The MAX471 is a solid alternative to an ACS712 for measuring DC Current. Its a high side device that is powered by a load source that can range anywhere from 3 to 36 VDC.
RS+: This connects to the positive pole of your supply source.
RS-: This connects to the high side of your load.
GND: This is circuit common on both the input and the output side.
OUT: This is an analog output that provide 1 volt DC per amp measured. The device can measure up to 3 amps DC.