Longish story.

Scenario was son had done deal to trade his car in and coming down through Gloucester warning light about low battery came up on dash. 17:00hrs Lashing rain. Has to get to Bristol that night.

Found a Kwik Fit shop (Thank you Google and iPhone). Kwik Fit very helpful. Diagnosed the problem as stemming from the regulator on the alternator. Too late to repair it and anyway car was sold. Popped in new battery. Got to Bristol that evening. (No air.con. No lights. No heater. etc. etc.)

Next morning auto electric shop in Bristol checked to find that alternator was fluctuating in its charge. Would we last a 250 mile journey ? He didn't like to commit himself but said he himself would risk it.

Got 250 miles under belt no problem and battery was placed on charge. Within matter of hours it was up to scratch so next day we finished the last 100 mile leg of the journey.

I guess the alternator was possibly under charging the battery by a small amount.

Anyway. Assuming the alternator wasn't charging at all how many hours does the team think the engine would have run on a new battery alone ?

fred wrote:

Anyway. Assuming the alternator wasn't charging at all how many hours does the team think
the engine would have run on a new battery alone ?

No idea but, in mathematical terms it'll be: Petrol common rail Diesel
mechanical injection Diesel - each requires less battery power to run
the engine than the previous.

(And that only holds at this time of year. In cold weather some common
rail Diesels use their glowplugs whilst running to keep cylinder temps up.)

--
Scott

On Mon, 01 Jul 2013 09:49:01 +0100
Tim Streater wrote:

In article ,
Scott M wrote:

No idea but, in mathematical terms it'll be: Petrol common rail
Diesel mechanical injection Diesel - each requires less battery
power to run the engine than the previous.

Hmmm, you said: "each requires *less* battery power to run the engine
than the previous" in which case it should be:

petrol common rail D mechanical injection D

and not:

petrol common rail D mechanical injection D


Which way round do you mean it to be?


I thought he was answering in terms of the time it would last, in which
case he was right the way he put it.
--
Davey.

Davey wrote:
On Mon, 01 Jul 2013 09:49:01 +0100
Tim Streater wrote:

In article ,
Scott M wrote:

No idea but, in mathematical terms it'll be: Petrol common rail
Diesel mechanical injection Diesel - each requires less battery
power to run the engine than the previous.
Hmmm, you said: "each requires *less* battery power to run the engine
than the previous" in which case it should be:

petrol common rail D mechanical injection D

and not:

petrol common rail D mechanical injection D


Which way round do you mean it to be?


I thought he was answering in terms of the time it would last, in which
case he was right the way he put it.

Yes, my bad. Should have been "". Having written much software in my
life I am very familiar with comparison operators and the associated
logic and don't get them wrong. But when it comes to this sort of
written usage (and reading it) I get it totally ar$e about face in my
head. It's a form of what I believe is referred to as TIS (Total
Incompetent Stupidity.)

Scott

On 01/07/13 09:17, fred wrote:
Longish story.

Scenario was son had done deal to trade his car in and coming down through Gloucester warning light about low battery came up on dash. 17:00hrs Lashing rain. Has to get to Bristol that night.

Found a Kwik Fit shop (Thank you Google and iPhone). Kwik Fit very helpful. Diagnosed the problem as stemming from the regulator on the alternator. Too late to repair it and anyway car was sold. Popped in new battery. Got to Bristol that evening. (No air.con. No lights. No heater. etc. etc.)

Next morning auto electric shop in Bristol checked to find that alternator was fluctuating in its charge. Would we last a 250 mile journey ? He didn't like to commit himself but said he himself would risk it.

Got 250 miles under belt no problem and battery was placed on charge. Within matter of hours it was up to scratch so next day we finished the last 100 mile leg of the journey.

I guess the alternator was possibly under charging the battery by a small amount.

Anyway. Assuming the alternator wasn't charging at all how many hours does the team think the engine would have run on a new battery alone ?


Id guess if no lights, no aircon or fans, and no waiting in traffic, you
might get away with a couple of amps, and you can get about 20 starts
out of a battery, so up to 20 starts or 30 hours of driving, or whatever
combination of the two..


