BQ34Z100: Chem ID selection with GPCCHem upload tool

Benjamin,

So i noticed a few things. 

1) I don't think our tool will understand the delimiter ";". Please follow the instruction for this. I think "tab" is the prefered, but i also think Comma works

2) You discharge rate looks very fast. you should be using a C/5 discharge or even a bit slower. The idea is to get a really good look at the voltage profile

3) you have 2 sections of Charge. The tool will not understand this

Thanks,

Eric Vos

Thank you Eric for looking at my data.

to 1) Thanks for pointing that out. Stupid german Excel is exchanging comma to semicolon, when saving to csv. Does the file roomtemp_rel_dis_rel  have to be csv? or can it be simple txt?

to 2) The discharge rate does not exceed 250 mA, which is C/10 of the A123 battery. Although, when switching my PSU to sink current, BQStudio meassures a sudden drop in voltage from 3.6 to 2.5 V, roughly the voltage i want the battery to discharge to. If I check the battery itself with a multimeter, the voltage does not drop that sudden, but is reduced in accord with the discharge current. Do you have an idea how to improve the procedure? Sink and Loading PSU are connected to the BQ34z1xxxEVM board as stated in the data sheet, but I had to connect an external power supply to the evaluation board, otherwise it would power off when the battery reaches below 2.5 volts. Could it be, that the cable connections from the evaluation board to the battery have much higher resistance, than from the PSU, so that the evaluation board is "seeing" the PSU voltage and not the battery voltage? Well, I will check that anyway. 

to 3) I can't see 2 sections of charge in my data. It is charge, relax, discharge, relax. The last relax part could look like a charge part, but the measured current remains close to 0.

Thank you very much for further insights. I would like to have your opinion on the remaining points prior to starting another experiment.

Benjamin Lang

Thank you Eric,

2) I found a solution and want to share. On the BQ34Z100EVM, one needs to connect on J3 the appropiate pins depending on the battery voltage (< 5 V or > 5 V). On said J3, Pins 1-2 only connect the battery to the BAT input of the BQ34Z100 for the voltage measurement. When connected, the voltage is sensed in path of the current flow, which is affected by voltage drops due to bad cabeling and such. What I did was connecting Pin 1 directly to the plus pole of the battery. Now the sensing is not in the current path anymore and I experience only a small drop  when turning on the PSU for charging or discharging.

3) Yes, it was sitting there over night until I came back to the lab.

Thanks so far, it seems I need to try again.

two further questions: In the BQStudio software in the Register section, there is two registers called Charge Voltage and Charge Current. Where do these numbers come from? The charge voltage states 4.2 V, although I have set the Termination Voltage to 3.6 V, the charge current seems to be half the capacity/hr. Are these two registers written by choosing/flashing a CHEM-ID ?

And: In the manual "Achieing a succesful learning cycle" slua903, it is written, that one needs to set the Design Voltage in the Gas Gauging section of the Data Memory. I cant find this register.

Thanks again

Benjamin Lang