YKL WORLD Battery Tester, Digital LCD Universal Battery Checker for AA AAA C D 9V 1.5V Button Cell Batteries (Model: BT-168D)

Updated review:When I first got this, the screen was garbled and illegible. At first I thought I fixed it by cleaning the contacts. But later I ran into the same problem and cleaning the contacts had no effect. What DID work was simply pushing on the case near the screen. Somehow that pressure got the display to work.So, at least in my case, the quality was clearly lacking in this device.—————Original review:I was seconds away from deciding to return this device when I couldn't get a legible readout from the display for the first few batteries I tested. I assumed at first that it just had a defective display. (I wish I had gotten a photo of this, but basically the digital display looked like an alien language or something when I connected a battery. No legible numbers.)But, before giving up, to make sure it was making a good electrical connection with the battery, I wetted each end of a battery before testing it, and voila, it suddenly worked perfectly and displayed a crisp and clear voltage number on the display. After this, I wiped the moisture off the contacts, and in doing so I can only guess I must have cleaned off some gunk that was preventing a good electrical connection with the battery, because every battery I tested after that worked perfectly even when the contacts were dry.So... seems to work ok now. But this annoying quality control issue almost led to a needless return.

This tester is very interesting. Once you find the sweet spot on the tester to hold the batteries it works great. I tested some batteries that had failed in a TV remote and a mouse. Both took two AA batteries rated at 1.5 volts. The dead ones tested out at 1.37+/- volts each and the brand new ones tested at 1.57, 1.43, 1.54, and 1.48. Now to me, this means the tester is very sensitive or the remote or mouse are. I put the "dead" batteries in a AA mini-Maglite and they worked. No telling for how long but if this holds true you could save money on throwing away batteries that aren't completely dead.

This tester comes also in analog version, but advantage of digital is to show any (exact) voltage. That way I can test any battery - it doesn't have to be 1.5V. I can even test 3V coin batteries. It doesn't need internal battery, since it powers itself from the tested one. It takes less than second to display results and it is stable, clear to see. The only case it doesn't work right is testing tiny hearing aid batteries (like size 10). It still works, but load on battery causes slow voltage drop. On the other hand I like that it puts some load on battery. It makes testing more realistic and prevents batteries with high internal resistance to pass. No wires, no swiches, tests everything and is very compact - what else you can ask for?!

A nice battery tested. It could be easier to load the battery in.

As advertised.

would spend more money on a better product

Simple to use.

This is an excellent, inexpensive battery tester. It is accurate enough for you to determine whether or not to keep or toss any battery. Showing the actual voltage is preferable to a simple go/no go screen or green/red indicator. Easy to use. Pays for itself in a very short time.