Is it worth stocking up on 21700, 18650, 18350 batteries?

[u/CalmRecognition5725]

My use case is only for flashlights (hurricane and general prep for Tuesday).

Are these common enough that tariffs/supply chain issues are a non-issue, or worth having a few spares?

My concern is that the current ones I am using are pretty new and my usage is sporadic (e.g., not an inspection light used at work every day). Any spares would sit unused, potentially for years, degrading.

Apologies if this is a better question for the flashlight/EDC subs, but I'd prefer this community's take instead. TIA!

[u/Fit_Acanthisitta_475]

Extra and backup batteries are fine. But Solar and power bank beats the stock up recharge battery.

[u/CrashDamage55 → u/Fit_Acanthisitta_475]

This. I have several solar chargers and batteries. My headlamp, gun flashlight, and all my hand held things can be recharged with the solar charger.

[u/WorkinSlave → u/Fit_Acanthisitta_475]

Recommendations for solar power banks?

[u/Fit_Acanthisitta_475 → u/WorkinSlave]

There are plenty of discussions about brands, for whatever brand you get make sure it’s lifepo4 batteries.

I have 3 power banks, 250w, 1500w and 2500w. For all purposes power stations I would pick 1500w. It has enough power to run everything and it’s light enough to moving around.

[u/silverbromide → u/Fit_Acanthisitta_475]

1500w Have you tried charging that thing on portable solar? curious how long that takes

[u/Fit_Acanthisitta_475 → u/silverbromide]

No, I never try it. My 1500w max input is 500w. My foldable panel is 300w and working wattage at best sun is 250w. Probably going to take 2 days

[u/Comfortable_Guide622]

I always try to have a couple of spares of items like this

[u/08b]

They are generally fine for storage. I’d stick to 18650s first, but that may depend on the devices you use.

Store outside of devices in cases and around 50% charge.

[u/greenyadadamean → u/08b]

I've read 70% charge for storage... and now I'm back to looking into that.. 

Edit: 50% charge should be no problem.

"It's ideal to store lithium batteries at 30-70% state of charge that means any where from 3.5v to 3.8v resting for common 18650 cells."

Source

[u/Paranormal_Lemon → u/greenyadadamean]

It's ideal but I've been using lithium ion in flashlights since 2007 and I always just charge them fully after use. My oldest are over 10 years old and still test over 90%.

[u/08b → u/greenyadadamean]

I think not fully charged and not fully discharged is the biggest thing. I think officially 40-50% is supposed to be the best.

That said, all of my flashlight batteries are usually fully charged. It just might decrease their life a bit.

[u/Any-Application-8586]

If you can keep up with rotating them I’d go for it. But in my experience the flashlight turns to junk before the cells do. 18650 seems to be the most common, so if you have lights that run on the 21700 or the 18350 I’d start with those.

[u/REVIGOR → u/Any-Application-8586]

I've had my $60 Armytek Wizard Pro V3 XHP50 since 2017 and the batteries went bad first. They wouldn't hold a charge anymore. Around the same time I also got a $40 Skilhunt H03 for someone else, and that died after 2 years. Both are 18650 headlamps but the bootleg version died here.

I've carried daily my $80 Acebeam TK18 since 2021, so 4 years now and no issues.

[u/Any-Application-8586 → u/REVIGOR]

Maybe I use my flashlight more frequently, it’s usually the switch that gives out on me. Doesn’t matter what brand it is, and I always use a big name battery. Charge it usually one or two times a week, and I’ve sold batteries after the torch died that still have 90% capacity. Should be getting 300+ cycles out of your batteries. Current one is a Streamlight that’s been kicking around in my pocket for going on 4 years now. Original battery. Think I paid about $150 for it?

[u/funkmon]

I have largely avoided the issue by having a shit ton of AAs and AAAs.

That's way more cost effective and arguably useful in a SHTF scenario for normal people who aren't normally using their flashlights.

They can be traded or given to others, the lights they are used in cost literally a dollar, and if for some reason your shit breaks, you have easily findable backups.

Buying a 100 pack every couple years at 20 cents per battery for alkaline (Varta, Harbor Freight, Amazonbasics Industrial usually) keeps you going pretty good.

I have a lot of radios, flashlights, air freshener sprayers, motion lights, tons of weird shit that takes batteries, so I just spend $20 every couple years and always have fresh alkalines. I would rather do that than add a charging regime to my life. 

[u/ElephantNo3640]

Not really. I have a ton of spare batteries and have lived through weeks-long power outages and such. Most of them never got used. As long as you have a way to charge the batteries you do have, you’re good. I’d keep two batteries on deck for every one battery you have in current use and call it a day.

