A while ago I wrote a simple Python script to do this testing with an airplane/drone flight controller (they have voltage and current sensors onboard) and a constant load. Here are some of the curves I did of my batteries:
https://notes.stavros.io/maker-things/battery-discharge-curv...
And here's the script itself:
https://gitlab.com/stavros/assault-and-battery/
As you can see, it's very easy to tell a new, genuine battery from an old or fake one.
What‘s the easiest and hopefully cheapest way to get a setup where I can do theses tests myself? Is there a charger / discharger with a USB interface that will let me access this data?
Hm the cheapest cheapest way is to discharge the battery to 3V and then charge it up again with a charger that tells you how much energy went into it. I'm afraid I don't know of an off the shelf way to get the curve, though... The way I did it isn't too hard, but it isn't the easiest either.
I think I‘ll try adding Bluetooth to my old Imax B6 charger to get that data.
Looks like Atorch DL24 battery tester can be used for that at a cost of around $22 or so. And the Tuya BW150 also has WiFi in and acts as a HID device for a couple bucks more.
Any explanation on the total lack of a voltage plataue around 3.6-3.8v?
What kind of plateau would you expect to see?
- [deleted]
There's (what I consider to be a poorly-named) subreddit with a great resource for buying legitimate 18650 batteries.
https://www.reddit.com/r/18650masterrace/comments/qp21o8/buy...
And https://old.reddit.com/r/battrees/ to enjoy the names of the bad ones
It's helpful, but it's 4 years old. Are they still actively updating said post?
> poorly-named
wdym?
I read the article... did I miss it? I still have no idea how to spot a counterfeit lith-ion battery without a CT scanner.
Looks like it was half written.
But, step #1 is pull up it's spec sheet and replicate their capacity testing method. At least for single cells. For packs there's not much you can do but buy from trusted places- manufacturer, bhphoto (for cameras).
18650batterystore has always been good to me, at least for the 300 Samsung 25R's I bought.
yea they note nothing can be verified visually but one option is to verify the part/mfg #,
“For most of these products, they are sold with part numbers that show an equivalency to a manufacturer’s part number."
Doubt i'd do that, would probably just source from name brands.
"One test, called a destructive physical analysis, involved dismantling small cylindrical batteries. This immediately revealed differences in quality."
hulk smash!
Obviously the appearance is not enough and it is easy to counterfeit, but measuring the voltage with a multimeter, the capacity with a smart charger and testing the discharge rate can be very indicative.
Actually the article does not provide any info about that and it just misses what is promises in the title.
- [deleted]
Asking chatgpt seems more useful than reading the article ;-)
- Too light: Counterfeit batteries often weigh less because they use smaller or inferior cells.
- Overheating or fast discharge: Fake batteries often fail to hold charge properly and heat up quickly.
- Use a charger to measure actual capacity. If it’s far below the claimed value, it’s fake.
- Use a multimeter to check actual voltage. If it’s far off from the expected range (e.g., below 3.0V or above 4.2V per cell), the battery might be damaged or fake.
> How to Spot a counterfeit battery
Section title. Proceeds to not elaborate on how to spot a counterfeit battery (besides CT scanning). Article seems unfinished and this qualifies as clickbait.
Somewhat related work using a blockchain to trace recycled Li-Ion batteries: https://www.sciencedirect.com/science/article/pii/S266737892...
Blockchan == straight into the dumpster.
How is it better than a git repository? Or even an Excel spreadsheet?
I recently found out something interesting about MC4 connectors for solar panels. It turns out the only legitimate MC4 connectors are manufactured by Stäubli. Every other MC4 connector you see is a clone of the originals, which is dangerous if they are mixed (a male of one vendor, a female of another). Differences in tolerance/fit can create unstable connections which can cause overheating, arcing, even fire. So Stäubli posts pictures so you can try to identify the clones (the easiest giveaway is Stäubli's O-rings are always black). It's such an issue that standards now require you to acquire connectors from one origin, and use the same brand and type. But I think a lot of consumers are buying random solar gear now and just plug in whatever connectors look like they fit together.
As the article was a bit light on actionable info, I'm throwing my favourite review website in the ring. I completely trust it and therefore don't have to do my own testing, as it is often recommended on sites like budgetlightforum.com:
lygte-info.dk/
Long, interesting, and doesn't actually give you a practical way to spot counterfeit. Click-bait.
The article didn't tell us how
I don’t think it’s common for consumers to buy 18650 lithium batteries, I mean I do and I know that they are all fake if you order them online… I’m not really understanding the point of this article. Most consumer products come with the batteries inside them already. The idea of somehow banning the import of unsafe batteries seems pretty unrealistic.
I think this article is also talking about things like replacement batteries for things like e-scooters, power tools, garden tools, vacuum cleaners, and so on. The original ones are quite expensive, and there are dozens of 3rd party batteries for popular items like Dyson vacuums and Ryobi 40V garden tools. I believe most if not all of these consist of a bunch of 18650 inside a plastic case with a charging connector.
And Dyson has legal liability if they catch fire and a name brand to uphold if they don’t meet advertised runtimes. Amazon does not.
If you want a new battery for your Dyson, buy a tool battery adapter from Amazon and buy the tool battery from your local hardware store. Same price or less and you get insane run time + a new tool battery.
> buy a tool battery adapter
This x100. The Dyson batteries are expensive and die quickly (someone mentioned their experience mitigating the failure time by waiting to put the vacuum back on the charger until after it has cooled off). Getting a Milwaukee adapter for my Dysons has worked out really well. Runtime is much better, and I have one less custom battery size to deal with in my house.
What do you mean they are all fake? There are no legit 18650 cells on places like Amazon?
The conventional wisdom here on HN is that every single item sold on Amazon is fake, without exception.
Realistically, there are probably some legit 18650s and lots of fake ones. But it could be difficult to figure out which ones are legit before buying them. Co-mingling of warehouse stock is often cited as a reason why this is impossible: a legitimate seller may list their items, and then some sellers of fakes come along and state that they are selling the same SKU, and Amazon will mix all of these in a single bin in the warehouses, and you don't know which one you're getting in your order.
Yeah, my first thought was, “well if it’s on Amazon you should probably just assume it’s fake and not waste time testing it.”
Just buy it on mouser or other providers that have direct relationships the manufacturers.
It's up to each seller to select if they want to allow co-mingling. There's no way to see whether the option is selected as a buyer as far as I know.
[flagged]