Battery Containment - Necessary?

[bschwartz]

..."Are there sparks from a brush-less motor?"

You know it's time to change the bearings when......

[rcavictim]

Geezzz,

I think my feelings are hurt.  I come up with this incredible idea about venting the batteries to the intake on the engine and no one gives me an "atta-boy".  You're not going to tell me the hydrogen generators for automobiles are bogus are you?

Are there sparks from a brush-less motor?

Casey

Casey,

I hereby award you 10-^18 boys, or one quintillionth of a boy, also known as an atto-boy!  Feel better? 

[LowGear]

Thank you rcavictim,

But is it a great idea or what?  OK, the using the fuel as a coolant outside the Artic Circle epiphany wasn't as great as I first thought but I think this one has real merit.

Casey

[mobile_bob]

Casey:

it was a good idea, where did you first post it?

i remember posting the idea too, so if i stepped on your idea let me know.

bob g

[LowGear]

Hi bob g,

I think I first posted it on Lister Engine Forum some 3 or 4 yeas ago.  Perhaps we were both caught in an extraterrestrial broadcast to this part of the galaxy.  Anyway, it was not warmly received.  Something about diesel and oils in general just not having the heat tendering ability of water.  

Now that I've settled on a Witte with its built in condenser I've drifted away from the idea.  But when I was in the cooling tank scenario I thought using the cooling tank and your primary fuel tank as the same vessel had real merit.  

I'm always proud to have someone come up with the same great idea.  It's one of the things I truly like about this site and Lister Engine Forum.  So many knowledgeable people willing to share their thoughts and experience (one of the rare elements on this planet.)  And I'm usually soothed by those that share my not so great ideas as well.  At least we're thinking and therefore we is.

Oh.    You were referring to the battery boxes venting into the intake on the engine something like the hydrogen generators being sold here and there but not by any automobile manufactures I know of.  If you thought of it more than a week ago then you're ahead of me.  Remember when all crankcase gases were vented back to the carburetor?  Same idea.

Casey

[WStayton]

A brief (!) update:

  I checked, with my own eyeballs, applied, sort of, to the product in question, and their bottom of the line, 6-volt golf-cart batteries are now $58.67.  The battery DID NOT display a part number on it but its tag did give its power rating as 575 cca.  I'm not sure how much relevance cold craking amps has to a deep-cycle battery, but that was the info that they gave, ALL of it!  <grin>

About capturing the hydrogen-oxygen off gasses:

  I think this is a GREAT idea, whoever thought of it!  It eliminates the explosion problem and gives you back a little of the energy that you threw away  electrolysing the electrolyte into the hydrogn and oxygen in the first place!  Looks like win-win to me!


About a "fume-hood" vs a "battery-box" approach to solving the gasses problem:

  If it can be done so that it works, I would prefer to have a "fume-hood"  that I can raise and lower since 1) It leaves the batteries open and I THINK that there will be more of natural convection around them to dissipate the heat built-up during charging.  and 2) A liftable hood means that both sides of the battery "table" are accessable for checking/watering.  The bunch of them will be 30" wide and 60'ish" long, so I COULD reach across the table to check/water the far string, but it is easier and will probably result in less spilled water if I have access to both sides.

  The problem of dropped wrenches is noted:  I THINK that my lowerable/raisable "fume" hood will ensure that this is covered except when I am actually engaged in checking/watering, but that is probably ALSO the time when a dropped wrench is most apt to happen - don't have a solution for that except vigalence(sp?), and I'm sure that gets better after the first wrench drop!  <grin>

Thats it!

As always, thanx for your input!

