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In the Netherlands many people use these kinds of detachable bike lights. I've never came across soldered batteries in the dozen or so I've replaced batteries for. Not always cheaper, but just tossing the whole thing seems like such a waste.

Well done!

There are also dynamo powered LED lights which only provide light while riding the bike, and about a minute afterwards (I assume from an internal capacitor). They are not detachable but why would that be necessary? From what I can tell they also don't require regular replacement.
These are fine for bike commuters, and I’ve had them before. But they are in general not fine for recreational bicyclists; these people pay a hundred dollars for a new tire to shave off three watts and are not about to add any unnecessary human-powered accessories.
An exception is bikepackers, who may prize reliability and runtime over brightness and weight. But then the dynamo we're talking about is $200-$400 and that's not including the light.
> An exception is bikepackers, who may prize reliability and runtime over brightness and weight. But then the dynamo we're talking about is $200-$400 and that's not including the light.

No, it's about a tenth of that, light included.

Amazon has the Shimano dynohub for $125. Then you have to build a wheel. You might be able to re-use your rim if it's got 36 holes.

I explored dynohubs in the past, but LEDs and LiPo batteries have really narrowed the gap. In my garage, I've got a super long USB cable that we all use for charging our lights. I've used cheap lights from AliExpress, and they are actually quite durable.

Nonsense. At $20 you'll be very hard-pressed to get even a cheap dynohub alone, and that's before the wheelbuild and the light. And bikepackers aren't going to be satisfied with ultra-low-end wheels, anyway.
> And bikepackers aren't going to be satisfied with ultra-low-end wheels, anyway.

bikepackers aren't an homogeneous population. Some are more instagrammers than bikepackers and are using expensive bikes and equipment, others bikepack on a shoestring budget with stuff from the thrift stores and you could mistake them for homeless. And finally some are actually homeless. And you get any kind of budget and requirement/vanity level inbetween these 2 extremes.

This summer while I was cycling I came accross an ukranian guy who was bikepacking accross europe with an old mtb from the 90's, using an old kids trailer to carry his gear and water supply. He was stranded in a climb in the middle of nowhere with a broken wheel, 3 or 4 spokes had given up the ghost, and the tire was flat you could see the casing instead of the tread on both wheels. We could only communicate using google translate on my phone but he told me straight nomoney. His tent, which he had setup on the side of the road to have a bit of shade could have come from a dumpster judging by its state and discoloration, that tent was 20 to 30y old. Since my daughter has a folding bike with 20" wheels and I was 20 minutes from home I convinced him to give me his wheel, filled his empty water bottle with my own, gave him some snacks and went back home to check if spokes length matched any of my daughter's bike wheel and relaced quickly his wheel using 4 spokes from my daughter's. Then I climbed back that climb with the repaired wheel, 2 tires from my daughter's bike, a veggie sandwich and 4L of water (having myself a bike that is bikepack ready made it easier) so he could eat something and set off. He paid me with what he had available: a big hug and proposed to help me with my back (I understood he was some kind of chiropractor) which I declined.

Wow, that was very charitable of you. I don’t have the wheelsmithing skills to even attempt that repair.

I also met a number of homeless people while on a long bike pack (C&O + GAP). They were usually pretty hard up: they lived in junky tents off the side of the trail and used their bikes to commute to work. It’s hard for me not to think that we have failed in an important way if somebody is dragging themselves to work while living out of a tent.

I remember my mum telling me about going climbing in the 1960s with people who would saw the handle off their toothbrush to save 10g or so in their backpack.

Seems a little performative to me, that's about the weight of all the raindrops on your jacket.

A reliable dynamo hub setup can be very cool for the right situation, but the up front investment to rebuild your wheel around a dynamo hub is expensive. The power output is also on the low side compared to the light output you can get from the battery units.

Not having to charge anything or worry about batteries running out in the dark is a real benefit.

It's all on the very opposite end of the cost spectrum than the cheap bike light in this post though

The old-school dynamos cost 10-20 bucks: https://axabikesecurity.com/product/axa-8201-right/

They're just generic DC motors held against the rim, as simple and cheap as it gets. Nowadays I'd add a basic voltage regulation circuitry to get stable 5V out of it.

That's why I said "reliable" in my post.

You'll spend more time futzing with one of or dealing with weather-related failures that you would have saved more time charging a pile of batteries before every ride.

