Measuring a DC current

I have this current sensor:


I am trying to measure how much current goes inside and outside of my electric scooter battery, but I get strange results, as it looks like I see an AC rather than a DC. How should I exactly connect this sensor to Arduino? I tried by closing the sensor circuit by a resistor, and connecting the resistor itself between GND and A0 on Arduino: is this correct? How can I know how big the resistor must be for proper measurement, considering that the current I'm trying to measure is between 1A and 20A?

Do the wiring changes if the current is DC or AC? And what about the SW? I have a SD card shield where I store A0 values.



Sergegsx's picture

Re: Measuring a DC current

I belive you cant use a CT sensor for DC current as current does not alternate and therefore no induction is done to the coil of the secondary (CT sensor).

You need to use something like this

I just received it by mail at home in order to do the solar panels measurements.

odellrivera's picture

Re: Measuring a DC current

Multimeter can be a good choice for measuring DC current.


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glyn.hudson's picture

Re: Measuring a DC current

As mentioned you can't use a CT for DC current measurements, only AC. For DC you choices are resistive shunt or hall effect.

DC current monitoring is documented here: 

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