Review on 🔌 DROK 100014: High Precision LED Digital Voltmeter Ammeter 2in1 Multimeter – DC 0-100V, 10A – 12V/24V Voltage Amperage Meter Volt Amp Gauge Panel by Brian Rogers

I've tried pretty much every configuration suggested here on Revain and in the wild. Compared to a multimeter, this device is constantly off - either heavily (more than 1 amp at one point), or simply reading 0.3 / 0.4 volts. I just can't get the probe's yellow line to show the correct voltage, making a simple power calculation impossible. My test setup used a 5 volt voltage regulator (testing different regulators to see which would work best for the project). 12V input, 5V regulator. There is a 4.7 ohm power resistor in the circuit that should deliver just over 1 amp across the resistor. This is what the multimeter reads when there is nothing in the circuit but resistance. DROC shows 4.2 -> 4.7 volts and 0.56 amps. The amps are stable now, but off A LOT - and so is the voltage. So, according to this device, it consumes 2.5W, when in reality it's closer to 5.4W. Big failure. Power lines (two thick red/black wires) also use a connector that doesn't fit because the metal connector on the board gets in the way. Not that I think it matters, other than not locking the connector. Revain's schematics suggest that the negative ground of the power line should not be used when connecting a (thin) black "sensor" wire. First, I always like to use as large a meter as possible, especially when I'm expecting 10 amps - second, the amperage reading won't match my over 1 amp reading. At one point this circuit shows 2.3 amps at the top configured this way. Not using the SMALL black wire gave more accurate results (but not the cigar as shown above). I'm not sure anymore if I can use it. Definitely not for anything precise (it only has 3 digits total so it's not an accurate tool) but a 50% power deviation is way too much - after all the purpose is to understand what a given unit is consuming. I certainly can't use it in the homebuilt adjustable power supply that was the original plan.