Possible offgassing strategy

[SternWake]

I saw these pics on a marine based forum.  The guy made this battery shroud for Equalizing his batteries on his boat. EQ charges cause a lot of bubbling and offgassing, but still, This fan size is overkill for that task.  Normal absorption stage charging causes much less volume of ofgasses to escape cell caps.

I can imagine a nice quiet 40Mm fan inset into such a Shroud, triggered at 14.2+ volts with a tube running outside the van body, could eliminate the offgassing issue for those sensitive to gassing batteries in the living space.  With positive fan pressure, One could direct the lighter corrosive gasses down and out  the floor, instead of trying to vent up and out passively. 

Here's a very low amperage 40Mm fan.

6.3 cfm is more than enough, even for a pair of GC-2 v batteries being held at 16 volts for an intensive equalization charge, and it draws a miserly  0.03 amps.  I have this exact fan inside my Vitrifrigo compressor fridge, for nearly 4 years now.  Very quiet. runs 24/7.  At 0.03 amps, one could just leave it on 24/7, or just turn it on manually during battery charging at higher charge rates which attain absorption voltage quickly, or when the battery finally reaches those higher states of charge  via slower rates, and offgassing is most prevalent.

http://www.frozencpu.com/products/1...r_Wire_-_KDE1204PKV3MSARGN.html?tl=g36c15s560


So far, I'm not finding any inexpensive voltage based relays that would trigger the fan automatically at 14.2 or 14.4v ect, but will keep looking. 

 A nice method for hooking the 40mm fan to the  still unfound exhaust tubing still escapes my googlefoo too.  
Any Ideas?

I've no intention of building something like this for myself, no need, but it would be neat to be able to point some 12v rv/van dweller Newbs to a thread here, providing an easy inexpensive solution to their possible  house/Auxiliary battery offgassing concerns.

Anybody want to find some plastic tupperware such item that would fit nicely over the tops of a pair of 6v GC-2 batteries and also for a standard group 27/31 12v marine/dual purpose battery?


A group 31 is ~ 13" long x 7 inches wide, and 9.25 inches tall.  Group 27 is about 12 inches long same width.

A pair of 6v  GC-2's needs a plastic cap a minimum of 21.5 inches long and 7 1/8th wide.  I'd say 3 inches deep minimum for either cap, with more being better.  Allow some space for the battery cables entry/exit, and battery tie downs.

 

[jimindenver]

One possibility is that some solar controllers have load terminals and can be set to turn on the fan when the bank would need venting the most. Being on solar means it should be some what predictable daily.

In my case I need ventilation not for off gassing but rather removing the heat. I will be taking a small fan on top on a piece of PVC tube to fit and running that down through the floor.

 

[Matlock]

SW, from a post you did a few months ago on small fans I looked into and bought a couple from Amazon. The SilverStone 180mm with speed control is the one I am using now.  As you mentioned in that post, this is a large fan, 7" in diameter. I wanted one that could be run at a really low rpm and still move a bunch of air. And it comes with a variable speed control.

The reason for choosing this fan is I opted for a pressurized interior. The slight pressure created by this fan is all that's needed to push out battery EQ gases and most of the humidity created from the small amount of cooking I do and the biggie is the humidity from the Buddy heater.  
I have a separate vent for batteries and a Marine hull inspection port (Amazon) for air inlet.

An automatic control relay would be nice but what trips it .......

 

[gcal]

Oh, I thought this was about eating too much TexMex. Yup, I really went there.

 

[jimindenver]

Oh, I  thought this was about eating too much TexMex.  Yup, I  really went there.

Fans help with that too.

 

[Matlock]

Would something like this work?
You can predict you'll be producing juice when the sun comes up so just set the timer for early AM to run for X hours/minutes during the EQ cycle.

uxcell DC 12V Digital LCD Power Programmable Timer Time Switch Relay 10A


http://www.amazon.com/uxcell-Digita...6-6938651?ie=UTF8&refRID=0CWA65PG0K543V84CB7M

gcal....
I haven't typed this in like forever....rotflmao  

 

[BradKW]

I was thinking of something down similar lines, but having the vent begin at electronics box, pass over fridge compressor, and finally through battery box to outside. I figured that the very low power draw from a 140mm fan really wouldn't put a dent in Ah, so thought a continuous run would be fine...

And as far as viable strategies, what good is a dog if you can't blame it?

 

[Canine]

Looks like a solution in search of a problem.

 

[SternWake]

Matlock, How is that SS FM182 fan?  Wish I bought one when Amazon was still selling them.  2000 rpm My AP182 failed, and they now want 40+ dollars for it.  Not too many 180Mm fan options.

One could wire the fan to the solar to controller wiring.  If the panel is a 12v nominal panel, then the fan would run with the sun, but 22 volts could easily shorten fan life when the batteries are full and the controller accepting little from the panel, and it might get loud at such voltage/rpm.

The voltage based relay I found was in the 40 to 50$ range, but I forgot to bookmark it.

I have 2 computer fans always running in my Van, one inside the fridge that i linked at 0.03amps, and another fan, a 24v fan which came on my failed Norcold fridge(0.05amps at 12.8v).  It exhausts my electrical cabinet, and if my cabinet partition is open, can draw some air across my fridge condenser.

Not meaning for this to turn into a computer fan thread, but if 24/7 operation is intended for simplicity, The noctua NF-f12 fan moves ~53CFM for just 0.05amps which is  very efficient, and it is very quiet and well built, with a 7 year warranty.  The fan also comes with 2 different low noise adapters ( inline resistors) which slow fan speed, and reduce amperage draw, and both can be used inline too for even less noise and current consumption.

