Item #: 300-48L
UPC: 300-48L
Price: $625.99
    Points to Purchase: 89428
    Availability: Available
    Usually ships In 3-9 business days (sooner, if drop-shipped)

    The 4QD-300 is a heavy duty motor controller for currents up to 300A.

    - 4 quadrant operation
    - Gain adjustment.
    - Adjustable acceleration and decelerationramps.
    - Input by 1k ohm to 22k ohm potentiometer, direct voltage -control, or PWM control by Pi or Arduino etc.
    - Regenerative braking [can be disabled].
    - Reversing.
    - Over temperature shutdown.
    - Battery discharge protection.
    - Pot fault protection.
    - High Pedal Lock-out.
    - Inhibit input for interlock with mechanical brake, deadmans handle etc.
    - Parking brake driver with current limit and anti-rollback.
    - Joystick (center zero) or single ended modes [selected by a movable link).
    - Forward – Off – Reverse push button operation is possible [see article in knowledge base]
    - Wide operating voltage: 48v controller can be used between 18v to 66v (subject to battery discharge protection setting).
    - Fail-safe, protected circuitry for reliable, safe operation even into a shorted output: no minimum inductance for safe operation.
    - Shut down circuitry shuts drive down safely under all likely failure modes, including internal or battery over and under voltage
    - Reversing speed threshold can be adjusted for operation on hills.
    - Brake Light Driver. Factory option, replaces parking brake (subject to minimum quantity order).

    Also on board is an adjustable torque limit, which limits the continuous motor current, to avoid overloading smaller motors.

    Direction switching and drive / brake switching is entirely electronic so in a vehicle equipped with a 4QD it is quite permissible to change the direction switch whilst travelling at full forward speed. The 4QD will brake, stop and reverse under full control. There are on board ramp controls to separately adjust acceleration and deceleration rates. With maximum rates the controller is very lively!

    Output devices are kept in their safe operating area so failures are rare. However 4QD have considered the possible failure mechanisms. Worst would be an output device failing short-circuit so the drive would go to full speed. Such failures normally cause the MOSFET gate to go short-circuit. This condition is normally detected by internal circuitry and shuts the controller off completely and safely. Control circuit failures can be over-ridden by the ignition switch.

    Mechanical construction is such that the controller can be mounted in thermal contact with the vehicle chassis, to allow additional heatsinking, although this is not normally required. However for continuous operation at high currents additional cooling will be necessary.


    Nominal voltage range24 – 48
    Minimum / maximum voltage18-66
    Motor current A [max]320
    Motor current A [1 minute]180
    Motor current A [continuous]* depends on cooling
    Half speed reverseLink selectable
    Regen brakingY [can be disabled]
    Gain adjustmentY
    Dimensions [mm]280 x 103 x 60
    Weight [g]1685
    Power connectionsM8 studs
    Input5k – 20k pot, or 0 – 3V [adjustable via gain]
    Reverse polarity protectionN
    Overvoltage protectionY [68V]
    Under voltage protectionY
    Pot fault protectionY [>40k]
    Thermal protectiontrip @95’C
    Current limit – driveY [Adjustable]
    Current limit – regenY
    High pot lockoutY
    Joystick/Wig-wag inputLink selectable
    Radio ControlVia DMR-203
    Selectable dual ramp reversingY
    Pre-select ReversingN
    RampingAcceleration and deceleration adjustable between 0.1S and 5S
    Parking brakeY [1A max]
    Inhibit functionY
    Powerdown state (motor)open-circuit
    Tacho feedbackVia tacho interface board and mod
    Ignition, ElectronicY
    Double headingY
    Switching frequency20 kHz

    *The continuous current ratings depend heavily on the cooling that is provided. This chart shows the difference between the cooling options we have available for the 4QD-300


    *This chart shows the effect a small PC case fan can have on the 4QD-200, in this case it was placed about 4″ away from the base plate at an angle of 45′ to it.

    thermal performance