Honda Car Forum

On Tue, 14 Feb 2006 11:51:26 -0500, Steve W. <Dugdug56@what.com> wrote:
>...work. The alternator requires voltage to it before it will generate any
>power. Spinning it won't make any difference.

Is that really true? How is it possible to push start a car w/
a manual tranny if the alternator will never put out any current when
the battery is dead? Perhaps when a battery is "dead", it still has a few
volts and that is enough for the alternator to operate?

AZ Nomad wrote:
>
> On Tue, 14 Feb 2006 11:51:26 -0500, Steve W. <Dugdug56@what.com> wrote:
> >...work. The alternator requires voltage to it before it will generate any
> >power. Spinning it won't make any difference.
>
> Is that really true? How is it possible to push start a car w/
> a manual tranny if the alternator will never put out any current when
> the battery is dead? Perhaps when a battery is "dead", it still has a few
> volts and that is enough for the alternator to operate?


Most batteries when run down will bounce back some when left to sit with
everything off. This used to be enough to fire up the alternators for a
push start.

The new ones can even have cranking power left at the 'groaning starter'
stage and yet still not have enough left to fire up the freakin'
computers. The new Jeeps are really bad for that.

If the battery has to also fire up an electric fuel pump, then it can
not have enough left to fire up the alternator so you fail in the push
start.

If the battery is dead, it just isn't going to go no matter how fast or
far you tow or push it unless you have a '1 wire' alternator. ;-)

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

AZ Nomad wrote:

> On Tue, 14 Feb 2006 11:51:26 -0500, Steve W. <Dugdug56@what.com> wrote:
> >...work. The alternator requires voltage to it before it will generate any
> >power. Spinning it won't make any difference.
>
> Is that really true?

Yes. You need field current to create the magnetic field.

> How is it possible to push start a car w/
> a manual tranny if the alternator will never put out any current when
> the battery is dead? Perhaps when a battery is "dead", it still has a few
> volts

Yes.

> and that is enough for the alternator to operate?

Irrelevant during starting.

Graham

Pooh Bear wrote:
>
> AZ Nomad wrote:
>
> > On Tue, 14 Feb 2006 11:51:26 -0500, Steve W. <Dugdug56@what.com> wrote:
> > >...work. The alternator requires voltage to it before it will generate any
> > >power. Spinning it won't make any difference.
> >
> > Is that really true?
>
> Yes. You need field current to create the magnetic field.
>
> > How is it possible to push start a car w/
> > a manual tranny if the alternator will never put out any current when
> > the battery is dead? Perhaps when a battery is "dead", it still has a few
> > volts
>
> Yes.
>
> > and that is enough for the alternator to operate?
>
> Irrelevant during starting.
>
> Graham

Say the battery only has enough to fire up the alternator field, then
the push start can have a sudden 12-14 volts injected into the spark
circuit which can be enough to start it up.

If the battery has a heavy draw like an electric fuel pump, it might not
have enough to fire up the alternator, well in my experience, it doesn't
have enough, so you get no start on a push.

The old carb systems didn't have any/many heavy draws with the key in
'on' so they were 'easy' to push start.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

On Tue, 14 Feb 2006 17:50:24 +0000, Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:




>AZ Nomad wrote:

>> On Tue, 14 Feb 2006 11:51:26 -0500, Steve W. <Dugdug56@what.com> wrote:
>> >...work. The alternator requires voltage to it before it will generate any
>> >power. Spinning it won't make any difference.
>>
>> Is that really true?

>Yes. You need field current to create the magnetic field.

>> How is it possible to push start a car w/
>> a manual tranny if the alternator will never put out any current when
>> the battery is dead? Perhaps when a battery is "dead", it still has a few
>> volts

>Yes.

>> and that is enough for the alternator to operate?

>Irrelevant during starting.

It's relevant if there's no voltage for the ignition system.

On Tue, 14 Feb 2006 13:02:51 -0500, Mike Romain <romainm@sympatico.ca> wrote:


>If the battery has a heavy draw like an electric fuel pump, it might not
>have enough to fire up the alternator, well in my experience, it doesn't
>have enough, so you get no start on a push.
I don't think the fuel pump is that great a current draw. Two bigger
problems are 1) it may not run at all on less than 9V or so and 2) it is only
run for a few seconds when the key is first turned on. By the time
the electrical system gets it's first kick of juice from the alternator,
that initial timeout has expired.





>The old carb systems didn't have any/many heavy draws with the key in
>'on' so they were 'easy' to push start.

>Mike
>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>88 Cherokee 235 BFG AT's
>Canadian Off Road Trips Photos: Non members can still view!
>Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>(More Off Road album links at bottom of the view page)

Mike Romain wrote:

> Pooh Bear wrote:
> >
> > AZ Nomad wrote:
> >
> > > On Tue, 14 Feb 2006 11:51:26 -0500, Steve W. <Dugdug56@what.com> wrote:
> > > >...work. The alternator requires voltage to it before it will generate any
> > > >power. Spinning it won't make any difference.
> > >
> > > Is that really true?
> >
> > Yes. You need field current to create the magnetic field.
> >
> > > How is it possible to push start a car w/
> > > a manual tranny if the alternator will never put out any current when
> > > the battery is dead? Perhaps when a battery is "dead", it still has a few
> > > volts
> >
> > Yes.
> >
> > > and that is enough for the alternator to operate?
> >
> > Irrelevant during starting.
> >
> > Graham
>
> Say the battery only has enough to fire up the alternator field, then
> the push start can have a sudden 12-14 volts injected into the spark
> circuit which can be enough to start it up.
>
> If the battery has a heavy draw like an electric fuel pump, it might not
> have enough to fire up the alternator, well in my experience, it doesn't
> have enough, so you get no start on a push.
>
> The old carb systems didn't have any/many heavy draws with the key in
> 'on' so they were 'easy' to push start.

