12V Car Battery Tester, TOPDON BT20 Battery Load Tester 100-2000CCA, Cranking&Charging Test via App, Record Voltage History, Automotive Battery Analyzer&Checker for Car Truck SUV Boat

I just got this battery tester today, but I have several batteries laying around to test it with and an old (15 years old) OTC battery tester to compare it to. I also have a couple multimeters to match both of them up with.This reads the voltage to the tenths of a volt on the tester itself, but to the hundredths on the app. It's accurate more than accurate enough, a bit of fluctuation in the hundredths between all my testers, but that isn't uncommon.First, this will actually drop the voltage during testing, quite a bit if the battery isn't very good. Can't say that of my old OTC.This will not give a read out of the cranking or cold cranking amps, my OTC will. How accurate is it? Who knows, but it hasn't let me down in 15 years.Now, here's where things get complicated. My old OTC will give one battery I have a pass, where as this tester fails it under a load. I trust this tester due to the drop in voltage (I didn't save the test or I would have the numbers and would post the picture) seen when testing it. It's a small battery that sat a long time, although it holds a charge just fine and the voltage is also fine at 12.6v.Overall, I'm impressed. This cost me about $20 on sale and I'm glad I jumped on it. I have other batteries I plan on testing with it, one had been sitting on the charger (just floating, already fully charged) for a while and needs to rest before I test it.Oh, and the app is very easy to use. I haven't used all of the features, but I intend to make a point to.I think this will work great and would be a great addition for any level of tech that picks it up for their home or shop toolbox or emergency tool kit.I will update sometime in the future after I've used it for a while.

Works great. accurate tests.

The tool itself seems to be good enough and worked simply, but in order to use more features which are part of the BT App, you have to agree to their policies and terms of service. I don't normally read through it all, but it also didn't take long to find the phrase multiple times, that you must agree to the policies set by the People's Republic of China. That's a red flag for me not to use the BT App with this tool (use at your own discretion of you wish).Unexpectedly, I was contacted by the seller after my initial review. They explained that the information in the policies and terms of service For the app was required (which I agree, it should be). To the sellers credit, they offered to upgrade my purchase to the BT100 at no cost to me (not expected). I accepted their offer. After receiving the BT100, I gave it a try right away. The BT100 does not require an app to use all the features of checking the battery, starting and charging systems of vehicle. It is also VERY simple to use. The only thing I would change would be to use longer cords, in order to use all functions without assistance of another person. In order to check the charging system you have to raise the RPMS to 2500 then hit the enter button, which is a little difficult to do by yourself. Otherwise, I do recommend the BT100, even for the extra minimal cost.

This is going to be a detailed review. The short version is, its a MUST buy!Lets start with the packaging, nice simple box with plenty of information on it. Once you open it up, you find the tester and instructions. The instructions are well written, and in a few different languages.The tester feels nice and solid, if you squeeze it the plastic does not flex or squeak. The clamps are compact but feel solid and they open really wide making it easy to get onto any battery terminal.The tester is simple and advance at the same time. When you hook up the tester to a battery, it will tell you if the battery is low on power right away as you can see in one of my pictures. The first battery was reading at 9.7v and the tester told me right away. On another picture you can see I am testing it on one of my cars that sits a lot. Battery shows 12.1v, but hitting the "TEST" button, it puts a load test and told me it was falling down to 10.6v.The tester is also advance, once you download the app to your phone, you can run a few different test. The load test will graph out the results if the battery drops down a lot. The best part, after every test you can save the results to check out anytime.The last test I tried was the cranking test, right away it told me the battery has low cranking voltage. I suspected this was the case, as it has gotten colder I have noticed the battery struggling a bit, this only confirms what I suspected.My ONLY complaint, I wish they would have put a QR code to download the app, either on the box or instructions. However the instructions does tell you to download the app from either the playstore or Apple app store.Over all this is a must buy for any dyi'er or even a professional mechanic. Also would make a great stocking stuff to any gear head!

Between two vehicles and a couple of boats one which has three batteries I really needed this tester. It worked great when I tested both batteries that were in good condition and a battery that I knew was weak. The tester detected the weak battery and the software app worked fine with no problems on my phone.