lifeline) batteries are not cheap, they are vertually maintenance free and have a limited 5 yr warranty.  Good Luck, TomC

[Brian Diehl]

Gary, I created only a 1 1/2" outlet for my battery box, BUT I have my inverter setup to turn on a ventilation fan once the voltage exceeds 26 volts.  This happens if I'm charging off the inverter or off the bus alternator.  This way I get positive ventilation any time charging is happening.