BQ27441-G1: How to enable IT (0x21)

Hi Andy,
Please find the application reports below to answer your questions.

www.ti.com/.../slua801.pdf

www.ti.com/.../slua544.pdf

Best,
Haidar

The reports did not answer my question about the "enable IT"  command.      I looked at the data sheets for other BQXXXXX chips and they do have it at offset 0x21,  but the technical reference for the BQ27441 skips right over it.

I have given up trying to get the golden image using my hardware and firmware and have decided to buy the Gauge Development Kit along with a Eval board for the BQ27441.   I thought from the quick-start guide that I could just program a few parameters and the chip would learn everything it needs.   But the more charge-discharge cycles I run the worse it gets.   I have a production line stopped and I have wasted enough time.

Hi Andy,

the bq2274xx devices have impedance track already enabled by default. You are not to enable it. If you are not getting any any improvements with continuous cycling it means the default chem id isn't a close match for your cell and you may be unable to use a ROM based gauge. Did you run a rel-dis-rel test and use our gpc tool to determine if a ROM based gauge would be ideal for your application?

pls use this tool to determine if a rom-based gauge is  suitable for your battery.

thanks

Onyx

Onyx,

I did not run the gpc tool. Another engineer who is no longer at the company selected this part. The battery is a Panasonic NCR18650B. Do you know if it has the right chemistry ? Is there a list of commonly used batteries and their chem id ?

I ran a learning cycle using the gauge development kit and got the following error: Error: [RUP_DIS / RDIS: Not Clear]. Any idea why ?

If I need to run the gpc tool, can I collect it using the GDK ?

Thanks
Andy

Hi Andy, 

1. Attached file is the chemID update. You could find Panasonic NCR18650B in it. As bq27441 support fixed chemID, you need to check whether the IC match your battery.

2. When do self-learning cycle, you need to send reset to make RUP_DIS clear to begin.

3.Yes, you could collect discharge-charge data using GDK.

Thanks.

Best regards,

Sammi Shang

Sammi,

1. I did not get any attachment.
2. I tried clicking on RESET, it said the part has to be unsealed. I unsealed it and then clicked RESET. I tried SOFT RESET. I tried cycling power. I don't know what I did right but eventually the RUP_DIS bit got cleared. But when I tried to do a learning cycle I immediately got the error message: "The RUP_DIS / RDIS bit must be set ON to Continue"

Thanks,
Andy

Andy,

pls run the gpc chem tool first with the aid of your gdk if you have one. If you do not pls do the test manually using a power supply and electronic load. This will allow you know if you can even use the bq27411 for your appplication and if you will ever get a suceessful learning cycle. if your battery is not a match for the default chem ids programmed in the gauge you will never get a successful learning cycle.

If perhaps you do the test in the gpcchem user manual and one of the default chem id is a match, then do learning cycle using the attached app note.

8666.LearningCycleOverview_bq274xx.pdf

it is for a similar rom device and is applicable to yours as well.

thanks

Onyx

I ran the test from the GDK tab in bqStudio. I set it up for one cycle, starting with charging. charge current=1000mA, taper current=100mA, relax time=120min. I set up the discharge for constant current, 340mA, Term Voltage=2900mV, relax time=300 minutes. Yesterday, I started the log from the Registers tab. When I checked the log this morning, it charged for about 10 minutes and didn't do anything after that. WHY ?

I guess I don't understand. Isn't there a list of battery part numbers and what chips they will work with ? The Panasonic NCR18650B is a very common battery. Why should I have to do this ? If you look at the previous response from Sammi Shang, he referred to a database (which I never got).

hi Andy,

Sorry for the challenges you are experiencing using this chip and we would like to have you move forward with your design. My colleague may have already reached out to you directly but if he hasn't, i will send you an email as well.

The data base of all the chemistries can be found by selecting any of the flash based gauge, eg bq27520 when you start bqstudio without your gauge connected and click the chemistry tab. I have also attached the excel sheet containing the cells and your chem ids.

Note that this gauge you chose only supports 3 default chem ids and similar batteries that match their profile. You determine that using the gpc. Given your situation is dire we will have to work directly with you and not through the forums make this ROM gauge work for your application.

thanks
Onyx

chemid.xlsx

see attached. I have sent you a friend request.

thanks

Onyx