Can somone explain WHY positive first when jumping a car battery?

rbowman wrote on 1/18/2023 9:40 AM:

"However, distilled water does not contain any impurities" is definitely a misconception. The writer of that article is definitely babbling nonsense without any real knowledge.

I am a self-made expert in distillation. I own two expensive fractional distillation columns, and I currently own about 5 counter-top water distillers. If you know how to use the digital counter-top water distiller in an inventive way, you can do fractional distillation professionally in your kitchen.

Fractional distillation column:

You can do very accurate fractional distillation using a digital counter-top water distiller from Amazon. You can set the boiling temperature digitally, and theoretically you can separately a mixture of many solutes with differently boiling points by distilling at different temperatures.

My own expertise is electrical engineering but I am, in a way, a crazy scientist.

There are a few varieties of digital counter-top water distillers from Amazon:

I'm thinking... I'm thinking... I'm trying to think this thing out. I don't think it matters all that much which cable goes first or last.

As far as I can think about it, the last connection is the one that sparks. And that means the first disconnection is the one that sparks.

Since you don't want that spark to be near any concentration of flammable hydrogen gas, I guess the theory that I'll concoct is you want the negative cable to be as far from that hydrogen gas as possible.

That makes it the negative cable to be the last to connect. And the first to disconnect.

Now, if the theory is to proceed accordingly, we have to decide which battery has the most chance of having excess hydrogen gas.

The answer likely is neither will have any, but if we have to choose, which battery will have more hydrogen outgassing?

(A) The donor battery (which is likely already topped off) or (B) The recipient battery (which is likely taking the greater charge)

The answer seems, to me, to be neither battery will have excess hydrogen gas, but if I was forced to choose, I guess the battery being charged the most has the most excess hydrogen gas, which would clearly be the donor.

All this is just "thinking it out" so tell me if I'm wrong so I learn from your expertise (the royal your that is, as everyone has something to say).

Didn't the conversation recently happen that rain water (now that "acid rain" is no longer a thing, thanks to the EPA), is just as good as distilled water nowadays?

Sure, it's slightly acidic at pH 5.6 (if it's not acid rain, that is, as acid rain is pH 5.5 or lower by EPA definition someone found out), but a bit of weak carbonic acid (from the dissolved carbon dioxide) won't hurt the strong sulfuric acid in a lead:acid battery, will it?

I'm guessing that rain water nowadays, unless you live within a few miles of a volcano (and you don't) or a coal-fired power plant (and you don't), is pretty damn close to distilled water in most parts of the country.

Sure rain water will have a bit of "something here" and "something there" based on the dissolved gases in the atmosphere, but so will any bottle of distilled water that has ever been open to the exact same atmosphere.

Someone said there are "particles" in the rain water, but I don't believe that as you can't see any when you collect it outside and even if there were, a coffee filter would filter them out just fine (and who says store bought distilled water doesn't have particles?).

Sure, both might have particles, but I can't imagine they could matter given how few there would be if you can't even see them with your eyes.

But I don't know. I'm just trying to reason this stuff out like the rest of you. If there's someone who actually knows what he's talking about (not me), then that person should set me straight before I go on with this line of reasoning.

I can think of a simple way. Connect jump cable clamps to the car battery terminals and then carefully loosen and lift the terminals from the old battery.

Another way is to connect a 12V cigarette lighter plug into the cigarette lighter socket to temporarily maintain a 12V to the whole system from another 12V power source before you disconnect your old battery. You may have to power on the accessories in your car if you car is designed to cut off the power to the cigarette lighter socket when the ignition is off.

You can make do with rain water or tap water to top up the lead-acid battery but doing it too often will accumulate too much impurities in the battery fluid.

You can make do with distilled water but that is not as good as deionized water, which technically should be processed from distilled water.

A responsible auto shop or car dealership should use deionized water to dilute the sulfuric acid to use as battery fluid.

It's a car battery. It's not a silicon based integrated circuit. Water is water. To a certain degree it's all the same thing.

I don't know the answer for sure, but I would reason out that almost all tap water will be just fine in a car battery although I don't doubt chlorine (or chloramines?) that they put in them might affect the lead:acid chemistry.

They add fluorine too I think, and there might be a decent amount of calcium carbonates and metallic ions such as copper and phosphorous.

I'm guessing that the minute amount of such things (having owned a pool, I'm aware they're in the PPM range, and PPB for phosphorous) in a car battery designed to last five years, won't make one bit of difference.

An example of tap water total alkalinity is around 50 to 200 PPM and the calcium hardness due to calcium salts would range a bit higher, maybe double (depending, of course, on the amount of old shallow seas in your area fifty to two hundred million years ago).

But distilled water is cheap and rain water is even cheaper, and, in fact, so is tap water - so since they're all dirt cheap, may as well use the rain water.

That's how I see it from a reasoned approach, where I'm very familiar with the scare tactics pool stores try to pull on people when they find something, anything, to say "oh that's going to damage your equipment."

