Mark Chin
Published

Pi18650 DUAL LI-ION BATTERY HAT

Twice the power, Twice the capacity to power your Pi.

IntermediateFull instructions provided15 minutes2,594
Pi18650 DUAL LI-ION BATTERY HAT

Things used in this project

Hardware components

Pi18650 DUAL BATTERY HAT
×1
18650 Lithium Ion Batteries
×2
Raspberry Pi 3 Model B
Raspberry Pi 3 Model B
×1

Story

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Schematics

Pi18650 Block Diagram

Code

Dual Battery Monitoring Scipt

Python
This Python script monitors two Li-Ion batteries in the Pi18650 DUAL Battery HAT.
import smbus
import time
from smbus import SMBus	
import RPi.GPIO as GPIO

SAMPLES = 5.0
battery_capacity = 0.0
fuel_guage_temperature = 09.0
battery_voltage = 0.0
sample_delay = 0.005

BAT1_V_MON = 23
BAT2_V_MON = 24

GPIO.setmode(GPIO.BCM)
GPIO.setup(BAT1_V_MON, GPIO.OUT)
GPIO.setup(BAT2_V_MON, GPIO.OUT)


DEVICE_BUS = 1 #device bus number
DEVICE_ADDR = 0x64
DEVICE_REG_ADDR_ID = 0x00  #registry for device id ascii string 0x00 - 0x07
DEVICE_REG_ADDR_08 = 0x08
DEVICE_REG_ADDR_09 = 0x09
DEVICE_REG_ADDR_0A = 0x0A
DEVICE_REG_ADDR_45 = 0x45

#Fuel Gas Guage Monitor Registers
FUELGUAGE_ADDR = 0x64		#0b01100100
FUELGUAGE_REG_ADDR_00 = 0X00	#status				(R) default()
FUELGUAGE_REG_ADDR_01 = 0X01	#control	 		(R/W) default(3C)
FUELGUAGE_REG_ADDR_02 = 0X02	#acc charge MSB 		(R/W) default(7F)
FUELGUAGE_REG_ADDR_03 = 0X03	#acc charte LSB 		(R/W) default(FF)
FUELGUAGE_REG_ADDR_04 = 0X04	#charge threshold high MSB 	(R/W) default(FF)
FUELGUAGE_REG_ADDR_05 = 0X05	#charge threshold high LSB 	(R/W) default(FF)
FUELGUAGE_REG_ADDR_06 = 0X06	#charge threshold low MSB 	(R/W) default(00)
FUELGUAGE_REG_ADDR_07 = 0X07	#charge threshold low LSB 	(R/W) default(00)
FUELGUAGE_REG_ADDR_08 = 0x08	#voltage MSB 			(R) default(XX) unknown
FUELGUAGE_REG_ADDR_09 = 0x09	#voltage LSB 			(R) default(XX)
FUELGUAGE_REG_ADDR_0A = 0X0A	#voltage threshold high 	(R/W) default(FF)
FUELGUAGE_REG_ADDR_0B = 0X0B	#voltage threshold low 		(R/W) default(00)
FUELGUAGE_REG_ADDR_0C = 0X0C	#temperature MSB 		(R) default(XX)
FUELGUAGE_REG_ADDR_0D = 0X0D	#temperature LSB 		(R) default(XX)
FUELGUAGE_REG_ADDR_0E = 0X0E	#temperature threshold high 	(R/W) default(FF)
FUELGUAGE_REG_ADDR_0F = 0X0F	#temperature threshold low 	(R/W) default(00)


bus = smbus.SMBus(DEVICE_BUS)

class i2cCommand:

	def __init__(self):

		global SAMPLES
		global battery_capacity
		global fuel_guage_temperature
		global battery_voltage
		global sample_delay

		global BAT1_V_MON
		global BAT2_V_MON

		global bus
		global DEVICE_ADDR
		global FUELGUAGE_ADDR
		global DEVICE_REG_ADDR_ID
		global DEVICE_REG_ADDR_08
		global DEVICE_REG_ADDR_09
		global DEVICE_REG_ADDR_0A
		global DEVICE_REG_ADDR_45

