BQ3050: BQ No-Load current goes above 4mA

Thanks Shirish,

Shirish said:

I would check if there is any actual current drawn from the battery.

Can you elaborate more...Practically how can we check ?

Put an ammeter between the negative of battery and BAT- input of bq3050

You mean , BAT- input is this one ?

No. That is PACK-

Connect ammeter between your cell and where it connects to 1N in the schematic

Thanks Shirish,

I check same way. Ammeter Shows 1.5 micro Amp. See below setup Image.

I followed following Calibration steps, Used BQEVSW calibration Tab :

1. Calibrated Voltage & Temp. 

2. Run Coulomb counter Offset

3. Run Board Offset

4. Calibrate Current using 743mA DC Electronic Load.

Now ,It shows Reverse Rest Current.

The ammeter readings seem fine.

Remove the ammeter when you calibrate. That could cause an issue like this. Such issues are also seen when the current source/sink for calibration is not very stable. Use a mV accurate sourcemeter. 

Okay,

1. Why it shows Minus ( - ) current ?

2. Moreover, I would like to know , It varies between 0 to 4mA during rest period  , would that be Ok ?

1. Minus is a discharge current. The sign shows the direction

2. If the current varies during test period, then there must be some kind of loading and actual current draw. If calibration was incorrect, then the current would be constant

Is the  deadband parameter at default?

Yes Shirish, deadband parameter is at default.

Test Period means Load Connected OR Disconnected ? In my case , current varies in NO LOAD period.

- Regards

The charger must also be disconnected

Hello Shirish,

One thing to know is : Do we need to calibrate again / Program senc file if Battery is removed from Guage  and then Reconnect ? I mean disconnecting Fuel guage PCB from all 8 Battery Cell connection ?

Oh, Okay.

So, In my case after removing Battery and Reconnecting it...When I start to Charge , the charging current Shows 982mA , while Actual actual charging current is 1.6A ( as per Ammeter).  During Calibration Measure current was perfect as per actual current.

Check if the load is drawing current. Both CHG and DSG FETs are on. Please check BAT and PACK are connected correctly.