Originally Posted by johnsiddle
Just out of interest how do you switch the high voltage off when parked, you just cant put 500amps thro an ignition switch.
Is that why I was looking for contactors yesterday Woodsmith????
Yes, that is what the contactors would have been for.
The ignition switch would control the 12V coil on the contactor and the contactor would make/break the pack voltage.
There would be a precharge resistor across the contacts to allow the capacitors in the controller to charge up first, for a few seconds, before the contacts are closed and so the huge inrush of current is avoided when the contacts close.
This is where the cost of these contactors become a small issue as cheap relays cannot handle the continuous current capacity not can they break high DC voltage without arcing and burning.
The ones I have on the tractor are 200A 80V contacts. They are fine for the 48V I have but I shouldn't open them under full load, 400A, as the contacts aren't rated to handle that. Once, or twice, I might get away with it in an emergency but in an emergency I might find they cannot.
Look up Kilovac