Forums

Hey David,

Ive upgraded the firmware on the EVM like you mentioned, and fixed a small number of configuration details that I missed before, and even after 3 or 4 more attempts I still can not get to an Update Status of 1. One thing ive noticed is that the RUP_DIS bit is set from the beginning, and does not clear until the relaxation time after the initial discharge before the IT is enabled. Ive read that the learning cycle is disrupted once this bit is set, but I cannot find anything that explains why it sets. Even right after I click the reset button on step 5 of bqEASY it is still set from the start. Can you think of any reason why this would be happening, or have any other suggestions as to why I am not able to complete a learning cycle? Thanks for your continued support!

Bryan

I'm experiencing the very same problems here with BQ27510-G1. And after just a few weeks, we seem to be lucky compared to others trying "3-4 months" already ;-)

Cycle update doesn't change either. Not even to a 1. And it doesn't even give the measured capacity.

It would be very helpfull, if the device (or software) could give a hint, of why it didn't want to accept a valid cycle. Just stating "didn't work" (my translation of the bit not changing to a 1) leaves me to making wild guesses about possible reasons. And try again and again. Maybe a future improvement of the firmware / BQeasy-software could detail on the reasons. It then would more deserve the name "BQeasy "...

As David has been emphasizing, the charge and discharge currents should be around C/2 and C/5. This would require my charger to charge with 3000mA. Our charger simply doesn't allow such high currents (max power dissipation!). Is this really an issue? Is a 1000mA charge ok? Recommended charging curves for Li-Ion batteries go from a constant current to a constant voltage charge. So, reducing the charging current is an inherent feature of the charger. Could this be the reason for the BQ not to accept the cycle as valid? (I would assume, the battery monitor would rather monitor, "as is" instead of insisting of "having an attitude").

Changing parameters in the BQeasy configuration often produces a runtime error when writing to the BQ. What is "runtime error 6, overflow " indicating? I would like to make the configuration, that I think suits best my setup. But how can I, if the software doesn't tell me, where the problems with my parameters is?

As temperature seems to be an issue, can the max. allowed temperature limit be changed, after the battery has been fully charged, or do I need to discharge / charge all the way again? (Charging time, waiting time, discharging time, waiting time: 2 working days...).

Is there a way to speed things up somehow? I have seen, the BQ is counting relaxation time, charging time etc. Can the BQ be fooled, to go with a reduced waiting time? Or does it insist on the very last second? I can go with a reduced accuracy of capacity prediction, but I need a sucess now! Is there a way to force the cycle count to 1, if I know the battery is actually full?

Our charger is reducing charge (tickle charge) to a few 100 µA. Is this low enough for the BQ to detect a full battery?

It seems like the voltage measurements are sensitive enough to detect changes of 4µV.  When discharging in a real-life device, some digital noise on the power paths is a common issue. Could that noise be a reason for the problem?

Termination voltage from the charger is nominally 4100mV. Accuracy is +/-50mV approx. Should I reduce this value in the configuration to make sure, this voltage is achieved in every circumstance?

Thanks for your help!

Phil

I'm experiencing the very same problems here with BQ27510-G1. And after just a few weeks, we seem to be lucky compared to others trying "3-4 months" already ;-)

Cycle update doesn't change either. Not even to a 1. And it doesn't even give the measured capacity.

It would be very helpfull, if the device (or software) could give a hint, of why it didn't want to accept a valid cycle. Just stating "didn't work" (my translation of the bit not changing to a 1) leaves me to making wild guesses about possible reasons. And try again and again. Maybe a future improvement of the firmware / BQeasy-software could detail on the reasons. It then would more deserve the name "BQeasy "...

As David has been emphasizing, the charge and discharge currents should be around C/2 and C/5. This would require my charger to charge with 3000mA. Our charger simply doesn't allow such high currents (max power dissipation!). Is this really an issue? Is a 1000mA charge ok? Recommended charging curves for Li-Ion batteries go from a constant current to a constant voltage charge. So, reducing the charging current is an inherent feature of the charger. Could this be the reason for the BQ not to accept the cycle as valid? (I would assume, the battery monitor would rather monitor, "as is" instead of insisting of "having an attitude").

Changing parameters in the BQeasy configuration often produces a runtime error when writing to the BQ. What is "runtime error 6, overflow " indicating? I would like to make the configuration, that I think suits best my setup. But how can I, if the software doesn't tell me, where the problems with my parameters is?

As temperature seems to be an issue, can the max. allowed temperature limit be changed, after the battery has been fully charged, or do I need to discharge / charge all the way again? (Charging time, waiting time, discharging time, waiting time: 2 working days...).

Is there a way to speed things up somehow? I have seen, the BQ is counting relaxation time, charging time etc. Can the BQ be fooled, to go with a reduced waiting time? Or does it insist on the very last second? I can go with a reduced accuracy of capacity prediction, but I need a sucess now! Is there a way to force the cycle count to 1, if I know the battery is actually full?

Our charger is reducing charge (tickle charge) to a few 100 µA. Is this low enough for the BQ to detect a full battery?

It seems like the voltage measurements are sensitive enough to detect changes of 4µV.  When discharging in a real-life device, some digital noise on the power paths is a common issue. Could that noise be a reason for the problem?

Termination voltage from the charger is nominally 4100mV. Accuracy is +/-50mV approx. Should I reduce this value in the configuration to make sure, this voltage is achieved in every circumstance?

Thanks for your help!

Phil

Hello Charles,

 thanks for your answer.

