measuring current in ni usb 6009

[walkup1j]

I am trying to chart the change in current of a CCCV charger, while it is charging a 60V lithium ion battery. I know the charge rate is (1/6) C and the rated capacity of the battery is 26Ahr resulting in a current of 4.33A during the constant current stage. I have the NI USB-6009 and the devices Analog I/O is rated at 50mA so I can not connect a breakout wire from the charger directly to the NI device. I was thinking about purchasing a CT that will connect directly to the NI device, and run the (+) output wire of the charger through the CT while it is charging the battery. Is this the best way to chart the current for a compete charging cycle? What are other options to chart the change in current?    

[Henrik_Volkers · Accepted solution]

A CurrentTransformer will only work with AC current.....

A compensated CT with Hall element (Search LEM) can measure AC and DC ....

I would look for a Allegro Hall current sensor...  the output has a galvanic isolation and the output fits the 6009 input range. 

[walkup1j]

Thank you very much!

[johnsold]

I agree with Henrik.  The Allegro Hall devices might be well suited to your requirements.

I caution you to consult with someone who has suitable knowledge and experience with such measurements. Using the wrong devices (CT) or using an appropriate device incorrectly may result in damage to the equipment and possibly injury or death to the operators. When someone asks a question which implies that they do not understand the issues involved, I feel it is important to make them aware of some of those issues.

Lynn