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

M

mike

Guest
When I looked up how to jump a car battery, they tell you WHAT to do, but
not WHY, which is infuriating as it\'s harder to remember unless you know
why.

https://blog.napacanada.com/en/how-to-safely-and-quickly-recharge-a-dead-car-battery/

First they say the cars shouldn\'t touch.
Why?

Then they said positive first.
Why?

Once started, they say remove the negative cable first.
Why?


Here, they say adding water damages the batteries. Why?
https://www.uetechnologies.com/add-water-to-battery-before-or-after-charging/

And how often do you need to add water?
This says to add water after every ten charging cycles?
Isn\'t that like every ten days?

And how do you know how much to add?
They say add water to the \"splash plate\" but what is that?

They say the six chambers produce 2.1 volts each for 12.6 volts?
Isn\'t it more than that?

They say adding water before charging will make it overflow.
Does it really change the water level that much from dead to charged?

And what happens if you tap water instead of distilled?
 
On 18/01/23 14:35, mike wrote:
When I looked up how to jump a car battery, they tell you WHAT to do, but
not WHY, which is infuriating as it\'s harder to remember unless you know
why.
First they say the cars shouldn\'t touch.
Why?

Then they said positive first.
Why?

Once started, they say remove the negative cable first.
Why?

These three questions only need one answer.

In case there is any hydrogen gas that has developed in the battery and
may be still concentrated enough to burn, any spark from completing the
circuit should be made at some distance from the battery. That is, but
connecting the earth to some metal part of the chassis, not to the
battery terminal itself.

The chassis is (usually) negative, which is why that is the first and
last contact point.

> And what happens if you tap water instead of distilled?

If there is any ionic content in your tap water, it is likely to
precipitate as conductive salts in the bottom of your battery,
increasing the self-discharge rate. Here in Sydney, our water is clean
enough not to need to bother - any effect on battery life is negligible.

CH
 
On 1/17/2023 10:35 PM, mike wrote:
When I looked up how to jump a car battery, they tell you WHAT to do, but
not WHY, which is infuriating as it\'s harder to remember unless you know
why.

https://blog.napacanada.com/en/how-to-safely-and-quickly-recharge-a-dead-car-battery/

First they say the cars shouldn\'t touch.
Why?

Then they said positive first.
Why?

Once started, they say remove the negative cable first.
Why?

Less potential for arcing. If the negative goes on first and you are
touching the car and positive cable you can be a conductor.


Here, they say adding water damages the batteries. Why?
https://www.uetechnologies.com/add-water-to-battery-before-or-after-charging/

And how often do you need to add water?
This says to add water after every ten charging cycles?
Isn\'t that like every ten days?

Last time I had a battery that was not sealed was probably 30 years ago.
Tap water can have chemicals.
 
On 18-01-2023 09:40 Clifford Heath <no.spam@please.net> wrote:

In case there is any hydrogen gas that has developed in the battery and
may be still concentrated enough to burn, any spark from completing the
circuit should be made at some distance from the battery. That is, but
connecting the earth to some metal part of the chassis, not to the
battery terminal itself.

Thank you for trying to explain why they said here to connect + first.
https://blog.napacanada.com/en/how-to-safely-and-quickly-recharge-a-dead-car-battery/

Isn\'t there a spark no matter what cable is the last point to be connected?

The chassis is (usually) negative, which is why that is the first and
last contact point.

I\'m not disputing that since I\'m the one asking the question, but didn\'t
that article above say the opposite?

They said to connect a negative cable last to the chassis of the dead car.
 
mike wrote on 1/17/2023 10:35 PM:
When I looked up how to jump a car battery, they tell you WHAT to do, but
not WHY, which is infuriating as it\'s harder to remember unless you know
why.

https://blog.napacanada.com/en/how-to-safely-and-quickly-recharge-a-dead-car-battery/


First they say the cars shouldn\'t touch.
Why?

The metal body of a car is connected to the negative terminal of the car
battery. In the old days the bumper was chrome-plated steel, but today
most bumper are covered with polymer so the metal part of the two cars
won\'t touch anyway.

Then they said positive first.
Why?