Regardz,

Wayne Stayton

[mobile_bob]

any battery that lists CCA is not a deep cycle battery

beware, of those hybrid types known as marine batteries, they are a cross between starting and deep cycle,  sort of a jack
of both trades but master of neither.

expect a marine battery to maybe make 100-300 cycles, a starting battery to make maybe 30-50 cycles, and a true deep cycle 1000 to as many as
3300 or more depending on depth of discharge.

with batteries you generally get what you pay for.

are those sam's club golf cart batteries listed with CCA too?

having said all that, i strongly suspect that a good automotive battery might well make many hundreds of cycles "if" the depth of discharge is very shallow. something like the top 5-10% and then a complete recharge, much like a car battery normally see's in daily use, might well work out to be effective, however not many applications can adapt to the parameter or provide rapid recharge as needed with that kind of frequency.


bob g

[Crofter]

Lest someone think you might be giving an engineers endorsement to this: Collecting the mixture of oxygen and hydrogen produced by battery charging is not a good idea! It might be if you could separately collect the components, then selectively combine small amounts at the point of combustion. Ignition by static electricity alone is enough of a certainty to make that a no brainer. 

Ventilation of charging batteries requires immediate dilution with large volumes of air to reduce the hydrogen / to oxygen ratio below the lower explosive limits.

[WStayton]

About the Sam's Club Battery:

  The battery for which I quoted the price was on the rack marked "Deep Cycle Batteries" in letters about a foot high - I asked a Sam's Club employee if there was more info for that battery - His reply: "What you see, is what you get!"

  It surprised me that there was NO identification number, model number, or any other number either molded into the case, or on a tag with the case.  I DID NOT turn the battery over and look on its bottom side, so it IS possible that there is some identification on it there.

  I have sent an email to Sam's Club asking them about there bottom-of-the-line Deep Cycle Battery, specifically why they chose to quote a cranking voltage for a battery that, if it was placed into the type of service that they are advertising it for, would NEVER see an engine crank cycle, but I'm not holding my breath!  IF I get a reply, I'll let eveybody know.

  Sam's bottom of the line battery is supposed, by the usual internet gossip, to be made by Exide and the figure's quoted for it are the same as for the Exide E-3600, as to weight, amps vs discharge rate, etc. but that is unsubstantiated information, at this point.


About charging hydrogen/oxygen back into a diesel engine:

  The diesel engine that I am going to use, will ingest 1.2 liters of air per revolution - less pumping losses.  Since the slowest that I am going to be running it is 1800 rpm, it will have 2160 liters per minute running into it.  Somebody here has quoted me 4% as the flammability-mixture of hydrogen necessary for sustained combustion.  So, if less than 86 liters per minute of hydrogen are coming off of the batteries, I should be safe.  I have also seen numbers like 1.5 gallons per week for the water requirement of a battery bank.  Since 1 GMV (gram molecular volume) of a gas is 22.7 liters, + / -, I will get 22.7 liter of hydrogen for each 18 grams of water that are hydrolysed into hydrogen and oxygen. so I can stand about 4 grams of water per minute being hydrolysed before I will reach a combusible mixture. That is 240 grams per hour or about 1/2 lb = 1/2 pint per hour.  If the batteries use 12 pints (1.5 galllons) per week, this must be spread over the solar cell operation AND the generator operation.  Solar operation is 10 hrs/day, + / -, times 7 days so we have 70 hours of solar.  How many hours of solar = 1 hour of generator, in terms of electrolysing ability?  I see numbers for solar panels like 1.5 operating voltage for max voltage, but I would think that the normal "charging" must be more like the same as a generator/battery-charger, otherwise there wouldn't be any charge if way less than that and it would "boil" the batteries dry if way more than that, so for a first order approximation, it must be more or less about what the generator/charger puts out.  So, we have 70 hours of solar + 12 hours of charger = 82 hours total.  So, for 12 pints of water over 82 hours, we get .15 pints per hour or something like 25% - 30% of what is necessary to supply a combustable mixture - so, it looks, on first blush, like I am safe, no?  Of course there are more holes in the analysis than you can shake a stick at, like is the water requirement for MY battery set going to be 1.5 gal per week, and is the panel outgassing really equal to the engine/charger outgassing, etc., etc., but it is far enough removed that I am willing to try it!  Watch upstate NY, there may be a large BOOM a few months in the future!  <grin>

  One last note, there is relatively little that goes on in the induction of a diesel engine that could/would set off an explosive mixture.  The hot stuff all occurs AFTER the intake valve has closed, they do, after all, run diesel engines with a relatively large percentage of their power requirement coming from mixing natural gas, or hydrogen from land fills, into the induction stream, and I've never heard of one of those having a catastrophic explosion - so it must be a relatively small risk, even with an explosive mixture - but I not real interested in running a lot of  hydrogen to find out for sure!  <smile>

Thats it for now - thanx for your input guys!