Same technique those Indian "Microsoft support tech" try to pull on you when _they_ call you and tell you to look in the Event Viewer and all those errors indicate your computer needs their expert help with ransomware addition.

Overall, does ANYONE have ANY real data that tap water actually degrades a car batter enough for someone to actually measure the results in 5 years?

Has anyone wondered whether the "pure" water will be "leaching" out the chemistry of the lead:acid plates inside the battery?

Having owned a pool, all water chemistry tends toward equilibrium, and dissolved salts (metal and a non metal) are no exception to the rule.

So the more pure the water, the more it will dissolve a bit of that lead:acid compound that they slather on the plates between rubber sheets.

Has anyone thought of that?

I say from the start that I'm only "reasoning" this out, purely theoretically, so while I'm sure adding tap water with high calcium carbonates will add "some" impurities.

Your use of "too much" is what bothers me, only because I've never seen a single reliable source that tested this for the five year life of a battery.

I'm sure someone tested it - but I've never seen those tests, where my assumption, without those tests, is sure, "something" will be added, but will it make any difference in a twenty-five pound battery designed to last only five years?

Again I'm only reasoning this out, and I would back off on my rationale the instant someone shows me batteries being harmed by rain water, which is distilled water nowadays, despite the "acid rain" scare tactics of some.

The Indian "Microsoft support techs" tried to pull the same scare tactics on me that the pool stores do, where they take a single tiny event and turn it into the explosion of the Maine in Havana's harbor.

A commercial outfit will always follow industry standards if they're reputable (most are not, in my humble opinion - most are scammers).

That's why you never believe anything coming out of the mouth of someone selling you a service without checking it (for example, they'll tell you that you "need" a fluid change when the owners manual will disagree).

They're all scheisters in my book - and I've been sheisted by them so I know this for a fact that some are sheisters who can't be trusted.

Back to this topic, how do you know that the "pure" water isn't leaching out all the good paste on the plates, now that it's devoid of ions?

I'm not asking this as a challenge - as the basic logic is sound.

What I'm looking for is a real answer to the practical question of how much could it possibly matter in a twenty-five pound battery designed for a short life in what turns out to be miserably inhospitable temperature & vibration conditions, not to mention discharge recharge redox cycles.

I say from the start that I'm only "reasoning" this out, purely theoretically, so while I'm sure adding tap water with high calcium carbonates will add "some" impurities.

Your use of "too much" is what bothers me, only because I've never seen a single reliable source that tested this for the five year life of a battery.

I'm sure someone tested it - but I've never seen those tests, where my assumption, without those tests, is sure, "something" will be added, but will it make any difference in a twenty-five pound battery designed to last only five years?

Again I'm only reasoning this out, and I would back off on my rationale the instant someone shows me batteries being harmed by rain water, which is distilled water nowadays, despite the "acid rain" scare tactics of some.

The Indian "Microsoft support techs" tried to pull the same scare tactics on me that the pool stores do, where they take a single tiny event and turn it into the explosion of the Maine in Havana's harbor.

A commercial outfit will always follow industry standards if they're reputable (most are not, in my humble opinion - most are scammers).

That's why you never believe anything coming out of the mouth of someone selling you a service without checking it (for example, they'll tell you that you "need" a fluid change when the owners manual will disagree).

They're all scheisters in my book - and I've been sheisted by them so I know this for a fact that some are sheisters who can't be trusted.

Back to this topic, how do you know that the "pure" water isn't leaching out all the good paste on the plates, now that it's devoid of ions?

I'm not asking this as a challenge - as the basic logic is sound.

What I'm looking for is a real answer to the practical question of how much could it possibly matter in a twenty-five pound battery designed for a short life in what turns out to be miserably inhospitable temperature & vibration conditions, not to mention discharge recharge redox cycles.

Have you thought of using corncob instead of toilet paper? Corncob is cheap, natural and reusable. LOL!!!

Although deionized water is 6 times more expensive than distilled water, but one gallon goes a long way.

Use deionized water if you want the best for your lead-acid battery.

Well. That makes sense. So maybe my initial reasoning was wrong that the last cable attach will spark, and you want that spark away from the battery, so that would have to be the negative cable.

However, you also said that the DISCHARGED battery is the one with all the hydrogen, so that means that you want to put the donor battery cable on last (because that's where the spark will be and the donor battery is presumed to have less hydrogen outgassing).

But then you made a good point that if you put the positive on first, then anything any negative touches by accident, will spark where it touched.

So now we have one good reason to put the negative on last and specifically the negative on the DONOR car on last by one line of reasoning, and by another line of reasoning, we have the positive going on last, presumably also on the donor car because it's going to spark.

Which is the correct line of reasoning?

(A) Put the negative on the donor car last because that spark is least likely to ignite hydrogen gases from the discharged battery or (B) Put the positive on the donor car last because you have less chance of accidentally shorting the circuit & the donor has less outgassing

Which is more logical?

Think those costs are off with two different sources and sizes.

