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Porter 40 Speed Controller

The Porter 40 has been replaced by the Porter 5 and 10.

The Porter 40 is a simple, economical, general purpose analogue controller for power handling machinery including golf caddies and wheelbarrows. It will also find applications for power assisted cycles and similar machines.

It is designed to be as simple as possible to use and install so has the simplest possible wiring – just six wires!

A small modification may be made to the board to make it work with a 0-10K throttle instread of the 0-5K.


  • Dimensions 100 x 48 x 33 mm approximately.
  • Operating voltage:
    • 36v version (standard): 12 – 36v battery
      10v to 46v may be used
    • 48v version: 12 – 48v battery
      10v to 56v may be used
  • Motor current: 30a continuous (with suitable heatsink)
    40A limited
  • Regenerative braking
  • Acceleration and deceleration ramps: linear, fixed
    Standard times, 0-100%

    • Acceleration: 2 seconds approx.
    • Deceleration: 2 seconds approx.

    Ramp times can be altered for quantity orders.

  • Input
    • Throttle potentiometer
      • Throttle Type: variable resistor (2 wire) 0-5K
      • Pot fault detect: 9.3K
        With a small modification a 10K resistor can be used. See instruction manual.
    • Voltage source
      • 3v gives full speed.
        Source should be low impedance (must sink at least 2mA)
      • Fault detect: 7V
  • Ignition: Off at zero speed or with pot fault detected.
    Automatic ramp-down at power off.
    Quiescent current when ‘off’ typically 3mA (24v)
  • Reverse polarity protection: Automatic electronic – (no fuse or manual reset)
    Max reverse voltage, 60V

Board Version

Porter 40

The board version uses the same aluminium fin as the boxed version.


Wiring is designed to be the simplest possible – just 6 wires, 2 each for battery, motor and throttle pot. Wiring is shown on a separate page – Porter wiring diagram.


The standard Porter can be used with any 5K potentiometer, for instance our Twist-grip throttle or plunger operated pot.

It can also be modified for use with a 10K pot (such as our Bell Throttle assembly). Details are in the instruction manual. If it is ordered with a 10K pot, this will be factory modified to suit. Such 10K modified Porters have a black curcular label on the heatsink and/or circuit board.

Beware of a pot marked 4K7: many of these have a tolerance of±20%. If they are 4K7 or over, they will work but values less than 4K7 will not reach full speed. The pots 4QD sell are marked 4K7 but are tested to be greater than 4K7.