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

This battery tester is compact, intuitive, and seems to produce repeatable results. Haven't tested the starting and charging readouts, but I've tested a few batteries and it seems spot on. One caveat is that in my car with a trunk-mounted battery, reading from the hood terminals (using the in-car reading option) produced a SOH (state of health) reading of 50% with instruction to replace, whereas reading directly from the battery produced a SOH of 90%. Not a fault of the reader as the long cables going from the battery to the remote terminals adds to total resistance and thus reduces the health rating, just a warning to those with similar setups to avoid an unnecessary battery replacement.

Great product

Positives: -Works as intended, providing accurate battery readings. -Easy-to-navigate menu for hassle-free operation. -Compact design allows for easy storage in the car's compartment. -Essential for regular battery checks, especially for those experiencing battery issues. Negatives: -Virtually no drawbacks; it effectively delivers on its promises. The KONNWEI KW208 12V Car Battery Tester has proven to be an indispensable tool in my car maintenance routine. As someone currently facing battery problems, I rely on this device to regularly check my battery's status, and it has been a lifesaver. The tester works exactly as intended, offering clear and accurate readings that help me determine when I need to charge my battery. The menu is straightforward, making navigation quick and simple, even for those who may not be tech-savvy. Its compact size is another standout feature; it fits snugly in my car's storage compartment, ensuring that it's always on hand when I need it. While there are no notable negatives to mention, it’s worth emphasizing that it fulfills its purpose effectively. Overall, the KONNWEI KW208 is a reliable and practical investment for anyone looking to keep their car battery in check.

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.

I bought this primarily because I had been dropping off some used motor oil to my city collection center and saw a pallet of used batteries submitted for recycling. Among them was an Optimus Blue Top combination starter and deep cycle battery commonly used in boats. This is about a $400 battery so I thought what the heck and took it home to see if it would hold a charge. Sure enough it charged up just fine and seemed ok. However, I know a battery can show full charge but still not have the cranking amps. This is a spiral agm battery so I set the unit accordingly and tested it. It tested good on both CCA and MCA. So lucky me. I also have a car that I just put a remanufactured battery in (bad idea, don’t waste your money) but the cranking rate seemed slow. No CCA rating was printed on the battery so I just guessed 550 and tested it. It tested ok but not great. Lastly, I have an old jeep that remarkably has had the same battery in it for over 15 years. If I kept on a 1 amp charger during periods of no use (a week or more) it will still start the car just fine and continue to start it if in daily use. The load tester showed to replace the battery. That battery is no going thru several repair cycles with a 5 amp NOCO charger. I’ll let you know how it works out. It also worked fine for testing the alternator. In summary, for a diy’er, I think this is a fine tool. It is solidly made, the wires are heavy enough and long enough, and the clamps are very well contructed and hold tight. One reviewer indicated the instructions are microscopic and very broken english and was kind enough to give some alternate instructions. However, it is very intuitive to use so once you’ve done it, you’ve got it. For $25, go for it. P.S. - i highly recommend NOCO Chargers. A touch on the pricey side but very high quality.

easy to use, accurate

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