newbiehere said:oh ok cool got it about the shunt resistor, but I still need to break the trace for the wiper connect, correct?
Ive seen complicated work arounds for measuring current with an arduino, seems this type of shunt could do the same thing?
Yes, you need to cut the trace to insert the divider.
An Arduino A/D input would not have very good resolution at the voltage level on the shunt. It would work better if the signal was first amplified about 10x. Typical circuits I've seen use an LM358 or similar op amp to boost the signal ahead of the Arduino.
Another option is to get an inexpensive power meter. There are several out there. I use a TK15 coulomb meter on one of my bikes and like it other than the screen is pretty small. I use it mainly to keep track of my battery level.