The metal frame of the car is permanently connected to the negative
terminal of the car battery. If you connect the black negative jump
cable first, then when you try to connected the red positive jump cable
you can accidentally drop the big clip into the engine compartment and
cause a fire or battery explosion.

Once started, they say remove the negative cable first.
Why?


Here, they say adding water damages the batteries. Why?
https://www.uetechnologies.com/add-water-to-battery-before-or-after-charging/

The electrolyte in a lead-acid car battery is sulfuric acid. Normally
the battery and the sulfuric acid are separate before the battery is
ready for installation. The technician dilutes the pure sulfuric acid
with de-ionized water to the proper strength to be used to fill the
lead-acid battery.

De-ionized water is purer than distilled water. If you use tap water,
then the minerals and ions in the tap water will be conductive and your
car battery will self-discharge internally rather than holding the
charge for a long time. You can easily prove that tap water is quite a
good conductor of electricity by dipping your multimeter test leads into
a cup of tap water.

You can normally get de-ionized water from some auto-parts or hardware
store.

If you cannot get de-ionized, then distilled water will suffice.

https://www.amazon.com/MAXTITE-Type-Deionized-Water-Laboratory/dp/B08RJVJSFB


And how often do you need to add water?
This says to add water after every ten charging cycles?
Isn\'t that like every ten days?

When you charge the car battery too fast or overcharge the battery, the
H2O in the electrolyte will separate into H and O2. That\'s why there is
an air vent to let the hydrogen and oxygen out so that it will not
explode. You can fill the depleted H2O with de-ionized water to the same
level when you got the battery. It is not exact science. A little more
or a little less won\'t make much difference in the concentration of the
sulfuric acid inside.

And how do you know how much to add?
They say add water to the \"splash plate\" but what is that?

They say the six chambers produce 2.1 volts each for 12.6 volts?
Isn\'t it more than that?

When your car is running, the battery is being charged so the terminal
voltage is higher than the theoretical nominal voltage of a lead-acid
battery. If you really want to check the nominal voltage of your car
battery, then open the hood to check the terminal voltage with a
multimeter after the car has not been used for a day.



They say adding water before charging will make it overflow.
Does it really change the water level that much from dead to charged?

And what happens if you tap water instead of distilled?
 
On 1/17/23 20:34, Mighty✅ Wannabe✅ wrote:
The metal frame of the car is permanently connected to the negative
terminal of the car battery. If you connect the black negative jump
cable first, then when you try to connected the red positive jump cable
you can accidentally drop the big clip into the engine compartment and
cause a fire or battery explosion.

Excellent explanation!

I always did positive first. I will switch!

 
On Wed, 18 Jan 2023 15:10:44 +1100, Clifford Heath <no.spam@please.net>
wrote:

On 18/01/23 14:35, mike wrote:
When I looked up how to jump a car battery, they tell you WHAT to do,
but
not WHY, which is infuriating as it\'s harder to remember unless you know
why.
First they say the cars shouldn\'t touch.
Why?
Then they said positive first.
Why?
Once started, they say remove the negative cable first.
Why?

These three questions only need one answer.

In case there is any hydrogen gas that has developed in the battery and
may be still concentrated enough to burn,

Don\'t buy that for two reasons. Firstly most cars and trucks
have the battery in the engine compartment and just opening
the hood/bonnet to get to the battery will ensure that any
hydrogen under the hood will be long gone by the time you
use the jumper leads. Secondly you will always get a spark
when connecting the last one anyway.

Presumably the \'logic\' for connecting the negative lead to the
body of the car with the dead battery is that the spark will be
further away from the battery, but as I say, it is a pretty dubious
proposition that there will be any hydrogen still around.

A few cars do have the battery in the passenger comparment or
the trunk/boot, so many that instruction is to cover that situation.

any spark from completing the circuit should be made at some distance
from the battery. That is, but connecting the earth to some metal part
of the chassis, not to the battery terminal itself.

The chassis is (usually) negative, which is why that is the first and
last contact point.

And what happens if you tap water instead of distilled?

