The controller is a big black box that sends electric current to the motor. I chose a Curtis 1221 controller, designed for a 120 volt system. The current and voltage to the motor are determined by a control signal, the resistance of a potentiometer in the pot box. The pot box is connected to the accelerator cable.
February 11. The controller will be mounted on a hinged non-conductive piece of MDF (medium density fiberboard). It will also hold
a. two contactors (big relays to actuate the high voltage circuit)
b. the pot box, a spring-loaded potentiometer that goes from 0 to 5000 ohms as its lever is rotated
c. the shunt, a low resistance conductor through which most of the current will pass on its way to the motor.
I cut and mounted a piece of MDF on an angle iron bridge between the two single battery frames in the engine compartment:
I welded a bracket that bolts to the old radiator support. A 5/16ths bolt holds the wing nut seen in the top picture:
February 14. I will lay out and mount everything on the board, then remove it all to paint the board, remount everything.
I added another bracket, bolt and wing nut, seen on the right below. Then I mounted the pot box on the controller board. :
The accelerator cable bolts firmly to a bracket I fashioned out of a piece of 1/8" flat iron:
The cable appears to work correctly:
The controller sits on bolts above the board on a 1/4" thick piece of aluminum left over from the coupler. The raised aluminum plate serves as a heat sink, lets air underneath to cool the controller:
February 15. The contactors are mounted. You can see the bridge between the two battery frames better in this picture:
I removed all the parts from the controller board, cut a 4.5" diameter hole in it for a cooling fan, primed it with Kilz:
February 20. I got 20 feet of 2/0 copper cable. EV books and sources recommend welder's cable but I thought I would try this stuff since it's about a dollar a foot. It's stiff but it still bends. Here is the end of the cable:
I slipped a lug over the end, put it in my new hammer crimper and bashed it a few times with a big hammer:
Looks and feels tight:
February 22. I painted the controller board black and remounted the components. Then I made my first 2/0 copper cable connection with crimped lugs:
Here is a close up of the connection on the right, with heat shrink tubing clearly shown:
The controller connects to the "+" side of one of the contactors:
February 26. The story so far. Battery frames primed, painted, mounted, controller board mounted, drilled, components mounted:
I am also working on the vacuum system and the 12-volt circuit.
March 10. I got instruments from EV America today, voltmeter and ammeter. I also got the shunt. The ammeter gets attached to this shunt to accurately measure a small fraction of the current without carrying all the current to the instrument panel inside the car:
March 11. I mounted the shunt on the controller board, cut and crimped cables to hook it up to the controller and motor. The ammeter connections will attach to the screws on top of the shunt:
March 15. The pot box lever has a return spring, but a second return spring is recommended to assure that the lever firmly returns to the home position when the accelerator pedal is up. I cut the end off a big old coil spring, drilled a hole in the end and bolted it to the adjacent battery hold-down. I connected the end of the spring to the pot box lever with a stiff piece of spring wire:
Here is a labeled view:
You can also see the keeper I made for the accelerator cable end, so that it can't jump out of it's hole in the pot box lever.
All components on the controller board are mounted. See the testing page for final hookup.