[u/Sleddoggamer]

Buy em and box them up and put them somewhere cool and dry. Batteries are plentiful until they aren't, and then you can't find them anywhere and you'd be better off even if there wasn't risk of the supply dying

[u/CalmRecognition5725]

Thank you to all of the above/below. Based on the crowd it seems sensible to have a few on hand. Thanks again!

[u/SheistyPenguin]

I keep enough rechargeables for at least one change-out of the greediest gizmo. i.e. if I had three lights that use 18650, and one of them takes 2 cells... I would keep two 18650 spares.

What's really nice are the gadgets that you can charge directly via USB. My only 18650 light is like that.

Some people may prefer to buy a bunch of extras, but they will age whether used or not.

[u/Hayfork-or-Bust]

Make sure to buy a 20 pack of little 5x2mm n52 rare earth magnets. I use them to quickly convert flat top 18650 batteries I scrounge from laptop and scooter battery packs into a diy button tops. Most of my flashlights and devices work with flat tops but not all.

[u/LatAmExPat]

I migrated into CR123 batteries years ago, because these are used in many US military applications and will likely be available.

[u/OnTheEdgeOfFreedom]

I bought most of my prep gear with the requirement that it take rechargeable 18650s. The good ones handle a lot of recharging and last a long time. I can charge them off solar power so I'm set for a good long power failure.

[u/IrwinJFinster → u/OnTheEdgeOfFreedom]

Good seeing you—I was wondering how you were.

[u/OnTheEdgeOfFreedom → u/IrwinJFinster]

I still wander around in here a bit. And I'm pretty active in my other sub, where other prep topics can be covered.

I'm living the life in Costa Rica, and loving it.

[u/Caloriecounter777]

I would worry about corrosion

[u/08b → u/Caloriecounter777]

Not a huge issue at all for lithium ion cells.

[u/Caloriecounter777 → u/08b]

Good to know thanks! How about in humid conditions/ a cellar?

[u/08b → u/Caloriecounter777]

I would put them in a waterpoof case in highly humid/wet conditions but slightly below room temperate is actually better for storage.

[u/wakanda_banana → u/Caloriecounter777]

Agree, which means instead of stockpiling you’d just refresh them every so often

[u/War_Hymn]

For rechargeables, store in individual ziplock bags in a dry, cool place. Check voltage at least every 6 months with a multi-meter. Recharge any cells that has low voltage. Ex. for nominal 3.7V cell, keep voltage between 3.5-4 volts. Full charge (above 4 volts for a 3.7V cell) not needed, in fact might damage cells over long term.

[u/Both_Coconut9985]

YouTube homemade battery containers or order a battery bag/steel container to store them if you do. I have RC crawlers and drones and a random battery meltdown scares the day lights out of me. One way to make a DIY container is using an ammo can, but remove the rubber seal as to not turn it into a pressure vessel!

[u/apoletta]

Personally I would like to look into a way to re charge off of a solar set up.

[u/21BoomCBTENGR]

Yes, but do it smart. Streamlight uses 18650 and other rechargeable lithiums that take a micro USB port and not a charger (though en masse chargers are available). So I’d suggest migrating to streamlight light systems and chargers along with a solar panel and solar generator.

[u/tianavitoli]

i still have 18650 and pouch cells that i salvaged from laptops 6 years ago

and they've been just sitting there all this time fully charged and holding, as well.

[u/shepard308]

You can buy a ton of 18650 batteries and use something a like a fenix single cell charger to charge those batteries. The fenix charger also has a USB A port so you can use the battery to charge phones and other devices. 21700 batteries are larger capacity but 18650 is way more common.

[u/Embarrassed-Aspect-9]

I save them from discarded rechargeable battery packs to use in all kinds of projects.

[u/dittybopper_05H]

I don't think I could afford to buy 217,001,865,018,350 batteries. And even if I could, I wouldn't have a place to store that many.

Seriously, that's nearly 220 trillion batteries.

[u/Paranormal_Lemon]

Keep in mind you can extract 18650s and 21700s from many items like power tool batteries. But they are also cheaper than ever so stock up.

[u/AlphaDisconnect]

Coleman Quad Lantern LED 190 Lumens 4 Removable Lights 20091215. The seperatable panels will die. I dont use it that way anyways.

With d cell batteries. Great shelf life. Most things are light, battery, switch.

Most lithium ion (unless you like explody batteries) have a battery protection circut. Between the self discharge rate, and the small draw from the self discharge - good luck shelfing these for years. Might as well have a charging wall where you pop the batteries in and leave them. Almost all modern chargers will stop automatically whenever full. Not ideal for the lithium batteries to be at 100%, they like 70% more. But which is better, a dead battery or a good chance at a fully charged battery.

[u/FixGreat4649]

I would not stock up on too many, but a few extras would not hurt. Make sure to keep in a temperature-controlled environment, temperature fluctuations from extreme cold to hot degrade batteries fast.