That overstates their unreliability. Such dynamos used to be universal before modern rechargeable batteries and worked well enough, I don't recall ever having to replace or maintain one. For dirt roads where mud gets everywhere, non-mechanical options are of course better, but simple dynamos perfectly are fine on regular city streets, country roads and dry paths. They're especially good for kids who can't be bothered to keep batteries charged.
I don't remember a period of my life where bottle dynamos have not been unreliable when it rains, and it rains a lot here (or it used to, anyway).

I have rigged all kinds of rubber contraptions to make them work better, I have made my own dynamos from old electric motors as a kid, and yet I have never in all those decades found a way to be sure they would work when I need them, never.

Aren't those dynamos going to wear down your rim quite fast ?
Aren't those dynamos going to wear down your tire quite fast ?
> The old-school dynamos

I recently bought a dynamo from what should be a good brand (dunno the name off the top of my head). Cost about 45 Euro's, not cheap. Just after a couple weeks, whenever I cycle through the rain my dynamo wheel would slip and I'd be fully without light. I thought it was not properly pressing the rubber of the tire. But I found that the wheel was just cheap plastic garbage, totally worn flat already. I guess capitalism flew by, enshittifying once more what was once good.

The old-school dynamo's were undestroyable iron casings, with an iron wheel with deep grooves. Now I am looking if I can find one of those again, to last me a lifetime.

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Depends which one you buy! I bought a SON about 10 years ago, have done around 20k miles in all weathers, and have had zero issues at all with it.
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Unfortunately most dynohubs are essentially un-servicable. The ones that do claim some level of servicability (eg, SP) mention a very tricky re-alignment process when replacing the bearings that can only be done successfully at the factory. I've gone for an Alfine on my new commuter - it's been fine for the past year, will see how it goes.
Shimano hubs are a bit heavy but quite reliable. No maintenance required, survive frost, rain, heat, any weather.
Love this. I have a pile of nice Cygolites (both front and tail) that my whole family uses that are maybe 8 or 9 years old. Their capacities have largely dropped to the point that I need to charge them every ride or two. Maybe get about 90 minutes of use, down from 3-4 hours previously.

They're not user-serviceable by design but I've been pondering cracking them open and having a go at swapping the batteries. This post may inspire me.

I've got a pile of new 18650s lying around and hopefully the front lights use those!

Depending on your lifestyle, IMO the USB-C cygolites are worth the expense vs dealing with old ones
Talk about burying the lead. This was a MEC bike light. It should have a replacable battery!

https://www.mec.ca/en/explore/sustainability-innovation

Ah, memories. I miss the old MEC, before they overextended on real estate and had to sell the farm to private equity. I have a pile of MEC branded gear I'm still happily using 20 years on. I have some restrained hopes for the new ownership group to bring it back, but I'll always miss the co-op.

These lights would have predated the private equity era but I'm guessing sourcing options were somewhat more limited back in 2016.

The best motorcycle sunglasses i every bought were mec, from the vancouver store in around 2005. Flat sided (for helmets) with interchangable lenses, and seriously dark lenses too. But when I walked in, in full sportbike leathers, i got more than a few dirty looks.
[delayed]
Actually, I should mention that I didn't know about their corporate change from a co-op with members. My first contact with the change was my account being erased and being told to create a new one because they are "changing over to a new system". No mention of having become a different, scummy company. Basically they started out by lying to long-time customers of the old MEC that it was just their database that was changing and for some inexplicable reason, not being able to migrate the old membership accounts. Just despicable.
Did we not just see the battery replaced? ;)
I don’t know what it is with Julia’s writing but it always makes me happy. It reminded me of replacing the soldered battery in Super Metroid so I could save my progress again. As a cheapskate I used a regular battery and connected the wires mechanically.
I wouldn't worry about matching the exact model number of the battery. Instead, it's more important to get roughly the same chemistry and a capacity equal or maybe a touch greater.

Specific batteries go in and out of production. But as long as it's the same CHEMISTRY, voltage, and capacity, it's likely compatible. Chemistry tends to set the voltage, size sets the capacity.

The chemistry set the voltage and the voltage and the size set the capacity. Everything else equal, a larger capacity battery is often compatible with an original smaller capacity battery in a given device because the charge current will be lower in relation to the capacity.
The corollary to this is that if you choose a smaller capacity battery, you run the risk of charging at too high of a current possibly leading to fire.
I know it's slightly offtopic, but the brand I am using - ExposureLights - offers a battery diagnosis/replacement service for their bicycle lights.

