BQ27441-G1: BQ27441-G1B Fuel gauge calibration

Shani Ravaliya

Part Number: BQ27441-G1
Other Parts Discussed in Thread: EV2400, BQSTUDIO

Hi Team, We are using bq27441-G1B part in one of our Low power design and want to measure minimum 500uA current, we are following document SLUA792 and are using the BQstudio tool , EV2400 (PC Interface Board). Below are the parameters we are using Paste table here. As we are multiplying the battery capacity, I am not able to understand how system will know the correct capacity and give correct readings.

We are using 100mE current sense resistor.

PARAMETER	CLASS	SUBCLASS	STANDARD VALUE	SCALED VALUE (STANDARD VALUE *10)
Taper Capacity (mAh)	Configuration	Charge Termination	45	450
Taper Rate (0.1 Hr Rate)	Gas Gauging	State	96	96
Chg Current Threshold	Gas Gauging	Current Thresholds	30	30
Dsg Current Threshold	Gas Gauging	Current Thresholds	2	2
Quit Current Threshold	Gas Gauging	Current Thresholds	23	23
Design Capacity (mAh)	Gas Gauging	State	470	4700
Design Energy (mWh)	Gas Gauging	State	1786	17860
V at Chg Term (mV)	Chemistry Info	Chem Data	4300	4300
Taper Voltage (mV)	Chemistry Info	Chem Data	4200	4200

over 4 years ago

0 Nick Brylski over 4 years ago

TI__Mastermind 19195 points

Hi Shani,

Can you describe the issue you are seeing in more detail.

Best,

0 Shani Ravaliya over 4 years ago in reply to Nick Brylski

Prodigy 190 points

Hi Nick,

Actually, previously we tried to calibrate fuel gauge but in BQstudio it was not showing our system sleep current which is ~1.5-3.0mA, whenever system current beyond 5mA we can see that current on BQstudio.

that time we were used 10mE current sense resistor.

0 Wyatt Keller over 4 years ago in reply to Shani Ravaliya

TI__Guru** 105590 points

Hello Shani,

The default deadband current is set at 5mA, it will report 0mA with +5mA or -5mA. You may need to edit the deadband current for your low current application, especially if it is scaled.

Sincerely,

Wyatt Keller

0 Shani Ravaliya over 4 years ago in reply to Wyatt Keller

Prodigy 190 points

Hello Wyatt Keller,

Thank you!!

Can you please help me to understand why by default deadband current set to 5mA ? Is there any significant?
Is there any impact in calibration if we set it to 0mA.

0 Wyatt Keller over 4 years ago in reply to Shani Ravaliya

TI__Guru** 105590 points

Hello Shani,

We set it to a default value to reduce the chance of false readings over time. I would keep it at some value higher than 0mA, but it may require testing to make sure you get good readings when 0mA or low current is flowing.

Sincerely,

Wyatt Keller

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BQ27441-G1: BQ27441-G1B Fuel gauge calibration