bq27425-G2A EVM questions

Hi Jason,

Yes, please update those parameters. Note that after changing these parameters, you will need to run another learning cycle for Qmax to update to the new value.

Best,
Justin

Hi Justin, 

Thanks for the input. I appreciate the help. I have a few follow up questions:

1. Is there a good manual on how to operate the GDK in more detail than it's user guide? I would definitely would prefer to RTFM, but I can't seem to find a good one. The below questions are just a collection of things that don't seem to work as I expected.... so I am obviously missing something.  

2. Running the Learning Cycle as you recommended: What is process to run the learning cycle? I get error message after discharge and relax that says the RUP_DIS bit is not set as expected. I was getting this when I first started the test, but found that I can get past this by UNSEALing the part before starting the Learning Cycle.  Seems like by the time the Learning cycle finishes relaxing the part reseals itself. Also, is there a way to shorten the relaxing period to something shorter? Is this recommended?

3. General Procedure to create a golden image: Assuming a factory fresh EVM, what would you recommend doing to generate a golden file? I would figure something like the below. Thoughts?

a. Setup GDK, EVM according to GDK user's guide

b. Program Design Capacity, Design Energy, Termination Voltage, Taper current, OpConfig (perhaps some SOC thresholds registers) 

c. Run a Learning Cycle.

d. Run a dozen AutoCycles loops to verify performance. 

4. bqSTUDIO stability: Specifically, I am trying to log multiple charge/discharge cycles with the tool. Unfortunately, I get EV2xx timeouts. I have tried logging using the Watch, Graph and 'Start Log' button in the Registers plugin. The results are about the same. Do you have any tips and tricks?

Thanks!

Jason

update/clarification

3 ... step 'e' would be to save off the golden image. step 'f' would be to program other parts.

4 ... When I get timeouts, the DashBoard plugin also grays-out much of the icons: the GDK summary, the IC icon, the battery and current sensor. I have to disconnect the USB, power down the GDK and restart the bqSTUDIO to get it to work again.

okay, last update, I promise :)

I updated the GDK firmware to 0.18... although this appears to only apply to the on-board EV2400. I did not see an update to the GDK mcu.

Hi Jason,

For the learning cycle, your device must be unsealed. You should only seal the device when it is ready for production. With that being said, here are some tips for the learning cycle. 

1. Discharge the battery to fully empty

2. Relax for 5 hours and send IT_Enable and Reset Command. Forgetting to send IT_Enable is a common mistake.

3. Charge battery to full (FC bit  should get set to 1 before the charger stops)

4. Relax for 2 hours

5. Discharge to empty at C/10 rate. This is where the resistance tables will update. 

6. Relax for 5 hours

The relaxations are important and should not be shortened. They will ensure that you are giving enough time for the voltage to stabilize and allow you to take a Qmax measurement.

After running a successful learning cycle, you can create your golden file in the golden image tab and program the other devices as you stated.

As far as logging goes, I recommend using the "Start Log" button without the other features you mentioned.

Best,

Justin 

Hi Justin, 

This is immensely helpful. Thank you. 

Last thing: What is "IT_ENABLE"? I don't see this command/register/bit for the bq27425. 

Thanks again, 

Jason

Hi Jason,

Actually for this device, you do not need to send IT_Enable because it is always enabled. You can just follow steps in my previous post and ignore sending IT_Enable.

Best,
Justin