Those are on the expensive side, but still, most brands would rather sell you a new one.

Love to see MEC gear - but I wish it were more repair friendly!
I recently had an even easier time changing the rechargeable battery in some mini Christmas lights. The unit was a solar panel in a box held by 4 screws. Took them out, and it was a regular AA nimh just slotted in there. Changed it out and the thing worked again.

I wonder how many people just chucked the unit when the battery wore out.

I just bought the Steam Frame, valve's new VR headset. After hunting for a USB port on the paddles i was shocked to find how eaily it is to replace thier batteries. They are Duracell AA.
Younger people probably do not know how bad rechargeable lights were in the past. In the 90s I bough a set of lights for my bicycle that I could directly plug into a 230V socket and I kid you not the battery lasted for less than 15 minutes, which was just one way from my appartment to the pool where I was training at night. I had to ride back without any light until I finally bought a new dynamo. There was not really much progress until lithium batteries suddenly solved many problem.
On the subject of bike lights. Most of the current lights appear to use some LEDs which makes sense, of course. However the brightness of output light looks like completely unregulated.

On so many occasions I would get blinded by overly bright lights of an incoming cyclist during late evening ride.

Probably depends on jurisdiction. E.g. in the UK there is no formal limit (and car headlights are more powerful than bikes') but light must not dazzle or cause glare to other road users, hence why headlights on full beam must only be used in certain circumstances, and beams in general must have specific orientation.

So if you are blinded by an incoming cyclist this is not legal... of course enforcement is another matter.

It's not a brightness thing, after all car headlights are probably 1000x brighter than anything you may have on your bike.

It's because 99% of bike lights are basically just flashlights, spraying light everywhere. The solution is the same as for cars — lights with horizontal cut-offs.

I do some optical engineering, and once took a course on lighting design. Indeed, bike lights are unregulated, and therefore, un-engineered. During the winter on my commute home from work, I usually have to cover my eyes on the bike path to avoid being blinded by oncoming cyclists.

I think Germany has regulations on this. I've bought lights on AliExpress that have a cut-off.

It might be complicated.

It is indeed unregulated and often blinding. But there is also no one limited use case as it can be for car lights:

- these lights are sold internationally so they don't assume one specific country in the first place

- it's not just for road use, people will use them in rougher bike paths where there might be absolutely no other light.

- seeing the path forward isn't often enough. You don't have a windshield nor can assume a cleared path, so knowing what's at head level can also be crucial. Even on dedicated bike paths there will be branches and unmaintained/unexpected bits that need avoiding.

- being seen can be as important as seeing yourself, and often back lights are small and a pain to recharge. Many customers will want a wide spread front light that reflect all around, even if it mean charging it more often etc.

All in all, it might be that biking itself is wholly unregulated so lights will have a hard time being single purpose and regulated as well.

I also hate flashing lights. Is it just me or do flashing bike lights cause some kind of strange mild disorientation? In addition, they are distracting and stop me seeing other things.
It's not just you. Objects that blink are hard to track (our brains aren't good at it), and working to process it anyway creates an unnecessary distraction as a secondary effect. And as a tertiary effect, this added distraction leads to a reduction in safety.

Having some movement can be good, though. This is why I went out of my way to mount reflectors on the back side of my aftermarket pedals.

Along with a constant red tail light. And a fixed red reflector.

(A grown-ass man with reflectors on his bike? You betcha. The dork disc is still intact, too. I don't like crippling surprises, and I'll look way better with a safer bike than I ever can in the hospital.)

I think flashing makes more sense at day time or twilight where they aren't nearly as contrast with the background brightness. You get massively better battery life blinking than solid on. But of course nothing stops a incompetent user using flashing lights pointed upwards at night.
Much of that (I'd like to say most) is due to a bad beam pattern and/or improper aiming.

For instance: Round beams suck. The first LED front light I ever bought was nothing more than a flashlight that took 3 AAA cells and attached to a handlebar mount.

It produced a round beam. If I aimed it up/far enough ahead that I could see the road ahead in any meaningful capacity, then it was also blinding to other riders and people in cars.

I could aim it down some and limit others' exposure, but then it was useless at letting me see what I needed to see, myself.

The most recent front light I have came from Walmart, and was sold in Schwinn packaging. It's rechargeable. With this light, other people have zero direct exposure to the LED because it is occluded by the housing.