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

In article ,
fred wrote:
Anyway. Assuming the alternator wasn't charging at all how many hours
does the team think the engine would have run on a new battery alone ?

Depends on so many things. Type of engine, so how much current the engine
takes. For example, some older diesels don't need electricity at all to
run. An older petrol car perhaps only the ignition. More modern cars,
power needed for injection and ignition.

BTW, a 'low battery' light doesn't necessarily mean the battery isn't
being charged.

--
*If you don't like the news, go out and make some.

Dave Plowman London SW
To e-mail, change noise into sound.

On 01/07/13 10:08, Dave Plowman (News) wrote:
In article ,
fred wrote:
Anyway. Assuming the alternator wasn't charging at all how many hours
does the team think the engine would have run on a new battery alone ?
Depends on so many things. Type of engine, so how much current the engine
takes. For example, some older diesels don't need electricity at all to
run. An older petrol car perhaps only the ignition. More modern cars,
power needed for injection and ignition.

BTW, a 'low battery' light doesn't necessarily mean the battery isn't
being charged.

mostly a warning light means just that. Not being charged.
I have never come across a 'low battery'' light, just a 'charge not
happening' light.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

On Monday, July 1, 2013 10:21:36 AM UTC+1, The Natural Philosopher wrote:
On 01/07/13 10:08, Dave Plowman (News) wrote:

In article ,

fred wrote:

Anyway. Assuming the alternator wasn't charging at all how many hours

does the team think the engine would have run on a new battery alone ?

Depends on so many things. Type of engine, so how much current the engine

takes. For example, some older diesels don't need electricity at all to

run. An older petrol car perhaps only the ignition. More modern cars,

power needed for injection and ignition.



BTW, a 'low battery' light doesn't necessarily mean the battery isn't

being charged.



mostly a warning light means just that. Not being charged.

I have never come across a 'low battery'' light, just a 'charge not

happening' light.





--

Ineptocracy



(in-ep-toc’-ra-cy) – a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

Thoigh I was driving it wasn't my car so interpretation of dash symbol may have been incorrect.

Sorry should have said it was a petrol engine.Honda Accord.

On 01/07/2013 10:21, The Natural Philosopher wrote:

I have never come across a 'low battery'' light, just a 'charge not
happening' light.



Some later cars with LCD displays have a low battery warning, I guess if
you have electric power steering and such that you may want to know if
the battery is lower than it should be...

In article ,
The Natural Philosopher wrote:
BTW, a 'low battery' light doesn't necessarily mean the battery isn't
being charged.

mostly a warning light means just that. Not being charged.
I have never come across a 'low battery'' light, just a 'charge not
happening' light.

I dunno what is on every car, but the more common ignition warning light
which goes out when the engine starts, doesn't always tell if the
alternator is charging or not. Ie, the warning light circuit may be faulty.

I'm not saying it is in this case - but it would explain why the car
appears to run for a long time with no charge, and the differing
diagnostics from the two 'experts'.

For fred - it is pretty easy to check whether an alternator is dead or
not. Simply connect a DVM across the battery. The voltage reading should
be something like 14v if it is charging. Ie, about 1.5v more than the
reading with the engine stopped.

--
*Eagles may soar, but weasels don't get sucked into jet engines *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
fred wrote:
Anyway. Assuming the alternator wasn't charging at all how many hours
does the team think the engine would have run on a new battery alone
?

Depends on so many things. Type of engine, so how much current the
engine takes. For example, some older diesels don't need electricity
at all to run. An older petrol car perhaps only the ignition. More
modern cars, power needed for injection and ignition.

And maybe the steering.

I could do 20 miles between Doncaster and Barnsley when my alternator failed
(no lights, no fan) and just have enough power to restart the engine at the
end of the journey. I have no idea how much further I could have gone before
the steering etc failed.


I managed that week by charging the battery all day whilst at work and then
overnight when I got in from work.
--
Adam

On Monday, July 1, 2013 6:53:18 PM UTC+1, wrote:
Dave Plowman (News) wrote:

In article ,

fred wrote:

Anyway. Assuming the alternator wasn't charging at all how many hours

does the team think the engine would have run on a new battery alone

?



