Sell me (and explain) rechargeable battery flashlights

[BPRoberts]

Looking into getting a new flashlight. It seems like everyone is all in on rechargables now, which I don't really understand.

1. They're (from what I can see) comparatively expensive. I can buy lifetime supply of AAs at Costco for what a couple of rechargables seem to cost.

2. Won't they lose charge? I know traditional batteries don't last forever, but they usually do ok for years if sitting, and seem to have at least double the runtime from what I'm seeing. And I assume I'll be lucky to get more than 2 or 3 years out of a set before they start to lose capacity if I do use them regularly.

Am I just doing a lousy job with my research? It feels like I should just upgrade to an LED Mini Maglite, grab a pack of AAs, and call it a day.

[PitCarver]

¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/⁠¯

[Millhouse]

It all depends what you want from a flashlight. If you are happy with AA or AAA powered flashlights, stick with them Get some Eneloops or equivalent for cheap running and kinder to the environment.

Several years ago, I made the switch to Lithium-ion powered lights. I was wanting more brightness, which an AA powered light could not provide. Modern batteries hold charge well. I am still using some batteries that are nearly 10 years old.

I still have a couple of AA powered lights that I keep for emergencies, loaded with Panasonic Eneloop (with spares), and also knowing alkalines are readily available.

[PitCarver]

Being perfectly honest, I've got one of the O-Light key chain lights that's rechargeable.  My issue is that I keep forgetting to keep it charged.  (I have enough trouble keeping my phone charged.)
 I mainly use a Streamlight NANO on my keys.  Gives me enough light to see my way from the house to my car and back.

[Antti Lammi]

Copied article here wha explains pretty easy LI-ON batteries advantage and disadvantage.
Also bit my info after

"Advantages of Lithium-ion:
No “memory effect”. This means that they’re not bound by any particular charging rituals, meaning they can be charged more frequently without the cell always depleting at the same interval.
Very powerful
Can be recharged hundreds of times
Very low self-discharge rate
Not affected by cold temperatures

Are There Any Disadvantages?
Yes. As with ANY battery – eventually they’ll wear out.

To explain further, the charging cycles leave internal deposits, which over time diminish its effectiveness and its ability to hold a full charge. This DOES however take a LONG time to have any effect.


Are Lithium Batteries Dangerous in Any Way?
Yes. BUT, ONLY in specific situations.

You would certainly not want to pair mismatched batteries in the same device. And that goes the same for ANY type of battery. You must also be careful you’re not using them in pairs, where the starting voltage of each one is significantly different. Each battery must be relatively close in voltage. In order to do all this correctly you’ll need a good quality charger and/or multimeter.

Other precautions include – to never over charge or over DIS-charge a lithium cell. Buying “protected” cells will take this worry out of your hands. This means that the battery will effectively shut down when the voltage gets too low. The protection circuit will also keep it from over charging. Just look for the term “protected” when purchasing Lithium-ion batteries.

As long as you know what you’re doing, and are using them in good quality equipment, you CAN use UNprotected lithium batteries…which are useful in high-drain devices such as flashlights. Most “IMR” lithium batteries are unprotected."




Good choice would be Lumintop Tool AA 2.0 or  FENIX LD12R both can use 14500(AA sized) or regular AA batteries.

Lumintop Tool AA 2.0
"it can take regular AA type batteries, Protected and unprotected 14500 cells, and even rechargeable NiMh batteries.
Since it does not provide a USB or magnetic charging, you have to use a third-party chargerg":

price on Lumintoponline.com 17.99$ including 14500 li-on

"FENIX LD12R RECHARGEABLE EDC FLASHLIGHT"

The Fenix LD12R Rechargeable EDC Flashlight is perfect for your everyday carry. This compact, rechargeable flashlight features dual light sources with a powerful main light with impressive brightness and a useful side light for utility. Powered by an included 14500 Li-ion battery, the flashlight is charged via the USB-C charging port—hidden for added protection and a clean look. The body clip includes a magnet allowing you to attach the LD12R to most metal surfaces for hands-free lighting. Versatility is the name of the game for this great EDC flashlight.

Price on Fenix-store.com 59.95$
 
So basicly with these flashlight you can be sure to have power even if rechargeable battery runs out of juice if you have spare AA with you.

AA-Sized 14500 Li-ion battery doesnt actually cost awful lot ( cheapest around 4$ mid price for good is around 10$)

And if you buy Fenix it comes with 14500 battery by looking few sites package includes it.
Lumintop Tool AA 2.0 doesnt necessary contai 14500 battery. But on that site you can biy with or without it.


Only Tools Matters

[BPRoberts]

Appreciating all the feedback here. As long as I can still use AAs as a backup (or lazy) option, then I think I'd like to give rechargables a try. The Fenix sounds good. Rechargable for day to day use, AAs in a drawer for when a hurricane blows through, I forget to charge, the batteries lose capacity over time, etc.

It does look like rechargables have come down a lot since the last time I looked (or, again, I just did a lousy job of looking). I see you recommending Liion. I feel like eneloop used to be the going rec. Has Liion overaken them, or should I look at them also?

[Antti Lammi]

Appreciating all the feedback here. As long as I can still use AAs as a backup (or lazy) option, then I think I'd like to give rechargables a try. The Fenix sounds good. Rechargable for day to day use, AAs in a drawer for when a hurricane blows through, I forget to charge, the batteries lose capacity over time, etc.

It does look like rechargables have come down a lot since the last time I looked (or, again, I just did a lousy job of looking). I see you recommending Liion. I feel like eneloop used to be the going rec. Has Liion overaken them, or should I look at them also?

