# Keeping Batteries in the Bedroom



## Rick (May 10, 2002)

Hello Folks

We are now living in a 12 by 20 bunkhouse, up on a high point on our property. It is a tight little builidng, and we heat with wood. We brought our solar panels up, and have them running into the charge controller inside, and then to our 2, 115 AH batteries, also inside. 

I know this is not the best arrangement, but I haven't been able to make time to set the batteries up outside. When we use our stove, we ventilate the room. 

Who thinks there is a large risk doing this, due to the fire, or just battery gasses?

Thanks for your thoughts.

Rick


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## 12vman (Feb 17, 2004)

I have 4-golf cart batteries on a rack in my bedroom and I never know that they are there. I don't have them in a cabinet or anything so the gasses don't have a chance to build up to dangerous levels..


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## mightybooboo (Feb 10, 2004)

12vman said:


> I have 4-golf cart batteries on a rack in my bedroom and I never know that they are there. I don't have them in a cabinet or anything so the gasses don't have a chance to build up to dangerous levels..


They say dont do it,BUT....
I have a friend with several inside his motorhome,no problems.I would still ventilate some to be on the safe side,Hydrogen does explode.

BooBoo


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## Jim-mi (May 15, 2002)

How many amps are you putting into the bats ?
Meaning do they gas a lot on a sunny day ?.
What type charge controll do you use ?
It is extremely hard to "contain" hydrogen (for it to build up to an explosive level). So if your 'bunkhouse' has a draft (or two) you will never have too dangerous of a build up.


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## Cyngbaeld (May 20, 2004)

I slept with them under my bed when we lived in a camp trailer. I've known several people kept them in the bedroom closet too.


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## Ed_Stanton (Dec 28, 2004)

Why not make a simple wooden battery box to contain your batteries and then vent the box/hydrogen to the outside? It's an easy and safer fix. Is it really worth tempting fate for the sake of a little plywood, silicone, screws, pvc pipe etc.? Most folks put batteries in a box or another room. I have 12 - 2 volt 1300 AH batteries in my box, 6 feet from my woodstove. The painted box is also sealed with silicone and a rubber gasket under the lid and the vent tube and cable tube to the DC disconnect box, both from the battery box are sealed with electricians putty (easier to apply from inside the box to the tube when one can't see, than using silicone, but that too would work). There are other good reasons for boxing your batteries, such as acid production and spillage onto the floor and ruining the floor, corrosion of nearby metals from gasses and other potential hazards if acid gets onto children or pets. Acid can spray out when batteries are topped up and then charged or equalized or when bumped, etc..

So, unless the charge IN were really high, your batteries might not gas off much at all normally, but when you Equalize the batteries, to be done once a month or two, they will gas off a LOT for that time period. You would be very wise to at least vent them during the equalization maintenance, and or not have your stove burning during that time if you do not box and vent your batteries.

I also have an electric vent fan in line of my 2" PVC vent tube, that turns on and off at set input voltages http://www.zephyrvent.com/ , but I have a larger system and potentially more gas off and I'm paranoid of problems and venting is cheap and easy, in comparison to the potential consequences of an explosion and fire. Why tempt Murphy's Law or think that "... only happens to other folks." The vent fan also has a back flow stop so that cold air won't come in when the fan is not blowing, so at -15 C tonight, no cold air will get in.

Read these: http://www.homepower.com/education/comp_battery.cfm

http://www.zomeworks.com/tech/H2/H2ventbasics.html


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## Rick (May 10, 2002)

Thanks for the replies.

Our bunkhouse only has drafts when we open the windows. 

Ed my gut is with you better safe, than sorry, and I'll address it asap.

Meantime, I have been making sure the air is renewed regularly.

Rick


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## hoofinitnorth (Oct 18, 2006)

I'm with Ed on this one - you need to keep your batteries in a heated area for max. performance but the gassing is dangerous - especially if you have a wood stove that could ignite the hydrogen fumes!


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## mustard (Aug 29, 2006)

I'll be looking at these same issues some time in the future...but I knew two people who had a battery explode in their faces, so I'll be putting mine in a ventilated box for safety...