It uses optics to shape the light. A curved mirror, and AFAICT a lens are inside. The beam it produces is shaped to evenly illuminate my path and it has a very sharp horizontal cutoff.

It's a very sensible design, in that when I aim it at the road so I can best see, other people's eyes are above the cutoff so they aren't blinded by glare. Everyone wins.

But not every bike light has a sensible design. And not every rider has sensible intent.

(The Germans have standards for this stuff enshrined in StVZO, wherein: Stuff like beam shape and cutoff is governed by law. Searching for StVZO lights tends to yield good results.)

Ok, so only loosely related - I find new matrix headlamps on cars to be pretty intriguing. Basically they have an array of lights that are focused like pixels, and they can turn off the pixels that would blind others.

Wonder if this kind of stuff can trickle down to bicycles and motorcycles and you only light what's important in front of you. This could be to light more stuff so you can see it, or less stuff and save power while seeing what's important.

I've experienced the same problem with newer car headlights, which despite being regulated are now far too bright and concentrated, creating a very bright and very dark region with a sharp line between them instead of the dimmer but more diffuse gradual cutoff they used to have. Eyes have dark adaptation so you can see farther with the latter, and it's also better for oncoming traffic.
In some European countries there are regulations for bike lights, some even require cut-off beam like Germany. However in US the front light is dual purpose - it's illuminating the road at night and keeps salmoning bikers/runners/electric motors enthusiasts from running into you so a cut-off beam is counter productive for this purpose.
You want StVZO compliant lights. It's originally a German standard but they're sold everywhere.

Easy to google, not much risk for overloading that particular word.

If it killed the first battery, won't it just do it again to the new one?
It didn't. The battery killed itself. Modern rechargeable batteries don't like being left discharged in storage.
If anybody's interested in what the meta is for buying bicycle lights:

  1. Reflectors are the best for baseline visibility, they cost nothing and are reliable.

  2. The tail light is the important one.

    a) Try to find ones with a pulsating mode, blinding other road users by shining bright rapidly blinking lights into their eyes is not good, actually.

  3. For the front, decide if you *need* illumination strong enough for you to see where you're going in darkness, or if you can get away with just being seen by others.

    a) For the former, make sure you get a front light that has a beam cutoff, preferably a lens-based solution. Then of course, install the light with a proper downwards angle, otherwise there's no point to the cutoff.

  4. Side visibility is important, this is usually accomplished by some see-through parts at the business end of the light.

  5. DO NOT use blinking modes at night. Blinking is for daytime, use only constant or at most, pulsating modes at night.
Some recommendations:

• If biking casually or without a need for strong front light, honestly just get the cheapest lights you can get + some reflectors. Having any light at all gets you 99% there.

• Magicshine lights in general, I myself have the EVO 1300 for front and the SeeMee 300 for back. Proper lensed beam cutoff for the front, pulsing modes for the back, and good side visibility for both.

• Bontrager Flare RT for the back — small but powerful thanks to a focused beam.

I’d replace #5 by “don’t use battery-driven lights, use a dynamo hub” (except for e-bikes, of course, which also won’t have strobing lights).
" b) If you've got the money, consider a radar instead."

Can you explain this? What is this and how does it replace a taillight?

A bike radar alerts you about vehicles behind you. It does not replace a taillight, rather they always (I think?) have taillight integrated. For more details:

https://www.cyclingweekly.com/group-tests/best-radar-bike-li...

Radars don't save you nor do they tell you which motorist will run you over and which will not. So it doesn't help you take decisions on wether to take evasive actions such as jumping in the field next to the road.

They are more a placebo than anything really.

> don't save you

Neither does a car's mirrors save you being run over by a truck

> nor do they tell you which motorist

They show the approaching car's speed and direction, which is quite handy to take an evasive action. Some also integrate an alarm and blink at highest intensity in case of an imminent danger. That won't stop the usual terrorist cab but might catch the attention of a distracted driver.

  > a) Try to find ones with a pulsating mode, blinding other road users by shining bright rapidly blinking lights into their eyes is not good, actually.
Note that in some (at least European) countries, only steady light is legal.
Actually my own recommedation is different.

Having steady rear lights mounted at the socks/ankles is the way to go. The movement of the feets makes you instantly recognisable and standing out from very far away.

I am still using a regular rear light powered by a dynamo hub though, as batteries can always die without warning.

