R1/R2 The ratio of these two resisters should be such that the voltage is 60 volts when the controller voltage reaches battery voltage minus 10%. R1 should be a value which is small enough to turn on the opto-coupler, but large enough to limit the current through the opti-coupler and the zener diode.

R3 should be just small enough to turn on the main contactor.

C1 should be large enough to remove any clitches which may occur. A few hundred uf should do.

R21 should limit the current through the zener diode

R22 should limit the current through the opti-coupler. Voltage across R22 will be 5v.

R23 should provide enough current through the transister to turn on the main contractor.

R24 should limit the current through the opti-coupler.

R25 should be set such that the opti-coupler turns on when the voltage is close to the pack voltage.

C21 should filter out any ripple produced by the controller.

C22 should keep the transister on during transition of releasing the throttel.