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Electric Vehicle with No Starter Relay

2543 Views 7 Replies 4 Participants Last post by  dtbaker
The college I am at is currently revamping our electric vehicle. And while we do realize that in a normal vehicle (gas powered) there is normally a starter solenoid or relay. We were curious if the one in the vehicle was even needed. What would be the benefits/ downsides to having no starter relay in the vehicle. Instead, we were debating on going to a 2 switch system, where the initial switch is a single pull double throw, allowing us to turn on the peripherals (lights, music, etc.) and the second switch would turn on the controller, allowing for a double failsafe system. We are using a Curtis 1238r controller at the moment. Any advice would be greatly appreciated.
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This is what I do in my conversion. First switch position closes the main contactor which powers up everything that was originally powered up in the accessory position and turns on the DC to DC converter. The second switch position applies power to the motor controller and once it goes through its precharge procedure the car can be driven. The start position is not connected to anything.

I think a lot of people set it up this way.
So is there any danger from a current spike when the power is first applied to the motor? A professor expressed his concern that this could be the case.
Not when applied to the motor. Motors are inductors and current through inductors changes (relatively) slowly.

I think you meant the controller. That has a large bank of capacitors that must be precharged slowly or the relay/contactor/switch contacts will weld shut. This function is integral to the controller I used. The control logic to do it is part of most all of the controllers.
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