https://www.digikey.com/product-detail/en/allegro-microsystems-llc/ACS770ECB-200B-PFF-T/620-1538-5-ND/4473977 Not sure where you are, but this is just $8.38 in the states. Limit is 200A, bidirectional. With a bit of heat shrink, you can fly with this also. Needs a 5V supply to the smaller pins, but then the output is 2.5V for 0A, 5V for 200A, 0V for -200A. I’ve used this device for FOC brushless DC motor drives, it is high bandwidth (120kHz), so will even be able to look at commutation/switching noise (to see how rough the ESCs are with the battery).