Real or BS ? start from flat battery !

[CharlieH]

 This is an jnteresting way to start a car !

 

https://vt.tiktok.com/ZSRRRrqmP/?k=1

[KhunLA]

Many people don't realize, you can push start an automatic trans car, same as popping a clutch.  Or could years past.  I've actually done it, just to see if you could, and damn if it didn't work.

 

No that I would do any of that now, just call up the 24hr service folks.

[OneMoreFarang]

I think with many modern cars the problem is that they need battery power to run all the electronics. If they are not ON then you can crank the engine as much as you want, it won't start.

[Kwasaki]

The front wheel drive car drives both wheels. !!

[alien365]

30 minutes ago, KhunLA said:

Many people don't realize, you can push start an automatic trans car, same as popping a clutch.  Or could years past.  I've actually done it, just to see if you could, and damn if it didn't work.

 

No that I would do any of that now, just call up the 24hr service folks.

I tried that once all the way down a multi storey car park, but I couldn't go fast enough for it to work. Once at the bottom a taxi driver helped me jump start it properly. I'd only ever driven manuals before so I didn't know at the time. 

[KhunLA]

16 minutes ago, alien365 said:

I tried that once all the way down a multi storey car park, but I couldn't go fast enough for it to work. Once at the bottom a taxi driver helped me jump start it properly. I'd only ever driven manuals before so I didn't know at the time. 

We did it with a car, and yea, you need to go faster than people are going to be able to push it.  

[Tropicalevo]

I have seen a guest start a car that had a flat battery - he squeezed the juice from a couple of fresh lemons into the battery. Left it for a short while and then started the car.

Mind you, that was about 15 years ago.

[Pooreye]

1 hour ago, KhunLA said:

Many people don't realize, you can push start an automatic trans car, same as popping a clutch.  Or could years past.  I've actually done it, just to see if you could, and damn if it didn't work.

 

No that I would do any of that now, just call up the 24hr service folks.

What model was that? An auto must have dual oil pumps for this to work, one on output shaft too. Very few cars, like some old Mercedes, have that

Edited July 15, 2022 by Pooreye

[toofarnorth]

57 minutes ago, OneMoreFarang said:

I think with many modern cars the problem is that they need battery power to run all the electronics. If they are not ON then you can crank the engine as much as you want, it won't start.

How can you crank the engine with no battery power ?

[Kwasaki]

37 minutes ago, Tropicalevo said:

I have seen a guest start a car that had a flat battery - he squeezed the juice from a couple of fresh lemons into the battery. Left it for a short while and then started the car.

Mind you, that was about 15 years ago.

Sounds like dirty connections.

[Kwasaki]

14 minutes ago, toofarnorth said:

How can you crank the engine with no battery power ?

Dynamo or these days alternator.

[Liverpool Lou]

13 minutes ago, Kwasaki said:

28 minutes ago, toofarnorth said:

How can you crank the engine with no battery power ?

Dynamo or these days alternator.

Generators/alternators cannot turn over an engine without battery power.

[Kwasaki]

9 minutes ago, Liverpool Lou said:

Generators/alternators cannot turn over an engine without battery power.

Why can you start a bike or a geared car then with a flat battery. 

[OneMoreFarang]

43 minutes ago, toofarnorth said:

How can you crank the engine with no battery power ?

Manually, i.e. pushing the car with a gear engaged.

With old fashioned cars and motorcycles that works just fine.

[Moonlover]

1 hour ago, Kwasaki said:

The front wheel drive car drives both wheels. !!

Front wheel drive cars have a differential, it's called the transaxle. If one wheel is lifted off the ground the it will spin freely 

Edited July 15, 2022 by Moonlover

[Kwasaki]

2 minutes ago, Moonlover said:

Front wheel drive cars have a differential, it's called the transaxle. If one wheel is lifted off the ground the other one will spin freely 

What about if it is in gear. 

[Liverpool Lou]

9 minutes ago, Kwasaki said:

20 minutes ago, Liverpool Lou said:

Generators/alternators cannot turn over an engine without battery power.

Why can you start a bike or a geared car then with a flat battery. 

Because the crank is turned by the action of the push start.  Generators or alternators don't turn the engine.

[Moonlover]

20 minutes ago, Moonlover said:

Front wheel drive cars have a differential, it's called the transaxle. If one wheel is lifted off the ground the it will spin freely 

 

17 minutes ago, Kwasaki said:

What about if it is in gear. 

If it's not in gear you could turn it by hand. When it is in gear you would not be able to do that. But this guy isn't doing it by hand, he's using the rope to gain leverage so that he can turn the engine over.

[Kwasaki]

7 minutes ago, Moonlover said:

 

If it's not in gear you could turn it by hand. When it is in gear you would not be able to do that. But this guy isn't doing it by hand, he's using the rope to gain leverage so that he can turn the engine over.

