KONNWEI KW208 12V Car Battery Tester, Battery Load Tester Automotive 12V Alternator Starter Tester Digital Auto Battery Analyzer Charging Cranking System Tester for Car Truck Marine Motorcycle Boat

Amazing for the price. You won’t be disappointed! Works straight out of the box, with no batteries or charging needed since it’s powered directly from the car. The instructions aren’t the best, so for those who might not know: connect it to the car by attaching the Positive (red) clamp to the positive terminal of the car battery first, then connect the Negative (black) clamp to the negative terminal on the battery. It can test batteries both in and out of the car. The device will power on once connected, and you get three options for testing the battery with step-by-step instructions. The three options are Battery Test, Cranking Test, and Charging Test. The Battery Test will determine the health of a battery, the Cranking Test will measure the battery's ability to start the engine, and the Charging Test will measure the voltage of the battery while the vehicle is running to determine if the battery and alternator are working. If you think you have a bad alternator, use this device first and run through the tests. It provides straightforward results (as shown in the photo) that tell you if the battery is good, needs to be replaced, or if the alternator has no output. Couldn’t recommend this device enough

I use it every day to test automotive batteries. It’s really easy to use and helps me diagnose problems with the ignition system. It tests, the batteries, the alternator, and the starter with ease.

This is a good battery system tester for the money. But the issue of surface charge is confusing and misleading. Even with battery left overnight where surface charge has been dissipated, the tester still indicates that surface charge has been detected and asks the user to turn on headlight for 10 seconds and to continue the testing procedure. The problems with these surface charge misleading instructions are: 1. With battery left without use for more than 6 hours and attained its resting voltage, testing should proceed without turning headlights or other electrical loads on. The tester will give an accurate assessment of the battery condition. 2. With battery at its resting voltage and then turning the headlight for 10 seconds as tester prompts the user, and to immidiatly proceed to testing the battery, the battery voltage will be noticeabley lower than the resting voltage. The tester will alwasy show a much lower state of cahrge, SOC, than the actual SOC. 3. Tester should not say that surface charge has been detected when battery is at ite resting voltage, but it does. 4. Instructions should indicate to user that if battery has been left unused for more than 6 hours to ignore the surface charge prompt and to continue testing. 5. Instruction should also say to user to wait for anout 15 minutes after turing on and off the headlights before procededing to continue testing. Otherwise, SOC reading will be lower than actual SOC. Regards.

Works great! Very easy to use and tells you what's going on before you run out and spend money on a battery that's rechargeable.

easy to use, accurate

It arrived on time in and good condition. I have used it twice to check my battery, starter, and alternator. It works great, and the instructions come up on the screen that also gives you the results, so you do not absolutely need to read through the manual to use the tester.

Works well

The leads are too short for some testing, we should be able to set in the vehicle while performing the tests. Outside of that it seems to work well.

Mul fácil de usar y amigable

As user Chafik said this doesn't give the correct SOH or SOC because it isn't taking into account the temperature. For example: I used this at +5 deg C today and it was reading 12.49V. But when I ran the tester it was saying my SOC was something like 68%. Why? That isn't remotely correct. A battery at +5C has a max charge of 12.501V meaning my SOC was closer to 99.9%. It was reading my CA as 760A and my CCA as 560. Bear in mind neither of those numbers are the true CA or CCA since this device doesn’t correct for temperature. You can estimate your CA and CCA using what this device gives though. It’s fairly easy using excel. CA is determined at 0 deg C and CCA determined at -18 deg C. CCA = CA/1.25 (which is all this device is doing when you switch between CA and CCA modes). Ignore the SOC and SOH %’s this device gives they are irrelevant and incorrect. So go in excel and plot your x-axis as temperature. Test your battery in CA-mode for your first data point. So for me I put +5C as 760A. and “CCA” is 18C lower than CA so I put -13C as 560A which I got by testing my battery in CCA-mode. Plot a trendline and you can calculate your true CCA and CA. My true CCA is then 504A and my CA is 704A. The device was telling me my SOH was 100% but in reality it’s closer to 97% since my battery is rated as 520A CCA. Taking more readings would make it more accurate of course. Update as of December 2025: Still using the same product today. Still works great. As long you plot the data as I mentioned above with x-axis as temperature, y-axis as amps, you'll get the right data. Just a tip: you need to let your battery adjust to ambient temperature. Lead acid battery containers are ABS which is a bit of an insulator. If you turn your car on, boost your battery, or charge your battery, the liquid in the battery will be hotter than ambient thus skewing readings even if you do the corrections as I noted. I see a lot of negative reviews and most seem related to not taking into account as to how much temperature affects battery chemistry. A hypothetical battery fresh off the production line with brand new lead plates charged to 100% will read as 0% health, 0% charge at -55 to -65ish celsius (the freezing point of battery acid). You either wait for ambient to match CCA or CA or you plot some graphs.

Lo he probado en varias baterías y funciona perfectamente, sencillo de utilizar y muy fiable. Una manera rápida de checkear una batería 12v de manera fiable. Complementario a otro probadores como puede ser el densimetro y comprobador de alta corriente para testesr la descarga.

This product is damaged please kindly guide next process of warranty

Easy to use, good quality, good battery analysis