Erratic ignition now no power, no start

[glang]

I wonder if some of the confusion is coming from this: Although simple electrical items like lights, heaters etc consume less current with a lower voltage across their terminals some more complicated items like induction motors do actually draw more amps to maintain their power output.

[Yellow650Loz]

Originally Posted by daktulos

I'm not sure where you've got this from, if the voltage across a (relatively) fixed resistance load drops, the current will also drop.

With a corroded connection, it's effectively an additional load in the circuit. Because of this, there's a voltage drop across it and therefore power consumed which must be dissipated as heat.

The easiest way to diagnose a problem is to check the voltages between the battery, R/R and load and either side of connectors between. In a perfect world they should all be the same. If there's a significant difference between any two, then your problem will be between the two points. The Haynes manual (if I remember correctly) gives acceptable voltage differences.

The same applies to the earth. A garage once needlessly replaced the starter motor on my car because they swore it was dead as they could see a voltage on it. It turned out that the earth bonding was shot and it was just the clutch cable providing a path back to the battery -ve.

you've just said the same thing, It's effectively an additional load on the system. However it also creates a problem on both sides, the component being supplied the power in the first place will have a reduction in voltage.
It's rated at 12v however Suzuki designed the system and the wiring to run at 13.8v curvy or 14.9 pointy IIRC.

Im sure the OP said a starter motor was used alot; because the bike wouldn't start, it would start to overheat the circuit, it's not designed to be used like that, eventually the weak link would be found. In this case the connector. Was the connector actually found to be rusty? Or just melted? I can't remember or mustav skipped that page

[SV650rules]

Originally Posted by daktulos

I'm not sure where you've got this from, if the voltage across a (relatively) fixed resistance load drops, the current will also drop.

With a corroded connection, it's effectively an additional load in the circuit. Because of this, there's a voltage drop across it and therefore power consumed which must be dissipated as heat.

The easiest way to diagnose a problem is to check the voltages between the battery, R/R and load and either side of connectors between. In a perfect world they should all be the same. If there's a significant difference between any two, then your problem will be between the two points. The Haynes manual (if I remember correctly) gives acceptable voltage differences.

The same applies to the earth. A garage once needlessly replaced the starter motor on my car because they swore it was dead as they could see a voltage on it. It turned out that the earth bonding was shot and it was just the clutch cable providing a path back to the battery -ve.

+1

Although the corroded connector should probably be described as 'an extra resistance' rather than 'an extra load' - but I understand that you mean a load in the sense that work is being done at that point by the current flow, the unwanted resistance caused by corrosion of the contact faces will cause extra work (heat) at that point. Second law of thermodynamics basically says 'All energy ends up as heat'

On every car I have owned I have fitted one of these braided leads between battery negative terminal and engine block, I do not trust all those small rusty connections between body and engine...

https://www.halfords.com/webapp/wcs/...ch=earth+braid