I doubt that the fuel pump draws that much. I suspect you'll need around 9 volts or
so still left in the battery for the elctronics to work.You most likely will have
that unless the battery is totally stone dead.

As for the alternator, there's always some residual magnetism left.

Graham

Sam Nickaby wrote:
> I have been thinking of a good way to prevent stranding
> myself from a dead battery. It happened twice. Once at a
> beach from leaving my lights on. The other was at a college
> campus which the stereo and the dome light ran down the
> battery. Unlike the beach, the college campus have lots of
> helpful students with beat up cars that have jumper cables.
> Now, I have a new idea. Once my battery runs dry, I
> remove my alternator belt and wrap a rope around the
> alternator pulley. I then pull the rope so it'll turn 10
> revolutions per pull. I keep doing this for about 20 times.
>
> What is the possibility that this will supply enough charge
> to start the car. If not, can somebody think of a clever idea
> to start an automatic?
>
> Thanks
>

You would have more chance of winning the lottery... without buying a
ticket. :-)

If you're that concerned about it, as other's have said, investigate
buying a booster pack. Another more expensive option is to have a dual
battery system setup, giving the starter motor it's own battery...
though that would be the first time I'd ever heard of such a setup in a
honda civic. :-)

<http://www.tjmproducts.com.au/dual_batteries.html>

There's the kill switch option, which if installed properly should cut
power to everything in the car. This also acts as an immobilizer, until
your potential thief finds the switch (though I cant vouch for the
intelligence of all car thieves.) The downside to that is if you have a
security coded radio you'd have to put in the code every time you start
the car.

Of course by far the easiest and cheapest option is not to run
significant amounts of electrics when your motor isn't running.

How long did you have your stereo and cabin light on for when they ran
down the battery? You should've been able to have the stereo going and
your cabin light on for a few hours without any problems. If it was a
relatively short period of time, you may need to look at purchasing a
new battery. Typical battery life in a car is 3 - 4 years.

SL.

Mount an Uninterruptible Power supply in the trunk, and give access to the
12volt connections inside. Charge it off the electrical system, using a
reverse current diode. When you get into a pinch, bypass the diode, and
start your car. It also provides full time 110 volt ac for your laptop,
coolers, or TV.

Al


"Sir Lex" <SL@no-spam.com.au> wrote in message
news:43f25965@mail.netspeed.com.au...
> Sam Nickaby wrote:
>> I have been thinking of a good way to prevent stranding
>> myself from a dead battery. It happened twice. Once at a
>> beach from leaving my lights on. The other was at a college
>> campus which the stereo and the dome light ran down the
>> battery. Unlike the beach, the college campus have lots of
>> helpful students with beat up cars that have jumper cables.
>> Now, I have a new idea. Once my battery runs dry, I
>> remove my alternator belt and wrap a rope around the
>> alternator pulley. I then pull the rope so it'll turn 10
>> revolutions per pull. I keep doing this for about 20 times.
>>
>> What is the possibility that this will supply enough charge
>> to start the car. If not, can somebody think of a clever idea
>> to start an automatic?
>>
>> Thanks
>>
>
> You would have more chance of winning the lottery... without buying a
> ticket. :-)
>
> If you're that concerned about it, as other's have said, investigate
> buying a booster pack. Another more expensive option is to have a dual
> battery system setup, giving the starter motor it's own battery... though
> that would be the first time I'd ever heard of such a setup in a honda
> civic. :-)
>
> <http://www.tjmproducts.com.au/dual_batteries.html>
>
> There's the kill switch option, which if installed properly should cut
> power to everything in the car. This also acts as an immobilizer, until
> your potential thief finds the switch (though I cant vouch for the
> intelligence of all car thieves.) The downside to that is if you have a
> security coded radio you'd have to put in the code every time you start
> the car.
>
> Of course by far the easiest and cheapest option is not to run significant
> amounts of electrics when your motor isn't running.
>
> How long did you have your stereo and cabin light on for when they ran
> down the battery? You should've been able to have the stereo going and
> your cabin light on for a few hours without any problems. If it was a
> relatively short period of time, you may need to look at purchasing a new
> battery. Typical battery life in a car is 3 - 4 years.
>
> SL.

On Tue, 14 Feb 2006 15:48:59 -0800, Al <agerhart2@nospam.charter.net> wrote:


>Mount an Uninterruptible Power supply in the trunk, and give access to the
>12volt connections inside. Charge it off the electrical system, using a
>reverse current diode. When you get into a pinch, bypass the diode, and
>start your car. It also provides full time 110 volt ac for your laptop,
>coolers, or TV.

That should be good entertainment. Better keep a fire extinguisher in your
car when 100 amps is running through the power cable and the little gell
cell in the UPS.