I'm trying to design a current sensing circuit that can achieve a 0.01A accuracy across 50A DC. It is a battery powered brushless DC motor drive (battery --> current sensor --> controller --> motor). I need the accuracy because I am trying to determine efficiency and therefore the current reading is quite important. Most of the time, the system only draws 5-10A. I only need to measure current in one direction at a sample rate of 50Hz. I don't mind using a current shunt however I would prefer not to lose the power.
I have a 16 bit ADC that I am trying to interface the sensor with. I've considered sensors such as the ACS759.I have looked at data sheets, application notes, pretty much everything I can find on the topic but I can not find any circuit that achieves this kind of accuracy. Any help would be appreciated, if anyone knows of a circuit or a sensor. Thank you!