bq40z60 stopped charging at 4.0V ?

Lankor Liu99

Other Parts Discussed in Thread: BQ40Z60

Hi, Tom,

My board using bq40z60 (designed based on EVM) will stop charging the battery before battery is full. I tested 3 times, all of them were stopped at around 3.9V or 4.0V. When the charging stopped, I captured the registers image as below:

- Battery status changed from 0x4080 to 0x8080. It means "OCA" -Over Current Alarm is set. Why?

- Operation Status A register changed from 0x0197 to 0x4993. "XCHG" =1, charge disabled; "SS"=1:Safety Mode actived. Why?

- Charging status register changed from 0x0008 to 0x0308. "CVR" =1, "CCR" =1. Why?

BTW, I am using 3S1P LiPo 5000mAH battery pack. I changed its cell capacity from defaulted 4400mAH to 5000mAH.

Could you please help to find out what the problem it may be? Thanks,

over 9 years ago

0 ThomasCosby over 9 years ago

TI__Guru 73830 points

Lankor
There is probably a parameter setup problem. Could you export a .srec file from the device and attach it to this forum posting?
Tom

0 Lankor Liu99 over 9 years ago in reply to ThomasCosby

Intellectual 300 points

Hi, Tom,

I uploaded the .srec file and a charging log file. When charging was stopped, the highest of cell voltage is around 4.086V. I think it is little bit low, I am thinking the battery cells voltage are supposed to be 4.150V (closed to 4.2V) when it is fully charged for a new battery.

Another question, In our system design the total load will be very high (>10A). So the most of load(for motor) will be connected to battery output rather than VSYS (but VSYS will be the system load - except the motor load). That mean the gas gauging will be not be used when discharging the battery. Is it OK? Should I disable the gas gauging?

Thanks,

BTW, I am trying to attached .srec and .txt files, but it is not allowed me to post. I have to remove the attachments first. How to attach files?

0 Lankor Liu99 over 9 years ago in reply to Lankor Liu99

Intellectual 300 points

Firmware.rar

0 Lankor Liu99 over 9 years ago in reply to Lankor Liu99

Intellectual 300 points

Hi, Tom,

I used IE instead of the Chrome to upload the firmware and test log file successfully. Please help to double check. Thanks.

L.

0 ThomasCosby over 9 years ago in reply to Lankor Liu99

TI__Guru 73830 points

Lankor

Your log data shows that you are charging in the Recommended Temperature (RT) range and the Charging Voltage is set to 4100mV / cell. You can increase this Charging Voltage to charge to a higher voltage. The other parameters look okay.

Also, we found that there was an error in a hidden register setting that will affect OCV measurements after charge. The attached .bqz file opens the hidden parameter to allow OCV measurements after charge.

Place the .bqz file in this directory. C:\ti\BatteryManagementStudio\config
Go to the Data Memory > Settings > Configuration and select the IT Gauging 2 Configuration. Set bit 6 (OCVCHG_EN) to 1 and press the Write to Data Memory button. Do not change any other bits in that register.

Tom

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/4600_5F00_0_5F00_13_2D00_bq40z60.bqz

0 ThomasCosby over 9 years ago in reply to ThomasCosby

TI__Guru 73830 points

Lankor
I still have your srec file programmed in my EVM and just happened to notice that the chemistry data is corrupted. You will need to reload the ChemID to correct it. You cannot see the OCV table, but check the Ra table and you will see that it has negative values.
Tom

0 Lankor Liu99 over 9 years ago in reply to ThomasCosby

Intellectual 300 points

Hi, Tom,

Based on the suggestion Ichanged the RT Charging from 4100mV to 4200mV, it can charge the battery to 4.2V now. Thanks.

But when using the .bqz file you provided, I can't find the " IT Gauging Configuration 2" register. I can see "IT Gauging Configuration" register only. Is there any other way to read and write this hidden register?

For the chemistry ID, I use the defaulted ID which is "LION". I am using below LiPo battery. It must be ok, right?

http://www.amazon.com/Venom-5000mAh-Battery-RC-Quadcopter/dp/B0027G9F9M/ref=sr_1_2?ie=UTF8&qid=1447165364&sr=8-2&keywords=lipo+venom+4s

Thanks for your help!

0 ThomasCosby over 9 years ago in reply to Lankor Liu99

TI__Guru 73830 points

Lankor,

The gauge should work with that battery, but I do not know which ChemID matches it. You can use the GPC Chem tool find a match.

I checked the .bqz and the IT Gauging 2 Configuration register should be available and located just below the IT Gauging Configuration register.

Tom

0 Lankor Liu99 over 9 years ago in reply to ThomasCosby

Intellectual 300 points

Hi, Tom,

Thanks for your help! I did some test and these setting are looking good.

Now I need to have the MCU to talk to the charger to get the voltage/current/capacity etc info. What is the bq40Z60's SMBus address? I saw you mentioned that its address is 16 in another post, is it decimal 16 or hex 0x16?

Thanks,

L.

0 ThomasCosby over 9 years ago in reply to Lankor Liu99

TI__Guru 73830 points

That would be 16H. 0001011 + the R/W bit

0 Lankor Liu99 over 9 years ago in reply to ThomasCosby

Intellectual 300 points

Thanks, Tom.

When I used the read word command to read battery voltage (0x09), I got below decoded data from the waveform:
0x16 0x09 0x17 0x32 0x41
I understand the first one 0x16 is the SMBus address; Second 0x09 is the command, and the 0x4132 = 16690V is the sum of measure cell voltage which is correct.

But what is the 0x17? Based on the Read Word Protocol, it is supposed to be the Slave Address that is 0x16, right? Why is it 0x17 here?

Thanks,

L.

0 ThomasCosby over 9 years ago in reply to Lankor Liu99

TI__Guru 73830 points

The 17 means that they are reading data from the gauge. Here is a document that should help with the various words.

6445.SMBus made simple_v6.pdf

0 Lankor Liu99 over 9 years ago in reply to ThomasCosby

Intellectual 300 points

Got it. The address is the same 0b0001011x, only the last bit is different which is for writing 0x16 and reading 0x17. Thanks.

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bq40z60 stopped charging at 4.0V ?