How much of an issue is battery off gassing?

[amwbox]

Yeah, but Hydrogen is also extremely light and extremely tiny...it rises quickly and escapes easily through even the tiniest gaps. It doesn't pool like heavier-than-air propane. I think in cases where you've overcharge the battery enough to get a huge amount of gas from it...I'd be more worried about the battery failing to vent properly and blowing up internally. 

Look at this guy and his death wish:

[video=youtube]

He's pushing insane amperage and voltage through it...but chargers/controllers could malfunction, I suppose.

 

[LeeRevell]

I have never understood this mentality, to massively overcharge a device to the point of destruction......   for what exactly?
Much like an idiot we had on a couple gun forums who liked to massively overload a certain caliber ammo far beyond safe published limits, fire it in a perfectly good handgun and blow it up, then has the gall to say the pistol was UNSAFE!  Sheesh........    :s

I'd guess these fellers pulled the wings off flies when they were kids.  

I am sure he could get a job hacking cars for the demolition derby.

 

[akrvbob]

This is a snip from the Lifeline battery website  http://www.lifelinebatteries.com/manual.php.

According to them their AGM batteries produce hydrogen gas when being charged They MUST be vented when they are charged.
Bob

= = = = = = = = = = =

 

[amwbox]

I have never understood this mentality, to massively overcharge a device to the point of destruction......   for what exactly?
Much like an idiot we had on a couple gun forums who liked to massively overload a certain caliber ammo far beyond safe published limits, fire it in a perfectly good handgun and blow it up, then has the gall to say the pistol was UNSAFE!  Sheesh........    :s

I'd guess these fellers pulled the wings off flies when they were kids.  

I am sure he could get a job hacking cars for the demolition derby.

Destructive testing is an extremely important part of gaining a real world understanding of a product or system. I worked the failure lab for a while, back in the day. The data you get from actually testing the limits of something, repeatedly, and with control...just can't be beat.

As for illustrations like the above video...its simply a matter of making a potential issue a real thing you can look at with your eyes, instead of speculate about with a calculator. This sort of thing actually gives us some sort of appreciation of the energies and pressures involved, instead of leaving them an abstraction. Its why we've got amp and volt gauges in the frame.

Its different from the "Will it blend?" guys, who put brand new cell phones and such into a blender just to shock mystified spectators. Or the guys who load an old washing machine with gunpowder and blow it up for the hell of it.

 

[LeeRevell]

Destructive testing is an extremely important part of gaining a real world understanding of a product or system. I worked the failure lab for a while, back in the day. The data you get from actually testing the limits of something, repeatedly, and with control...just can't be beat.

As for illustrations like the above video...its simply a matter of making a potential issue a real thing you can look at with your eyes, instead of speculate about with a calculator. This sort of thing actually gives us some sort of appreciation of the energies and pressures involved, instead of leaving them an abstraction. Its why we've got amp and volt gauges in the frame.

Its different from the "Will it blend?" guys, who put brand new cell phones and such into a blender just to shock mystified spectators. Or the guys who load an old washing machine with gunpowder and blow it up for the hell of it.

Well, maybe so.....  :-/
I will let the fellows who are far better heeled than I expend THEIR equipment this way.  I figure the manufacturer did all the destructive testing necessary.

 

[ccbreder]

As for the original question. It is not much of an issue if you don't over charge your batteries and have minimum ventilation. If you have breathing problems, you know your limitations and should be extra careful.

 

[SternWake]

All AGM batteries can offgass if overcharged.  They will not offgass if not overcharged or overheated. If an AGM battery offgassed each and every time it was properly recharged, they could not last very long as one cannot replace the lost electrolyte.

No AGM battery is going to say their batteries can charged in a completely sealed container.
  Batteries do get warm when charging, and ventilation is needed just to keep the batttery from getting too hot when charging.  The venting of AGMS  in normal usage is wise just to keep them from getting too hot.  Same with flooded batteries, but Flooded batteries emit Hydrogen and Oxygen and carry with it a sulfuric acid mist every time they are fully charged.


