Specifications
- Power: 2750 Watts
- Top Speed: 23 mph+
- Max Distance: 7 miles
- Charge time: 1h 20min
Parts
Motor
Turnigy Aerodrive SK3 - 6364-190KV Brushless
ESC
VESC- Benjamin Vader's Electronic Speed controller
Battery
Turnigy 5000mA 4 cell
Mechanical Kit
Torqueboards single bolt on motor mount
Calculations
Battery type: 2 5000 mah 4s lipo batterys in parallel
Motor kv: 190kv
Gear ratio: 2.25:1
Wheel size: 82mm
Efficiency = approx 80%
Top Speed:
R = 0.00003728226
Volts = 2 batterys * 4 cells * 3.7 volts/cell = 29.6 volts
Motor RPM = 190kv * 29.6 Volts * 80% efficiency = 4499 RPM
Top Speed = 4499 RPM * 82mm * pi * R * 2.25 = 19.2 MPH
Max Distance:
Whr = 29.6V * 5000 mha = 148 WHa
Watt hour per mile = 21.25 (estimated based on rider weight and average speed of 8mph)
Max Distance = 148 Wh / 20.5 = 7.22 Miles
Charging Time:
Balance charge two 5000 mah battery = 10A
Power supply output =12.15v x 47A = 564W
Balance charger output = 500W / (3.7v * 4 cell) = 16.9 A per cell
Fast Charge time = 10A / 16.9A * (60 min / 1 h) = 35.5 min +- 10 min for ramp up time
Normal charge time at 1c = 10A / (10A * 1c) + balance time = ~1h 20 min
Controls
To control the board I use a 2.4Ghz remote and receiver. The remote has a built in 500 mah 1s lipo. The controller allows for acceleration, deceleration and when not using the controls the longboard coasts. There is also another switch on the remote to control the second channel (Currently not in use).
How to Power on
I wanted to reduse the cost of the longboard as much I could so instead of going with a power switch I chose to use a XT90 connector shorted. Shorting the XT90 allows for me to complete the circuit which interns powers on the electric longboard. In order to avoid sparks from pluging in to 30V, I opted to use a anti-spark XT90. This special two-stage connectors put a 5.6 ohm resistor in series with the positive leads before making a direct connection and bypassing the resistor.
