Electric Kart

Homemade Electric Kart using a 2,9 kW Forklift Motor

Homemade Electric Kart using a 2,9 kW Forklift Motor

Specification

  • Top-Speed: 35 km/h forwards and backwards
  • Weight: 240 kg
  • Turning radius: 0,5 m
  • Brake: Rear only, wodden block
  • Suspension: Rear swing arm only

    Features:

  • Switch for selecting driving direction
  • Switchable differential-lock
  • Front light
  • Trailer hitch

image Front view of the finished vehicle

Components

Motor

  • Type: Serial wound DC motor
  • Previous application: Forklift
  • Power: 2,9 kW
  • Voltage: 24 V
  • Current:
    • Rated: 156 A
    • Measured: 25 - 500 A
  • Rotational speed: 1780 rpm

image Early setup with temporary wiring

Drivetrain

  • Custom adapter from motor (helical cut spur gear) to sprocket for chain
  • Chain: 06B-1(3/8’ x 7/32’)
  • Sprockets:
    • motor: Z13
    • axle: Z40

Tires

  • from car trailer
  • 4.80/4.00-8
  • Tubeless
  • diameter 400 mm

Control

  • Custom PCB with ATMEGA 8 microcontroller
  • Control method: 124 Hz PWM
  • 600 A 1000 V IGBT (FUJI 1MBI600PX-140-01)
  • Audi gas pedal
  • Custom knife switch for direction selection

image Drivetrain maintenance

image Direction selector, IGBT and Diode

Battery

  • Voltage: 24 V (2x 12 V in series)
  • Capacity: 2,4 kWh (2x 12 V 100 Ah)
  • Type: Deep cycle AGM

Experience with battery types:

Over the years different kinds of batteries were tested:

  1. VRLA Starter battery
    • Positive: Very high discharge current
      -> Noticably higher motor torque
    • Negative: Fast loss of capacity when discharged too much and often
      (bad deep cycle capability)
  2. Lead GEL battery
    • Positive: Suitable for very deep cycle applications (high actual usable capacity, with comparably less capacity loss)
    • Negative: Low discharge current
      -> Significantly reduced torque in combination with this very current demanding motor (was almost unusable)
  3. AGM deep cycle battery
    • Slightly less discharge current than the Starter battery, but higher cycle stability
    • Best option so far
  4. Lithium-Ion battery?
    As Experienced in the E-Bike and Armchair projects, Li-Ion would be the best type in terms of weight to capacity ratio and cycle stability.
    But building a lithium-ion battery in the appropriate size for this project would simply be too expensive.

image Different battery types used: VRLA, GEL, AGM deep cycle

image Battery change

Videos

YouTube video


Tests

First test drive

2015.04.16

First motor test

2015.03.01

Suspension test

2015.12.10

Fails

Battery pole melts

2019.05.27

Short circuit

2015.12.10

Build process

Axle thread cutting

2018.07.06

Casting battery pole

2019.06.01

Gallery