Learning cycle VOK (bq27510-g3)

Hi Shlomi,

The exact voltage your battery will relax to will depend on the battery you are using, but it is possible for the voltage to rise this much during relaxation.

VOK: "Voltage OK for Qmax Update": This bit tracks when the gauge measures the battery's voltage. This bit is normally set when charging/discharging starts, and is cleared when discharging stops, the gauge has detected that the battery voltage has stabilized, and the gauge has taken the OCV measurement.

The important key is that during this relaxation time, you want VOK to be set to 1. You will not manually change it.

Try to fully discharge your battery and allow 5 hours of relaxation to occur and see if VOK is being set by the end of the relaxation. If you are still having problems, log your data with BQstudio and feel free to send a copy for review.

Best,
Justin

Hi,

After the battery went empty i could not read the gauge in bqstudio so i cant know if VOK is set.

I only know that while discharging it was never set and even after waiting 5 hours i couldnt see

the gauge's data on bqstudio meaning the battery was still below operating level.

after 5 hours relexation time i plugged in the charger and then i could see the guage data.

i sent IT_ENABLE and QEN was set but VOK is not set.

any idea why VOK is not set while charging/discharging with significant load?

please see my other reply,

thanks.

Hello Shlomi,

VOK is not a threshold, it is a flag that lets you know when the gauge took an OCV measurement that is valid. For an OCV measurement to be valid, it must meet certain requirements: the cell voltage must be relaxed (a dV/dt of 1uV/S) and there shouldn't be any charge/discharge going on at the moment.

VOK doesn't set during charging or discharging, only during relaxation.

What voltage are you discharging your battery to? Do you have an automated discharge setup or are you manually discharging the battery?

Are you logging the cycles? If you have one, please provide it.

Best,
Justin

My battery is 4.2 v at full and I'm discharging it manually to empty untill I can't read the evm on the pc anymore at about 2.9 v.

I don't have a complete log yet.
Should I discharge it so there's still enough to read the guage at about 3 v?

Hi Shlomi,

Are you measuring the 2.9V directly from the battery? Where are you seeing this voltage?

Also, it is not recommended to discharge until it is discharged to the point that the EVM can't be read anymore. What is the termination voltage for your application? You want to discharge until termination

Best,
Justin

Hi Justin,

My system shuts down at 12% battery which is about 3400mv.

I'm measuring directly from the battery and comparing to bqstudio data from the gauge and the results are equal.

I watched closely as the voltage came around 3000mv and saw the shutdown at 2950.

*also i charge my battery to full (4.2v), let it rest all night and still no VOK set.

thanks,

Hi Shlomi,

Our gas gauge should operate at 2900 mV.

1. Discharge battery to termination voltage (3.4V)
2. Relax for 5 hours
3. Before charging, Send IT_Enable command and Reset command (VOK should change to 1)
4. Charge at C/2 rate until full, then relax 2 hours
5. Discharge at C/5 rate until empty, then relax for 5 hours

Have you been sending both of the commands above? They must be sent *before* any charging/discharging takes place. Please follow these steps, and create a log. If you are still having problems, send us that log along with an SREC file.

Best,
Justin

Yes,

 this is exactly what im doing and VOK is not set.

I even gave it a 2 days' rest.

attached are the log and the srec file.

thanks.22.11.15.rar

Shlomi,

Your log file shows less than 3 minutes of logging. Can you please do the above 5 steps and log this? It will be helpful to look at a full learning cycle. Also which battery are you using? Do you have a datasheet?

Best,
Justin

Hi,

I've run 2.5 cycles and they are not good (no cycle count was set).

the FC bit does not change to 1 (thought it was fully charged for more then one day and still connected to the charger) when the battery is full so i had to manually set FC SET% = 100 instead of -1.

the VOK did finally change to 1 (before charging) but when the battery was full and  FC was set i waited a couple of hours (more then 3) and update status did not change to 1

also the QMAX was not updated.

(is it possible to update qmax and update status manually ?!)

my battery is Boston Sonata 5300 mAh.bqlog211115 - Copy.log

HI Justin,

I have run the full cycle which ended with success and update status = 2.

i flashed the DFI to the g3 the same way i did with the g2 and i still have the problem when the g3

power source (battery) is disconnected the g3 loads in ROM MODE.

this is very urgent (!!!).

please review the log and inquire what could be the problem.

i also attached my output files.

do you have a program to send me to flash the DFI on my own board?

i think maybe the dfi update process for the g2 and the g3 are different somehow.

thanks.

011215_01.log03.12.15.rar

Hi Shlomi,

It looks like your update status and resistance tables have updated, which is good.

I flashed a new bq27510-g3 v4.0 firmware onto the device, and then I flashed your DFFS file, and it did not load into ROM mode. Can you try to do this as well? It seems to work for me.

Best,
Justin

Do you have a sw that I can useto flash it on my production board?

My current sw only updates the dfi (and thus causing the Rom problem)

Thanks,

Are you using bqStudio to flash the device? This method should work, and should not put you into ROM mode following my above method of making sure you have v4.0 firmware and flashing DFFS.

Best,
Justin

I can't use bqstudio on my production board..

Thanks,

Are you using this guide for production?

Best,

Justin

Yes, to the letter.

and the DFI update succeeds (im seeing changes when reading data).

but after disconnecting/re-connecting the battery it still load in ROM mode.

I think that maybe the bqfs/dffs which bqstudio outputs may contain a troublesome value that the CI encounters when starting and then stops.

thanks,