Not if you have the cable clamped to the starter housing.
Starters are notoriously low-resistance devices. Possibly less than the internal resistance of the battery, let alone its effective resistance to being charged.
It wasn't exactly an experiment. I had a (70a starting current) *charger* hooked up to the car, directly on the battery poles. The starter wouldn't spin. I remembered the advice above from someone, so I moved the negative clamp and gave it a shot. The starter *did* spin. No; it doesn't make theoretical sense to me, either. I only know it works. Not to mention it's safer:
Yet another good reason.
-- C.R. Krieger (No theoretician)
Not necessarily true. Physical length of a circuit path only matters when the construction of the path is identical to the alternatives.
Don't bet on it. An uncharged battery is not a purely resistive load.
Yes, but that's quite common.
Yes, that is generally preferred.
No.
If the alternator can't put out 100% of its rated capacity for the duration of a jump start, then whoever built it shouldn't be building alternators. Alternators are self-protecting- they'll only produce a fixed amount of current, regardless of load (within reason- don't short-circuit one to ground just for grins, although shorting an alternator to ground is probably less likely to damage it than running it open-circuit where it will develop excessive voltage).
Probably not possible. That would require that 100% of the starting current flow through the jumper cables. Charging the dead battery for a few minutes with the "good" car's alternator splits the load- some of the energy to start the dead car comes from its own (now partially re-charged) battery, and only a portion has to come through the cables.
Yes, I have. I've seen the results. Its not pretty.
Right, its MORE than a purely resistive load. The voltage on a dead-but-otherwise-healthy lead-acid battery jumps up to 10-11 volts in just a few seconds of charging, even starting with a dead battery. The starter WILL be the lower resistance path within a minute of hooking up jumper cables. That is assuming the battery isn't failed (shorted) internally).
Well you are just a little off there....
The cables provide the return path for the current, the current comes 'from' the ground on a Direct Current system.
To make
A friend of mine did that.
He is now on the waiting list for the second replacement hip after the first one wore out in 10 years.
His car ran him down and shoved his leg through his hip.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's
What kind of car was it? Sounds like you've got a pretty crappy ground somewhere.
IMO, most cars benefit from having all the parts that are supposed to be grounded properly bonded together and to the battery ground post with the heaviest gauge conductor you can manage.
Near zero? You have an ohmmeter that will read the resistance of a couple feet of 6ga or larger stranded copper as anything but zero?
When I was doing mobile electronics installation, we bonded every body/frame piece we dealt with until the Fluke couldn't measure the resistance to the battery anymore. That took care of a lot of RFI problems people didn't even know they had until they were gone.
Any ohmmeter worthy of the name should indeed do so. My Fluke certainly will. Hell, I built a railgun for my senior EE project out of aluminum bar stock, and yeah, it measured out as greater than zero.
The bottom scale of a non-lab multimeter is almost always 200.0 ohms and that is barely adequate. Unless you have a four wire probe, the meter's leads will add about 0.2-0.5 ohms uncertainty.
A better way to check for excessive resistance is to turn the amp on with a load and measure the voltage drop between battery and the negative power connection at the amp. Anything over a half volt indicates a bad connection.
The meters I've seen will not read zero even if you short the probes together.. you'd need something special to measure the resistance of a piece of wire like that. Or measure the voltage drop when a given current is passed through, which is how it's usually done (or should be done) when troubleshooting a starting problem..
Ah. Well, there you go; I don't have any experience with non-lab multimeters.
What, pray tell, is the lowest scale on that meter you use? 20.00? 2.000 ohms? Or is it a 4, 5 or 6 digit meter?
Does it use a four wire probe? It would be pretty damn silly not too as there's no point having a milliohm resolution when measuring through 200-500 milliohms of probe.
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