Jumping cars with differing #s of cylinders?

[Dustin_S]

Why do people think it matters? Granted, I don't know 100% that it doesn't, but I can think of no logical reason from my (admittedly simple) knowledge of cars that it SHOULD matter...

I ask you guys, is it true that the number of cylinders when Jumping a car matters, and if it is false, where do people get this misconception? it seems EVERYONE older than 35 (that may have something to do with it, perhaps it only mattered in older cars?) falls into the category mentioned above.

Edit: if it IS true, I feel sorry for the poor SOB who buys one of those mercedes 5 cylinders....

[Punk_187]

No, the # of cylinders doesn't matter in the slightest. I just jumpstarted my V-6 '86 Thunderbird a few weeks ago with my dads 2001 Ford Turbo Diesel V-8 F-350. Don't know where people could get this misconception from, never even heard it. Any good 12V battery should be able to jump start another 12V battery.

[JohnnyWash1]

Never mattered for all I know. It has to do with the electrical system, not the mechanical operation of the engine. As for the 5 cylinder engine, aren't you speaking of Volvo? I can't remember a 5 cylinder Merc...


Jon

[MioCLK]

Mercedes has a 5 cynlinder diesel engine

[iowamadman]

well, i do know that a Willys Jeep w/ 4 cyl don't got the juice to jump the V16 in my caddy

[Cavallino]

Originally Posted by iowamadman

well, i do know that a Willys Jeep w/ 4 cyl don't got the juice to jump the V16 in my caddy

I don't see why it would matter. It's the batteries that get connected when you jump a car not the engine, and since most car batteries have the same output it shouldnt matter. Also, if the number of cylinders mattered then the emergency jump kits you keep in your trunk wouldn't work. You would have to carry a spare engine around in your trunk that was the same size as the one in your car, in whicxh case good luck toting a spare V16 around.

[ivymike1031]

Originally Posted by iowamadman

well, i do know that a Willys Jeep w/ 4 cyl don't got the juice to jump the V16 in my caddy

You've hit on the one big concern. While nearly all automotive batteries currently in use are 12V, they vary significantly in "cold cranking amperage" output. There is a reason why a honda civic has a tiny battery and a ford 450-series truck has a big one, and it's not because it looks better. Generally speaking, a larger engine will require a larger starter, and a larger starter will draw more current. The volume of a battery is (roughly) related to the max current it can muster (really it's the surface area of the plates, etc., inside that matters, but whatever).

In all honesty, the proper way to jumpstart a car, if you ask a guy selling jumper cables, is to use the running car to recharge the battery of the "dead" car, then use the battery in the "dead" car to start it. Drawing 600 amps through a 00-gage wire 10 feet long can only be done for brief periods, at best. The jumpstarting procedure most people seem to use, which is to hook up the cables, rev the engine for a while, then try to start the "dead" car, uses a combination of the "dead" battery and the "live" one to start the car. When you try it and it doesn't work at first, then you wait 5 minutes and try it again successfully, it's because you've managed to put a bit more charge on the "dead" battery.

[JohnnyWash1]

Originally Posted by ivymike1031

You've hit on the one big concern. While nearly all automotive batteries currently in use are 12V, they vary significantly in "cold cranking amperage" output. There is a reason why a honda civic has a tiny battery and a ford 450-series truck has a big one, and it's not because it looks better. Generally speaking, a larger engine will require a larger starter, and a larger starter will draw more current. The volume of a battery is (roughly) related to the max current it can muster (really it's the surface area of the plates, etc., inside that matters, but whatever).

In all honesty, the proper way to jumpstart a car, if you ask a guy selling jumper cables, is to use the running car to recharge the battery of the "dead" car, then use the battery in the "dead" car to start it. Drawing 600 amps through a 00-gage wire 10 feet long can only be done for brief periods, at best. The jumpstarting procedure most people seem to use, which is to hook up the cables, rev the engine for a while, then try to start the "dead" car, uses a combination of the "dead" battery and the "live" one to start the car. When you try it and it doesn't work at first, then you wait 5 minutes and try it again successfully, it's because you've managed to put a bit more charge on the "dead" battery.

This is the info I was looking for. I knew it had something to do with that. Anyway, I always jump a car by charging its battery. Seems more logical to me.


Jon

[SaabJohan]

Most starters require around 150 amps. The exact number depends of course of the starters power output.

In many cases a motorcycle will be able to jumpstart a car. The internal resistance of the battery is what really matters, this is what determine cranking amps, or the voltage drop at a certain current load. A larger battery doesn't neccesary need to have a lower internal resistance, the size is also related to the energy reserve, Ah. Most batteries used in racing are very small and have a low energy reserves, down to around 15 Ah but can start a car just as easily as a much larger one.

Furthermore, a car battery should not be used to charge another car battery, they can take damage of this. If an extra battery is connected it should be disconnected as soon as the car has started.

[Cavallino]

Ill be damned. Sorry bout that Iowamadman.