Depends on so many things. Type of engine, so how much current the

engine takes. For example, some older diesels don't need electricity

at all to run. An older petrol car perhaps only the ignition. More

modern cars, power needed for injection and ignition.



And maybe the steering.



I could do 20 miles between Doncaster and Barnsley when my alternator failed

(no lights, no fan) and just have enough power to restart the engine at the

end of the journey. I have no idea how much further I could have gone before

the steering etc failed.





I managed that week by charging the battery all day whilst at work and then

overnight when I got in from work.

--

Adam

I managed to drive from Prague to Leicester in my 1981 Honda Civic with the charging light on all the way. I stopped (and restarted the engne) 5 times in total. I crossed the channel at Calais and had to switch the lights on on the other side, which seemed a bit dim, so I drove 10 miles or so, found a layby and parked up until the next morning when it was light and continued. The battery voltage was 10v when I finished the journey so I don't think it would have gone much further. I make that nearly 1000 miles, including 5 engine starts and 10-15 minutes with the lights on.

That car had a carb engine with an engine management system. I guess in modern cars you wouldn't get quite that far!

On 06/07/2013 15:48, Bodgit wrote:
On Monday, July 1, 2013 6:53:18 PM UTC+1, wrote:
Dave Plowman (News) wrote:

In article ,

fred wrote:

Anyway. Assuming the alternator wasn't charging at all how many hours

does the team think the engine would have run on a new battery alone

?



Depends on so many things. Type of engine, so how much current the

engine takes. For example, some older diesels don't need electricity

at all to run. An older petrol car perhaps only the ignition. More

modern cars, power needed for injection and ignition.



And maybe the steering.



I could do 20 miles between Doncaster and Barnsley when my alternator failed

(no lights, no fan) and just have enough power to restart the engine at the

end of the journey. I have no idea how much further I could have gone before

the steering etc failed.





I managed that week by charging the battery all day whilst at work and then

overnight when I got in from work.

--

Adam

I managed to drive from Prague to Leicester in my 1981 Honda Civic with the charging light on all the way. I stopped (and restarted the engne) 5 times in total. I crossed the channel at Calais and had to switch the lights on on the other side, which seemed a bit dim, so I drove 10 miles or so, found a layby and parked up until the next morning when it was light and continued. The battery voltage was 10v when I finished the journey so I don't think it would have gone much further. I make that nearly 1000 miles, including 5 engine starts and 10-15 minutes with the lights on.

That car had a carb engine with an engine management system. I guess in modern cars you wouldn't get quite that far!

My Sierra happily ran a couple of hundred miles, with at least 3 starts,
use of wipers and for part of the time lights - it would still start the
next day. My Focus TDCI managed 3 miles after the charge light came on,
a start, 2 miles home, a start, 2 miles to garage and was then
completely dead.

SteveW

Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

JGH

On Mon, 1 Jul 2013 07:33:51 -0700 (PDT), wrote:

Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

JGH


Me too. It's a long time since I had to do it, to get safely to the
left of the road.
I think the trick was to select top gear.



--
Graham.

%Profound_observation%

On 01/07/2013 16:24, Graham. wrote:
On Mon, 1 Jul 2013 07:33:51 -0700 (PDT), wrote:

Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

JGH


Me too. It's a long time since I had to do it, to get safely to the
left of the road.
I think the trick was to select top gear.

That'll get you the maximum distance per turn of the starter motor, but
will have the slight disadvantage that the starter motor could well burn
out :-)

On 01/07/13 16:30, Clive George wrote:
On 01/07/2013 16:24, Graham. wrote:
On Mon, 1 Jul 2013 07:33:51 -0700 (PDT), wrote:

Oh, I thought this would be an interesting discussion on how far you
could
drive a car using the starter motor. I seem to remember seeing a
video
of somebody driving out of a river that way.

JGH


Me too. It's a long time since I had to do it, to get safely to the
left of the road.
I think the trick was to select top gear.

That'll get you the maximum distance per turn of the starter motor,
but will have the slight disadvantage that the starter motor could
well burn out :-)



yup. we built a go kart powered by two truck batteries and a starter
motor., Good for a few laps anyway.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

In article , Graham.
scribeth thus
On Mon, 1 Jul 2013 07:33:51 -0700 (PDT), wrote:

Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

JGH


Me too. It's a long time since I had to do it, to get safely to the
left of the road.
I think the trick was to select top gear.




