# Why Won't a Frozen Battery Start a Vehicle.

D

#### Denny B

Jan 1, 1970
0
A battery that is perfectly good why when it is -30C
won't it start a vehicle.
Please note we are referring to a perfectly good battery
and a totally functioning car.
What is happening to the battery that it cannot crank
the starter fast enough.
Chemically something is happening inside the battery.
Is it the electrolyte that freezes and chemically do what
it should do? Does something happen to the lead plates?
Does the 12 volts drop to a lower voltage? Does the current
output of the battery drop?

The cold is doing something to the battery What Is That
Something?
Well informed auto mechanics please step up to the plate!

I do not need to start my vehicle my spare battery connected
in parallel with the frozen battery does that.

it and take it indoors and let it heat up to house temperature,
after reinstall it on the vehicle' it will then start the vehicle.

What is happening to the battery internally at -30C?

Denny B

T

#### Thomas C. Sefranek

Jan 1, 1970
0
Denny B said:
A battery that is perfectly good why when it is -30C
won't it start a vehicle.
Please note we are referring to a perfectly good battery
and a totally functioning car.
What is happening to the battery that it cannot crank
the starter fast enough.
Chemically something is happening inside the battery.

Actually, Chemically something is NOT happening.
peroxide
to produce enough electron mobility. Denying the necessary voltage and
current.

It's pretty simple.

How do you stop a fire?
Remove: Fuel, or Air, or HEAT.

Is it the electrolyte that freezes and chemically do what
it should do? Does something happen to the lead plates?
Does the 12 volts drop to a lower voltage? Does the current
output of the battery drop?

The cold is doing something to the battery What Is That
Something?
Well informed auto mechanics please step up to the plate!

I do not need to start my vehicle my spare battery connected
in parallel with the frozen battery does that.

it and take it indoors and let it heat up to house temperature,
after reinstall it on the vehicle' it will then start the vehicle.

What is happening to the battery internally at -30C?

Denny B

--
*
| __O Thomas C. Sefranek [email protected]
(*)/ (*) Bicycle mobile on 145.41, 448.625 MHz

http://www.harvardrepeater.org

D

#### DarkMatter

Jan 1, 1970
0
A battery that is perfectly good why when it is -30C
won't it start a vehicle.

Density.

J

#### JeffM

Jan 1, 1970
0
What is happening to the battery
Actually, Chemically something is NOT happening.
It's pretty simple.
How do you stop a fire?
Remove: Fuel, or Air, or HEAT.
Thomas C. Sefranek

Yup. High school chemistry.
How do you alter the rate of a chemical reaction?
Change 1) concentration 2) surface area or 3) temperature

D

#### Doug

Jan 1, 1970
0
Thomas said:
Actually, Chemically something is NOT happening.
peroxide
to produce enough electron mobility. Denying the necessary voltage and
current.

It's pretty simple.

How do you stop a fire?
Remove: Fuel, or Air, or HEAT.
The other factor is an engine at -30C is much harder to crank as the oil is
much thicker. It is also harder to start because gasoline doesn't vaporize
as well.

D

#### DarkMatter

Jan 1, 1970
0
It is also harder to start because gasoline doesn't vaporize
as well.

Fuel charges are denser at colder temps and final pressure at TDC is
greater. It isn't about vaporization as the exploded fuel actually
delivers more energy. Ask any dragster racer if a cold dry day or a
hot desert sun is better for the race.

B

#### Bob Masta

Jan 1, 1970
0
Fuel charges are denser at colder temps and final pressure at TDC is
greater. It isn't about vaporization as the exploded fuel actually
delivers more energy. Ask any dragster racer if a cold dry day or a
hot desert sun is better for the race.

The exploded fuel may contain more energy, but at really low
temperatures (as the OP was talking about) it is a lot harder
to vaporize and hence to get it to explode to begin with.
(I doubt many dragsters run at below-freezing temperatures. )
Gasoline is specially formulated for the season of the year in
temperate climates. The winter formulation is much more volatile,
specifically to address this problem. The relevant parameter
here is "Reed Vapor Pressure". But they usually only formulate
for broad temperature ranges, so you may only get a generic
"winter" blend that is a compromise.

Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

B

#### Bill Vajk

Jan 1, 1970
0
Bob said:
On Fri, 30 Jan 2004 22:18:24 -0800, DarkMatter
The exploded fuel

snip

I'm chiming in because I hate to see loose language like
this lead to misunderstandings by neophytes.

Let's just get rid of that idea right now. Fuel in an
internal combustion engine does not "explode," it burns
at a finite rate depending on a number of variables. It
is a fast burn, but hardly an eplosion.

D

#### DarkMatter

Jan 1, 1970
0
The exploded fuel may contain more energy, but at really low
temperatures (as the OP was talking about) it is a lot harder
to vaporize and hence to get it to explode to begin with.

Fuel does not get "vaporized" in a car's induction system. It gets
atomized at best. Such task is no harder to perform in cold dense
air.

The carburetor or injector has no added work load on the starter.
The denser charge does. It increases the TDC pressure in the
cylinders.

The only thing that fire lag causes is the need for more cranking to
occur until the car starts, it doesn't change the power required to do
the job. Just the length of time it takes to do it... sometimes.

A good set of platinum tipped plugs on a high energy ignition system
all but negates that claim.

D

#### DarkMatter

Jan 1, 1970
0
(I doubt many dragsters run at below-freezing temperatures. )

That is exactly where they would most like to race, and there are
tracks all over the country. Ever heard of the "winternationals"?

They very much so like cold whether on race day.
Gasoline is specially formulated for the season of the year in
temperate climates.

Dragster operators formulate their own.
The winter formulation is much more volatile,

You're nuts.
The relevant parameter
here is "Reed Vapor Pressure".

Yeah, if we were talking about vapor. We are not.

Reid vapor pressure (the proper spelling) is about the final
pressure a volatile liquid reaches in a contained space. It varies
with temperature, and has not a thing to do with hard starting cars in
the winter. AGain, fuel in car induction systems gets atomized NOT
vaporized.
But they usually only formulate
for broad temperature ranges, so you may only get a generic
"winter" blend that is a compromise.

Sorry, but octane rating determines the energy output of the fuel,
as well as its ignition parameters. I don't see big swings in octane
numbers at the pumps in winter locales. In fact, I don't see ANY

D

#### DarkMatter

Jan 1, 1970
0
snip

I'm chiming in because I hate to see loose language like
this lead to misunderstandings by neophytes.

Let's just get rid of that idea right now. Fuel in an
internal combustion engine does not "explode," it burns
at a finite rate depending on a number of variables. It
is a fast burn, but hardly an eplosion.
Ever heard a dragster engine "chime in"?

Sure it is burning at a defined rate. Since that rate exceeds the
speed of sound, we humans define it as an explosion. The forces
created are combustion forces or can be argued as explosive forces.
The language you should have chimed in on is the fact that cars do
NOT "vaporize" their fuel charges.

Z

Jan 1, 1970
0
You can always tell when a mechanic just had sex.

He has one clean finger.

D

#### DarkMatter

Jan 1, 1970
0
You can always tell when a mechanic just had sex.

He has one clean finger.

E W W W W WWwwwwwww!!!

B

#### Bob Masta

Jan 1, 1970
0
That is exactly where they would most like to race, and there are
tracks all over the country. Ever heard of the "winternationals"?

They very much so like cold whether on race day.

Dragster operators formulate their own.

You're nuts.

Yeah, if we were talking about vapor. We are not.

Reid vapor pressure (the proper spelling) is about the final
pressure a volatile liquid reaches in a contained space. It varies
with temperature, and has not a thing to do with hard starting cars in
the winter. AGain, fuel in car induction systems gets atomized NOT
vaporized.

Sorry, but octane rating determines the energy output of the fuel,
as well as its ignition parameters. I don't see big swings in octane
numbers at the pumps in winter locales. In fact, I don't see ANY

It's a popular misconception that high octane means high energy.
It doesn't, basically only determines anti-knock properties. The only
reason high performance engines need higher octane is because they
use higher compression ratios, either straight mechanical or due
to supercharging. And difference in energy content is trivial.

