bq769x0 Arduino Library

Arduino-compatible library for battery management system based on Texas Instruments bq769x0 IC (bq76920, bq76930, and bq76940).

This library offers most features for a simple BMS (including automatic fault handling and balancing). See also BMS48V hardware files.

Example Arduino sketch

#include <bq769x0.h>    // Library for Texas Instruments bq76920 battery management IC

#define BMS_ALERT_PIN 2     // attached to interrupt INT0
#define BMS_BOOT_PIN 7      // connected to TS1 input
#define BMS_I2C_ADDRESS 0x18

bq769x0 BMS(bq76920, BMS_I2C_ADDRESS);    // battery management system object

void setup()
{
  int err = BMS.begin(BMS_ALERT_PIN, BMS_BOOT_PIN);

  BMS.setTemperatureLimits(-20, 45, 0, 45);
  BMS.setShuntResistorValue(5);
  BMS.setShortCircuitProtection(14000, 200);  // delay in us
  BMS.setOvercurrentChargeProtection(8000, 200);  // delay in ms
  BMS.setOvercurrentDischargeProtection(8000, 320); // delay in ms
  BMS.setCellUndervoltageProtection(2600, 2); // delay in s
  BMS.setCellOvervoltageProtection(3650, 2);  // delay in s

  BMS.setBalancingThresholds(0, 3300, 20);  // minIdleTime_min, minCellV_mV, maxVoltageDiff_mV
  BMS.setIdleCurrentThreshold(100);
  BMS.enableAutoBalancing();
  BMS.enableDischarging();
}

void loop()
{
  BMS.update();  // should be called at least every 250 ms
  BMS.printRegisters();
}

What's changed from the original upload (as of September 2019)

Now supports CRC (thanks to mikethezipper)
Automatically finds bq769x0 address and CRC
Tested on bq76940

To Do list

Proper SOC estimation and coloumb counter implementation
Testing for ICs with more than 5 cells
Software protection for charge overcurrent

LibreSolar/bq769x0-arduino-library

bq769x0 Arduino Library

Example Arduino sketch

What's changed from the original upload (as of September 2019)

To Do list