Review on Dual Display LED Digital Volt Amp Meter: DaFuRui 2Pack for Precise Voltage and Current Measurement – DC 4.5-100V/50A with Shunt by David Nelson

I received these and although they showed voltage they showed 0 amps. Reading other reviews I assumed they were just as bad as the others. I ordered several from another seller, hooked them up and encountered the same problem. 0 amps! So this is NOT a counter. It turns out I mixed up the thicker red and black wires measuring the load. Your change resulted in the APPEARANCE of AMPS! MARVELOUS. hahaha So if YOUR meters read 0 amps I suggest rechecking your wiring. Flipping the thicker red/black wires might fix this for you. Your mileage may vary. Some of the diagrams on the internet are probably wrong because I connected them according to what I found in a google search. Measuring devices are ok.