BQ34Z100-G1: IT ENABLE prevents updating data flash

Hi, Me again.

I reprogrammed my EVM module with the bq34z100_G1_v0_16_build_17.srec file that I downloaded from the devices product page bq34z100-G1 Device Firmware  (ZIP 4170 KB )    25 Feb 2015 

I have updated all the data flash, which is great, but now I can't calibrate the voltage.

I have VOLSEL and CalEn selected in Pack Config

Number of Series Cells  set to 6

I have entered 16000 in Voltage Divider

When trying to calibrate voltage:

Gauge says 10800 mV, in Applied Voltage I enter 12965, I check the Calibrate Voltage box, and then click the Calibrate Gas Gauge button.

Which results in a cross by the button and a message in red at bottom left of screen: Calibration - calibration cell voltage entered out of range. This value is in millivolts. Please check value and retry.

Its enough to make you weep!

Can I get your gg or srec file?  I will take a look.

3731.0100_0_16-bq34z100G1.zip

Hi Andy.

I still haven't got anywhere with the learning cycle.

I am using a 12V 7AH lead acid glass matt, not the same brand as Yashua, but identical in specs.

Can you take a look at the attache .srec and .gg auto exported files.

The battery was near empty when I began logging. I enabled IT, reset, then discharges to terminal voltage. Rested for more than 5 hours, Qmax DOD0 was taken before I began charging. When taper current went below threshold of 200mA FC flag was set and I stopped charging. I waited for 6 hours or more but Qmax was never taken. Update Status still 04.

Can you see anything obviously wrong?

Thanks

MattfirstDischargeGG.zip

Hello Matt,

Make sure to set gauge_enable as well.

Hi Kang

I cannot find any command or register called gauge_enable. Do you mean IT_ENABLE? 

Hi Kang

The log files I attached earlier were of the initial step in the procedure as described in the app note.

The IC was programmed, calibrated, IT_ENABLE() then RESET(), battery discharged to terminate voltage, rested, QmaxDod0 was taken (FLAGS OCVTAKEN, VOK, and QFN all set), charged to taper current FC set, rested but QmaxDOD0 is never taken and Qmax is never updated, update Status remains 04.

There is no point continuing with the learning cycle,, ie doing another discharge as Qmax is not set.  As you have pointed out, Qmax needs to be taken before Ra can be updated.

My problem is that Qmax is never calculated after charging has finished.  Can you please review my files to see if anything obvious is not in order.

Thank you

Hi Kang.

I've got a bit of a problem in that I don't trust any advice given about this IC on this forum because there is so much contradictory advice.  I'm fairly certain that none of you actually know how to use this chip. I expect that you have had no practical experience with it and are just relating what you intemperate the data sheet to mean.  If you aren't an expert and are just going to to tell me what you think the data sheet is saying I will ask you to pass my case to someone who has actually had real hands on experience using this chip with lead acid batteries.

Having said that, and I mean no offence by it, can you tell me: should I be following the learning procedure in the https://www.ti.com/lit/ds/symlink/bq34z110.pdf datasheet, or the procedure in the http://www.ti.com/lit/ds/symlink/bq34z100-g1.pdf data sheet. Because I have read contradictory advice, some saying one and others the opposite.

Can you please clarify what the parameter Cell Terminate Voltage is and how it relates to the learning cycle.  The learning cycle procedure in the bq34z100-G1 data sheet says that this is the voltage under load that you should discharge to, where as the bq34z100 data sheet says this is the open circuit voltage of a fully discharged battery, and should be close to the voltage that the Pba battery springs back to when at rest. Two very different things wouldn't you agree?

Right now I'm discharging at C/10 down to 10.2V and it springs back to around 11.4V at rest.  The Yashua NP712FR data sheet says that at C/10 the absolute minimum you should discharge to is 1.75V per cell, beyond this damage occurs to the battery. As it is I am discharging beyond this down to 1.7V per cell just to get the resting voltage a little lower because the bq34z100 data sheet says to do this.

What should I be setting Cell Terminate Voltage to and why?

Thanks you kindly

Regards

Matt

Hi Kang

My problem persists.  When resting DOD0 is never taken. 

Folder "Step 1 charge" contains log file and .gg exports of charging the battery from flat. The battery had been discharged, rested, Qen set, charged untill taper current met, rested, but DOD0 was never taken at rest.  DOD0 is taken at end of charge, but is never taken while resting, Qmax DOD0 was never reset.

Folder "Step 2 discharge"is discharging from where the lat files left off.  When the battery discharges to Cell Terminate Voltage the battery is left to rest, but again DOD0 is never updated.

I reset the IC at this stage before charging the battery again with RUP_DIS set, just to see if this made any difference. See "charge after reset" folder. Again DOD0 was never taken while resting. I waited thirty six hours resting this time, with a DvDt of approx 500nV/S.

When resting dV/dT is well below 1uV/S, the current is 0, below Dsg Current Threshold, Chg Current Threshold, and Quit Current, and the IC is in Sleep mode.

Can you see any condition or setting that is preventing DOD0 from being taken while at rest? If not, I suspect there is a problem with the firmware. 

DOD0 never taken.zip

Hi Kang,

I am using a 12V 7AH AGM PbA. Why would it have to wait 48 hours if the dV/dt condition is met?  The chip would be useless if every time the battery was charged the gas gauge needed 48 hours at rest before calculating Qmax. Most applications will not afford 48 hours at rest and I don't know any client who would wait 48 hours for an estimation of charge. Fair suck of the sav, waiting 48 hours means something is not working properly.

I have spent several weeks now trying to get this chip to work.  I don't feel like this line of support is going anywhere. Can you please direct my case to someone who is more able to give me the support I need.

Kind regards

Matt