Regardz,

Wayne Stayton

[mobile_bob]

i don't think you will generate anywhere near enough hydrogen to make an explosive mix for the engine,

but i hope you do!

reason being you would be the first to generate nearly the amount of hydrogen needed to run the engine, given the engine is
driving the generator that is providing the electrolysis to generate the hydrogen.  it would be the first example of an engine that
truly could run on water alone.

however we know this isn't going to happen, sadly not even close.

if you generate enough hydrogen to provide a dual fuel offset to the primary fuel (diesel) for it to provide even a measurable
reduction in primary fuel consumption i would be very surprised.

however if it is proven to even reduce the primary fuel consumption even 2% i wanna know about it.

not holding my breath here

bob  g

[mbryner]

The key word here is "negligible".

[Crofter]

Wayne, you are a marvel with that calculator but in the meanwhile an awesome amount of the obvious seems to escape you. I wont bother checking to see if you are off an order of magnitude again in your windy calculations, but I will point out that there is a very big and easily explainable difference between the handling of explosive gases and the handling of them in a mixture with oxygen well within their explosive range. You entirely missed the part about static electricity. It can be caused by gas flow amongst other things. You may have noticed the phenomenon of lightning? Hmmm?

You seem intent on justifying as a potentially good practice, the idea of taking oxy/hydrogen gasses from battery charging and piping them into an internal combustion engine. You say there is nothing hot on the way. What, physically, stands between the combustion event and the intake runner?

Maybe you should do an in depth workup on the process and see if you can get it into the white papers section here on the forum; it certainly is a ground breaking approach to an age old problem. You should be able to arrive quite closely at the potential Btu reclaim but you may have to access the expertise of Lloyds of London  to calculate the risk / benefit analysis; engineers don't seem to be especially good at that and most especially so on their own creations.

[mobile_bob]

something else to consider, batteries don't really start to offgas before they get to about 80% state of charge

so while most of the heavy charging is being done, there will be little if any offgassing or production of hydrogen
and when the gassing starts (usually around 13.7volts or so) the amperage drops dramatically up until full charge.

so i would think that if you hook the intake to suck up the gasses, they will start to increase very slowly and the airflow
into the engine should be much higher than what is needed to assure that the hydrogen % never reaches 4% or even close.

if you are concerned about it just put a flame arrester inline to the engine intake,

now you might have issues with solar charging when the engine is not running but it is very hard for me to see a problem
ever arising with engine charging.

as easy as it is to vent to the great outdoors, why even bother with sucking it up in the engine?

then there really is no concern?

a good use for engine intake would be to take the intake air from close to the floor, that way if there is any heavy gasses, CO2, CO or perhaps propane that accumulates it could be sucked up and moved outdoors assuring that the levels of bad stuff remain acceptably low in the engine room while the engine is running?  this is something i am seriously considering myself.

bob g

[WStayton]

Crofter:

"You say there is nothing hot on the way. What, physically, stands between the combustion event and the intake runner?"

  The last time  checked, it was called an INTAKE VALVE, which closes tightly against it's seat to contain the heat of compression (2800 psi + / -, depends on compression ratio, ring health, valve sealing, etc., etc,)  I think it is highly unlikely that a flame from combusiton is going to translate back into the intake manifold and cause an explosion, if you have a good enough seal to generate the compression necessary to have combusiton in the first place.

