Arduino E-bike computer is alive!

In the last few days I made some improvements and changes to my arduino e-bike computer.

It displays various informations given from the sensors:
+Battery voltage
+Battery temperature
+Amps
+Watts
+Ah used (stored in eeprom)
+Speed in Kph
+Distance in Km (stored in eeprom)
+Km left with the current battery.

Pushing a button I can see the maximum values of the data.

Pushing another button the data stored in the eeprom can be reset to zero.

I want to thank my friend “Ccriss” for helping me (a lot) with the code!

Soon there will be other upgrades!

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13 thoughts on “Arduino E-bike computer is alive!

  1. Hi Ccriss!
    Thank you so much for your help!
    Yes the sensors are very stable, considering the fact that I don’t use any capacitors (yet) to stabilize the in/out voltage, except for the voltage divider.
    🙂

  2. Hi jacopo,
    i’ve seen your great job with the arduino and the ebike in endless, and i’d like asking you about how do you measure the amp?? do you use a special chip?? stunt??, i’m trying to do something similar, but i’m not sure how i can do it…
    Thanks..

    • Hi Nio,
      I use a current sensor from Allero: ACS758, there are different models, I suggest the 50A model for more precision for an electric bike. I tried the 100 and 200 Amp ones and they are not as precise at low power levels.
      🙂

  3. Hi, I trying to do the same thing and i get your blog.
    I decided also to get a ship for the current. But for the voltage mesure, did you use only a divider resistor like 10Mohm and 1Mohm ?

    • Hi!
      The values of the resistors depends on the maximum voltage you want to read on arduino. I used 82k and 3.9k resistors to read up to 100v. Remember that feeding more than 5.5v into any arduino pin can fry the atmega.

      • Ok, i understand. For me i’d like to reduce 50v (48v) to 5v. So with your advice, i will test 1MOhm and 100k. But for you, 82k and 3.9k is it enought with the power dissipation ?

      • Yes, the values I used they work pretty well. 1/4W is enough for power dissipation if you use them only to do the reading with Arduino. It’s not recommended to use a voltage divider as a dc/dc converter even for small loads. There are some examples in the arduino forum too.
        I would take some room with those resistors values. For example my voltage divider can take up to 100v even if the maximum I use is 84v when the battery is fully charged. Remember that any voltage above 5.5v can fry your atmega.

      • Great. That’s pretty simple.
        Now i have to test if the bus i2c accept 2 meter wire.

        Because, i’d like to put the arduino to the back on my bike et just have the lcd in front of me.
        Do you use i2c with your screen ?

      • Hi Sylvain,
        I use a common 4×20 lcd screen and I use the digital pins and not the i2c interface.With the latest version I am doing the same as you, the arduino is close to the controller and I use a ethernet cable to power up and receive signals from arduino. The cable is about one meter long and there are no problems :). You should have no problems with the i2c interface.Let me know how it goes 🙂

      • that exactly i imagined. I think also to get the alimentation of arduino with my controller.
        Otherwise, i saw a cc converter but if i can avoid that should be easier.

      • I strongly suggest a dc/dc converter to power up the arduino and lcd screen. The 5v feed from the controller will not tolerate a lot of current, just a few mA for the motor hall sensors and the throttle. Good luck with your project!

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