M


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## MELOC (Sep 26, 2005)

what if the vent fan shorts out? :shrug:


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## Ed_Stanton (Dec 28, 2004)

Meloc: Not sure what your question is asking? But the link to the above vent fan has a fuse wired in line from the batteries. Otherwise if the fan does shut down, then the down draft baffle would slow down good venting. The down draft baffle can move up slightly on it's own, but not down. If wired in correctly, why would there be a short?


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## Jim-mi (May 15, 2002)

We've got two issues here.
Yes Ed Stanton is doing it proper with his Big bat bank. . . . .no question there.
But . . .I had the feeling that the very small bats that Rick mentioned might have only been fed by a small PV pannel.

Yes my large bat bank is 'contained'

Ed, the 24 Surrette KS-33's (two volt) bat bank I installed not so long ago is a big- dream-bank. WOW . . .contained in a box 4' x 10'. . . .
If the Bergey 10k is cranking out a really good charge into that system . . . I shure wouldn't want to be sleeping on top of it . . .or for that matter even in the same room. 

Rick's 115 amp bat verses the Surrette KS- 33's at 1766 anp-hrs-----times 24 . . . . . . .

apples and oranges here...........big time.. . . .


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## Rick (May 10, 2002)

Jim-mi said:


> How many amps are you putting into the bats ?
> Meaning do they gas a lot on a sunny day ?.
> What type charge controll do you use ?
> It is extremely hard to "contain" hydrogen (for it to build up to an explosive level). So if your 'bunkhouse' has a draft (or two) you will never have too dangerous of a build up.


Hey Jim-mi

My panels are 30 year old 35 Watt Arcos.

What is the formula for figuring the amps?

Rick


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## Jim-mi (May 15, 2002)

Rick, no formula there just use a good multi meter and see what the current reads.
Assuming that the pannels are wired for 12vdc the current at 35watts would be 2.9 amps.
For those oldy but goody pannels if you were to see 2+ amps put a big smile on your face.
No telling how those Arco's have aged.

Yet another example that PV pannels have a very long life.

PS . . .excuse me shure there is a formula . .its called Ohms law.
In this case amps times volts equals watts or I x E =W


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## MELOC (Sep 26, 2005)

i think my concern was for ignition of the hydrogen fumes in the event of a winding failure or even a static spark. i would opt for ventilation without a fan.


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## Explorer (Dec 2, 2003)

Do gel cell battries off gas?


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## Jim-mi (May 15, 2002)

Yes . . . . but internally, and since their 'sealed' it is not the issue that it is with 'flooded lead acid' bats . . . .with the vent hole in their cap.

Gasing is why you have to be very carefull with the high end voltage that you feed them (sealed) . . . .or you'll cook them.

MELOC, theres no question that venting is a " safe than sorry issue"
But if the bat is reasonably *small* you would play hell ever building up a high enough Hy. level to worry about it.
Unless of course you were feeding them a unreasonably high (and totally wrong) charge current-----or not using a good charge controller.


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## MELOC (Sep 26, 2005)

yeah...i just tend to over-think some issues. can you imagine not venting and having a closet full of gas ignite from an acrylic sweater spark. explain that one to the insurance company, lol.


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## Dubai Vol (Mar 22, 2006)

Says here that the lower explosive limit for hydrogen is 17%. You'd need a very confined space or a very large battery bank to get there.

I do see MELOC's point, if you are venting a battery bank with an electric fan, the fan would need to be explosion-proof in an industrial environment. That's expensive. One way around that would be to have a fresh-air intake before the fan that drew in enough air to dilute the H2 to below the LEL before it gets to the fan. Like so:










Assume the vent gas (orange) could be 100% H2. Size the fresh air vent to draw 6+ times as much as the battery vent pipe. Allow enough length to give good mixing, and you don't have to worry about your fan motor sparking and causing an explosion.


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## Ed_Stanton (Dec 28, 2004)

Thanks for the vent design & illustration! Good to add to this thread.