It is recommended for getting a car off a railway level crossing..

Mind you not a lot of use if the battery's shagged in the first
place!...
--
Tony Sayer

On 01/07/2013 16:24, Graham. wrote:
Me too. It's a long time since I had to do it, to get safely to the
left of the road.
I think the trick was to select top gear.

I didn't see this until someone reposted it.

The trick is to select first gear. And hope you don't have an interlock.

Andy

In message , Graham.
writes
On Mon, 1 Jul 2013 07:33:51 -0700 (PDT), wrote:

Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

JGH


Me too. It's a long time since I had to do it, to get safely to the
left of the road.
I think the trick was to select top gear.

1st, surely (most engine revolutions for least distance moved, so
easiest on the starter). You use top gear when pushing/rocking the car
back and forth to free a jammed starter dog, or to turn the position of
engine over when setting valve clearances (etc).

If it's a manual, and the clutch is working, crank the engine on the
starter, and use the clutch as usual. If it's automatic, I doubt if you
use the starter. In emergencies, not many people realise that you can
probably use the starter to get yourself out of immediate danger.
--
Ian

On 04/07/2013 17:33, Ian Jackson wrote:
If it's automatic, I doubt if you use the starter.

If it's an auto get out and push. It won't crank fast enough to get
anything useful past the torque convertor[1]. IME they all have
interlocks anyway.

Andy
Out of date experience

In message , Vir Campestris
writes
On 04/07/2013 17:33, Ian Jackson wrote:
If it's automatic, I doubt if you use the starter.

If it's an auto get out and push. It won't crank fast enough to get
anything useful past the torque convertor[1]. IME they all have
interlocks anyway.

Andy
Out of date experience
When I had an Austin 1100 auto you could tow start it but all my more
recent autos said it's a no-no. Don't know about DSGs or the type of
auto fitted on small cars theses days. Suspect you could as they are
essentially a normal box with a robot lugged on the side.
--
bert

In article ,
wrote:
Oh, I thought this would be an interesting discussion on how far you
could drive a car using the starter motor. I seem to remember seeing
a video of somebody driving out of a river that way.

Moral being don't get stuck in a river with an auto.

--
*WHOSE CRUEL IDEA WAS IT FOR THE WORD 'LISP' TO HAVE 'S' IN IT?

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
wrote:
Oh, I thought this would be an interesting discussion on how far you
could drive a car using the starter motor. I seem to remember seeing
a video of somebody driving out of a river that way.

Moral being don't get stuck in a river with an auto.


Anyone know what happens now with start/stop buttons, you generally need
your foot on the clutch before the starter will work. Can you mechanically
crank the car in an emergency?

TW.

On 01/07/13 15:33, wrote:
Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.
I haver certainly done a few tens of meters.

In fact its the only way to start a car with no clutch fluid....

JGH


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

In message , The Natural Philosopher
writes
On 01/07/13 15:33, wrote:
Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.
I haver certainly done a few tens of meters.

In fact its the only way to start a car with no clutch fluid....

Or if the clutch plate has seized 'engaged'.
Or if the clutch cable has broken.
--
Ian

On 04/07/13 17:49, Ian Jackson wrote:
In message , The Natural Philosopher
writes
On 01/07/13 15:33, wrote:
Oh, I thought this would be an interesting discussion on how far you
could
drive a car using the starter motor. I seem to remember seeing a
video
of somebody driving out of a river that way.
I haver certainly done a few tens of meters.

In fact its the only way to start a car with no clutch fluid....

Or if the clutch plate has seized 'engaged'.
Or if the clutch cable has broken.
Yup. haven't had a cable clutch for years tho.



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

The Natural Philosopher wrote:
On 04/07/13 17:49, Ian Jackson wrote:
In message , The Natural Philosopher
writes
On 01/07/13 15:33, wrote:
Oh, I thought this would be an interesting discussion on how far you
could
drive a car using the starter motor. I seem to remember seeing a
video
of somebody driving out of a river that way.
I haver certainly done a few tens of meters.

In fact its the only way to start a car with no clutch fluid....