If there is any ionic content in your tap water, it is likely to
precipitate as conductive salts in the bottom of your battery,
increasing the self-discharge rate. Here in Sydney, our water is clean
enough not to need to bother - any effect on battery life is negligible.
 
On Wed, 18 Jan 2023 at 03:35:29, mike <this@address.is.invalid> wrote: (my
responses usually follow points raised):
And how do you know how much to add?
They say add water to the \"splash plate\" but what is that?

I have no idea what a splash plate is, but most of the fill tubes are about
an inch long in each cell and they\'re slotted to make a meniscus for you.

Here\'s an explanation of that meniscus but I wish it had a photo of it.
https://www.wikihow.com/Check-Car-Battery-Water-Levels

Anyone here have a good photo of the slotted meniscus eye shape for him?
 
On Wed, 18 Jan 2023 10:03:32 +0530, mike wrote:


I\'m not disputing that since I\'m the one asking the question, but didn\'t
that article above say the opposite?
They said to connect a negative cable last to the chassis of the dead
car.

If you connect the negative first and inadvertently touch any grounded
surface you\'ll get a spark. That\'s also the reason for not having the cars
touching although that advice is seriously out of date. Plastic to plastic
contact isn\'t a problem. The majority of the vehicles any more don\'t have
steel bumpers.
 
On Tue, 17 Jan 2023 23:25:15 -0500, Ed Pawlowski wrote:


Last time I had a battery that was not sealed was probably 30 years ago.
Tap water can have chemicals.

The pickup battery isn\'t sealed, but the bike batteries and the Toyota\'s
are.
 
On Tue, 17 Jan 2023 20:39:24 -0800, T wrote:

On 1/17/23 20:34, Mighty✅ Wannabe✅ wrote:
The metal frame of the car is permanently connected to the negative
terminal of the car battery. If you connect the black negative jump
cable first, then when you try to connected the red positive jump cable
you can accidentally drop the big clip into the engine compartment and
cause a fire or battery explosion.

Excellent explanation!

I always did positive first. I will switch!

It\'s a little different situation but the battery on a Harley Sportster is
a pain in the butt. The easiest way to get the positive terminal screw
tightened is to come in across the engine with a long screwdriver, then
snug it down with a 10mm. If you do the negative first you\'re probably
going to have some fireworks.
 
On Wed, 18 Jan 2023 16:00:39 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin\'s latest trollshit unread>

--
John addressing the senile Australian pest:
\"You are a complete idiot. But you make me larf. LOL\"
MID: <f9056fe6-1479-40ff-8cc0-8118292c547e@googlegroups.com>
 
On 18 Jan 2023 06:23:44 GMT, lowbrowwoman, the endlessly driveling,
troll-feeding, senile idiot, blabbered again:


> The pickup battery isn\'t sealed

If there\'d only be a way to seal your mouth for good, bigmouth!

--
Gossiping \"lowbrowwoman\" about herself:
\"Usenet is my blog... I don\'t give a damn if anyone ever reads my posts
but they are useful in marshaling [sic] my thoughts.\"
MID: <iteioiF60jmU1@mid.individual.net>
 
On 18 Jan 2023 06:28:37 GMT, lowbrowwoman, the endlessly driveling,
troll-feeding, senile idiot, blabbered again:


It\'s a little different situation but the battery on a Harley Sportster is
a pain in the butt.

Somewhat like your big mouth? LOL

--
More of the senile gossip\'s absolutely idiotic senile blather:
\"I stopped for breakfast at a diner in Virginia when the state didn\'t do
DST. I remarked on the time difference and the crusty old waitress said
\'We keep God\'s time in Virginia.\'

I also lived in Ft. Wayne for a while.\"

MID: <t0tjfa$6r5$1@dont-email.me>
 
On 18 Jan 2023 06:20:37 GMT, lowbrowwoman, the endlessly driveling,
troll-feeding, senile idiot, blabbered again:


If you connect the negative first and inadvertently touch any grounded
surface you\'ll get a spark.

I wonder what would happen, if one plugged a car battery to your lips. Would
that stop your mouth for a while, or wouldn\'t it?

