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:
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.
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.
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.
"One test, called a destructive physical analysis, involved dismantling small cylindrical batteries. This immediately revealed differences in quality."
Hezbolla would also like to know. Seriously though, batteries make me nervous, they can seemingly go up in flames anytime, though it has only happened to one person i know so far. The only trouble i've ever had is old AAAs eating up some unfortunate alarm clocks.
From the article it sounds like it's practically impossible to tell if your battery is dodgy.
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.
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.
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.
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.
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.
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.
"One test, called a destructive physical analysis, involved dismantling small cylindrical batteries. This immediately revealed differences in quality."
Hezbolla would also like to know. Seriously though, batteries make me nervous, they can seemingly go up in flames anytime, though it has only happened to one person i know so far. The only trouble i've ever had is old AAAs eating up some unfortunate alarm clocks.
From the article it sounds like it's practically impossible to tell if your battery is dodgy.
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.
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.