Hey everyone, newbie here who’s been bitten by the flashlight bug. I’ve recently acquired a handful of lights as well as a bunch of li-ion batteries (with more on the way :person_facepalming: ).
From what I’ve been able to read it seems long term storage of li-ions should to be at about 40% (3.8V) preferably in a ziplock in the refrigerator.
My first question is what constitutes “long term”; is there a hard cut off like 2 weeks or longer, or more than 1 month?
Secondly, do you leave your batteries in the flashlight if you only use it say once every week or 2 for a few minutes at a time and just do a tail cap lock out?
Or is it better to “exercise” the batteries daily in the lights that I don’t use often
I think 3.5v or 3.6v is closer to 40% charge. 3.8v is definitely more.
I wouldn’t bother storing the cells in the refrigerator if you keep them at 40% charge. Unless you’re planning to store them for years, the additional benefit from cold won’t be a big difference.
You don’t need to exercise the batteries if you keep them partially charged. Check them every few months to make sure they’re still around 3.5v, and top them up a bit if they drop.
I’d just leave your cells in the lights you use, even if they’re only used every few weeks. Yes, loosening the tail-cap is a good idea for lights with an electronic switch (i.e., standby drain). Though I’d only bother if I don’t plan to use the light much.
If you really want to make your cells last, then you could rotate your batteries into the lights you use (or plan to use shortly). Only keep a couple of batteries (at the front of the queue) fully charged. Leave the others partially charged, until they get to the front of the queue.
That uses all your cells. Although, it’s really not much different than storing all your batteries except a couple of extras.
Or, just leave your cells fully charged, and don’t worry about it. You might lose up to 20% capacity after a year or so, but they’ll still last several years with a reasonable capacity. Eventually, age will get them, regardless of what charge you use to store them.
First up I regularly keep my Lions and Lipos (for RC trucks) topped up
I don’t store the batts in the flashlights (my edc lights I make sure the tail cap is quarter turned)
Then I keep the rest of them in ex military Ammo metal cases and keep in my garage
The lipos are also in fire proof bags in the ammo box too
The Lions are also in battery cases in the ammo boxes too
Has anyone had an (undamaged) individual lithium-ion cell vent or flame, while in storage? That is, as long as it wasn’t shorted against something metal, or hit, or heated, etc. Even a horrible cell, like an Ultrafire?
I guess there’s a chance of a random internal short, but has that ever happened to an unused cell? Every bad story I’ve heard has resulted during charging, or discharging, or some external violent event.
I try to not keep too many cells around, period. A dozen or so is about it, I think. And the more usb-power-thingies that go mental that I end up pulling the cells from, the more that number grows. :person_facepalming:
The reason I want to keep cells at a minimum is twofold. First, the more they linger, the more they age and end up being wasted as a great cell loses capacity over time. Second, I just plain forget I have them. Either they’re in some lights I played around with and locked-out (tailcap), or I put them somewhere “safe” then never find them again. Got a 4-pack of panny-Bs somewhere that are nice and protected in a padded envelope, but fiicr where they are.
I started out thinking I needed 1 battery for every light. But now I realize there will be lights I might not use for a while so it doesn’t actually need its own battery. Plus a lot of lights share the same battery size. On top of that once I started getting short and extension tubes and corresponding size of battery I’d end up with an extra battery.
Luckily my light and battery collection is still at a manageable quantity…for now.
I guess it’s a matter of convenience. I keep a battery in almost every light I have (at least the ones I haven’t retired). If it’s a light with an electronic switch, I’ll lock it out. That way, I don’t have to bother getting a battery (or batteries) and installing it in the light if I want to use it. I know it doesn’t take much time, but it’s enough of a bother that I might not use the light at all.
meaning if I have some crap cells (but better than Chinese #$%^ fire cells) like laptop pulls I use them any dam way I feel like. when they give up the ghost FINE, NEXT.
As far a storage, “time” is a very very minimal factor. 3.6ish is to me considered 50. math says 4.2 - (4.2 - min V / 2) = 50
heat is the enemy and number of cycles.
So keep what you “use” and maybe an extra matched pair as working inventory out. keep the rest at storage V in a cool-cold place.
consider that battery tech is getting better so fast, that in all likelihood you will not want to use some of the cells long before they actually should be retired. So it really does not matter.
Got a 4-pack of panny-Bs somewhere that are nice and protected in a padded envelope, but fiicr where they are.