BQ78350-R1: BQ78350 _ R3

Hardik Mehta

Part Number: BQ78350-R1
Other Parts Discussed in Thread: BQ78350, BQSTUDIO

Tool/software:

Hi Team,

we are using BQ78350.

In our application we are shutdown the BQ78350. after that when we again wake up, we see the OCV estimation and in next cycle we are facing SOC jump issue at EDV2. Our Actual capacity is 50 AH, but I am configuring it 46.5 AH in both Design & FCC because I want to reduce the voltage window in other word to reduce the DOD. but I OCV estimation use a full voltage window from 4.18 to 2.5 cell voltage. Need support on it.

1. Design & FCC = 46.5 AH

2. DOD at EDV 2 = 15232

3. Battery Low % = 7%

how can I reduce the voltage window limit in OCV estimation.

Regards,

Hardik

8 months ago

0 Jose Couso 8 months ago

TI__Mastermind 27321 points

Hi Hardik,

I would set FCC to the true usable capacity by manually coulomb counting (calculating passed charge). Then, increase terminate voltage (cut off voltage) to where you get exactly 46.5 AH.

0 Hardik Mehta 8 months ago in reply to Jose Couso

Prodigy 50 points

Hi Jose,

Thanks for Quick update.

Can you help me how I can increase terminate voltage or it is a charge termination voltage.

& how It will Update the OCV.

Because for me issue is in lower range. I want OCV estimation at around 2.9 Cell voltage SOC become zero. but as per parameter it is going up to 2.7 Cell voltage.

0 Jose Couso 8 months ago in reply to Hardik Mehta

TI__Mastermind 27321 points

Hello Hardik,

Please note the gauge does not use OCV table all the time. It only uses OCV at wakeup from shutdown. This is the difference between IT and this particular CEDV gauge. Note other CEDV gauges do not use OCV table at all.

As for how to edit the terminate voltage parameters. Please navigate to Data Memory in bqStudio and change the value to the following registers.

Terminate voltage = lowest discharge voltage where gauge reports 0% for SOC. This one is fixed EDV 0.

Reference to: https://www.ti.com/lit/an/slua924/slua924.pdf

and

Where do I start with a CEDV gauge?

0 Hardik Mehta 8 months ago in reply to Jose Couso

Prodigy 50 points

Hi Jose,

so as per your suggestion, if I want to limit based on Voltage window then I have to use Fixed EDV & in that based on Current & temperature compensation will not happen.

still, I will Test it

Power management

Power management forum

BQ78350-R1: BQ78350 _ R3