Technology

Lithium-ion batteries are being used in lots of modest gadgets in which they don’t belong, such as flashlights and TV remotes. There is a class of gadgets that you should never have to charge—ones that tend to be needed right away, at specific moments. A flashlight, for example, serves its most essential purpose during a blackout, when juicing up its battery would be impossible. Yet some flashlights are now designed with batteries that cannot simply be swapped out—as if having lithium-ion cells somehow made them better instead of worse.

The guys at !flashlight@lemmy.world really like flashlights with removable lithium-ion 18650 cells.

goes looking

https://en.wikipedia.org/wiki/Self-discharge

That has 2–3% per month self-discharge rate for lithium-ion.

It has low-self-discharge NiMH batteries -- Eneloop is a popular example -- as having the lowest self-discharge rate of the rechargeable types, at 0.25% per month. That's higher than alkaline, but for a lot of things, that's fine (and alkaline does have self-discharge too).

Recently, I had to go into my attic to investigate a roof leak. It’s dark up there, so I pulled out a nifty headlamp that I’d purchased on a lark a while back, on the premise that sometimes you need a headlamp. That time had come! But then I realized that my headlamp needed to be charged, which meant digging up the right cable and AC adapter, and waiting hours until its battery was full. All that waiting turned out to be in vain, because the recharged light went out minutes into my task, just when I had reached the deepest darkness of my attic. Somehow, I got out again.

I have a headlamp that takes AA batteries, a battery charger, and a bunch of NiMH Eneloops. They don't have the energy density of lithium-ion batteries, but I can do what the author wants with it, charge and let them sit for a reasonably long period of time, and still have them pretty usable.

But I generally don't even bother these days, because I also have a cell phone always with me with a rechargeable lithium ion battery that gets charged every day and has a built-in flashlight, and is good enough for most small flashlight stuff. I have a couple of flashlights floating around (as well as one of those fancy 18650-lithium-ion ones with a firmware that the !flashlight@lemmy.world crowd likes), but I just don't use them any more, because the cell phone is good enough for most stuff, and it's always with me.