I use this Noctua fan on my fridge condenser, pushing air instead of pulling.

As far as a solution in search of a problem. well battery offgassing is a concern for some, and not for others.  If you have strong opinions one way or the other and need to argue them, go find one of those threads to express your opinion there.

For 12v dwelling newbs wanting to live in the same space with a charging battery, and who do not want to sniff charging batteries (sulfuric acid mist is a known carcinogen) then perhaps we can come up with an inexpensive solution along the lines of a positive pressure battery hat. 

http://www.atsdr.cdc.gov/phs/phs.asp?id=254&tid=47

 It seems the sealed battery box with a Vent to exterior is a stumbling point when designing a system. Sealing the box around the battery cables is not simple, and a rising vent to allow hydrogen/oxygen and sulfuric acid mist to passively escape, might be ineffective.  Lots of effort to still smell rotten eggs.  The vented battery hat sucking air around the battery could be way simpler and way more effective.

AGM batteries seem like a solution too, but they cost significantly more, and they need more charge loving to achieve an acceptable number of cycles in a deep cycle application.

The 6v GC-2 flooded golf cart battery is simply the best house battery a van dweller can employ, being tolerant of less than perfect charging, but they are not easy to locate and they have the ofgassing issue.

With 'CHEAP' right in the forum title, let's find a cheap way of getting these 6v gc batteries, or the 12v  group 27/29/31 marine batteries  gasses safely outside any living space, so the Newb can not stress this particular factor of transitioning to living on Wheels and on 12 volts DC

 

[bcbullet]

I started a thread a while back asking about opinions on covering the whole shitteroo with pond liner and venting out the top with a bulkhead fitting and flex hose. It did not gain any traction, but I still believe it to be a viable option. And why not put the batteries on the lid of the storage bin using it to catch any fluid escaping and then put the bin upside down over the batteries, again using a bulkhead fitting and flex hose?

 

[SternWake]

Certainly viable options.

When I saw the Pics in the original post, and liked the simplicity of the idea, I thought I'd share, and thought perhaps we as a group could run with it.

Folding up a pond liner around a battery with all the cables going to it, and securing the battery to floor wall, seemed problematic to my mind. A plastic battery hat with fan and tube run to exterior seems simple in comparison, but I bet I could complicate it to a ridiculous degree.

 

[highdesertranger]

if you are going to use a fan to directly vent hydrogen make sure it's an explosion proof fan. highdesertranger

 

[SternWake]

Computer fans are brushless, and 'should' be sparkless.

Here is a sub 12$ voltage based relay which one should be programmable to turn fan on at 14.2v and should turn it off at some other preselected voltage.

Keep in mind I do not own one of these, and cannot say definitively that it would work for this purpose:

Well here are a few links to compare/decipher the chinglish instructions:

http://www.ebay.com/itm/12V-Voltage...Under-Voltage-Protection-Module-/171518613069

http://www.ebay.com/itm/DC-8-35V-Vo...-Switch-Module-LED-Display-15DU-/381501166803

http://www.ebay.com/itm/12V-24V-Dig...-Timer-Time-Delay-Switch-Module-/181635863945

http://www.ebay.com/itm/Charging-Di...ontrol-Board-Module-DC-12V-F3QN-/311480176614

If my income was at a more satisfying level I'd get one to experiment with, but it is not, so I wont.

 

[Matlock]

SW, the SilverStone works great and does not make a sound running on low. I'm still experimenting with the plastic box project in the earlier photo. I wasn't sure what would work best;
1. Pulling air out from one location, (which I found would pull out the humidity and heat created by the Buddy heater as well as any other gasses present inside, not my preference) or ....
2. Push air in and then control where that pressurized air was vented using smaller separate vents. One vent down low just above the batteries and another vent at the top of the wall above stove and heater on the other side of the van.

When pulling fresh air into my interior on low setting, like 65 cfm. It should cycle my 360 cf of air about 5 times an hour. If I'm generating a lot of foul air from various sources then I crank it up for a bit.
It's worth mentioning that my Box van is pretty air tight when everything is closed up. Cracking a couple vents with a fan works well.

Thanks for the links to the relays. I'm think I'll try the 12-24V version. It looks pretty straight forward. Probably a mid-summer project, I'll let you know how it goes and how long it takes me to fry it.....

 

[Spaceman Spiff]

I started a thread a while back asking about opinions on covering the whole shitteroo with pond liner and venting out the top with a bulkhead fitting and flex hose. It did not gain any traction, but I still believe it to be a viable option. And why not put the batteries on the lid of the storage bin using it to catch any fluid escaping and then put the bin upside down over the batteries, again using a bulkhead fitting and flex hose?

Why upside down?  It will be difficult to take the bin off with battery cables running through it.  If a battery leaks the top will hold very little liquid.

Install batteries in bin, put vent and fan on cover; easier to take off to check and service batteries.

A waterproof bin made to store file drawer contents fits two GC2 batteries just fine, seals well.

 -- Spiff

 

[wcurtin1962]

I’m thinking a vacuum line with a one way valve like a PVC valve could be ran from the engine to a sealed battery box to draw off the gasses while driving.

 

[Putts]

Are the gasses from batteries lighter or heavier than air?

 

[CautionToTheWind]

^^^ lighter

 

[highdesertranger]

hydrogen = lighter than air and highly explosive. no open flame or spark when off gassing. now that I scared everybody the likely hood of having the correct concentration to cause a problem is highly unlikely. highdesertranger

 

[Putts]

Thanks. That's what I figured. I've got a plan.