Battery box design info that I've read normally have vent holes for fresh air intake at the base (lowest point) of the box and the opposite corner to the exhaust vent tube. One can either make several small holes or one larger one. Mine has a 2" intake screened over vent hole. This is supposed to help dilute the H2 gas off and draw cooler air off the floor to help cool the batteries, which create heat during deep charging and equalization. If the batteries are contained in well sealed and vented box, then sparks from a sweater in the same closet should not be able to reach the H2? Also, my inverter which is placed outside of the battery box, has a relay that turns on the fan, so I'd think that the electrical connection (spark?) if there is one, is there not at the vent fan or near the H2 gas. As well, the fan is 4 feet above the battery box and not instead just inches above any battery. The box is also built with a sloping lid to move any gassing and fresh air up toward the vent. Gravity venting is effective and a fan may not be required for a small system. I opted for the fan after using gravity venting on a smaller system for a year, for two reasons. The first was due to increasing the number and size of batteries and I felt better with more substantial mechanical exhausting and cooling and the second reason being the baffle in the vent fan, which prevents cold outside winter air from coming back down the exhaust tube back to the batteries. Today is -24 C and I wonder which would win a gravity exhaust situation inside the vent tube, the cold dense outside air or warmer H2 gas mixed with fresh air? With an inline exhaust fan with a baffle, I don't have to worry about the battle or allowing freezing air to reach the batteries. If I didn't have to deal with cold winters and a large battery bank in a room fairly close to a woodstove ignition source, then I'd have felt fine with a boxed battery set, with an gravity exhaust tube and a floor level fresh air intake screened hole(s).


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## Dubai Vol (Mar 22, 2006)

Sounds like a good set-up, and I'm sure it will never give a problem. I was just looking at one way to get around needing an explosion-proof fan to feel 100% certain. The only risk comes from a possible malfunction of the fan causing a spark. Can you tell I used to work in a refinery? We did a similar thing for vent gases while loading tankers, but in reverse. The fumes coming out of the tanker were potentially an explosive mixture, so we added natural gas to bring it ABOVE the upper explosive limit, piped it to a furnace, added air and burned it.


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## rambler (Jan 20, 2004)

Years ago I was hauling/unloading corn wagons for dad. Hopped on the tractor, hunched forward turned the key, pressed the starter button, and BAM. Bits of plastic & acid & stuff flew everywhere. On the Ford 960, the battery is right below the steering wheel, and you hunch forward to push that starter button...... The battery is not at all enclosed.

Well the hood top & my glasses saved my eyes. My hearing went away for 5 seconds - that was an odd sensation! I mean, it really went _bam_.

I would _never_, not _ever_, sleep on top of lead acid batteries.

My opinion.

--->Paul


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## offGridNorthern (Jan 1, 2006)

Cyngbaeld said:


> I slept with them under my bed when we lived in a camp trailer. I've known several people kept them in the bedroom closet too.


I must be missing something ... our batteries are huge, red 208 lb. things..they wouldn't fit under the bed.


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## Jim-mi (May 15, 2002)

What-do-ya-mean wouldn't fit under yer bed . . ?

Dosen't everybody use a step ladder to git up into bed . . .??


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## Rick (May 10, 2002)

rambler said:


> Years ago I was hauling/unloading corn wagons for dad. Hopped on the tractor, hunched forward turned the key, pressed the starter button, and BAM. Bits of plastic & acid & stuff flew everywhere. On the Ford 960, the battery is right below the steering wheel, and you hunch forward to push that starter button...... The battery is not at all enclosed.
> 
> Well the hood top & my glasses saved my eyes. My hearing went away for 5 seconds - that was an odd sensation! I mean, it really went _bam_.
> 
> ...


Hi Paul

Thanks for the input.

We have a local fellow I asked about our batteries b eing inside. He told me he was welding in a garage in which batteries were being stored. There was aso a wood burner going strong, and maybe the 02 was low in the building. Anyway- BOOM the Hydrogen fumes met the welding spars and the explosion knocked paint cans open etc...etc....

Certainly not anything to take lightly. 

Rick


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