> steady rear lights mounted at the socks/ankles

> pedals with integrated lights

Happy to discover those two ideas, thanks!

There are also reflector pedals (see above for reliability etc)
Ironically one of the reflector on the set of pedals in my "town bike" fell off so it is not perfect on all models as far as reliabikity is concerned!
> company that sell pedals with integrated lights too but I can't remember the name

I use https://redshiftsports.com/products/arclight-pedals - originally bought them on Kickstarter.

They're not super cheap, but I'm very happy with them. You can change the mode from always on to pulsing. They automatically turn off when not in use, and they sense the direction of the pedal so that the front light is always white and the back is always red.

Seconding point 3a. I think many people assume brighter is better and also assume they can't possibly be dangerously blinding bright compared to a car's headlights or even deliberately want to fight back against headlights. But despite how bright and poorly aimed a lot of headlights are, a small light with literally no cutoff can be even worse. You could make it so a pedestrian can't see a car, or make it so a driver can't see a pedestrian.

Plus it's annoying. I was in a French city a while ago with a very nice pedestrian area full of outdoor tables. It's so nice to sit for dinner and look out at the surrounding old buildings, canal, people going by. Unfortunately every 30s or so you get blinded by the lights of a cheap scooter.

Ive been using Costco headlamps with the strap bracket ziptied to the handlebars. The li-ion usb rechargeable light snaps into the bracket at whatever angle desired. When the 3-pack goes on sale they're $7 each, which is a small fraction of the equivalent made-for-bike lights I've seen around. Haven't found a use for all the headbands yet.
> I wasn’t sure how to find out what an “LI????77” was […]. I would be interested to learn non-LLM ways to figure this out though. There must be a way.

Reading https://en.wikipedia.org/wiki/Button_cell#Type_designation would have indicated a solution: The third character must be an R (for rechargeable), the “77” would be the height in tenths of millimeters (which makes for a good plausibility check), and then you can measure the cell’s diameter to obtain the remaining digits in the middle.

And this is why you don't ask an LLM such questions. An LLM will give you a random battery type as it doesn't have calipers nor hands to measure the size of the battery.
An LLM might know there's a system to this, but equally depending on training material it might not. If you find a battery nerd they will know. For a whole bunch of topics there will be a nerd who cares a lot about that topic and knows the answer, and one of the lovely things about having connected ~all the world's humans is that you could find that nerd.

The nerd, unlike an LLM is clear on the difference between reality and imagination and where exactly the grey areas are. They can tell you whether your question just has an answer like this one (measure the battery, now you know) whether it has an accepted canonical "answer" but it's made up so if you hate that just make up your own canon, or whether it's absolutely MST3K Mantra material ("repeat to yourself it's just a show, I should really just relax").

This is an unsolvable problem for an LLM. An LLM is not physical, it can not measure the diameter of the battery and thus will never know the correct battery type.
Word of warning: batteries from AliExpress might not be the size it says on the tin.

Also: not all lights require soldering to change the battery. Some brands, like Fenix, offer lights where you can change the battery on the go.

I had a light from a lesser known Taiwanese brand - an INFINI Lava 500. At some point it stopped working, so I took it apart with my iFixit kit and inside was a 102660 battery (1700mAh instead of the advertised 2600mAh), so I bought a 102560 unit - 10mm thick, 25mm wide and 60mm long (supposedly).

It was a good few millimetres longer and didn't fit. What's worse - AliExpress stopped shipping the batteries to my address, because due to safety regulations you can't ship batteries via airmail, it's just that one vendor who chanced it, so now I couldn't even buy a smaller replacement.

Local vendors didn't have anything nearly the same format, so I gave up and bought a LEZYNE LED Macro Drive 1300XL. Inside there are two 18650s wrapped in a pack that has a plug, so should they die, you can replace the battery without soldering.

Was it a protected cell? They have a little circuit board on one side, sometimes you can see it through the shrinkwrap.
Both were protected - it's just that the battery I bought was genuinely the wrong size - it wasn't 60mm in any axis.
Yeah, I really like that Fenix lights just take a Li-ion 21700 or 18650 (and they have a little caddy to adapt the latter for the former).

However, the manual is very specific about only using their specific batteries and not just arbitrary batteries of matching size and chemistry (generic 18650s). I'm currently trying to get some information out of the manufacturer about whether there is risk of damage or they're just trying to avoid people using shitty batteries and blaming them for a bad experience.