		global FUELGUAGE_REG_ADDR_00 #= 0X00 #(reg name A)
		global FUELGUAGE_REG_ADDR_01 #= 0X01 #(reg name B)
		global FUELGUAGE_REG_ADDR_02 #= 0X02 #(reg name C)
		global FUELGUAGE_REG_ADDR_03 #= 0X03 #(reg name D)
		global FUELGUAGE_REG_ADDR_04 #= 0X04 #(reg name E)
		global FUELGUAGE_REG_ADDR_05 #= 0X05 #(reg name F)
		global FUELGUAGE_REG_ADDR_06 #= 0X06 #(reg name G)
		global FUELGUAGE_REG_ADDR_07 #= 0X07 #(reg name H)
		global FUELGUAGE_REG_ADDR_08 #= 0X08 #(reg name I)
		global FUELGUAGE_REG_ADDR_09 #= 0X09 #(reg name J)
		global FUELGUAGE_REG_ADDR_0A #= 0X0A #(reg name K)
		global FUELGUAGE_REG_ADDR_0B #= 0X0B #(reg name L)
		global FUELGUAGE_REG_ADDR_0C #= 0X0C #(reg name M)
		global FUELGUAGE_REG_ADDR_0D #= 0X0D #(reg name N)
		global FUELGUAGE_REG_ADDR_0E #= 0X0E #(reg name O)
		global FUELGUAGE_REG_ADDR_0F #= 0X0F #(reg name P)


		GPIO.output(BAT1_V_MON, False)	#set both n-chan mosfets to off for multiplexing I2C clk line
		GPIO.output(BAT2_V_MON, False)

		return None


	def 	set_fuelguage_control_reg(self, adc_mode_bit7_6, prescaler_bit5_3, al_cc_bit2_1, shutdown_bit0):



		#set bit7_6-11 (0xC0) for auto mode temp and volt convertion every 1 second
		#bit7_6-10 (0x80) for manual volt mode
		#bit7_6-01 (0x40) for manual temp mode
		#bit7_6-00 (0x00) for sleep mode

		#leave bit5_3-111 for prescaler default 128
		#equation 2^(4*B5 + 2*B4 + B3) ie. 2^(4*1 + 2*1 + 1) = 2^7 = 128

		#leave bit2_1-10 for output alert mode (can connect to pin on rasp pi compute module


		#leave bit0-0 as the 3V3 power will be turned off by user, but current drain will not be monitored when 3V3 off
		
		

		#hardcode for now	
		adc_mode_bit7_6 = 0xC0
		prescaler_bit5_3 = 0x38
		al_cc_bit2_1 = 0x04
		shutdown_bit0 = 0x00
		

		value = adc_mode_bit7_6 | prescaler_bit5_3 | al_cc_bit2_1 | shutdown_bit0

		print "set_fuel_gauage_control_reg value: ", hex(value)

		for i in range(2):

			if i == 0:
				print("Initializing Battery 1 Monitor")
				GPIO.output(BAT1_V_MON, GPIO.HIGH)
				GPIO.output(BAT2_V_MON, GPIO.LOW)
			else:
				print("Initializing Battery 2 Monitory")
				GPIO.output(BAT1_V_MON, GPIO.LOW)
				GPIO.output(BAT2_V_MON, GPIO.HIGH)
			try:

				bus.write_byte_data(FUELGUAGE_ADDR, FUELGUAGE_REG_ADDR_01, value)
			
			except IOError as e:
				
				print("Could not connect to battery monitor: (set_fuelguage_control_reg) "), i

		'''
		print "checking fuel_gauage_control_reg value: "
		
		(device_str_ctrl) = bus.read_byte_data(FUELGUAGE_ADDR, FUELGUAGE_REG_ADDR_01)

		print "ctrl reg: ", hex(device_str_ctrl)	
		'''

		time.sleep(0.1)	

		return 0

	def 	fuelguage_check_volt(self, battery_sel):

        if battery_sel == 1:

            GPIO.output(BAT1_V_MON, GPIO.HIGH)
            GPIO.output(BAT2_V_MON, GPIO.LOW)
            
        elif battery_sel == 2:

            GPIO.output(BAT1_V_MON, GPIO.LOW)
            GPIO.output(BAT2_V_MON, GPIO.HIGH)

        else:

            GPIO.output(BAT1_V_MON, GPIO.LOW)
            GPIO.output(BAT2_V_MON, GPIO.LOW)
            

                        

		#voltage is 14bit (reg's I and J) and temperature 10bit (reg's M and N)resolution 
		#convert I and J to 16bit variable, then (value / 65535) x 6V = Voltage 

		#read registers I and J (8 and 9 sequentially)
		voltage_msb = float(0.0)
		voltage_lsb = float(0.0)
		temp_msb = float(0.0)
		temp_lsb = float(0.0)

