Dlyfull Battery Tester, LCD Display Universal Battery Checker for Ni-MH, Ni-CD, Li-ion, Alk & LiFe04 Batteries(AA AAA C D 9V 12V 18650 CR123A 2CR5 CR2032 Cells), 2X AAA Batteries Included

Works fine

So far this tester has been able to test every battery I tried. It seems to quite accurate. It has a battery of its own and has a self-test button to test that battery.

I purchased this tester because I had a much less expensive one that had problems with making connections. This tester runs on 2 AA batteries (included). There is an array of test contacts on the face that may take some getting used to. For example, you need to know the battery voltage and composition to use the correct contact. As an example to check a 1.5 V AA battery there is a specific contact. Batteries are held + pole to contact with an additional contact on a short cable for the - pole.The readout is automatic and tells you the voltage and remaining charge consistently. Just this morning I checked 3 AA batteries out of a portable burglar alarm and 2 were at zero volts and zero charge. The remaining battery was a 0.9 V and 5% charge. The advantage of a tester like this is that you know for sure what the charge is if you have devices that give you low battery warnings. I you use rechargeables it will also tell you the measurements at the time of replacement in the event a battery needs additional charge.There are only two minor downsides to this tester. The labelled contacts are embossed in the black plastic surface and in some lighting conditions they are hard to see. The readout is black on gray and that can also be hard to see in certain lighting conditions.

The large LCD display is easy on my old eyes without chasing down reader glasses. Smartly engineered so it stays in place during testing sessions, but compact and light enough to stow away easily. The coiled hide-away wand is a clever solution for managing the test lead wire — beats the tangle of alligator clip wire leads I always had wrapped around my previous tester. Two inexpensive AAA batteries power this tester vs. the pricey pair of less commonly available button batteries that my old tester used insures much longer and more economical juice life. Easier for my shaky old fumble fingers to install too.

I want to test the % of battery left in the battery. I want to make sure it is not just sitting around and is a new one mixed up with some used batteries. Lithium batteries are a little different. They hold a higher charge longer, It will say the battery is 100%, but put it in a device like a trail camera and it will only read like 25%. Precent left in battery drops off quickly. It should be a good tool for the other batteries, like the button batteries I take out at the end of the year and see if they are good enough to put back in next year.

The first one I received produced wildly inaccurate readings for each NiMH battery I tested. The replacement was just as bad as the first one. When I test the same battery five or six times in a row, each reading was different. From reading to reading I would get: 1.20 V, 1.16 V, 0.96 V, 1.05 V, 1.10 V. I used a high-quality digital voltmeter to check the same battery and got 1.26 V every reading. I tried testing the battery with the voltmeter in parallel with the battery tester, again the voltmeter would read 1.26 V every time and the battery tester would be all over the place. I did try testing some alkaline batteries using the alkaline terminal, those readings were more consistent and only slightly lower than the voltmeter. Trying a few other battery chemistries, it seems the problem is mostly with accurately measuring NiMH batteries. For a device like this to be useful it needs to achieve two goals: one accurately read the voltage and two repeat the same reading each measurement. Both devices that I tested did neither.

Works as advertised right out of the box.

Works fine providing accurate readings. Good value for the price.