 Chronic undercharging is much more likely to happen than overcharging. My Van will hold 14.9v for much longer than my Northstar AGM needs.  My Ammeters can't even measure the tiny currents it requires to hold the battery up at these levels after the battery reaches full charge, and the battery does not even get hot.  I've no Idea if the vents released some gas.  I do know the battery is still performing very well in my load tests.


  I do know my flooded battery held at 14.9v after Specific gravity maxed out would bubble and gurgle and offgass  and heat up quickly under the same conditions and take about 1.5 amps when new and over 3 amps at the end of its life to be held at 14.9v after SG maxed out.

Lifeline has a conditioning procedure which is similar to a equalizing cycle on a flooded battery. Voltages are to be held at 15.5v for 8 hours.

Lifeline is the only AGM manufacturer that recommends this procedure, and it will cause the vents to open.  They do recommend this procedure be applied whenever capacity loss becomes obvious.

They also have a deep discharge recovery procedure for a overdepleted battery which does not respond to a normal charge, and these voltages are expected to climb to 18+ volts and require special equipment to achieve these voltages.

As far as failure testing, that tiny AGm battery being fed 120Vac at 50 amps is extreme.  

I once sacrificed a cheap 23$ an adjustable voltage power supply for science.  The power supply has no protections against overload.  it was rated at 350 watts.


After 17 minutes at providing 538 watts into a depleted AGM battery, the magic smoke was released, along with some sparks and short lived flames from the power supply.

Forcing things to fail is how one learns.  precautions are, of course, necessary.

I had once recommended that cheap power supply here on this forum, but then realized there were a whole bunch of if's ands or Butts included in its  safe operation.  I asked moderators that the thread be removed, and then I pushed the power supply until it failed.  I even tried to replace the smoked transistors, unsuccessfully.

I now use a 100$ adjustable 500 watt power supply that maxes out at 600 watts, and has all sorts of overload protections built in but it is used as  a manual charger and can indeed overcharge a battery, and while perhaps not cause the failure as extreme as in the video above, I know I could pop the vents on any AGM battery and force any 12v battery into thermal runaway with it.

We now live in a world where nobody is responsible for their own actions, and instructions must be written as if the reader has absolutely no common sense, and that their friends and family are lawyers who seek to profit from the stupidity of their clients.

 

[highdesertranger]

here is an article about proper venting. http://bdbatteries.com/hydrogenventing.php . highdesertranger

 

[Canine]

Leerevel,When the primers fall out of the case as fast as you put them in,you,ve reached max load.

 

[MK7]

if you are using a fan to move hydrogen gas.  you better make sure it's explosion proof.  highdesertranger

Crap, what does that mean? The spark caused by the fan can set off the explosion? If the fan stays on all the time (since it's only 2.5w), wouldn't it be dispersing the gas and preventing it from pooling in one area to increase its concentration in one place?

 

[BigT]

And wouldn't a fan be OK it was on the intake side of the box where the fumes wouldn't be passing through the windings?

 

[highdesertranger]

I don't know let's ask Wile E Coyote. or better yet let's ask Murphy. highdesertranger

 

[Matlock]

BigT, you mentioned in another thread  you sleep with a C-PAP so your already where I don't want to be.

I have developed a touch of sleep apnea and it's important I have fresh air circulation through the night.
Don't need the mask but I need to be aware of closed environments with reduced "clean" air circulation.
Regardless of the amount of off-gassing that's produced, I must vent my batteries outside to breathe. Chemicals in the
air kill my brain cells. (Can't speak to what it does to other folks)

There are several net write-ups on building a wood battery box or just buying an existing plastic battery box.
Just make sure whatever version you use has a lid/cover with a hose in the top to allow the hydrogen to escape to the outside.
Hydrogen rises so the vent tube needs to be higher than the battery box top.
No need for a fan, just keep the tube above the box all the way through the outside wall. I think I recall you saying someplace that you were not thrilled about cutting a hole in your Transit. Obviously, your choice/your life.

As Oberneldon mentioned in post #20, Hydrogen can explode between 4% to 75% by volume. IE. It does not take much
accumulation to make things ripe for explosion. That's why you mount the battery/(s) in their own box and vent them to the outside.
In my case, the dementia fumes are probably gonna kill me long before it goes boom.....

