I am using the resistance impedance function of CN510 to measure the INR18650 lithium-ion battery, but the measurement accuracy of its impedance spectrum seems to be very poor, or is there something wrong with my connection method or parameter settings?

Hi,

    Typically, DC Bias is set to 1200mV for battery impedance test using Eval-AD5940BATZ to allow AC voltage swing in both directions.

May I know if you have set DC bias to 1200mV and checked?

Akila, thank you. Yes, I have tried to set the DC bias to 1200mV, but the measurement accuracy is still the same. Is there any other way?

Hi,

   Is there a particular reason to set AC amplitude to 5mVpp? Default configuration is 300mVpp as in manual.

Hi Akila,

I have the same problem: by using  Eval-AD5940BATZ I get only a trash data. I tested the evalboard on a battery and on two resistors. It looks like I'm not getting any data at all. But the measurement is going through without an error message. 

I have ensured the correct contacting of the DUT.

Hi,

    Battery impedance technique doesn't work on resistors. It expects supply voltage from load which should be a battery.

Hi Akila,
jep, I already saw that in the documentation. But even with a battery it still doesn't work.

Hi,

      May I know if you have verified the polarity (swapped the polarity of battery and checked?). 

   You may start with 10 points for easy verification.

Hi Akila,

thank you for support, the polyrity is verified, the issue is still there.

Does the length of the BNC Cable matter for the measurement? I use about 1 m long cable.

Cable length matters depending on cable's impedance.

You may export the excel data of measurement and check 

because nyquist plot doesn't show the number of measurements at each plot point.

Is there an expected reference graph for your load battery?

I tried to measure the impedance of both, a Nickel-Metal AA Battery and a NiMH AAA Battery. I don't have a reference data, but I'm expecting an usual half circular graf.