[4x4ish]

apart from the starter, why does a sierra need a battery to run. ive always wondered.

im assuming something to do with the distributer. I didn't think they had a computer and it was all mechanically run.

[JrZook]

4x4ish wrote:

apart from the starter, why does a sierra need a battery to run. ive always wondered.

im assuming something to do with the distributer. I didn't think they had a computer and it was all mechanically run.

Waaaaaaaaaaaaaa??Where are you gonna get your spark from?
Need battery for ignition coil to generate spark to make it run. Its not a diesel.

[atari4x4]

[PJ.zook]

Realistically they dont, other than to start em as you said. Once they are running you could disconnect the battery and it would still run as the alternator would keep the voltage up, but its not good for it, as a battery acts to smooth out the spikes from the charging system and provides a nice healthy current flow for a good spark (not that sierras draw a lot). I dont think it would be good for your alternator either, as correct me if im wrong, but I would think the alternator would be charging at full current the whole time as it would have no reference voltage from battery, only itself (not quite sure on this, anyone know for sure?).

[sleeperzook]

Yeah it depends how they're wired. Fair chance it will try to charge at max voltage without a refernce but unless it's a self exciting alt it either won't charge or only charge to the limit of the residual magnetism in the rotor/ stator.

[BlueSuzy]

Why only a sierra?

All cars should be able to run without a battery.

[mightymouse]

If the alternator runs disconected from the battery it will in time fry the diodes

[skelaaleks]

Alt will fry like an egg.

[Chris88]

if you dont want a batery you could get a crank handle and a magneto haha

[Benz]

on a old carb engine you should be able to run it without a battery

ever had a stuffed battery? you can dive around for as long as you want.
but if you stop... you best get out and push

and on the same note. if you have ever had a stuffed alternator. the electric fuel pump stopping is what will get ya. unless you have a manual fuel pump.

think of lawn mowers and dirt bikes.

[christover1]

Many racing cars don't have a battery,
hence push start vehicles,
and rolling starts.

[Gwagensteve]

christover1 wrote:

Many racing cars don't have a battery,
hence push start vehicles,
and rolling starts.

Are you sure about that Chris? Do you have any examples?

AFAIK, I can't think of any race cars that don't run a battery. There might be some that don't run a starter, and others that don't run an alternator, (for weight and horsepower consumption reasons), but it's pretty hard to run an electrical system without at least some kind of small battery, even if it's not sufficient to be used as a starting battery.

Rolling starts were used to save driveline components from the shock of a standing start.

Push starting has more to do with no starter motor IMHO.

Steve.

[christover1]

Gwagensteve wrote:

christover1 wrote:

Many racing cars don't have a battery,
hence push start vehicles,
and rolling starts.

Are you sure about that Chris? Do you have any examples?

Rolling starts were used to save driveline components from the shock of a standing start.

Push starting has more to do with no starter motor IMHO.

Steve.

Your idea sounds much more logical than mine


Maybe its my oldness showing thru.

Lots of early bikes I road had maneto ignition,
but had no lights, so no battery.

I probably just assumed cars were same,
but your reasoning makes sense.

I hate it when your're right

[christover1]

Some Sprint car, mini modified and other cicle track classes dont allow electrical systems http://www.centuryperformance.com/mallo ... pg-76.html

http://en.wikipedia.org/wiki/Sprint_car_racing

The World of Outlaws (WoO) is a division of winged sprint cars that run all over the United States and have a few events in Canada. The cars have 15-inch (380 mm) wide right rear tire and a 410 cubic inch engine with mechanical fuel injection. These sprint cars have no battery or a starter in them, necessitating a push start by a quad or truck. They also do not have flywheels, clutches or transmissions, but the direct drive system can be engaged or disengaged from the cockpit. This is done both for weight reasons and tradition

[JrZook]

christover1 wrote:

Some Sprint car, mini modified and other cicle track classes dont allow electrical systems http://www.centuryperformance.com/mallo ... pg-76.html

http://en.wikipedia.org/wiki/Sprint_car_racing

The World of Outlaws (WoO) is a division of winged sprint cars that run all over the United States and have a few events in Canada. The cars have 15-inch (380 mm) wide right rear tire and a 410 cubic inch engine with mechanical fuel injection. These sprint cars have no battery or a starter in them, necessitating a push start by a quad or truck. They also do not have flywheels, clutches or transmissions, but the direct drive system can be engaged or disengaged from the cockpit. This is done both for weight reasons and tradition

Mechanical injection cool but what about the ignition side of things?

[4x4ish]

Hmm interesting. The reason is ask is that the other week my brother and i were on rainbow beach and his alternator died. It was at night so the lights were getting dimmer and dimmer as you would expect.

Because the alternator was dead, this explains why the car stopped then the battery ran out. so if the battery was a dud and alternator was fine, it should have worked.

We swaped batteries 3 times on the way home. that was a fun trip thou.