Google sez this:

"However, in general, distilled water is more expensive than deionized water. This is because it takes more time and energy to produce distilled water, and it also requires special equipment that not all companies have."

When I worked in the lab we had a distilled water line to every bench but it was replaced by deionized water to save cost.

Been decades since I had a car battery that needed water but I am hearing it is better to put distilled or demineralized water in your car radiator if needed as minerals are bad there too.

Oh yeah, I think they say to do that too, but I've never worried about that. And I've gotten tired of standing there holding my battery cables waiting for someone to offer me a jump, so I bought what is no longer sold, Battery Buddy. It was great. When the car voltage got low, it disconnected the battery and all you had to do was open the hood, push a big red button, and the car woulds start. The first one lasted iirc 12 years, but I had planned ahead and bought another, tthat came in an unlabeled brown box. It lasted only a year or two. I think it came from their stack of likely defective ones, that say in a corner until the company folded. (a lot of assumptions here, but I coudlnt' find any more for sale.)

Finally I found Priority Start, 4 or 5 times the price, but it has a motor, so all I have to do is sit in the driver's seat and put my foot on the brake and it reconnects the battery. I've had it 3 or 4 years and I've used it twice and it's great. It seems to be made mostly for commerical trucking fleets, so they would lose money if the truck doesn't start, and they tolerate the higher price.

The car radio forgets most of what it wants knew, and the engine timing information is forgotten I guess, although I've never noticed a change in how the car runs, at least not for more than 5 minutes. Newer cars might forget even more, but at least I wasn't late to my doctor's appointment.

I don't see any reason to doubt what the poobahs say.

I've got a 6 year old U1 lawn tractor battery in the snow thrower and a

Off season, I throw a Battery Minder Plus 1510 on them so they don't discharge/freeze/sulfate.

The point is to first connect the positive lead to the battery positive, and then the negative lead AWAY FROM THE BATTERY by connecting to the engine metal. In that order for safety.

After the engine starts, then disconnect the negative lead that is AWAY FROM THE BATTERY so any spark created at the disconnect point is unlikely to cause the battery to explode if hydrogen gas was created. Perhaps you left the jumpers connected for a few minutes while charging the battery which leads to more hydrogen gas which makes a spark more and more likely/dangerous as time goes on...

John :-#)#

Distilled water is good enough for being devoid of "almost" all impurities except some ions. Distilled water is still quite conductive if you test a glass of distilled water with a multimeter.

Deionized water for home use is done with a canister of resin beads inline with your water pipe. The water is passed through the canister that can capture most, but not all the ions. Since the resin beads has charges that can capture only ionized particles in the water, other impurities in the water that have no electrical charges will not be captured.

Therefore, as I have explained before, the highest grade of pure water is deionized water made from distilled water.

Theoretically pure H2O does not conduct electricity, but in reality only deionized water made from distilled water can approached that theoretical state of being purely dielectric.

There is also C: Put the positive on the recipient car last because you have less chance of accidentally shorting the circuit & there is no hydrogen there.

Of A and B, they might both be logoical but B is more important. Shorting the donor battery, even at the other car, is going to cause a lot more trouble, cause a lot more damage, than hydrogen gases. That's why B is recommended.

Usually the guy helping me is also putting the cables on his car, but I still look at them before I finish my car. For various reason, I've had many dead batteries. Once a pretty girl stopped to give my car battery a jump.

Yes it does. First, set any thoughts of sparks causing an explosion aside. That's a *very* low probability occurrence as compared to the real reason. Unfortunately, a lot of people focus on the sparks issue and don't mention the real reason. And please note that the real reason also involves sparks.

The real reason has been mentioned earlier, but apparently needs to be repeated, maybe with more detail, so here goes. The real reason: there is a huge area of metal in the engine compartment, the car bumpers and fenders (if metal) etc. It is very easy to inadvertently touch the bare end of a jumper cable to that bare metal. If the negative jumper cable is connected first, and you're connecting the positive cable to the bad battery, you'll get a short circuit with that inadvertent touch, powerful sparks, a possible tack weld of the jumper cable, and a very bad day. (Possible fire, burns, dead battery, ruined cables, etc.)

If you connect the positive jumper first, the end of the cable CANNOT cause a short when it touches ANY bare metal in the car receiving the jump.

The proper procedure:

The above recognizes - and mitigates - the possibility of sparks, but focuses on the real potential hazard: short circuit. I wish all this talk of exploding hydrogen gas had never appeared, because it hides the extremely more probable event of a short circuit, which, of itself, creates a more powerful spark than connecting (or disconnecting) a jumper cable to a battery.

Ed

What happens to the dissolved carbon dioxide concentration of that "highest grade of pure water" once you open the jug & leave it for a while at STP?

Henrys Law says it will reach equilibrium based on the partial pressure of the carbon dioxide in the air.

That ionic carbon dioxide dissolves and turns into carbonic acid.

pH about 5.6

It's only "pure water" for an instant.