That's true, but it's pretty common to stick a protection circuit on the end of a cell, making it similarly safe to the proprietary Li-ion batteries that power cameras and the like.
It's also common to not put protection on the end of an 18650, which is probably a big reason we don't see more of these in user-serviceable devices. Even if you ship a device with a protected cell, the inherent implication of an 18650 socket is that someone is going to buy a cell from somewhere else and stick it in there. (and maybe throw a few in their junk drawer along with some loose change and rusty silverware)
Perhaps one of the things that should be included in right to repair legislation is stronger liability protection in cases where a third-party battery is installed in a device.
I do often stick unprotected cells in flashlights that came with protected ones. It's important to know whether the flashlight can over-discharge the cell, but most can't, and it's important to not short-circuit them. I suggest people who don't want to learn about batteries stick with protected.
Eh... I strongly disagree... We shouldn't let companies put out products that burn parents' house down because grandma didn't research 18650 protection circuits when she bought the grandkids some batteries for their toy on Amazon.
Consumer product safety regulation is written in blood, and exists for a very good reason.
Let the advanced right-to-repair audience open up the device with a screwdriver and install a new LiPo pouch. We don't need a battery door to let kids in like it's as safe as AAs in a gameboy.
The screw on the battery door is typically a choking hazard mitigation. The idea being, if you know how to use a screwdriver, you are skilled enough to not eat the battery.
I think there’s still a big chasm between that level of skill and knowing there’s a difference between protected and unprotected 18650s… or even knowing what an 18650 is at all. Most people have never heard of them.
The right-to-repair “I know what I’m doing” crowd can disassemble the device as long as it isn’t glued shut.
Other mitigations are possible, such as a battery compartment designed for cells that are 69mm long, as is typical for protected cells instead of 65mm. I'll admit I complain about this when reviewing a flashlight (use longer springs so it's not picky), but it's likely the right choice for many applications.
It's not the right choice for all applications of course. Products intended for children and that are particularly demanding in terms of electrical power require greater caution than speakers or most flashlights.
> The batteries that come with the light are perfect, but all the panasonic 18650s I have purchased are about 1/8 (3mm) too short.
> I was thinking of using aluminum foil.
If people on enthusiast forums are struggling to put batteries in their devices safely, the mass market is doomed. Proper safety engineering is to design a device in a way where foreseeable misuse by a layperson does not result in a safety issue.
This isn't incompatible with a right to repair. Just simply don't glue the device shut. The LiPos used in many devices are common jelly-bean components.
I don't think it should be required that devices protect users from unsafe modifications even if they're foreseeable. I can also tape down the safety bar on the lawnmower, remove the guards from the circular saw, and take the firing pin block out of the gun. I'm sure people have done all of those things, and some have regretted it.
What I'm advocating is a bit beyond just repairability; field-replaceable batteries the ability to charge spares externally, and the ability to share spares between devices are substantial benefits.