As for the seasonal RVP changes, my info does go back a "few"
years. In the mid-70s I was an engineer at GM Cadillac, and we
most definitely *did* have seasonal and regional RVP changes.
When we were doing cold-start tests in the summer (in a huge
drive-in chassis dynamometer cold-room), we had to take care to
get the proper fuel blend. RVP was indeed the relevant parameter,
whether you believe it or not. I expect that it affects cold-starts
just as much now as it did then, and that gas companies still
change it with the seasons. No, it won't show up on octane
numbers... not that I think the station owners would run out and
change the pump stickers every season anyway.

Why not just keep the winter blend all year? Because in hot
weather it causes vapor lock and similar problems.

Incidentally, one other thing that helps a cold start is to
have seriously retarded timing, so the ignition is pretty
close to TDC. That was hard to do on the ignition systems
of the early '70s, so I came up with a sneaky way to do
it using only simple electronics, which I called ESS (Electronic
Spark Selection). Cadillac only used it for a couple of model
years before EST (Electronic Spark Timing) became standard,
but ESS cost only $20 to add to a car, where EST cost$180.
ESS also gave big fuel economy improvements compared to the
stock system, since the timing for normal operation could
be advanced farther. It didn't just operate at start, but allowed
cheapo switches to change the timing. So I used manifold
pressure switches and transmission speed switches that were
already there to tailor the timing for best emissions and
economy. Cheap and effective.

Ahh, the good old days!

Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

K

#### Keith R. Williams

Jan 1, 1970
0
You sure are, DimBulb!

As has been noted the chemical reaction in the battery is far
lower in colder temperatures, so the current available is lower.
Chemical reactions are exponential functions WRT temperature
(batteries die during the summer, but aren't stressed until
winter). The "Cold Cranking Amps" spec attempts to quantify the
current available at low temperature.

The second major factor is the oil. The engine oil (and
transmission fluid) is about the consistency of peanut butter,
the engine needs far more torque from the starter, thus current
from the battery, to turn over. Thus CCA is important.

These two factors far outweigh any other engine or fuel dynamics.

D

#### DarkMatter

Jan 1, 1970
0
It's a popular misconception that high octane means high energy.
It doesn't, basically only determines anti-knock properties.

Racers use 100 octane fuel so that they can run higher compression
and get higher energy output. It yields higher energy in that it can
be used in an internal combustion engine better. The number itself
refers to its ability to only detonate when told, and not as a result
of temperature or pressure.

The fact that alcohol is now used to increase that number means that
even less energy is produced by ethanol added fuels. True gasoline of
higher octane numbers, however, does also produce higher levels of
energy as measured in BTUs.

Yer not gonna be able to **** with me on this one, because I am not
one of your subjects that has the "popular misconception" which you
describe. Try again.

D

#### DarkMatter

Jan 1, 1970
0
The only
reason high performance engines need higher octane is because they
use higher compression ratios, either straight mechanical or due
to supercharging. And difference in energy content is trivial.

The energy delivered is a direct function of final compressed
cylinder pressure, and is far from trivial, dufus.

D

#### DarkMatter

Jan 1, 1970
0
As for the seasonal RVP changes, my info does go back a "few"
years. In the mid-70s I was an engineer at GM Cadillac, and we
most definitely *did* have seasonal and regional RVP changes.
When we were doing cold-start tests in the summer (in a huge
drive-in chassis dynamometer cold-room), we had to take care to
get the proper fuel blend. RVP was indeed the relevant parameter,
whether you believe it or not. I expect that it affects cold-starts
just as much now as it did then, and that gas companies still
change it with the seasons. No, it won't show up on octane
numbers... not that I think the station owners would run out and
change the pump stickers every season anyway.

RVP was a big problem in HOT environs. Vapor lock was a problem in
hot engines with the wrong fuel. Carbureted induction systems was the
reason. Modern fuel injected engines won't see these issues, and fuel
is a lot different these days as well.

D

#### DarkMatter

Jan 1, 1970
0
Why not just keep the winter blend all year? Because in hot
weather it causes vapor lock and similar problems.

No shit, but the consideration was for hot environs, not cold.

D

#### DarkMatter

Jan 1, 1970
0
Incidentally, one other thing that helps a cold start is to
have seriously retarded timing, so the ignition is pretty
close to TDC.

Since engines already typically operate from 10 to 30 degrees BEFORE
TDC, ADVANCING it toward TDC would NOT be termed "seriously retarded".

Your logic, perhaps, but not the engine timing.

D
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