(The manufacturer is fenixlight.com, but the seller is fenixlighting.com. It's kind of confusing.)

OK, got a response back, although it was possibly slightly AI flavored? But they said no, a good quality 18650 shouldn't harm the light. It just might not power the top modes.
Good to know, thanks.

Manufacturers really push those batteries to the limit - I resoldered the battery to a tail light that I dropped and currently the highest power mode just flashes at a high rate, which isn't how it originally worked - clearly not enough current from the battery.

> I wasn’t sure how to find out what an “LI????77” was […]. I would be interested to learn non-LLM ways to figure this out though. There must be a way.

Back in my days I simply googled my way through the nomenclature of batteries. I feel pretty old, somehow.

I'm pretty sure that's what most people would do now and the AI summary would still be wrong half the time anyway.

I don't think much has changed at all. The LLMs don't magically have new information that didn't already exist out there.

In recent months (I don't use it enough to confidently state when the change occurred) Google's LLM summary more often answers the wrong question rather than confidently answering the question wrong.

If it answers and the answer is for what I asked, it is right much more often than not. With that said, "trust but verify" is more like "don't trust and also verify" anyway, which is the same metric that should be used for most websites.

That is why I turned off the AI summary on Google. Useless 90% of the time, takes up space on my screen.
> google

he specifically asked for non-LLM, tho :)

Back in my day, Google wasn’t an LLM. And we liked it!
Julia = she
Very irritating tendency of people here to assume everyone on the internet is “he”.
To be fair, the grandparent comment being replied to has a username beginning with Mr.
(comment deleted)
I went the obvious path, back in the days.
> googled

Could've been a trip to a local library!

This guy is funny, he spent~$20 and at least 10 hours to fix a product that can be purchased with $5.
So what?

I replaced a lezyne light battery too. There was no point buying a complete light, send this one to waste when I could just look up for the actual reference in a search engine, find the correct one and replace it.

It is not about money, it ia about not sending unneeded stuff to waste management, which we pay for actually.

I would say $15 is cheap for the learning, growth and experience. Interacted with humans too along the way. People pay much more than this for schooling which teaches you less.
It's weird that rechargeable bike lights almost universally use soldered batteries. Conventional flashlights with onboard charging often use standardized cylindrical Li-ion cells that are field-replaceable by unscrewing the tailcap. They're usually 14500, 18350, 18650, or 21700 size, sometimes with a protection circuit stuck on the end (making it semi-standard, but easier to handle safely).

The light in the link uses an absolutely tiny 0.5Wh battery, which strikes me as insufficient for cycling. I use a light with a 21700 cell (20Wh).

It’s more of a “be seen” light rather than one that lights the way ahead.

My jurisdiction requires a solid white light facing forward at night, but you can have a flasher in addition to that (cuz drivers still won’t see you with a solid light…).

Also a good backup it your main light does to stay legal.

I'd love to see an actual standard for user replaceable batteries. Raw lithium cells are just far too dangerous considering they can explode from being short circuited. So products have the choice of either non replaceable, or proprietary packs.

Given the EU is mandating replaceable batteries very soon we might see some momentum on this.

The premium flashlight market has solved this with semistandard protected button-top cells.

These consist of a standard cell with a protection board stuck on the end, and usually a smaller raised positive terminal. This adds 3-5mm to the length, and temporarily breaks the circuit in the event of over-voltage, under-voltage, or over-current/short. There's no written standard, but most brands are making pretty much the same thing, and they almost always interchange. Safety does not require it to be proprietary.

Here's an example from a flashlight manufacturer: https://www.skilhunt.com/product/bl-135-3500mah-18650-protec...

Here's an example from a third-party battery distributor: https://illumn.com/18650-keeppower-p1840c-4000mah-protected-...

I did something similar recently. One thing you don't get to check before buying a light is the age of the battery within it. In two cases now expensive lights I have purchased had 8 year old LiPo puch cells in them, and died within a year of use.

It was a surprisingly repairable light except for one catch: I could not find a pouch cell LiPo with this kind of connector nor shape anywhere. Not even in part catalogs let alone for sale. So I have snipped the leads of the connector and will revisit this when a cell that suits shows up.

I would be surprised if they rolled their own but perhaps their factories have a B2B supplier that was able to.

>So I went to the local queer makerspace

Would a normal makerspace do?