Review on ⚡️ MICTUNING MIC-DV-077 LED Digital Panel Double Voltmeter with Rocker Switch Style, Blue Voltage Monitor for Car Pickup RV Truck Dual Battery Pack by Bob Fasho

I bought this unit to work with isolated batteries in my car and to monitor the voltage on both batteries when they are not connected. I got it, hooked it up to a DC power supply and connected the wires, the MAIN voltage shows up with no problems, when I connect it to the "AUX" connection point I get nothing. When I connect the MAIN jack and the AUX jack, it shows voltage. I don't have to keep both of them all the time just to display one. What if I turn on the momentary switch so it's not "always on" as other reviews state? It doesn't show any voltage when I just want to check the AUX battery. This is a serious design flaw and should be corrected so that you can read each one independently. In combination with the missing power switch, this would mean an empty battery over time. I understand that LEDs don't use that much power, but I don't want my car to be lit all the time when I'm not in it.