Universal Battery Checker Tester with Leads LCD Display, Battery Capacity Voltage Resistance Tester for AAA AA C D 9V Digital 12V 3.7V Li-ion 18650 CR123A CR2032 Button Cell Batteries More

This battery tester works quite well. It accurately tells the battery's power level, not just good, bad, or needs replaced like some testers do. The price isn't bad for the item. It is pretty well built also. It has an electronic display and takes batteries. It tells the % of battery power left from 0 to 100%. It can test about any type of battery.

Bought this to test CR2032 CMOS batteries and it found the weak ones!It does measure the batteries under load (a Pro) but it does not leave the load on (also a Pro). It seems to pulse the load on and off twice before giving the ESR measurement but the voltage displayed is a snapshot of when it was under load (a Pro).This is backed up by the fact that primary lithium batteries (non rechargeable) always give you ~3v when not under load so a multimeter will never be accurate. That is why a tester that puts load on the cell is a must when checking them. I was seeing voltages from 3 to 2.5 to 1.8 to 0.1 and I got rid of any that were under 2.5 around 2.2 to 2.3 or less so I am sure the batteries are going to last a long time in the computer I put them in.Pro's-Auto off feature that almost instantly wakes up, no different than a modern soldering iron (I have a TS-100)-Springy tips for stable contact, one note on those is that the wires are attached directly to the tips so the wires move when the tips move so you dont have to worry about that being an extra variable.-Almost true 4-wire, the cables are thicker than what might be needed is because there are 2 wires inside each. The reason it is almost true 4-wire because the wires connect in the tips not on the contact of the battery (see Con's).-Has a boost converter for low battery stability and accuracy. The internal voltage is higher (5v) than the battery voltage (<3v) so if the battery voltage gets low the output will still be the same until it cuts out completely.Con's-Uses AAA batteries, it could have been greatly improved if it had a rechargeable li-ion battery. It is so close because internally it uses a 5v boost converter to power the internals, so a li-ion battery, protection, charger and usb port would not be hard to implement, I would spend 5$ more if it had that.-Not true 4-wire, as stated in Pro's the 4-wire ends at the tips not continuing onto the battery to be tested, so always test 2 or 3 times to make sure you are making good contact on the terminal and the true reading is the one you get the most.-Rotary power switch, I like toggle buttons so I am not spinning the rotary dial all the way around to turn it off then spinning it all the way back to turn it to the same mode.I am overall pleased with the meter it is great for the price and I think some simple improvements would be great additions in a V2.

First, this meter is designed to test mostly individual cells. It is accurate. It gives a better indicatio of the battery's health than most other testers. The attached test probes are much above average. The spring loaded gold-plated probe tips are pogo-pins with multiple pyramidal tips for excellent contact and consistent readings. The test lead wires are less flexible than I would like. The individual test probes are handy if you store your batteries in organizers that allow access to the battery contacts, but they are otherwise awkward. Good luck testing button cells. Some kind of holder built into the case would be welcome.The manual is difficult to undrestand.This instrument present several indications of a battery's health. It seems to report the open circuit (unloaded) voltage which is what a multimeter would measure. The open circuit voltage alone is not a very good indicator of the battery's state. While alkaline batteries have a gradual decline in voltage with use, other chemistries do not. For example, lithium cells have a very slight decline followed by a precipitous drop. All batteries Have a lower voltage output under load (when they are supplying current). So, the open-cicrcuit voltage may look good, but they won't run your device.. Many testers measure the battery's voltage under somel sort of load to get a better estimate of capacity.. This meter displays the battery resistance, which is the reduction in voltage divided by the change in load current. The resistance becomes higher with use. The meter uses the unloaded voltage, the measured resistance, and assumptions of other factors related to battery type and typical load requirements to estimate the remaining battery capacity. Obviously this can only be a guess of how the battery will perform for you, but it's better than other testers. You need to account for the load's characteristics. For example, does it draw high current? You must use the information from this meter --more than you get from most battery testers--together with your knowledge and experience to decide if you need to discard or charge--if appropiiate-- the battery.On another note, cells that have been in use will often have widely differing meter readings among rhe set. This is not a fault of the instrument. Cells are not made equal; they have slightly different discharge characteristics. Cells in battery packs influence each other as they discharg, resulting in differing discharge rates between individual cells. . Cells that are connected in series can even try to charge the cell that runs out of capacity first, backward! For best results, batteries should always be replaced as a set.