Proof-of-Concept DIY Isolated Voltage Meter using an Arduino and a couple ATTiny85 (can use ATTiny45). There are always better, smaller, cheaper ways of doing things; please comment with your insight and experiences!
BMS Part 2:
https://www.youtube.com/watch?v=I2Fcmnnc460BMS Part 3:
https://www.youtube.com/watch?v=fUT1GW9gx7YATTiny Voltage Reference and Calibration Information:
http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/Things to consider to fully develop this project:
- Sleep Mode (reduce to micro-amp draw)
- Arduino Power Supply Isolation
- I2C/SPI LCD Display to view each cell (or paralleled cells)
- Audible Alarm, LVC/HVC
- Throttle Commander, "Limp Home Mode" near LVC, kill at LVC
- Cell input voltage noise reduction
- Add balancing loads?
If you want an even more easy to implement battery monitoring system for your project, check out the 8S CellLogs from HobbyKing.com, they have HVC/LVC output using an NPN transistor. I also recommend soldering directly to the LVC/HVC output terminals, ask me about the time when my FPV Ground station shut off mid-flight because of a defective connection. CellLogs wont have the advantages of this DIY style monitor such as being able to show all cell voltages on one LCD screen in addition to the endless custom-ability that a micro-controller offers.
*This video is for educational purposes only, Mega Mechatronics cannot be held liable for damaged parts, loss of equipment, and personal injury or death, related to the information contained in this video and the scope of information expressed.