DROK USB Load Tester, Electronic Load Test Resistor Module 25W LD25 USB and Type C Interface Discharge Adjustable Constant Current 0.25A-4A Intelligent Temperature Control with Cooling Fan

I was very pleased. Because of the ability to set the load, I was able to identify some USB cables that could not support very much current. This explains why there were some charging issues. I decided to use it to test another batch of five cables that were still packaged. Three of the five were open, no connectivity through the cable.It also helped identify a cable whose temperature rose 4 degrees in five minutes with a 2 ampere load. That cable contributed to charging issues.The current indication is also very accurate when measured with a USB Multimeter..I would recommend this. It is good controllable load. It has met all of me expectations.The photo shows it as the load for a cable being tested. The cable is held on a flat surface so that an infrared thermometer can measure the temperature at 30 second intervals.

DROF load module with fan. 5 stars with one caveat! Works great. Only issue is the PCB standoffs. No room on PCB to add nuts and use longer threaded standoffs.This is a preliminary review. DROK works at multiple voltages up to 4amps. Some reviews say there is no way to select 5v, 12v, etc. NOTE the voltage is set by the USB CABLE automatically. There are 2A, 3A, etc.; 18W, 65W, 100W, and at the moment the highest 240W. These are SMART cables and have control logic in the connector housing that sets the power to 5, 12, or other PD voltage. A basic dumb USB cable will be only 2AMPS. A cable that is MARKED 65W, 100W, or 240W, or "3.1 Amps" is required to get those power levels.I tested this DROK load unit drawing 3.7 amps at 5 volts at which point my tester shuts down. Which is normal. For newer larger batteries I used the DROK load tester with a short USB Y cable and a second resistor bank load that comes with the tester (tester had fan and heatsink). The resistor bank can be set to 1,2 or 3AMPS. If you want more load, that is how to get it. Used the DROK to add 3.5 more AMPS with fine tune adjustment. Note the fan only comes on when the unit gets hot at about 2 amps.More later...

Works well. I was able to test USB-C chargers up to 20 V and a little more than one amp. If you exceed the 25 W rating, the display reads OOP and it shuts off.

This device, is the second half that you need if you want to determine how much your USB chargers are actually putting out, and if your USB cables are any good.Combine this with something like Eversame 2 in 1 Type C USB Tester, and you'll be all set. The only downside (and the reason why I only gave it 4/5, it's because it's missing the port for that funky iPhone plug. So I was not able to test my iPhone cables the same way, but I could test all of my other types of USB cables.Also, I saw there's a different option that uses switches to achieve specific amps (and with no fan)... I did not go that route, and I would recommend that you stick with this. Having the dial to fine tune the load is crucial, and that fan is completely needed! I can't imagine running a resistor without it because it gets so warm.For those that are not electrical engineers like myself, this is simple to use. You plug your USB tester into your charger. You plug this load device into the USB tester (with or without a USB cable in between, depending on what you're trying to test).Then simply start with a low amperage pull, and adjust the dial, slowly increasing the amperage until the USB tester drops below 5v. Then back it up until you get above 5v again.You will then know the max voltage, amps, and Watts your USB charger is capable of.I actually had fun testing everything in my house, and ended up throwing away like half of my USB chargers because they couldn't put out at least 10 Watts, and several USB cables because they were junk. Some of my USB cables were losing between 12% and 25% of the power load!

Extremely handing power supply tester. I've used mine dozens of times. Many power supplies crumble in the face of this little power hog. I like to take my gear to the limit, so this tool lets me verify that the power supplies I rely on will deliver the rated power. Most do not. A few survive the test. The few that do, get to travel with me into the field.The voltage is very accurate, within about 0.1V of what I read with a fluke meter. I have compared this by putting the black lead of the fluke on the metal connector of the USB, and the red lead of the fluke on the screw of the on-board voltage regulator 3-pin device. It's awkward to hold the fluke leads like this, so it's nice to know the on-board indicator is accurate.I have yet to kill my device, but I like it enough that I decided to buy a second as a backup.My only complaint is having to toggle between voltage, current, power. I wish I could see voltage and adjust current at the same time. As a workaround, I use the DROK inline USB meter, which does a great job of showing voltage and current at the same time.One novel use of this tester is to measure the resistance (and gauge/thickness) of the wires in a USB cable. I found a lot of "high current" cables were lying - using thin wires that were too small and had too much resistance, and too much voltage loss. The way I did this was to set it up for 1A of current, measure the voltage at the power supply, then insert the USB cable, and measure the voltage again. (Vin-Vcable)/1A = resistance. Using a chart with resistance vs. gauge of wire, I was able to find some cables that were excellent, and others that were too thin to deliver the rated power for charging.This is a bit of a niche product, but if you NEED TO KNOW that your chargers deliver under load, this is the only way to go. For the price, anyone who uses USB devices (phones, tablets) and wants to know if the problem is a cable, the power supply, or something else should have one in their toolbox (along with a DROK inline USB power meter).

Works well for what its supposed to do. I do wish I could control the Voltage as well, but I understand this isn't a function of this device, so not a flaw. Otherwise, works well out of the box, instructions are okay.