Adjustable Constant Current Electronic Load - 150W USB Electronic Load Battery Capacity Tester USB Resistor Load Multimeter Voltage Current Tester Voltmeter Meter Amperage Reader 0.2-25A 2-200V

I'm in the process of building a 100Ah LiFePO4 battery pack for the 48v Torqeedo outboard motor that I have on my pontoon boat (I live on an e-motor only lake). I first discovered this device being used as a battery capacity tester in one of Will Prowse's YouTube videos. It looked like an affordable / easy option for confirming that the batteries I bought did, in fact, have the advertised 100Ah . . . so I clicked on his link to the Amazon store. When I got here, I saw the newer version available and went for it! Note again: this review is for the "New upgrade" purple version. A few comments:1) The device is working great! I attached a picture of the 6th consecutive cell that I am running through capacity testing. A little smoke rolled off the device when I started discharging the first battery, but stopped within a few seconds. The resistors on the sides of the heat sink get pretty hot when discharging at the 20A I'm using for this cell (0.2C discharge rate), so I expect it was some residual solder flux burning off. In any case, it didn't affect operation in any way that I can see and it hasn't repeated since the first run.2) The separate discharge and voltage measurement terminals are a must! The discharge terminals measure ~0.4 volts less than the voltage measurement ones due to resistance in my leads (likely the fuse - your results may vary), which would significantly affect measurements. It's a must-have feature, in my opinion, and the older version (the one Will used) doesn't have it.3) There is a PC app that you can download from a janky-looking website (accessed via the QR code on the back of the device) so you can monitor / control the device from your PC. I'm not trusting enough to install something like that on my PC so I can't comment on it, but the pictures looked pretty cool!4) No instructions were included with the device. However, the QR code on the back of the device brings up a site (the one referenced above) where you can download them. Unfortunately, there are several downloads there and no indication of which is the correct one (use DL150B). Worse, they are written in VERY poor English and are incomplete! For example, if you want to erase the data from a previous run, you need to press the button and encoder down at the same time until "Data Erase" shows up. Hold them for a moment longer and it factory resets. Neither function is indicated in the instructions. Nor is any information on how to use this kind of device. If you don't know how to use it, don't buy it until you spend some time on YouTube watching people use similar models (I couldn't find any videos with this version). You're likely to hurt yourself or someone you love!!!In summary, great little device if you're tech savvy and one of those people who only resort to instructions as a last resort. You will definitely leverage those "figure it out on my own" skills here! If your using the instructions as your sole method of understanding the device, good luck! Looking at a lot of the bad reviews, I'm guessing a lot of those folks were in this category.I'm on cell #6 now, but will update my review if anything changes before I get through cell #20! Peace!

Ok, I've got a few 12v batteries, both lithium and lead acid. The volt meters show volts and the battery health meters show SOH and SOC (state of health and state of charge), but what is the "real" capacity of a battery!?!?!?!I was able to verify the KWH capacity of my lithium batteries and figure out that one of my lead acid batteries was almost at the end of its life.The UI is easy to use and the build quality is great.100% recommended if you need to have a "real" test for batteries. Volts, internal resistance, and capacitance testers are only marginally accurate.

UPDATE 06.02.21 I've had this unit for about 9 months. During that time I had been using it to test small lead acid agm batteries in the 3-9 AH range. I thought it was doing well. Today, it became glitchy and unstable with the current drain varying widely. I've found out that the timer and measurements don't update if you drop the current below .05 A and you cannot adjust it finer than .02 A increments. I got it stabilized and adjusted it to .05 A. I ran it for 10 hr. This should amount to .5 AH usage. It was reading about .3 AH. So it is WILDLY inaccurate. I'm considering something else like the West Mountain Radio battery analyzer or an electronic load bank, both of which cost $ 200 or more. Downgrading to 1 star.This is an adjustable electronic load that can dissipate up to 150 W at an adjustable current level. If you were to buy this, learn to adjust its alarm settings. I'm using the following.Minimum Voltage: 11.1 V (for draining small 12 V AGM lead acid batteries)Maximum Voltage: 54 VMaximum Current: 10 A - 15 AMaximum Power: 150 WHere's why I chose those values. I want to discharge my AGM battery to 20 % SOC. When NOT under load, the standing voltage should be around 11.6 V. Don't just take my number and use it. Do your own research to find out what you should use. Every battery type has different numbers. But, the voltage droops when under load. So, I want the load to cut off once I hit 11.1 V. This may not be the best way to do things and it may not work for all AGM 12 V batteries. But that's what I'm doing. If you're using the loading device I mentioned, with these settings, it will start complaining with no battery or with a battery that's below 11.1 V. When you attach a battery with more charge, the alarm will shut off.My logic for the maximum voltage was mainly that I wanted to know if I attach a battery to the load with a voltage high enough that I start to have to worry about getting shocked. This number is arbitrary, and I'm NOT saying that lower voltages won't shock you.I put the maximum current as I did simply because I don't think the provided wires and terminals can handle any high current.The unit I got was set for a maximum power of 185 W. But, the instructions say the unit cannot handle more than 150 W with the supplied fan. So, I reduced that alarm value. Make sure the fan and heat sink have plenty of air flow. Be aware that the heat sink will get very hot if you're putting 150 W through it.I like this unit, and it's doing what I want, allowing me to drain small batteries. I prefer to power it with a micro USB cord. Always start with the control knobs counterclockwise or off. This way, there will be no load on what you're testing when you attach it. Then gradually inch up the fine adjustment to see if it goes high enough for what you want. If not, start adjusting the course adjustment slowly. You can adjust the alarms by powering up the load with the button pressed, or while the load is operating. You'll have to study the instructions as the procedures take some getting used to.Although fully functional, this is more like a prototype device. There is no case. The circuit board is exposed. The heat sink is exposed. The knobs are near the heat sink. You should be VERY careful moving this device around and operating it or you'll likely damage it. Also, as I write this, we're going into winter. That means low humidity in most buildings, and that means static charges on people's bodies and clothing. If you touch a light switch or water pipe and feel a shock, that is way more than enough to destroy electronics. So, you should discharge static from your body BEFORE touching this device, or any other bare electronics.So, although I only have a few hours using it, I like it. I cannot say how accurate it is, though. Nor can I say how long it will last.Ron