		#all_regs = bus.read_i2c_block_data(FUELGUAGE_ADDR, FUELGUAGE_REG_ADDR_08, 16)
		#status, control, acc_msb, acc_lsb, chrgthhi_msb, chrgethhi_lsb, chrgthlow_msb, chrgthlow_lsb, voltage_msb, voltage_lsb, voltth_msb, voltth_lsb, temp_msb, temp_lsb, tempth_msb, tempth_lsb = all_regs
		#print "all regs1: ", all_regs 

		battery1_status_flag = 0
		battery2_status_flag = 0

		try:

			voltage_msb = SMBus(1).read_byte_data(DEVICE_ADDR, FUELGUAGE_REG_ADDR_08)
			voltage_lsb = SMBus(1).read_byte_data(DEVICE_ADDR, FUELGUAGE_REG_ADDR_09)
			#print "voltage_msb: ", voltage_msb
			#print "voltage_lsb: ", voltage_lsb

			temp_msb = SMBus(1).read_byte_data(DEVICE_ADDR, FUELGUAGE_REG_ADDR_0C)
			temp_lsb = SMBus(1).read_byte_data(DEVICE_ADDR, FUELGUAGE_REG_ADDR_0D)
			#print "temp_msb: ", temp_msb
			#print "temp_lsb: ", temp_lsb

			if battery_sel == 1:
				battery1_status_flag = 1
			else:
				battery2_status_flag = 1

		except IOError as e:
				
			print("Could not read to battery voltage monitor: "), battery_sel 
				
			if battery_sel == 1:
				battery1_status_flag = 0
			else:
				battery2_status_flag = 0	


		#(voltage_reg_I_J) = bus.read_i2c_block_data(FUELGUAGE_ADDR, FUELGUAGE_REG_ADDR_08, 2)
		#voltage_msb = bus.read_byte_data(FUELGUAGE_ADDR, FUELGUAGE_REG_ADDR_08)
		#voltage_lsb = bus.read_byte_data(FUELGUAGE_ADDR, FUELGUAGE_REG_ADDR_09)

		#print "voltage_reg_I_J: ", voltage_reg_I_J
		#voltage_msb, voltage_lsb = voltage_reg_I_J

		#print "voltage_msb: ", voltage_msb
		#print "voltage_lsb: ", voltage_lsb

		if (battery_sel == 1 and battery1_status_flag == 1) or (battery_sel == 2 and battery2_status_flag == 1):
			

			voltage_16bit = float(0.0)
			voltage_msb = voltage_msb << 8
			#print "voltage_msb: ", hex(voltage_msb)
			#print "voltage_lsb: ", hex(voltage_lsb)

		
			voltage_16bit = float(voltage_msb | voltage_lsb)		

			#print "voltage_16bit: ", voltage_16bit


			#voltage at battery
			battery_volt = float(0.0)
			divisor = float(65535.0)
			multiplier = float(6.0)
			battery_volt = ( voltage_16bit / divisor ) * multiplier		

			##print "battery_volt: ", battery_volt

			battery_capacity_percent = 0
		

			#battery capacity reference table
			if battery_volt >= 4.20:
				battery_capacity_percent = 100

			elif  battery_volt < 4.20 and battery_volt >= 4.15:
				battery_capacity_percent = 98

			elif  battery_volt < 4.15 and battery_volt >= 4.10:
				battery_capacity_percent = 95

			elif  battery_volt < 4.10 and battery_volt >= 4.00:
				battery_capacity_percent = 85

			elif  battery_volt < 4.00 and battery_volt >= 3.95:
				battery_capacity_percent = 75

			elif  battery_volt < 3.95 and battery_volt >= 3.90:
				battery_capacity_percent = 65

			elif  battery_volt < 3.90 and battery_volt >= 3.85:
				battery_capacity_percent = 55

			elif  battery_volt < 3.85 and battery_volt >= 3.80:
				battery_capacity_percent = 50

			elif  battery_volt < 3.80 and battery_volt >= 3.75:
				battery_capacity_percent = 48

			elif  battery_volt < 3.75 and battery_volt >= 3.70:
				battery_capacity_percent = 44

			elif  battery_volt < 3.70 and battery_volt >= 3.65:
				battery_capacity_percent = 38

			elif  battery_volt < 3.65 and battery_volt >= 3.60:
				battery_capacity_percent = 36

			elif  battery_volt < 3.60 and battery_volt >= 3.55:
				battery_capacity_percent = 34

			elif  battery_volt < 3.55 and battery_volt >= 3.50:
				battery_capacity_percent = 31

			elif  battery_volt < 3.50 and battery_volt >= 3.45:
				battery_capacity_percent = 29

			elif  battery_volt < 3.45 and battery_volt >= 3.40:
				battery_capacity_percent = 26

			elif  battery_volt < 3.40 and battery_volt >= 3.35:
				battery_capacity_percent = 24

			elif  battery_volt < 3.35 and battery_volt >= 3.30:
				battery_capacity_percent = 23

			elif  battery_volt < 3.30 and battery_volt >= 3.25:
				battery_capacity_percent = 21

			elif  battery_volt < 3.25 and battery_volt >= 3.20:
				battery_capacity_percent = 18

			elif  battery_volt < 3.20 and battery_volt >= 3.15:
				battery_capacity_percent = 16

			elif  battery_volt < 3.15 and battery_volt >= 3.10:
				battery_capacity_percent = 15

			elif  battery_volt < 3.10 and battery_volt >= 3.05:
				battery_capacity_percent = 11

			elif  battery_volt < 3.05 and battery_volt >= 3.00:
				battery_capacity_percent = 10
			else:
			      battery_capacity_percent = 0
		

