DROK DC Power Meter, 8-100V 100A Volt Amp Watt Meter, LCD Display Multimeter Voltage Current Energy RV Battery Monitor Voltmeter Ammeter Wattmeter with 100A Battery Shunt

Added a 12v RV AC unit and wanted to monitor the amp draw. What a simple and great monitor. Easy to wire and use for battery draw tracking.

The meter works as advertised and for the price it has excellent value. Note that the current meter is in the negative side between DC IN - and Load -. This is important if you use a switch, like I do, to change the meter's polarity between charging and discharging a battery. The current meter will not run backwards. In other words, the meter will only increase its reading when positive current flows in the direction of DC IN + to Load +. Current will flow in the other direction, but the power and current meters will not read negative values, and the Watt-hour meter will not decrease its reading. To use the meter to monitor power from a solar panel to a battery, I connect the solar panel to the DC IN + and DC IN - terminals, and the battery itself to the Load + and Load - terminals. When discharging the battery into the intended load, I reconnect the meter (using a switch) into its conventional connection topology. Since the current meter is in the negative side, DC IN + and Load + are connected together in the unit. In other words, they are the same node. The unit is made to mount in a square hole in 0.032" thick material. I used a thin bead of Silicone adhesive around the bezel to strengthen this mechanical connection. The operation of the screw terminals can be confusing, and can lead to damage if one is not careful. They come tightened down, so to connect a wire first loosen the terminal by turning the screw counterclockwise several turns, insert the wire in the gap that's just been opened, and then tighten the screw in a clockwise direction. I verified that the terminal block will accept 12 gauge wire.

I've got a few of these in my go boxes and RV. I love that they are simple, basic and just work. I also love that they have a watt hour use meter that can be reset to count again. A feature all shunts should have, but most don't. It's fairly accurate when measured against my Fluke 289 but off a few 10s of mV. It has higher resolution at 10mV and 10mA than most shunts. I wish it had "bi directional" readings so could read charge and discharge and I wish the shunt itself had holes in it to better mount. Lastly the 50A version is no longer available, but great for smaller installs. But even with the small draw backs this is a great shunt for the money. If you are wanting bi directional or SOC (which is never really accurate anyway) this may not be the shunt for you.

Works great, tested against another meter and readings are extremely close. Great addition to my 290w 36v solar panels. Mine shuts down around 5.9v, but it remembers the cumulative energy. UPDATE: After 4 months, it started reading wildly high voltages, current was still correct. Finally I contacted DROK, and they wrote me a helpful email within 24 hours. Bonus points for them for being responsive and knowledgeable. The 20A version can be recalibrated. The difficult parts are soldering a switch to the internal contacts on the board and finding a 20.0v 1A power supply and 20 ohm 20w resistor. I did, and it calibrated within about 5 seconds. Dear customer, If it is possible, would you please try to calibrate it with following method. 1. Turn off the power supply. 2. Connecting power supply (20V/1A) and load. 3. Short connect two calibrating spots (Open the back cover, you can find two holes which marked by “W” on the edge of board) 4. Turn on the power supply. 5. When the screen display changed from “CAL---“ into” ---PASS”, that means the calibration is finished. Any more questions, please let us know. Best regards, DROK

So I bought this as an indicator for a 24 volt solar power system built into a tote. I found that it worked very well although as others have mentioned, it needs some sort of enclosure so I designed and 3D printed a suitable housing for the shunt. This worked great for me. One thing to keep in mind is that the quality of the wire connections to the shunt and the battery are really critical as far as accuracy. The shunt itself is only a few milliohms of resistance and the voltage drop across that is very small, so the slightest bit of extra resistance introduced by a substandard connection on one of the wires will completely throw the readings off. Use really good quality crimp ons and then solder the wires after they're crimped. If you do that and follow the installation instructions to the letter, there shouldn't be any issues with accuracy. I don't know about longevity at this point but for the price this is a really good meter.

I am specifically referring to the new USB version with the black "sensor" It says to hook up between the battery- and load- "First loosen the nut, insert the wire between the copper plates, and then tighten the nut" "The DROK DC Power Meter accepts up to 12 gauge wire in its screw terminals" I can promise that if you put 12ga stranded wire in there, its going to be impossible to get a decent connection. Im fairly sure that 10ga is also too small so hopefully I have some larger cable around here

This meter does a good job for my purpose. I bought it to monitor the charging voltage and current for my ebike. You must hookup the wires per the instructions or you will not get a correct reading. I experimented with the hook up to see what would happen and it makes a difference. This meter does not actually monitor the current directly. It measures the voltage drop across the shunt and it is important that the shunt is the last part of the circuit per the instructions. I 3D printed a case to contain all of the wiring and it turned out to be a good tool for my needs.

Using this on a battery charger and it's very accurate! Note, that it needs to see about 6.5 volts D.C. on the input or it won't turn on! Remembers Energy usage even when shut off/no voltage coming in!