  As to a dedication to some technology that is risky and questionable, my thinking was more, I need something to vent the hood, and if the engine provides the airflow to do this, without the expense of the electricity to run ANOTHER fan/motor,etc. and maybe even generatres a little power, it was truly a win/win situation - taking horse s@!t and making horsepower, so to speak.  As Bob so correctly points out, due to the restrictions of the laws of thermodynamics, you ain't EVER going to make enough power to run the engine, outright, even if all of the current generated goes into making gas.

  Also, as Bob points out, if spark/ignition from the engine is a problem you can put a spark screen in the intake flow, such as what used to be placed in the intake stream of commercial spark ignition marine engines, which had a much higher liklyhood of a backfire, etc., to preclude any flames into the bilge and thus igniting any bilge fumes.  They did, however, ocasionally have a shattering explosion reducing the boat to rubble, but I don't think that came from the induction system, more likely from a plug/coil wire - back in the day before computerized ignitions, heck, some of them used magnetos just to preclude having a problem because the generator quit.

The gas from a landfill is not a combustibe mixture, usually being something like 2/3 methane + 1/3 carbon dioxide, so that was a sort of bad example, except that they DO mix it with the incoming air, somwhere upstream of the engine, so some of it has to be an explosive mixture, somewhere in the process otherwise why do it?

  Am I going to write an SAE paper about "using battery outgasses to generate power", no, not even an angels chance in h#ll!!!!  Having collaborated on a couple of SAE papers, on topics that merited disemmination, I have seen the nasty process of writing a proposal, addressing complaints to the proposal, writing, submitting, addressing issues raised, rewriting, resubmiting, readdressing new complaints, etc., etc., ad nauseum!  I have nothing I want to say badly enough that I am willing to put up with the bullspit that the review committee puts you through, largely just because they can.  YMMV, it HAS been 30 year since I had anything to do with submitting a paper to SAE!


As to having enough power generated, from outgasses, to be able to measure it:

  Since the engine will be buring something like 2 gallons an hour at 20 kW, and the hydrogen we are talking about is something like 1% of the intake charge, I am EXTREMELY skeptical that, with my "yard stick scale" instrumentation, I would eve be able to see it.  A coomercal dynomometer such was Ford used 30 years ago (not sure what they use now, probably something "smart" and computer controlled that requires zero knowledge to run it), measure things to an accuracy of + / - 0.! HP, and torque to 0.1 Ft-Lbs - not sure what the fuel flow accuracy was but it was eyball of a glass graduated cylinder so there had to be something like 1%, what with meniscuses and all, so I am not even sure that they could measure the small differance that feeding 1% hydrogen into an incoming airstream would make.  We did do several test evaluating various "gadgets" offered over the years that were supposed to improve your fuel economy, and fund these instrumentation limitations were frequently sighted when the efforts were almost, but not quite, a complete waste of time - there were a couple of water injection devices that did improve the fuel economy by something like 5% - something about the heat of vaporization of water being less than the specific heat of exhaust gas, but they were very fussy to get to work since they had to get the liquid water into the combustion chamber BEFORE it turned to steam to do any good.  Several parties have designed 6 cycle engines over the years that had the usual intake-compression-power-exhaust cycle but then they tack on a water intake/injection and rankine steam cyle power stroke after that, before the whole thing repeated - showed some gains in efficiency but the logistics, in pre-on-board-computer days were just to complicated to think about mass producing for anything like a reasonable cost, so they fell by the wayside,

As always, thanx for the criticisms - I do enjoy responding even if I sound like a crabby old f@#t, which, maybe, I am!  <grin>

Regardz,

Wayne Stayton

[Tom Reed]

Plausible scenario: Batteries under heavy charge 90% full and gassing. Engine shutdown due to false trip on engine safety controls. Batteries still gassing. Engine restart and a BACKFIRE into explosive mixture (I've seen my diesel fire and run backwards!). 911 call for unrecognizable body covered with acid and burned in a house fire. I'm a software engineer and design has to take into account what can go wrong, because eventually it does. A failing battery can also out gas prodigiously.