--
Yet more of the so very interesting senile blather by lowbrowwoman:
\"My family loaded me into a \'51 Chevy and drove from NY to Seattle and
back in \'52. I\'m alive. The Chevy had a painted steel dashboard with two
little hand prints worn down to the primer because I liked to stand up
and lean on it to see where we were going.\"
MID: <j2kuc1F3ejsU1@mid.individual.net>
 
On 2023-01-18 05:34, Mighty✅ Wannabe✅ wrote:
> De-ionized water is purer than distilled water.

The reverse.

--
Cheers, Carlos.
 
On 2023-01-18 04:35, mike wrote:
When I looked up how to jump a car battery, they tell you WHAT to do, but
not WHY, which is infuriating as it\'s harder to remember unless you know
why.

https://blog.napacanada.com/en/how-to-safely-and-quickly-recharge-a-dead-car-battery/

First they say the cars shouldn\'t touch.
Why?

Then they said positive first.
Why?

Because of the danger of touching metal with the positive lead when the
two negatives are connected.

This assumes the car has negative ground, although a positive ground is
very rare in cars nowdays.

Once started, they say remove the negative cable first.
Why?

Same reason.

Here, they say adding water damages the batteries. Why?
https://www.uetechnologies.com/add-water-to-battery-before-or-after-charging/

I don\'t know about damaging, but you dilute the existing liquid, will
not have the proper proportions when you start charging immediately.
Better wait.

However, if the plates are partially out of the liquid, don\'t attempt to
charge, fill first. The battery may be dead in any case, though.


Also, read about bubbles below.


And how often do you need to add water?

You find that from observation of how fast the level goes down.

This says to add water after every ten charging cycles?
Isn\'t that like every ten days?

And how do you know how much to add?

There is typically \"something\" to show you the level.

> They say add water to the \"splash plate\" but what is that?

As you add water, the level touches the rim of a \"tube\" and the
reflection of the light in the water surface suddenly changes shape.
Stop there.

They say the six chambers produce 2.1 volts each for 12.6 volts?
Isn\'t it more than that?

Depends on charge level.

They say adding water before charging will make it overflow.
Does it really change the water level that much from dead to charged?

Gas bubbles form inside when charging. If you do fast charging, they can
be big. Those bubbles inside the liquid make its volume bigger, and it
may overflow. A car battery is designed considering that the vibrations
of the motor will release the bubbles fast, before they become big. A
battery designed to be on a room has more space between plates so that
the bubbles release easier without vibrations.

So, if the level is too low (close to the plates) add some water, but
not the maximum.

And what happens if you tap water instead of distilled?

Damage.

In chemistry, you only use distilled water, for every reaction. You do
not want extra chemicals.

--
Cheers, Carlos.
 
Carlos E.R. wrote on 1/18/2023 5:19 AM:
On 2023-01-18 05:34, Mighty✅ Wannabe✅ wrote:
De-ionized water is purer than distilled water.

The reverse.

De-ionized water is pure than distilled water.

https://bescocommercial.com/di-water/deionized-vs-distilled/

Two common types of treated water are distilled and deionized water.
Here are some similarities and differences that are key to understanding
them:

    Both distilled and deionized water are fit to drink.

    Deionized water is purer than distilled water.

    Distilled water conducts electricity, while deionized water does not.
 
In alt.home.repair, on Wed, 18 Jan 2023 09:05:29 +0530, mike
<this@address.is.invalid> wrote:

When I looked up how to jump a car battery, they tell you WHAT to do, but
not WHY, which is infuriating as it\'s harder to remember unless you know
why.

https://blog.napacanada.com/en/how-to-safely-and-quickly-recharge-a-dead-car-battery/

First they say the cars shouldn\'t touch.
Why?

IIRC when cars had metal bumpers and people didn\'t have such good jumper
cables, they would touch the bumpers together in place of the negative
cable. And then maybe it could leave damage on the chrome from
sparking. ??? Now all the bumpers are covered in plastic or rubber and
it makes no difference. But the warning is still there.
Then they said positive first.
Why?

Once started, they say remove the negative cable first.
Why?