 

[BigT]

Good point on the sleep apnea.  Also, when I hit about 30 years old, I suddenly found myself extremely sensitive to smells, fumes, and chemicals.  

I'm looking at AGM batteries to address the issue.

 

[Oberneldon]

I posted the following in another thread but it seems appropriate here too.

My Prius 12 v battery is stocked with an AGM battery. It has a vent tube as the battery is in the rear passenger compartment. They apparently sell AGM batteries that the tube can be added but I have not researched it. Here is a link on how to vent an AGM battery. http://www.m5board.com/vbulletin/e60-m5-...ics/302977 Possibly you can add the AGM inside your vehicle & drill a hole through the floor and vent it with the vent tube. Then hook it to your 12 v vehicle to charge & get an appropriate charger to make it happy from time to time as SternWake has so well stated many times

Brent

 

[MK7]

I don't know let's ask Wile E Coyote.  or better yet let's ask Murphy.  highdesertranger

Here's a guy with a giant battery box and a fan to blow out the gas.   His is setup is six L16 batteries at 385 AH each, so it doesn't seem like amateur hour.




(it's at the 5:20 mark)

 

[highdesertranger]

well I can spot several things with his set up that points to amateur hour. just because someone post a video on you tube doesn't mean they know what they are doing. I can go on and list what I see wrong but the simple line right at the beginning should have given you a clue. "I don't live off the grid now nor am I totally self sufficient". with only a fan and a CB radio plugged into that how much charging does he actually do. go ahead use a fan to vent off hydrogen I don't care, all I said was make sure it's explosion proof and I stand behind that. I only posted the wile coyote thing when people where trying to make excuses for using the fan instead of just using an explosion proof fan. btw explosion proof fans are common, an engine bay fan for boats must be explosion proof a lot of fans for industry must be explosion proof. so what's the big deal just use an explosion proof fan when trying to vent hydrogen gas. you are venting a highly explosive gas, this is not rocket science. geez. highdesertranger

 

[Matlock]

Not to belabor the point, but..... Hydrogen rises.... it's lighter than air. If you really want to run a fan to vent hydrogen then a roof fan might work. Dunno, just might be fine. Maybe not.

If anyone wants to leave any battery uncovered, and add a fan that is explosion proof in a confined space then you need a "NEMA 7, Explosion Proof and Intrinsically Safe in Confined Spaces" fan and prices run around $500. and up. Pardon the pun but that is a tad overkill. Again, you don't need a fan, just cover the battery and vent outside. And.... AGM's do vent, slightly, on occasion, when being charged properly. Same deal, vent outside from the top of the battery cover to an outside wall.



Not trying to ruffle feathers here just say'in........

 

[Optimistic Paranoid]

Not to belabor the point, but..... Hydrogen rises.... it's lighter than air. If you really want to run a fan to vent hydrogen then a roof fan might work. Dunno, just might be fine. Maybe not.

If anyone wants to leave any battery uncovered, and add a fan that is explosion proof in a confined space then you need a "NEMA 7, Explosion Proof and Intrinsically Safe in Confined Spaces" fan and prices run around $500. and up. Pardon the pun but that is a tad overkill. Again, you don't need a fan, just cover the battery and vent outside. And.... AGM's do vent, slightly, on occasion, when being charged properly. Same deal, vent outside from the top of the battery cover to an outside wall.



Not trying to ruffle feathers here just say'in........

I dunno, either.  Bilge blowers on boats, by definition, must remove potentially explosive fumes from a confined area, must be approved for that purpose by the U S Coast Guard, are 12 volt dc, and can cost less than $50.  I'm pretty sure you don't need a $500 Commercial Unit.  I'm also sure I wouldn't use a computer muffin fan for that . . .

Regards
John

Here's another question.  I'm sure the hydrogen gas will rise and exit by itself.  Will the sulfure dioxide gas?  Is it lighter or heavier than air?  I dunno.

 

[dogear52]

Heavier.