Updated 7/25/19 Completed, manufactured, and test REV4 of board. It works! REV3 is also complete.
This repository includes information needed to built a display to output the speed, mileage, power, current, pack voltage, individual cell voltage abd State of Charge of an electric bicycle/powerwall using an Arduino Nano! This repository includes the necessary Arduino files, a custom Arduino shield PCB designed in EAGLE and various information about the components required to build this system.
There are two versions of this system which you can build:
REV3: This is a simple board that requires little soldering or PCB design experience. Beginners start here!
REV4: This board is identical to REV3 but it embedds the arduino nano onto the board, instead of through-hole mounting a off-the-shelf arduino nano.
Both REV's function identically. Think of REV3 as a demo board where you can develop firmware and prototype the system. REV4 gets into the low level side and allows for greater custimizations and smaller size.
Here is a brief list describing the necessary high level components for this system.
-
Arduino Nano. REV4 embeds the ATmega328P micrcoprocessor on the board to significantly reduce system size and weight.
-
20x4 LCD Display with I2C.. The I2C communication bus drastically reduces the number of wires going to the LCD and the #include <LiquidCrystal_I2C.h> library seamlessly integrates the I2C protocol into your arduino.
-
JBDTools Compatible BMS: Here is a link to the one I purchased. . Make sure the BMS you buy is compatible with JBDTools software. My arduino script uses the communication protocol used by the JBDTools software. This protocol can be found in an excel file call JBDTools Communication Protol at the homepage of this repository. Simat also has a great description of it as well.
-
DC/DC Converter. The linear voltage regulator on this type of BMS is not designed to handle high amounts of current. REV3 of this project includes this or this DC/DC converter to provide 12V at a max of 1.25A to the system.
-
Hall effect sensor.. This type of sensor send a HIGH pulse whenever a significant magnetic field acts upon it.
-
EAGLE PCB design software. I used OSHPark to manufacture the PCB and had no issues.
- Input Voltage Range: 18 - 72 Volts
- Max Power Output at 12V: 1.67 Amps (20W)
- Reverse polarity and fuse protection on power input
My ebike uses the Cyclone 3000 ebike kit. The throttle/ignition has a built in switch on the B+ line. My system draws power from the B+ after this switch so that if the switch opens, the system turns off. I recommend configuring your system this way so that it only draws power when the bike is on.