			##print "battery_capacity_percent: ", battery_capacity_percent


			#temperature conversion to celcius ------------------------------------------------

			#print "temp_msb: ", temp_msb

			#print "temp_lsb: ", temp_lsb

			temperature_16bit = float(0.0)
			temp_msb = temp_msb << 8

			#print "temp_msb: ", hex(temp_msb)

			temperature_16bit = float(temp_msb | temp_lsb)	

			#print "temperature_16bit: ", temperature_16bit

			#voltage at battery
			temperature_kelvin = float(0.0)
			temperature_multiplier = float(600.0)
			temperature_kelvin = ( temperature_16bit / divisor ) * temperature_multiplier	

			##print "temperature_kelvin: ", temperature_kelvin

			temperature_celcius = float(0.0)

			temperature_celcius = temperature_kelvin - 273.0

			##print "temperature_celcius: ", temperature_celcius

		

		elif (battery_sel == 1 and battery1_status_flag == 0) or (battery_sel == 2 and battery2_status_flag == 0):

			print("No measurements available for battery: "), battery_sel
			battery_volt = 0.0
			battery_capacity_percent = 0
			temperature_celcius = 0.0

		return battery_capacity_percent, temperature_celcius, battery_volt




		


testpoll = i2cCommand()
 
testpoll.set_fuelguage_control_reg(0xC0, 0x80, 0x10, 0x00)

while 1:

	battery_capacity = 0.0
	fuel_guage_temperature = 0.0
	battery_voltage = 0.0
	battery_capacity_temp = 0.0
	fuel_guage_temperature_temp = 0.0
	battery_voltage_temp = 0.0

	for i in range(int(SAMPLES)):

		battery_temperature = testpoll.fuelguage_check_volt(1) #1 for battery 1, 
		battery_capacity_temp, fuel_guage_temperature_temp, battery_voltage_temp = battery_temperature
		battery_capacity = battery_capacity + battery_capacity_temp
		fuel_guage_temperature = fuel_guage_temperature + fuel_guage_temperature_temp
		battery_voltage = battery_voltage + battery_voltage_temp
		time.sleep(sample_delay)
		
	battery_capacity = battery_capacity / SAMPLES
	fuel_guage_temperature = fuel_guage_temperature / SAMPLES
	battery_voltage = battery_voltage / SAMPLES


	print "-----------------------------------------------"
	print "Battery 1:"
	print "Battery Capacity Percent: ", battery_capacity
	print "Fuel Guage Temperature: ", fuel_guage_temperature
	print "Battery Voltage: ", battery_voltage
	time.sleep(2.0)
	print "-----------------------------------------------"


	battery_capacity = 0.0
	fuel_guage_temperature = 0.0
	battery_voltage = 0.0
	battery_capacity_temp = 0.0
	fuel_guage_temperature_temp = 0.0
	battery_voltage_temp = 0.0

	for i in range(int(SAMPLES)):

		battery_temperature = testpoll.fuelguage_check_volt(2) #1 for battery 2, 
		battery_capacity_temp, fuel_guage_temperature_temp, battery_voltage_temp = battery_temperature
		battery_capacity = battery_capacity + battery_capacity_temp
		fuel_guage_temperature = fuel_guage_temperature + fuel_guage_temperature_temp
		battery_voltage = battery_voltage + battery_voltage_temp
		time.sleep(sample_delay)
		
	battery_capacity = battery_capacity / SAMPLES
	fuel_guage_temperature = fuel_guage_temperature / SAMPLES
	battery_voltage = battery_voltage / SAMPLES


	print "-----------------------------------------------"
	print "Battery 2:"
	print "Battery Capacity Percent: ", battery_capacity
	print "Fuel Guage Temperature: ", fuel_guage_temperature
	print "Battery Voltage: ", battery_voltage
	time.sleep(2.0)
	print "-----------------------------------------------"
	print "*************************************************************************"
	print "*************************************************************************"

Credits

Mark Chin

Mark Chin

5 projects • 10 followers
Entrepreneur and Innovator of embedded systems, RFID and IoT.

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