-- This is what I tried to do. I discharged the battery down to 3400mV (below this voltage, my system will shut down anyway, so this is the lowest voltage the battery will see). I gave it some relaxing time and then started the cycle. If wouldn't want to post the logfile here, it's a bit lengthy ;-)  If you give me your email-adr, I can send it.

I indeed reduced the termination voltage to 4100mV in the configuration. After it reached 4080mV, I forced the charger to shutdown, reducing charging current to 0. I then gave the BQ another 40 mins to "think it over".  Taper voltage is 100mV, so it should have seen a full state.

-- You said, the charger needs to charge, even after the current dropped below the taper current. So, this means, I_charge>0 but < I_taper? How long does it need to see this? How large must this current be?

-- Here's my configuration:

[Device]
Type=0510
Version=0112
DFI Filname=C:\Program Files\Texas Instruments\bq Evaluation Software\Plugins\Device Defaults\bq27510_1_12.dfi
[Setup]
1A_Proj_Name.Project_Name=bqn8mare
[Project]
Name=bqn8mare
[Completion]
1B=True
2A=True
2B=True
2C=True
2D=True
2E=True
2F=True
2G=True
2H=True
3A=True
3B=True
3C=True
3D=True
3E=True
3F=True
4A=True
4B=True
4C=True
[Configuration]
2A_Cell_Char.Num_Parallel_Cells=1
2A_Cell_Char.Nom_Cell_Capacity=5600
2A_Cell_Char.Min_Cell_Vltg=3000
2B_Chg_Params.Max_Chg_Cell_Vltg=4100
2B_Chg_Params.Max_Chg_Taper_Curr=100
2B_Chg_Params.Max_Chg_Temperature=80
2B_Chg_Params.Min_Chg_Temperature=-5
2C_Dsg_Params.Min_Dsg_Cell_Vltg=3400
2C_Dsg_Params.Max_Dsg_Temperature=70
2C_Dsg_Params.Max_Steady_Dsg_Current=1200
2C_Dsg_Params.Min_Active_Dsg_Current=150
2C_Dsg_Params.Initial_Standby_Current=10
2C_Dsg_Params.SOC1_THRSH=150
2C_Dsg_Params.SOCF_SET=90
2C_Dsg_Params.SOCF_CLEAR=120
2D_Reserve_Capacity.Capacity=0
2D_Reserve_Capacity.Capacity_Units_mAh?=True
2E_Load_Characteristic.Is_Constant_Current?=True
2F_Application_Configuration.PFC_Code=0
2F_Application_Configuration.Bat_Low_Active_Low?=False
2F_Application_Configuration.Bat_Gd_Active_Low?=True
2F_Application_Configuration.LOW_GD_FN=0
2G_Rem_Capacity_Method.Is_Constant_Load?=True
2H_Misc_Info.CurrentSenseResistor=10
2H_Misc_Info.ThermistorConfig=1
2H_Misc_Info.Int_Focv=0
2H_Misc_Info.Int_Brem=0
2H_Misc_Info.Soc_Int_Pol=-1
2H_Misc_Info.OpcfgB_Wrtemp=-1
2H_Misc_Info.OpcfgB_Bie=-1

-- As the temperature window seems a concern, I set the limits as wide as possible. I'm using the internal temperature sensor, as the external sensor is connected to the battery charger (I'm aware, that this will reduce accuracy later). Internal temperature of  the BQ never went beyond 47°C.

-- Is there a way to work with an adjustable power supply in order to simulate a real life battery? While this wouldn't give any meaningfull impedance values, it could be a way to get a success in the cycle procedure. I start losing faith, I'll ever see cycle count turn to 2 before xmas...

-- And again: Why doesn't the software SAY, what is wrong? If I tell BQeasy, the battery is full, it IS full. If the BQ believes, some condition is not yet met, I expect it to just tell me.
Like "temperature too high", "cell voltage hasn't reached maximum value", "taper current too high", "cell voltage hasn't stabilized". Is this really asked too much?

-- If TI believes, it's all so easy, would it offer a service to obtain the golden configuration for us? We are willing to pay for it!

Regards,

Phil

 ...another day over, another day hoping in vain. The flags VOK and QEN keep staying zero.

Unless you can point out a reason in my configuration, I'm giving up. I now understand, why competitors advertise their component with "no training cycle needed"...

Please email a configuration, that you think will work for my battery data. I'm willing to test everything, if there is a realistic chance, the counter will finally go upwards.

Regards, Phil

hi Phil,

The screen shot you attached has show VOK and QEN bits are not set. Have you sent IT enable command?

I assume you already went through the app note: http://focus.ti.com/lit/an/slua544/slua544.pdf  on how to generate golden image. No training cycle gauge is low end gauge and will not provide the high accuracy unless you want to go that route. If you can attach your gg file I will be happy to take a look. We have many customers who decided to use TI gauge for the best performance they are looking for.

Thanks

Ming

Hello Ming,

 I can see, those bits are not set. The key question is: why not? Of course, I have sent the IT command on the BQeasy.

Are you sure, I should include the logfile in this post? I've been logging the whole day and it is LONG. Maybe you can contact me by email, so I can send you the logfile that way.

Yes, I have read that app note. However, it still leaves my questions open.

I'm amongst the customers, who decided to use a TI gas gauge in order to get best perfomance - that's, why I have it on my PCB now. However, I'm not convinced, this was a good decision...

Regards, Phil

Hi Phil,

I actually is looking for DF dump (gg file) or DFI file so that I can see what has been programmed into the gauge. How do I contact you? May be a short phone call can clear things up.

Thanks

Ming