Are ALL BMW owners this f´in stupid??

[ducsix]

The HD guy had a point, he was just fooled into thinking cables were the problem. Its not a good idea to boost off a running car because of the amperage produced, which can damage your battery in theory. The solution is to boost off a car that isn't running. Cables don't make any difference unless they have a power converter (regulator) built in - which I do not think exists.

I don't see why it would matter whether or not the car is running.  The current drawn by the battery being jumped has nothing to do with the car alternator output, just the terminal voltage....which is the same whether the car is running or not.

I've jumped my bikes from a running car at least 3 times with no problems whatsoever.

EDIT: never mind, it just occurred to me that a current source in parallel with 2 batteries, which each contribute a parallel RC term, will divide the current between the batteries.  Since the bike battery presumably has a lower impedance than the car barttery at full charge, it will suck more of the alternator current and may indeed hurt the battery........

[motogpfan]

Are ALL BMW owners this f'in stupid??

yes

[Popeye the Sailor]

Its not a good idea to boost off a running car because of the amperage produced, which can damage your battery in theory.

I don't see how.

[NeufUnSix]

Fully charged car battery on its own - 12.8 V
With the alternator running at idle - 14.5 V+ depending on the vehicle

That's a lot of juice to throw at a small motorcycle battery. Like I said "in theory" it can overcharge the battery and even blow it up. Doesn't mean it will happen. Some cars have the same alternator output as a modern bike (or vice versa).

[Howie]

Jumping from a running car is not a voltage issue it is an amperage issue.  Most of the time you will get away with it since the car alternator is usually putting out less than full output.  Many new cars are capable of producing more than 120 amps at full output.  There is simply no need to risk damage.  If your car battery with, four, six or more times the CCA of your car battery doesn't do the trick you have a bigger problem.

[Le Pirate]

hrm....

I dunno. I've never thought about this. I've jumped bikes off of cars since I got my license at 16 and have never blown up a battery. First ride of the season....jump it off. This is all new to me.


Either way....I still think the HD brand cables are BS. Just like the Harley service truck that will come jump you off (for a large sum of money, I'm sure). 

Cause, if thats the case...his HD cables are still going to draw the same amps as my cables i bought at Western Auto, right?

[Popeye the Sailor]

Cause, if thats the case...his HD cables are still going to draw the same amps as my cables i bought at Western Auto, right?

Depends on the gauge 


But I'm guessing when a tow truck jumps a bike, they do it with the same amperage as a car.


Anyone ever hear of anything bad actually happening? I is curious.

[Howie]

I've seen batteries blow from being charged at too high an amperage.  It ain't pretty!

[NAKID]

There's a difference between overcharging and jumping though. I bet the battery you're talking about was being charged over a longer period of time than one that is just jumped...

[Howie]

There's a difference between overcharging and jumping though. I bet the battery you're talking about was being charged over a longer period of time than one that is just jumped...

Nope.

[BWClark]

[NeufUnSix]

Bahaha, good example right there. I only got about 3/4 through though, I can't stand high minded philosophy
(says the History major).

[NvrSummer]

Speaking of dumbass BMW Owner's...

Taking a right hand turn out of a parking lot yesterday on my Monster onto a road that had been stripped for repavement.  Big drop off the curb and gravel everywhere, so I take it pretty easy.  Rush hour too.  I look to the left, I'm clear, so I go.  Didn't realize a brand new GS was behind me coming out of the parking lot, but he cuts me off to the outside and guns it, almost losing the rear end on the road gravel.  Classic part, this bike was cherry as can be, but the rider was wearing a tee-shirt, backwards hat, shorts, and FLIP FLOPS!

I'm usually not one to care what gear other riders wear, but it just goes to show you squids come in all types.  More money than brains I guess....

[ryandalling]

I jumped my 1990 Zx-6 with a car... as soon as they guy started the engine... I freaked telling him to shut it off... and by that time the voltage regulator / rectifier was smoking and had actually smoldered into a useless husk of plastic. That was a fun day.       I did replace all of the parts myself though. No dealer.
   
Doesn't matter the bike brand... there are some stupid people out there... I don't think you can spend any time on any board and not see it. 

[Speedbag]

Cause, if thats the case...his HD cables are still going to draw the same amps as my cables i bought at Western Auto, right?

Probably. But they won't have a kickass logo on them, and won't have cost double or triple. But they will be made in China just the same.