Or if the clutch plate has seized 'engaged'.
Or if the clutch cable has broken.
Yup. haven't had a cable clutch for years tho.



tongue in cheek What's a clutch? (1)

I used to have a Bedford HA van with a cable operated clutch. The cables
were supposedly "fit and forget". You fit them after they forgot to tell
anyone that they weren't actually lubricated from the factory. They
lasted a lot longer when I started greasing them before I installed
them.....

--
Tciao for Now!

John.
(1) I do actually know, my Lard Roller has the normal transmission for
its age with no synchro in 1st, 2nd or reverse.

In message , The Natural Philosopher
writes
On 04/07/13 17:49, Ian Jackson wrote:
In message , The Natural Philosopher
writes
On 01/07/13 15:33, wrote:
Oh, I thought this would be an interesting discussion on how far
you could
drive a car using the starter motor. I seem to remember seeing a
video
of somebody driving out of a river that way.
I haver certainly done a few tens of meters.

In fact its the only way to start a car with no clutch fluid....

Or if the clutch plate has seized 'engaged'.
Or if the clutch cable has broken.
Yup. haven't had a cable clutch for years tho.

I once had a Chevette, and unlike Anglias and Cortinas, it was almost
impossible to change gear without a working clutch. I was led to
understand that they had a reputation for clutch cable problems, so I
carried a spare - but never needed it.
--
Ian

In article , wrote:
Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

Years ago I was told that if you stall on a level crossing and can't start
the car and the lights start flashing, you can get clear using just the
starter motor faster than you can abandon the car to be hit by the train,
especially if you have e.g. small kids strapped in child seats.
Fortunately I've never seen it tested though.

http://www.drivingtestsuccess.com/te...vel-crossings/
http://www.smartdriving.co.uk/Drivin...es/Railway.htm
just say you can try it if there is time.

On 16/07/2013 18:09, Alan Braggins wrote:
In article , wrote:
Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

Years ago I was told that if you stall on a level crossing and can't start
the car and the lights start flashing, you can get clear using just the
starter motor faster than you can abandon the car to be hit by the train,
especially if you have e.g. small kids strapped in child seats.
Fortunately I've never seen it tested though.

I have moved my car out of a car-wash that way, when the underbody wash
was a bit overenthusiastic and soaked the HT leads. I was also a
passenger when we moved another car out of the way when stalled in a
ford - we thought the ignition was soaked, but it was actually the
impact switch had cut off the fuel pump when the towbar drop plate
bottomed out.

SteveW

Alan Braggins wrote:
In article , wrote:
Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

Years ago I was told that if you stall on a level crossing and can't start
the car and the lights start flashing, you can get clear using just the
starter motor faster than you can abandon the car to be hit by the train,
especially if you have e.g. small kids strapped in child seats.
Fortunately I've never seen it tested though.

http://www.drivingtestsuccess.com/te...vel-crossings/
http://www.smartdriving.co.uk/Drivin...es/Railway.htm
just say you can try it if there is time.

An increasing number of cars (like mine) have a clutch interlock preventing
the starter working without the clutch pedal depressed. Guess I just die
horribly. ;-)

Tim

In article , Alan Braggins
scribeth thus
In article ,

wrote:
Oh, I thought this would be an interesting discussion on how far you could
drive a car using the starter motor. I seem to remember seeing a video
of somebody driving out of a river that way.

Years ago I was told that if you stall on a level crossing and can't start
the car and the lights start flashing, you can get clear using just the
starter motor faster than you can abandon the car to be hit by the train,
especially if you have e.g. small kids strapped in child seats.
Fortunately I've never seen it tested though.

http://www.drivingtestsuccess.com/te...vel-crossings/
http://www.smartdriving.co.uk/Drivin...es/Railway.htm
just say you can try it if there is time.

x-posted to uk.railway for comment;!..



Well..

I once tried it on a level crossing .. but it was a line that had been
long closed .. but for the sake of accuracy..

Took the HT cap off so the engine wouldn't start and sure enough it did
manage to drag it off the crossing. I stopped it right in the middle of
the crossing, prolly worse case, and I could have gone into reverse but
went forward in second gear 'tho first might have been that bit better.
Didn't take long BUT..

