Quote:
Originally Posted by DGthe3
I know all about voltage and amperage and how batteries work. Amperage is a function of the voltage supplied and the resistance of the circuit, not a driving element of the circuit. The maximum amount a battery can supply has little to do with how much it actually supplies in a given circumstance. If the circuit needs 5 amps, the battery supplies 5 amps -not 60 amps (or whatever) it could supply. It will only do that if the circuit is needs 60 amps.
Now, back to the burnt down Karmas. While its true that the battery is in the 300V range, not every single component of the electrical system operates at that voltage level. In fact, about the only thing that does is the drive motors. Most of the remainder is at the same voltage as any other car. Afterall, it is an awful lot easier to bring down 300V to 12V (or 60 or 3.87 or 189) and use a standard component (like a power window motor) at a normal voltage than it is to redesign all those other components to run off of 300V. Consequently, the vast majority of the wiring on hybrids and EVs is no more dangerous than it is in a conventional car (and keep in mind that those conventional systems cause tens of thousands of fires per year). And that also means that unless there was a failure within the battery or some other problem with drive circuit, the fire cannot be attributed to the high voltage system of the car.
I still say that the problem will be traced to some conventional component that failed due the the fact that it was submerged in salt water for an extended period of time. No car should be expected to survive that, and the fact that so many did is impressive. The fact that some Karmas didn't is more of a reflection on how poorly the cars were engineered/built than it is on the nature of their power-train.
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Not likely as the ignition was not on so you would have to believe that simply submerging a 12V battery would cause fires.
The 12V fires you are refering to are generally caused by a short that creates heat not simply 12V of current passing.
Now 300 V getting submerged? If not designed properly that can be a problem.