Hello! I’m using a Qwiic Scale NAU7802 with an arduino which supplies the required 3.3V across the I2C interface. However, I’m trying to run the load cell with a 5V excitation voltage. There is a 5V output voltage on the arduino, so I just need to know how to connect the 5V appropriately so that the Qwiic Scale behaves as desired. Thank you!
You just wire the load cell like so Qwiic Scale Hookup Guide - SparkFun Learn (roughly, like it mentions some load cells have different colored wires but this covers the majority)
Thanks Russell! The hookup guide definitely gives an overview of connecting the load cells, but everything is running off the 3.3V I2C power as listed. I’ve used Qwiic Scales as described above previously.
My question concerns running a higher excitation voltage than the 3.3V provided by the Qwiic Connector. Is it possible to run a higher excitation voltage (say, 5V) and remain compatible with the Qwiic Scale?
The specs section of the product page lists as compatible with 0.1-5v external excitation reference voltage 
The load cell excitation spec is probably a suggested value and perhaps used as a reference for other specs. But 3.3 volt excitation isn’t so bad, I’m aware of some OEM scales that use less than that for battery life but also for use in explosive environments*.
You can also use external excitation. A very stable 5 volt supply for excitation might get you a little better resolution at the fringe but I probably wouldn’t bother and instead make improvements to the mechanical performance of the scale.
*Here’s a scale controller for use in a hazardous & highly explosive environment (Class 1, Div 1 suitable for munitions, acetylene, Mg) that lists 2.5 volts excitation right there on the first page of specs.