KONNWEI KW650 6V 12V Car Battery Tester, 100-2000 CCA Battery Load Tester Automotive Battery and Alternator Tester for Vehicles/Marine/Motorcycle/Lawn Mover

Simple to use and gets the job done. Wanted something that was not overpriced, with good features and the ability to test a variety of batteries, alternator, and starter condition. After using this on several vehicles and batteries I have learned how the resistance of the battery and expected life of battery work. The feature for running voltage and ripple current graph have become very handy during load test. The starter crank test and time have helped find two starters that needed to be replaced. The screen is easy to read, menu functions are simple to navigate, and battery clamps / wire are of good quality.

I've been having some doubts about my fairly new car battery (Interstate, 700CCA) recently and wanted to make sure I test it before taking it back to the store.I am aware that batteries will lose charge if the car is not used for extended periods of time (which is my case due to WFM for months), but I was thinking that it would take much longer to a new battery to get there, maybe at least 1-1.5 months, especially in nice weather. I have been driving my car about every couple weeks or so, but mainly short drives. I thought that maybe the battery I picked did not quite happen to be the pride of Interstate product quality.Since I've wanted to own one of these battery testers for a while now, I figured that this situation would be a good time to get one, so after looking through several models to get familiar with the common feature set offer vs. cost, I settled to this Konnwei KW650, even though I was a bit reticent about the brand unknown to me.There are a bunch of these testers available, many of them offering similar if not identical feature package, even though the prices differ a lot in some cases, but the reasons that made me go for this one were the nicer processing speed and display, car starting voltage waveform capture and the software update capability.I figured that my risk would be minimal considering all the good reviews and Amazon's easy return policy.Well, I must say that I am very happy with my choice; this one is a keeper. After updating the software as soon as I received it, which was pretty easy to do BTW, I checked my battery and found that even though it was in a pretty badly discharged state, the tester showed that the battery was in very good condition and just needed a good charge. The state of health was 100% and the state of charge was shown to be only 10%. I have also tested a known weak battery I had stored until I can find the time to dispose of it. I tested it both before and after charging it, and in both cases it indicated a very low state of health and prompted replacement. I was planning to rent a professional battery tester and check the full instrument accuracy for parameters like the battery resistance, SOH, SOC, but at least from what I am seeing so far from my tests (lead-acid battery only) everything makes sense.The voltage measurement had only a small accuracy deviation of 0.06-0.1 max over a wide measurement range when verified against a professional meter, but that is meaningless for the purpose of this tester. The voltage ripple was also slightly off, but you can see some of that even when comparing more expensive equipment. The min/max voltage captures during engine start were also reasonably accurate.Considering the cost and intended purpose of the device, I believe that it is more than adequate for the job, and in my opinion, paying any more for a known brand would not be justified from the performance stand point. At least not for my home garage use.In terms of workmanship, I have nothing to object: It comes in a nicely looking plastic case, light weight and just the right size to hold with one hand, clear color graphic display with an easy and intuitive user interface. It has thick yet reasonably flexible 38 inch cable to protect the 4-wire Kelvin test leads, with solid connections to the battery connection clamps. I wish the cable were just a bit longer to reach the vehicle cabin when performing some of the tests more comfortably from the inside, like the car charging system. Not a deal breaker, because these tests are still easy to accomplish, but it would have been more comfortable that way.Now the one feature I was hoping to have on this device, was to be able to factor in the battery temperature into the CCA measurement and SOC calculation, as temperature is a huge factor in battery performance. Again, not a deal breaker at this price for me, but since most higher end devices can compensate for temperature, I believe that it would be a great feature addition and a cheap way to gain an edge over the competition. I wouldn't expect the addition of a battery post temp probe/sensor (although I would actually pay for the cost difference) but at least by manually entering the batt. temperature during battery test setup.Since the software can be updated online, I am hoping that this feature can be added later, and perhaps along with some other good things in the future. Who knows, maybe Konnwei is listening.

Work's great I checked my battery with this device and it was easy to use and it was accurate it showed that I had a bad battery cell when the dealership said I had a good battery I went to Advanced Auto and got a better battery and warranty plus they installed it free. I recommend this device.

I got this for a truck I was working on & it turned out that battery was OK. A couple of weeks later the battery died in another vehicle. This came in handy. Even not connected to USB and with a battery voltage under 8 volts, it powered up. I input the type of battery and cold cranking amps (CCA) and it showed the battery was only at 3%. When I tested the replacement, it came in at 97%. This was a good value for a handy tool to have in my shop.

I used the Konnwei battery tester on two cars (one very old, one brand new), and 4 small lead-acid batteries used in a UPS (Uninteruptable Power Supply). The new car had a battery that was in very good shape, but didn't have much of a charge, as it was sitting at the dealer lot, and was shipped from abroad. The new car was a 2019 Hyundai Kona with a 60 AH, 640 CCA AGM battery, and it was at 100% SOH (State of Health), but at 56% SOC (state of charge). After charging it, the Konnwei unit showed the charge up to 98%. It is important to keep lead-acid cells near full charge, as if they are allowed to sit partially discharged, they will form sulfates on the plates, shortening the life of the battery. The second battery, on a 2003 Hyundai Santa Fe was about 3 years old, and the car isn't driven much, so the battery loses its charge because of typical parasitic current draw from the on-board computer, clock, radio, etc. The pictures show the SOC, SOH, and a photo of the Konnwei connected to the battery with a disconnect switch on the battery. While the battery is good, it shows 82% SOH, as the photo was taken at 28 degrees Fahrenheit, and lead acid batteries don't have as much 'get up and go' at lower temperatures. The four small lead-acid batteries that I checked that came from a UPS were 7 years old, and only showed about 2% SOH, so they were ready to be recycled. I also like the feature where you can get an 'oscilloscope' style display (graph of voltage over time during the car starting up), and so you can see if the battery is getting near end of life, or is still good for a few more years. Both batteries in both of my cars showed good starting performance at 30 degrees Fahrenheit. This is a must-have for folks with cars more than a few years old, as you will know when to replace the car battery before it gives you trouble, and leaves you stranded somewhere. This unit uses a new technology where it judges SOH from the rated CCA (cold cranking amps) and the internal resistance of the battery. An excellent tool to add to your garage.

Came in the original box, sealed. Work out of the box . Easy to use, plenty of youtube on how to use the tester. No complaints