The second goes with the first, so that making/breaking is with the
negative cable, but that leaves the origial question. The correct
answer seems counter-intuitive. I used to know the answer and it\'s not
obvious. It had to do with accidentally ....aha it had to do with
accidentally touching both cables to the frame of the car. Say you\'ve
hooked it up to the car with the good battery, and then you connect the
negative first. Then while you\'re trying to connect the positive (and
sometimes that\'s not easy. It has a cover or it\'s tucked away, or you
can see it but can\'t get the clamp on, you touch the metal body or
engine or frame of the car. Now you have both cables touching the frame
while at the other end, at the car you are using to jump your own, they
are connected to a good battery. Big spark. Thing you are touching it
to gets damaged. If you manage to clamp or hold it on, cables get hot,
insulation melts.

If you connect the positive first, you know you have that cable in the
right place, and then the ground cable would have to accidentally touch
specifically the positive terminal to be a short circuit. Anything else
it touches would be okay. In fact they also urge people to connect not
the negative battery post but to some other body or frame part, so that
that spark is away from the battery where the hydrogen is generated.

I suppopse hydrogen must have been a problem at least one time in
history -- a spark will ignite the hydrogen, and the flame could spread,
I suppose, to the hydrogen still in the battery, which would cause the
battery to explode and burst which will ruin the battey and spray acid
all over the place. But as Rod said, hydrogen is light and disperses
quickly and iirc it\'s only made when the battery is charging (wrong. See
below) and is also (so this is wrong too:) discharged enough to take a
charge, and your dead battery lately, unless it has been and ylu got
interrupted and have to put the cables back on. And the good car
battery has enough alternator voltage to charge all the time, but it\'s
probably fully charged and not making any hydrogen anyhow.

So to correct myself, it makes hydrogen when the battery is discharging.
I suppose by the time you go find someone to jump the car, there has
been loads of time for the hydrogen to blow away. Maybe the explosion
happened in a testing lab where they were all set up and they discharged
the battery and then recharged it immediately. ?????

So this is less likely to be a problem and I still use my negative
battery post for a jump, but the first question, negative on last, makes
sense. Even though I know where to put the cable, eventually I will
touch something I shoudln\'t so it\'s better to go in that order.
Here, they say adding water damages the batteries. Why?
https://www.uetechnologies.com/add-water-to-battery-before-or-after-charging/

And how often do you need to add water?

Very rarely, unless the charging voltage of the alternator is too high,
because the regulator isn\'t working right. These things continue to get
more reliable.

This says to add water after every ten charging cycles?
Isn\'t that like every ten days?

Or ten trips??

I don\'t know what they mean by charging cycle, but I check maybe once a
year. If I needed more than a little bit of water, I\'d would plan to
check again in a month or two. Doesn\'t mean I would do so. I\'ve been
sluggish and actually checked only once in the last 5 years. Two years
ago. I did need quite a bit of water.

>And how do you know how much to add?

When the water looks flat, it needs water. When the water reaches the
right level, it touches the bottom of the tube-like thing that is the
filler for the chamber and you can see the meniscu, where the water
curls up at the edges, so when you look, it\'s not flat everywhere. It\'s
curled at the edges like water in a glass is where it touches the glass.
That means you\'ve put in enough water.
https://en.wikipedia.org/wiki/Meniscus_(liquid) Water forms a concave
meniscus. Maybe liquid mercury forms a convex one. Oh, yeah sure
enough, that\'s what it says. You can see it in any glass of water,
although I think soap keeps it from forming.

>They say add water to the \"splash plate\" but what is that?

Never heard that term but they must mean what I just said.
They say the six chambers produce 2.1 volts each for 12.6 volts?
Isn\'t it more than that?

No. Charging voltage is intended to be 13.4 or something like that
because if you only have 12.7 it will charge too slowly to recharge what
it lost during starting or running lights while the engine is off.
They say adding water before charging will make it overflow.
Does it really change the water level that much from dead to charged?