[christover1]

Alternators need a field current to get started.
A dud battery would probably be enough of a field to let alternator work.
But all alts I know of would not work with out a battery.

I could be wrong tho, can happen

[fordem]

christover1 wrote:

Alternators need a field current to get started.

It depends on the alternator - some are self exiciting, single wire, and most of those which require a field connection will also "self excite" due to residual magnetism.

[royce]

JrZook wrote:

christover1 wrote:

Some Sprint car, mini modified and other cicle track classes dont allow electrical systems http://www.centuryperformance.com/mallo ... pg-76.html

http://en.wikipedia.org/wiki/Sprint_car_racing

The World of Outlaws (WoO) is a division of winged sprint cars that run all over the United States and have a few events in Canada. The cars have 15-inch (380 mm) wide right rear tire and a 410 cubic inch engine with mechanical fuel injection. These sprint cars have no battery or a starter in them, necessitating a push start by a quad or truck. They also do not have flywheels, clutches or transmissions, but the direct drive system can be engaged or disengaged from the cockpit. This is done both for weight reasons and tradition

Mechanical injection cool but what about the ignition side of things?

Magneto, same as a lawn mower

[christover1]

royce wrote:

Magneto, same as a lawn mower

You saying a zook engine is the same as a lawn mower engine

[christover1]

fordem wrote:

christover1 wrote:

Alternators need a field current to get started.

It depends on the alternator - some are self exiciting, single wire, and most of those which require a field connection will also "self excite" due to residual magnetism.

I think I understand self excitement

[Benz]

Benz2369 wrote:

on a old carb engine you should be able to run it without a battery

ever had a stuffed battery? you can dive around for as long as you want.
but if you stop... you best get out and push

and on the same note. if you have ever had a stuffed alternator. the electric fuel pump stopping is what will get ya. unless you have a manual fuel pump.

think of lawn mowers and dirt bikes.

haha yeah i'm a bit wrong here.
well alot wrong...
guess i'm use to working on dirt bikes and lawn mowers

the ignition coil needs power too.............

[skotup]

the ignition coil get power from the alternator, everything gets power from the alternator when the engine is running, even the battery GETS power from the alternator, it doesnt power anything directly, only kicks in in extreme circumstances where you might have 20 spotties and several compressors running... or on the bass thumps of a fully sick sound system.

as was mentioned above, if the alternator does not have a permanent magnet, the residual magnetism in the rotor will allow the alternator to produce a voltage on start up from a prime mover.

SO i reckon that as long as you dont demagnetise/depolarise it with a AC electromagnet ,,, and that you can push start or hand crank it.. then no, no need for a battery is my vote. Altho you may struggle with volt drop if you try to run 2 decent compressors at once.

[MacDaddy]

Every car, and Zook i have owned, would stop running as soon as the battery was disconnected, my first 1L Sierra did it, my 1.3L Sierra did it, my 89 Vit did it.... havnt been game to try it on the GV, to much electronicals that might get damaged... but if the battery is still connected, even if it is not holding a charge, will still run...

[fordem]

skotup wrote:

SO i reckon that as long as you dont demagnetise/depolarise it with a AC electromagnet ,,, and that you can push start or hand crank it.. then no, no need for a battery is my vote.

It's going to take a lot of pushing to get that alternator up to a speed where there's enough output to get a spark without a battery, but, if you have a battery that's too weak to crank but can still deliver an amp or two at around 10V, you can get it started.

So - no battery - no starty.

[fordem]

MacBear wrote:

Every car, and Zook i have owned, would stop running as soon as the battery was disconnected, my first 1L Sierra did it, my 1.3L Sierra did it, my 89 Vit did it.... havnt been game to try it on the GV, to much electronicals that might get damaged... but if the battery is still connected, even if it is not holding a charge, will still run...

I wouldn't recommend you try it with one of today's EFI equipped cars, but on the old carburetted cars of my youth, you could start it, and as long as you kept the revs up, remove the battery without the engine dieing, and in fact I watched someone do this with a GDI Mitsubishi three weeks ago - the Mitsu battery was too weak to get a start, even with jumper leads - the guy swapped the battery out, started the Mitsu, had the driver hold the rpms up, and then swapped the dead battery back - without the Mitsu dieing.

I did tell him afterwards what the risk he had taken was.

[skotup]

some1's going to have to try it, and video it, to settle this.

OR.. does ne1 know the phone number for mythbusters?

[steak_knife]

skotup wrote:

some1's going to have to try it, and video it, to settle this.

OR.. does ne1 know the phone number for mythbusters?

I pull the battery out running on a regular basis, probably cause my flat mate owns a shit box ford tho..

It work's on some car, not on others, as for the risk you run, same a jump starting or wiring in accessory's..

[skotup]

ive disconnected the battery while its running before too, we know cars run without a battery but what we want to know is will it START without a battery?

[steak_knife]

skotup wrote:

ive disconnected the battery while its running before too, we know cars run without a battery but what we want to know is will it START without a battery?

Clutch start.

Starter's don't run on plankton..