WEEK 9: BMS Wired up! 100kg more batteries! Array Coding fail + Finalizing Temperature Monitoring Arduino LCD

This week was mock exams week, so I didn't get as much work done as normal.

Last weekend, I began to wire up the BMS to 9 of the battery modules as a test. (This BMS supports between 8 to 32 modules in series).

It took me a while to figure it all out, but after hooking up balancing wires, positive and negative, the LCD and ON/OFF switch, and downloading the app, I managed to get it all going!


This is the BMS I am using, which I paid just under $200 for from Aliexpress:

Wiring the BMS up to the modules:

I really like the display, it shows a lot of data from the batteries which is crucial for a rebuilt recycled battery setup from old laptop batteries!

It has 2 internal temperature sensors (1 on power mosfets and 1 on balance circuitry) + 4 optional external sensors, which I will probably use for 3 stator temp sensors in the electric motor, and an outside temp.

The phone app allows you to configure many parameters, such as cell count in series, max current, high and low voltage cut off, etc. which is just awesome for this setup.\

Another thing I did over the weekend was buy over 100kg more 18650 cells, as an investment for future projects and to possibly complete the battery modules for the electric car battery.

This is an estimate of over 2000 cells!

I was having a lot of trouble with the array coding in the Arduino and it was causing me lots of issues with the LCD display, so I have left the idea. 

Over the week, I came into school and worked on getting the whole setup working with a button to toggle display modes.

This is how it is looking now:

So each Arduino UNO can monitor 6 temperatures and display 3 at a time, which the button toggles between the 2.

In future, if I get the time, I plan to integrate cooling fans if needed and LED indicators for high and low temp warnings, etc.