I need to detect up to 50 amps of DC current from a 12v battery to a trolling motor with a microcontroller.

Most hall effect sensors I'm finding that are packaged for direct micro interface are < 20A, and the larger ones lack a clamping action (I believe the term is 'split core').

Is there a better way to search for a high current transducer? Is there an easy way to buy just the hall effect IC and build a clamp for it?

 

Why not use a 50A resistive shunt?

 

google : copper shunt resistor.

 

I considered a shunt, but my micro ADC has only 10 bits of precision, so detecting a range of currents from1 - 50 amps reliably would require more voltage drop and more wasted power.

 

You can using the op amp to amplifying the voltage.

 

I've used these in a few current sensing projects to measure solar panel current. Direct interface with a 5vdc controller but your 10bit resolution might be a problem unless you over-sample and software filter the input as you have about 4.88mv per ADC step and the output of a 50A sensor is 23mv per amp.

http://amploc.com/amploc.com/AMPLOC.html
http://ampsense.com/HANDBOOK web.pdf