I want to get an inexpensive button cell tester.
I found this on AliExpress for $3.32 (direct from China):
https://www.aliexpress.com/item/1005001382138427.html
It tests many different types of batteries, and it doesn't require a battery to power the device.
Now, I didn't do a lot of research, and I'm sure there has to be something better (or cheaper) out there somewhere.
What would you recommend?
Interested also.
I am still waiting for one of these from the beginning of October when someone else pointed out a deal….annoying as it arrived in the UK on October 23rd, and then it seems to have vanished. I can claim on 12th Jan from Paypal. Mine was the digital version, but the around the same price off ebay. LINK
I suppose I’ll have to order another one.
Thanks, G0OSE!
That digital version appeals to me a lot more than the analog one I linked to.
Here's one on AE:
Cheers RC 
, if the one off ebay fails to show (likely) I’ll go for that one.
Looks good.
Does anyone know what the Pro version has over the regular digital version?
If it does not test under load its worthless. I doubt anything that cost $3.32 does.
There is a reason the ZTS tested cost as much as they do.
Just get a multimeter. It’s much more useful. being able to test your car battery and see what your alternator is putting out and check voltage at outlets in your house. And do continuity tests.
I have a multimeter, and I've never used it, and I'm not sure where it is right now.
I just want something very simple to test button cells to see if they're any good.
Funnily enough, it seems to do button cells RC, look at the drawing on the actual item - is just what u want! also does down to 1.2v the other is 1.5v.
Watch a few YouTube videos on how to use a multimeter. For checking battery voltage it is very simple.
Yes for testing the alternator works, little use for testing capacity? ie, how much juice is left.
I am no expert, but that isn’t going to show you how much capacity is left is it?, just that there is voltage in the battery - a dead battery still reads 12v, last month I had one in my car - still showed 12v but was dead as a DoDo. Bizarrely charged right back up and seems ok for now.
I don’t know how good/bad these are, but a similar one i have (with a battery in) supposedly shows how much juice is left…… supposedly lol!
Although a multi meter is an invaluable tool, it cannot reliably test a battery. Batteries need to be tested under load.
I think I'll order that same battery tester.
It looks the best of the ones that I have seen so far.
Buy like 5-10 of those testers. Seriously.
The wire on the slider is pretty much hair-thin, and will break at the joint where the hair wire is soldered to one of the tabs. (Ask me how I know.)
But they are handier than dragging out a meter. When mum dumps a pile of 3×AAA craplights on me to change the batteries, I can diddle with battery and 2 leads while trying to watch the display, too, or I can just stick the battery in the doodad and clamp it to see the reading.
That depends a lot on what you’re testing. If you’re testing the SOC (State of Charge - i.e. is this battery fresh or dead?), a voltmeter is very useful with a little knowledge. If you’re trying to test how well a rechargeable battery is performing, yes you will want to test either capacity or load (or both).
A typical car battery at 12.0V is past dead. They’re typically considered dead at 12.4, and when I had to load-test them for warranty they were required to be at or above 12.6 when beginning the test. A fully charged car battery will usually be slightly above 13v.
So, a guide off the top of my head to battery OCV (open-circuit voltage):
The freshest lithium coin cells I’ve ever seen were at 3.33 new. We recycled them below 3.0v. However, some cells performed better at 3v than others.
Fresh alkaleaks are usually around 1.65 in my experience. If I open a new cell and it’s at/below 1.5v I worry about them expiring/leaking. Depending on the load you’re looking for, alkaleaks can stop performing anywhere from 1.5v for high loads down to under a volt for very low drain applications.
Silver-oxide button cells tended to start at about 1.55v. I don’t remember testing dead ones though, just replacing when the watch stopped lol
NiMh 1.4v fresh off the charger, don’t allow below 0.8v. Typically dead around 1v. NiCd essentially the same
Li-Ion 4.2 full, or 4.35 if you hate your cycle life. To me 3.0 is dead, below 2.5 I’m extremely careful recharging and below 2.0 I recycle them.
LiFePO4 I’m not familiar with - they’re pretty flat, though, IIRC
Lead-acid: 12.6 for a solid charge. Your car isn’t really expected to start if the battery is below 12.6v, though for a healthy battery it can often continue to perform for a bit longer. for AGM batteries they must be stored above 12.6v to avoid sulfation - for wet batteries our manufacturer asked for 12.4v+ but we did 12.6v anyway. Full charge a bit over 13v
For the 3.6v lithium primary chemistries, they are very flat. I tested fresh and dead cells both with voltages at 3.6x, YMMV
Because common lithium primaries are 3.3v and alkaleaks 1.65v fresh, the 9V lithiums work very well. 3x3.3 = 9.9, which is about what you get with 6 alkaline cells. NiMh 9Vs are weird because you can buy them in 8.4v or 9.6v versions, but the 8.4v will hit 9.8v on a full charge while the 9.6v will hit 11.2v on a full charge. Various devices will respond to those in interesting ways. You of course are also working with either 7 or 8 cells, so the lower voltage might get you more capacity… and generally it’s just a mess.
It’s a nice little tester.
I found another battery tester that looks pretty good.
It's called "168Max" and here's a cheap one on AE:
https://www.aliexpress.com/item/1005001762414283.html
Other sellers on AE (and maybe elsewhere) have customer feedback on this item, but this seller doesn't have any yet.
So, there's 168, 168D, 168 Pro, and 168Max.