[Alex Hao] and [Andreas Bastian] of Lumafield recently visited with [Adam Savage] to share their battery quality report, which documents their findings after performing X-ray computed tomography scans on over 1,000 18650 lithium-ion batteries.
The short version — don’t buy cheap cells! The cheaper brands were found to have higher levels of manufacturing defects which can lead them to being unsafe. All the nitty-gritty details are available in the report, which can be downloaded for free from Lumafield, as well as the Tested video they did with [Adam] below.
Actually we’ve been talking here at Hackaday over at our virtual water-cooler (okay, okay, our Discord server) about how to store lithium-ion batteries and we learned about this cool bit of kit: the BAT-SAFE. Maybe check that out if you’re stickler for safety like us! (Thanks Maya Posch!)
We have of course heard from [Adam Savage] before, check out [Adam Savage] Giving A Speech About The Maker Movement and [Adam Savage]’s First Order Of Retrievability Tool Boxes.
the hard bit is actually buying reasonable batteries, and have the same ones still exist a year or two later when you want more..
and hitting the ‘get the report’ doesn’t result in any way to get the report..
Hi Ian. The report can be downloaded for free from the link given, but there is a form that asks for some of your details before they give you the link to the PDF. We have asked Lumafield if we can direct link to the PDF from our article. We’re waiting to hear back from them.
ahh, it is probably a pop up form that isn’t poping up as I don’t allow them..
Sensible choice. In ordinary circumstances the following link will take you to the download form where you can enter your details to receive the report. If Lumafield gives us the okay to direct link to the PDF we will update our links. Thanks for your patience. https://www.lumafield.com/battery-report#battery-quality-report
ordinary circumstances for me is not to allow popups :-) – they should have done it as a normal page…
They are doing great marketing act on this one, milking the cow. How long and how many times I’ve seen these results.
I’m really sure they are not that worried about the quality of 18650, just marketing in a sneaky way.
It’s a useful service. First, the public now knows they have the ability to look inside these things; second, the manufacturers know that the public knows and can see what sort of bullshit they’re peddling. Keeps everyone on their toes.
Didn’t we already do this article?
Oh no! We did! The thing that is new is their appearance on [Adam Savage]’s Tested program. When I checked for duplicates I only checked for the YouTube video, not the Lumafield report. Sorry! The first Lumafield article is here: https://hackaday.com/2025/09/29/lumafield-shows-why-your-cheap-18650-cells-are-terrible/
I read this report before wtf hackaday you cant generate enough clicks now? this sucks damn
Sorry for the duplicate. It’s not a conspiracy to generate clicks, just an honest mistake because the video from [Adam Savage] was new.
That stuff in the video about the wavy nature of the separation being so bad was such absolute rubbish, as long as it is separated only someone who is at medication-needed level OCD would care about the waviness.
And yeah if you count that then it seems very bad, while if you go by the actual issues they had what? 1 battery where there was no separation? And some manufacturers don’t use a valve? A valve that when present might cause its own issues I would think.
Just use your own brain folks and not some hype-wagon.
Oh and who had the big combusting batteries issue again? Samsung had with their line of smartphones back when, and Boeing with their battery pack in their planes. But we should trust the big brands with all our hearts and souls.
It can be all about statistics and karma. If you can decide between more and less safe way, you have some clues here. But if you have bad day, you will eat all the mud. Use the seatbelts everyday but if you meet truck in microsleep you are lost. Long term stability, short term pitfalls and so and so.
So your average German or Japanese engineer is at medication OCD levels? Lol
Here is me using my brain to combat your willful ignorance. The “wavy nature” of the jelly roll inside the call matters because although the separation is there, the vertical variation can lead to “shoulder shorts”, where the top of the jelly roll can short with the can.
Lion cells generate gas internally, which is why the better manufacturers uses valves. That helps (does not prevent) the cell bulging.
The Samsung issue was not with the cell but with the case design not allowing enough room for the call to expand.
Boeing doesn’t make battery packs.
OK I was wrong.
Asking people to use their brain at this point in time.. and not only that, but asking them to not get on the hype train.
Yes indeed, that was pretty silly of me.
Anyway, if you ever see a wavy line somewhere be sure to self-immolate, that’ll show em.