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 Kyle Robinson

Problem #1: I shorted two contacts for two battery inputs, connected a battery and the two displays show 0.1V different. I then hooked up a Fluke voltmeter and found that one was high at 0.08v and the other was low at 0.07v. I have tried other batteries with similar results. The normal voltage of a battery changes about 1 volt from fully charged to almost empty, so I believe this is a 10% SOC error. I bought this dual battery monitor to read the voltage of two batteries in a starter and "home" battery situation. Batteries can be isolated so accidental overuse will only drain your household battery. I need to know if both charge together as isolation is automated and equal voltage means they are connected. It won't work with that, they will never be the same. Problem #2: The main battery must be present to get readings. If only the additional battery is present, there is no display. So when the starter battery dies I can't read the home battery charge level to see if it can be replaced to start my truck. I'll have to get a volt meter to find out. So you can't even tell it's a dual voltmeter. It's more like a half. Incidentally, the power consumption is around 17 mA. Not so bad if it stays on all the time. Since it is connected to the battery, it is not clear how to turn it off. You can insert a switch between earth and the equipment earth terminal. If the switch is a relay, where the relay is energized when the ignition is turned on, then it is automatic. As I bought it well before it was fitted I can't return it or I would definitely do it. Not recommended but gave two runs as I can see how someone could be okay with their limitations to get it for a low price.