Never tried such a thing so I wouldn't know.

[Liverpool Lou]

7 minutes ago, Moonlover said:

this guy isn't doing it by hand, he's using the rope to gain leverage so that he can turn the engine over.

or maybe his mate, ducked down out of sight of the camera, is using the ignition key!

[Kwasaki]

28 minutes ago, Liverpool Lou said:

Because the crank is turned by the action of the push start.  Generators or alternators don't turn the engine.

An alternator will turn and produce a spark when a the car is in a suitable gear for a push start.

 

Edited July 15, 2022 by Kwasaki

[Liverpool Lou]

It's curious that this car with the dead battery still has electric windows that operate, before the dubious rope yank.

[Liverpool Lou]

3 minutes ago, Kwasaki said:

An alternator will turn and produce a spark when a the car is in a suitable gear for a push start.

 

I know.

 

We're at cross purposes, toofarnorth posted...

"How can you crank the engine with no battery power?".

You responded, "Dynamo or alternator".

 

Alternators don't crank engines that's the point I was trying to make.

Edited July 15, 2022 by Liverpool Lou

[Kwasaki]

7 minutes ago, Liverpool Lou said:

I know.

 

We're at cross purposes, toofarnorth posted...

"How can you crank the engine with no battery power?".

You responded, "Dynamo or alternator".

 

Alternators don't crank engines that's the point I was trying to make.

It was a clue to the question asked. ????

[KhunLA]

2 hours ago, Pooreye said:

What model was that? An auto must have dual oil pumps for this to work, one on output shaft too. Very few cars, like some old Mercedes, have that

Wow, that was a long ago.  63 Chevy Impala or a Buick 'Special/Sport wagon' station wagon, one with glass around the roof, not the Olds' Vista Cruiser.  Actually forget which was being tested, probably the Impala.  I liked my wagon too much to risk an oops

 

This, but without the roof rack, it also had a 3rd row of fold down seats: 

https://www.curbsideclassic.com/curbside-classics-american/coal-1967-buick-sport-wagon-forty-years-of-sky-roofs/

Edited July 15, 2022 by KhunLA

[JimGant]

Join the 21st Century. Buy a 70MAI -- a lithium battery pack, with mini jumper connects, used to jump your dead battery. About the size of two cell phones roped together. I have two cars, and each now carries one of these, instead of the jumper cables I used to carry.

 

Found out about this when my dead battery had me call my neighbor, to bring his car over for a jump. Instead, he showed up with a 70MAI battery pack, and wham bam, car jump started immediately, even tho' the battery was completely dead. And, as my car was parked in  the driveway, engine compartment forward, I doubt jumper cables off my neighbor's car would have worked...... Anyway, all's well that ends well -- and I learned something new and meaningful about latest technologies usefully packaged.

[KhunLA]

7 minutes ago, JimGant said:

Join the 21st Century. Buy a 70MAI -- a lithium battery pack, with mini jumper connects, used to jump your dead battery. About the size of two cell phones roped together. I have two cars, and each now carries one of these, instead of the jumper cables I used to carry.

 

Found out about this when my dead battery had me call my neighbor, to bring his car over for a jump. Instead, he showed up with a 70MAI battery pack, and wham bam, car jump started immediately, even tho' the battery was completely dead. And, as my car was parked in  the driveway, engine compartment forward, I doubt jumper cables off my neighbor's car would have worked...... Anyway, all's well that ends well -- and I learned something new and meaningful about latest technologies usefully packaged.

I prefer just to keep my vehicle running properly.  Just replaced battery when car told me it was time.  Can't remember last time I needed a jump.  If I do, 24hr service is a phone call/push button away.  I actually have cables in my car, but for someone else's benefit, not mine.  Always willing to help a damsel in distress.

 

Wonder if my DIY power bank would work.  12.4v when full charged & 13,000mah 60C rating.

Edited July 15, 2022 by KhunLA

[HauptmannUK]

To get a modern car started you need two things:

1. Enough battery voltage to drive the fuel pump, injectors and ignition system.

2. Turn over the engine.

 

For (1) 6-7V is required. So even a very depleted battery will still provide sufficient voltage.

For (2) a starter motor will probably need 11V or more.  But you COULD manually turn the engine, as shown in the video. Its really just the equivalent of the old 'starting handle'.  

 

 

So yes this will work so long as you have enough juice to power the engine management.  If the battery is completely flat then it won't work. The altetnator won't charge either because it requires a rotor excitation current from the battery to start charging.

 

The little lithium booster packs will work if the battery is just a bit weak. If the battery is heavily depleted they do nothing. In the workshop we have several jump packs - these are basically just big high capacity batteries.

Edited July 15, 2022 by HauptmannUK