FWIW this was a car that was some years old, good battery and all that
but more modern ones?. Have to put the clutch pedal right to the floor
to start on the other car I sometimes have to use, then put your foot
on the brake to release that electric handbrake (spawn of Satan those
things);!.

Would it be something that you'd do under live conditions, remember you
have very little time and you'll have the think about what to do and for
most drivers perhaps .. they'd best abandon the car.

Suppose also its a very difficult decision depending how many nippers
are in the car too, older ones just yell at then to get out but babe
and/or toddler in a car seat perhaps siblings not much older also?


Then what's the best call?...



--
Tony Sayer

You can't use the starter motor with an automatic transmission.

I've not owned a standard shift since 1970, but then I live in Canada where
even five ton trucks are all automatics. :-)

tony sayer wrote:
In article , Alan Braggins
scribeth thus
In article ,

wrote:
Oh, I thought this would be an interesting discussion on how far
you could drive a car using the starter motor.

Well, asuming it had a 12 volt 50 Amp battery that was fully charged, and
you
could convert all that electrical energy to useful mechanical work, you
could
expect to get about 0.8 horsepower - and that for only the hour before
the battery went flat.
What distance that might move the average car I leave to others to guess !

Jim Hawkins

On Wed, 17 Jul 2013 20:34:14 +0100, "Jim Hawkins"
wrote:

tony sayer wrote:
In article , Alan Braggins
scribeth thus
In article ,

wrote:
Oh, I thought this would be an interesting discussion on how far
you could drive a car using the starter motor.

Well, asuming it had a 12 volt 50 Amp battery that was fully charged, and
you
could convert all that electrical energy to useful mechanical work, you
could
expect to get about 0.8 horsepower - and that for only the hour before
the battery went flat.
What distance that might move the average car I leave to others to guess !

If you're stuck on a level crossing then it is what can be delivered
in the next ten seconds or so that matters, the other 55m 50s are
comparatively irrelevant. About 200A from a fully charged battery
should not be that unusual when starting so you're probably looking at
at least 3hp. Short circuit currents for lead acid cells of car
battery size and above are typically measured in thousands of amps.

On 17/07/2013 20:34, Jim Hawkins wrote:
tony sayer wrote:
In article , Alan Braggins
scribeth thus
In article ,

wrote:
Oh, I thought this would be an interesting discussion on how far
you could drive a car using the starter motor.

Well, asuming it had a 12 volt 50 Amp battery that was fully charged, and
you
could convert all that electrical energy to useful mechanical work, you
could
expect to get about 0.8 horsepower - and that for only the hour before
the battery went flat.
What distance that might move the average car I leave to others to guess !

Jim Hawkins

Purely out of interest, the construction and uses regs (I think it was
there that I saw it last week) only require vehicles to have a power of
4.4 kW per tonne (not going anywhere fast there either!), so a boot full
of batteries, an oversized starter motor and plenty of spare time to get
there and you could go zero emissions

SteveW

On Mon, 1 Jul 2013 01:17:27 -0700 (PDT), fred
wrote:

Anyway. Assuming the alternator wasn't charging at all how many hours does the team think the engine would have run on a new battery alone ?

String, piece of, how long?
I've had to do that more than once and can tell you that an old
points-ignition system that draws 4A will exhaust a battery in 6~10
hours, depending on condition.
Electronic ignition isn't too different, really, in many cars might be
more or less power-hungry, depending on design.

Diesels traditionally used a mechanical stop lever on the pump
(operated by a cable), so once they were running, they'd run until the
tank ran dry. Diesel cars of up to ~12 years ago had a simple
electrical stop solenoid, which would draw a couple of amps, so on a
par with the old points ignition, if that's all that's running.
Modern diesels will draw a lot more, with their extra pumps and kit
and caboodle, and I'd not be surprised if the current draw is well
above 10A.
Of course, some modern cars have electric power steering, so all bets
are off, even if it only works on the non-ahead position, it's still a
substantial drain and the difference it makes to the journey length
might be enough to leave the car stranded.
You don't really have a choice over the use of the engine cooling fan
either, and there are a lot of circuits drawing current on a modern
car, compared to the bare necessities that you could get away with.