E-bicycle computer

It has been a while since the last post.

During the last few weeks I have been experimenting with Arduino and I’ve assembled ad little computer for  my electric bicycle. As you can see from the photo I am using a 16 x 2 LCD display where I can see some useful information:

  • External Temperature
  • Distance in Km (data stored in the eeprom so it will stay in memory even when the power is off)
  • Speed in Kph
  • Battery Voltage

This is just a little experiment and I am really satisfied with the results. I have already ordered a bigger LCD screed (20 x 4) to add more data such as:

  • Amps drawn from the battery
  • Watt-hours used from the beginning of the trip
  • Estimate range left based on Watt-hours used
  • Battery temperature
  • Trip Distance (can be reset pushing a button)

I have some problems with the current configuration because I am using a hall sensor from the motor to calculate speed and distance. My hub motor has a sort of  “clutch” or “freewheel” built in so that when I am not accelerating the motor stop turning and the wheel can still rotate freely. For this reason as soon as I stop accelerating the Kph goes to “zero” and no distance is registered. The solution is simple, I will use a common bicycle computer sensor to get the speed and distance data. If I had a direct drive motor there would be no problem 🙂

Here is a video of the road testing:

 

I used a voltage divider to measure the voltage with Arduino and despite the delay compared to the Turnigy Watt  Meter the voltage is pretty accurate (within 0.08 Volts or less difference).

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3 thoughts on “E-bicycle computer

    • Hi Ccriss,

      Thank you!You inspired me 🙂 . The only negative thing about using an Arduino is that if the supply voltage (and consequentially internal voltage) is not adequate, some values will be incorrect (for example the temperature). Other than that the potential is BIG! My limit is the code, but I am learning quickly :).

      Did you solve your problem with bmsbattery & charger?

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