Testing and balancing HV batteryes in progres

This is fully automatic tester, you can chose different programs to execute, 

1.  Manual operation (charge, discharge, charge-discharge-charge, deep discharge, select only one block to operate or start from - end to... repeat ch-ds-ch cycle up to 5 times)
2.  Automatic operation
3.  Deep discharge
4.  Calibration
5.  Balancing
6.  And more

Before testing began, device read settings file from SD card and setup device, After that you can change some of values and start testing.

During testing, device keep all relevant data on SD card (battery voltage, charger voltage, charging-discharging current, no of battery, no of block, time, PWM sig for ch-dis...) couple times in second and create two files, one with all data and second with sum data (no bat, no block, and time - which is crucial for evaluate condition of each block). 

After whole battery is finished I put SD cart in my PC and analyse recorded data and sort battery blocks by quality. After couple finished batteries I have x*28 block and I chose 28 block with similar quality for one battery pack. Next step is balancing, each block are connected in parallel (all positive to one wire and all negative to second wire), the battery block stay that day or two and after that is ready to put orange connections and install in vehicle. Balancing can be done without jumper wires (as I do) using tester, but I use wires to save testers time and test another  battery pack during balancing first...

Tester is based on Arduino Mega board, which is opto isolated between  relays and their drivers, each block use its own relay (28 of them). On top of the box is resistor for discharging which can draw more of 30 Amps so charging and discharging current is monitored with current sensor and processor calculate how much to open MOSFET transistors for charging and discharging.

To operate I use ordinary 12V/20A battery charger and ordinary battery to deliver power during charging cycle. 

Under the battery is holder which is also designed to be used as air cooling in tandem with blower motor. 

That is it for now.

https://toyotahybridbatterytester.blogspot.com/