Battery Charger + Fuel Gauge

Anbu,
This concept looks correct. You could use the bq20z65 and drive the LEDs from the gauge. Also, the bq40z50 is our recommended gauge now and it also supports LED display. Are you using Li-Ion cells or LiFePO4? The voltages that you have listed above look more like LiFePO4. I would definitely recommend using the bq40z50, if you are using LiFePO4 cells. You should buy EVMs and start working with the gauge and charger. There are several parameters in the gauge that will need to be configured for your pack. You will also need to find a ChemID match for you cells and run an optimization cycle to fine tune Qmax and the Ra tables for you pack. We have several documents in the gauge product folders that will help with these tasks.
Tom

Hi Thomas,

Thanks for your immediate reply.. iam going to use Li-ion battery find attached datasheets for your reference.

The device bq20z65 not able find out in TI site  but BQ20Z65-R1 is  datasheet but it is NRND state.

bq20x65-r1 - states "Supports the Smart Battery Specification SBS V1.1"   any significance for specification .

I request to provide clear picture on this .. since bq40z50 (not specified andy SBS Version).

looking for your advice according to attached battery spec..

LIR18650(2600mAh).pdf

Anbu,

All of our SMBus Gauges meet the SBS spec, including the bq40z50. The bq20z65-R1 should also work well for your cells. We have not characterized that cell, but we can use a Mathcad program to check for a ChemID match. You will need to collect data and I can check it for you. You can use the attached document for guidance in collecting the data.

Tom

3806.Chemistry selection.pdf

Hi Thomas,

Happy day ..

We can go with bq40z50 for my design since bq20z65-R1( NRND) state and I believe that bq40z50 is newer part than bq20z series.

For Fuel guage : bq40z50

For Charger : bq24725A

if OK , i will order the evm for both above parts for evaluation.

Anbu M

Be sure to order the EV2300 or EV2400 as well, if you do not have one. You will need the adapter box to communicate with the EVM.

i have EV2300 and i need to order other two parts..

Hello Thomas,

Happy day..  i received the both evm (bq40z50) & (bq24725a).

For bq40z50:

i was made inital setup battery connected with 3S configuration and run bqStudio. i can able to read battery voltage and did DISPEN switch LED's are

glowing 5sec and turn off .. and voltage measurement are ok..  Since bq40z50 have so many register , i need advice from you to quick start  for better understanding of device operation.

1. how to change 3S to 4S configuration ?

2. Charging & Discharging done by manual via software or auto ?  since in right side CHG_FET_TOGGLE,DSG_FET_TOGGLE button are available. 

    when i toggle the those buttons only i can get volgate in evm connector(J3,J4) PACK+,PACK-.

3. Also you told that  battery learning cycle to be done for my battery for better performance.

Looking you advice.

Regards

Anbu M

Anbu, 

You will need to configure the gauge for 4S in the DA Configuration register. Most of the parameters are set at a cell basis, so they will not have to be changed. But, you will need to update the Design Voltage and the Termination Voltage for 4S.

You should use the FET_EN (22) command to enable the FETs. The 1F and 20 commands are intended for diagnostics.

You will need to run an optimization cycle on the pack to fine tune the Ra table and Qmax. You can find a document on the TI website that can provide some guidance. Search for SLUA597.

Tom

Hello Thomas,

Happy day .. i got the battery chemistry from EEMB battery mfr  which we are using Li-ion battery.

LIR18650(2200mAh) battery chemistry is LiNiCoMnO2

But i could not find the exact "LiNiCoMnO2" in chemistry table .. could you pls advice which one will match.

Regards

Anbu M 

Anbu,

We have not characterized that cell, but we can use a Mathcad program to try to find a ChemID match for your cells. You can use the attached document for guidance in collecting the data. We will have to characterize your cell, if we cannot find a Mathcad match.

Tom2061.Chemistry selection.pdf

Hi Thomas,

happy day... 

Now we received and populated both charger (bq24735RGR) and Fuel guage (bq40z50RSM) ..  

i would like to do the basic test with default chem ID. now iam working with bq2473x BenchTest program for programing charger and bqStudio for programming

bq40z50. 

i want to do the charging & discharge test sequence. since when iam using command 0x22(FETEN) , 0X1F (CHGFET) and 0x20(DSG_FET) to stimulate the

charging and discharging .. CHG FET get oscillating 8v to 27v and charger voltage oscillating.

Test Setup

Charger input : 17.5 V

Battery voltage : 15.617V

Charger voltage : 16.384V (Setting done at bq24735RGR)

Cell Configuration : 4S 

Regards

Anbu M 

You do not need to send the 1F and 20 commands. Just send the 22 command to enable the FETs and the 21 command to enable IT. The FETs should turn on as long as the SYSPRES pin is valid and there are no faults. If the charger is oscillating, then that usually means that there is not enough charging current or you are hitting a current limit.

Hi Thomas,

Happy day.. 

This is inform you the load current is almost 140mA only but the bq studio shows the 1500mA to 2000mA current and oscillating.. the problem due to 

may be correct chem id not selected ? shall i send the battery to TI for learn cycle to form the chemi for my cells.

i have two current capacity of cells 2200mAh and 2600mAh with EEMB battery LIR18650,chemistry detail is LiNiCoMnO2.

Also can you pls select nearest battery chemistry will suits for functional verification for initial development.

Procedure which iam doing  for your kind refernece.

1. Open the bq24735 software and configure charge voltage 16384mV and charge current 1024mA. 

    (i checked hardware and observed 16384mV on BAT terminal of bq24735)

2. Closed the bq24735 software.

3. Open the bqStudio software to configure the bq40z50.

4. Given 0x22 command to enable FETs. 

     (Now iam observed the oscillation in battery terminal and also observed current oscillation in bqstudio software).

i request to kind advice anything i missed to configure..

 

Anbu M

Hi Thomas,
happy day..

I waiting your advice for nearest match of chem id for my battery..

Anbu,

We have not characterized the cell that you are using. Please collect data and I can check for a Mathcad match and you can use the attached document for guidance in collecting the data.

Tom

4466.Chemistry selection.pdf

ok thomas , i will do log the data using bqstudio and send you.

Hi Thomas,

I collected charge and discharge data for battery  using bqstudio, find the attached logfiles.

to find nearest chem ID match. 

Also we are facing establishing SM bus communication wiht bq40z50. my colleague Mr.ArunKumar working on it . 

I asked him to create separate post.  

 charglog_27052015.log

Anbu,

The discharge log did not get attached. Can you please provide it?

Tom

hi thomas,

find the discharge log..batterydischarge.log

Anbu,

The closet potential match is ChemID 1123, but it is not close enough to be acceptable. Please provide an email address, if you would like to submit cells for characterization. I will send you a list of what to submit.

Tom

Hi Thomas,
Happy day..

Pls send list to submit for cell characterization to my email I'd anbu@qmaxtest.com

Meanwhile I will do my development activity using 1123 chem I'd.

Also I request help to I2C communication issues posted my Mr.Arunkumar .

Thanks & Regards
Anbu M