I\'m sure they didbn\'t make this up, but I don\'t worry about timing like
that and I\'ve never noticed it overflow. OTOH, I have had shmutz on the
top of the battery, white crud, and that is from the acid in the
battery. Plus even if you don\'t see white crud, if you pour some baking
powder on the battery and then add water (this is to the outside so it
doesn\'t have to be distilled) and you see bubbles, that means there is
acid on top of the battery. When the bubbling ends, all the acid has
been neutralized. There very often is some. (Even sealed batteries have
a vent iirc, but maybe not). does it get there because of evaporation
and then condensing, can acid do that? or did the battery overflow when
I was driving. I very rarely overfilled even one of the six chambers,
and even then there is room for expansion. You have to overfill a lot
before it\'s near the top. .

>And what happens if you tap water instead of distilled?

Tap water has minerals and they would combine with the sulfuric acid
without generating electricity, or maybe with the lead itself. Something
like that. They\'d get involved in the chemical reactions and slightly
lessen the power of the battery. Pb + H2S04 -> PbS04 + H2, when
discharging**, and the reverse when charging, or something like that.
The reverse is tricky because the PbS04 should release the lead and it
should go back onto the plates. If you charge too fast it does but it
gets covered by some other compound, probably PbS04, and it makes
\"spongy lead\". then the surface of the plates isn\'t entirely lead and
the battery isn\'t as powerful as it originally was. Also some lead etc.
drops into the bottom, which is empty for a half inch or an inch, so
the junk in the bottom doesn\'t short out the plates. Not easy to
build a good car.

**Oops This would mean that hydrogen is made during discharging, not
charging like I said.

As to sealed batteries, even non-sealed batteries pretend to be sealed
now. They don\'t have 6 screw on caps. They have 2 wide flat plastic
plates you can pry off, that look similar to sealed batteries. IIRC
they hoped car charging systems would all work so well that sealed
batteries would be fine, but it didn\'t always work out that way and
people still had to add water and they were annoyed when they coudln\'t,
so non-sealed made a resurgence, but they try to look like sealed so the
police and border guards won\'t stop and interrogate them.
 
In alt.home.repair, on Wed, 18 Jan 2023 07:09:56 -0500, Mighty? Wannabe?
<@.> wrote:

Carlos E.R. wrote on 1/18/2023 5:19 AM:
On 2023-01-18 05:34, Mighty? Wannabe? wrote:
De-ionized water is purer than distilled water.

The reverse.


De-ionized water is pure than distilled water.

https://bescocommercial.com/di-water/deionized-vs-distilled/

Two common types of treated water are distilled and deionized water.
Here are some similarities and differences that are key to understanding
them:

    Both distilled and deionized water are fit to drink.

    Deionized water is purer than distilled water.

    Distilled water conducts electricity, while deionized water does not.
Indeed it does say that, but it doesn\'t give much in the way of reasons.
Pretty much proof by assertion.

OTOH, my googling yielded contradictory results!!!!

I haven\'t read them yet, or looked for tie breakers, becusae I think
it\'s worth reporting the mere fact that it has contradictory results:

Here is my search
https://www.google.com/search?client=firefox-b-1-d&q=deionized+water+vs+distilled+water+for+batteries
and, not counting the Q&A part, these are the first two hits.

Water that has been purified of dissolved minerals and salts through a
process called deionization is recognized as the best choice for
maintaining lead-acid batteries. Deionization eliminates more impurities
from water than distillation or conventional filters.
The Perfect “Solution” for Maintaining Your Lead-Acid Batteries
https://www.crown.com › articles › energy-management

vs.

Can you use Deionized Water in Batteries?
https://www.phlsci.com › news › articles › can-you-use-...
Oct 12, 2021 — Whilst deionized water is not as pure as distilled water;
it is perfect for industrial battery watering. It is a cost-effective
method


Plainlly, the second article was written by a Brit, or someone from the
Commonwealth. As an American, I should favor the first article, but I
don\'t, so I will control my patriotism and wait for more information.


If the only ions in distilled but not de-ionized water are hyrogen,
oxygen and/or hydroxide ions, I don\'t see how they would cause a probem
in a battery. Doesn\'t any water in a lead acid battery ionize into
those very ions? And how could there be other ions than those three in
distilled water? Maybe the answer is in the articles, but I\'ve already
spent a lot of time on this thread, so I\'ll either wait until you guys
resolve this, or I\'ll come back later with renewed energy.
 

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