I personally avoid using eneloops nowdays, i dont see advantage on use since i dont have daily use on devices that benefits longer run time. (I dont use that much my flashlight)
Eneloops are better if you daily use device what uses them but on flashlights it means lower lumens but longer usage. On Fenix it means you cant use high-mode 600 lumens but all others modes.

https://1lumen.com/review/fenix-ld12r/
I recommend too read that review since there you can see approximately run times and lumens with diffrent batteries.

Best option is use that 14500 (included on Fenix) and eneloop and other AA (AA mostly last resort)

The biggest benefit of going to rechargeables, whether NiMh or lithium, is the reduced risk of the batteries leaking and destroying your device.


Only Tools Matters

[Antti Lammi]

I personally use these as my EDC lights, and also have Suprabeam V3pro from work if i need high light, but usually LedLenser P3R gives enough light for daily use and backup (if needed) i use P3 AFS



Only Tools Matters

[nate j]

It all depends what you want from a flashlight.

This.  I can’t tell you what you should do, but here’s what I do, as well as what I see as pros and cons of some common batteries:


Alkaline (disposable) AA/AAA
Pros
- Low cost
- Can run devices nearly continuously, as long as you have fresh batteries to swap in
Cons
- single use
- Low energy compared to some other options
- Mediocre shelf life compared to some other options
- Poor cold weather performance
- Risk of leakage damaging devices

I personally don’t have much use for these in my gear.  I pretty much only buy them for kids’ flashlights and toys.


NiMH (rechargeable) AA/AAA - I probably have the least experience with these, as I tried them once few years ago and didn’t have a good experience.  (They were fairly expensive, but wouldn’t charge properly after only a handful of charging cycles.) I can’t personally recommend them at all for anything, though in fairness Eneloops seem highly regarded and the ones I had were not Eneloops.


Lithium (disposable) AA/AAA/CR123
Pros
- good cold weather performance
- Higher energy than alkaline equivalents
- Excellent shelf life
- Lighter weight than alkaline equivalents
- No chance of devices being ruined by battery leakage
Cons
- expensive
- Single use

These are what I put in all emergency kits and my keychain flashlights.  They are pricey, but they won’t ruin your devices and will work when you need them.


Li-ion (rechargeable)
Pros
- highest energy
- Reusable
- Not prone to leakage
Cons
- expensive
- Limited shelf life
- Mediocre cold weather performance
- Small chance of thermal runaway

The energy capacity of these batteries makes them the only viable option for modern high performance lights, i.e. if you are looking for high brightness, very long run time, or both.  My primary lights are single 21700 models, as I find these lights (multi-mode of course) offer the best mixes of brightness, runtime, and pocketability for my needs.  I believe it is recommended to charge Li-ion batteries at least every 3-4 months even if not used.  And over time and use (think years and or perhaps 1000 or so charge/discharge cycles), the capacity and performance of the batteries will become noticeably degraded.  Now, I would argue this isn’t a major issue for a flashlight, as most likely a replacement battery will still be available at a reasonable price (provided your light uses a standard replaceable battery and not something that is integral or proprietary to a specific manufacturer).  More to the point, at least for me, is that I will most likely upgrade to a different flashlight entirely before I have noticeable performance degradation in my Li-ion batteries.

[BPRoberts]

It seems like Li-ion rechargeable are pretty near the consensus for the main power. I can certainly look into grabbing a set or two of those as my primaries (I don't really know what I'd put them in besides the flashlight to justify having more. Maybe the TV remote? Off the top of my head, the only non-integral battery devices I think I own right now are a couple of flashlights and the remote.) and we have a decent pile of basic alkaline for backups. I might upgrade to Li disposable at some point, but no reason to be wasteful and throw out what I have.

The numbers (21700 vs 14500) refer to the physical dimensions of the battery, correct? I don't need to worry about "picking" the optimal one, I just use the one that fits?

And beyond that, I'd need to figure out (and I know I got some good recs already, thanks!) what light I want. I'm imagining something ~5 inches long, since that'll fit comfortably in my pouch. Prefer on the thinner side, again, for fit. I think I'd prefer something that has a longer run time than a heavy throw. Just charge it "seasonally" like the smoke detector batteries (I guess that's the other battery thing I have...) and stuff. I doubt it'll get used a ton. I have a little keychain light now, and I probably use it once a week on average for a minute or so. Mostly just trying to move some of my carry off my overcrowded keychain and into my pouch, which has plenty of room.

[Sos24]

It looks like you got a few good answers for your question.

Something I did not see mentioned, but might have missed, are rechargeable batteries with charging ports built in.  If you like AA, there are both Li-ion and NiMh with built in usb-c recharging ports. 

I like them especially for travel, because I get the benefit of rechargeable batteries others mentioned without needing a separate charger. 

[Antti Lammi]

It looks like you got a few good answers for your question.

Something I did not see mentioned, but might have missed, are rechargeable batteries with charging ports built in.  If you like AA, there are both Li-ion and NiMh with built in usb-c recharging ports. 

I like them especially for travel, because I get the benefit of rechargeable batteries others mentioned without needing a separate charger.

True, those are handy but rechargeable AA usb-c also have bad habit to die, without warning since it gives from start to end 1,5v current (thanks to current regulator) if there isnt something to show capacity from that we come to capacity  what is smaller than regular chargeable AA and depening quality of battery (what company made them) real capacity might be much smaller than stated.

Real advantage comes from steady current from start to end (even if they die suddenly) meaning devices like flashlight, light doesnt fade but keeps it same amount lumen all the time until battery dies.
Like Sos24 mentioned those are handy on a trips where you can charge them allmost anywhere (if you have cable with you) and home if you have misplaced batterycharger.

I have used these kind but those broked after 2 months, then i used batteries lot and thought those would come handy, first those were handy but some of those are badly made and usb became loose until it was point of break. Whole usb part wobbled and didnt charge anymore. So avoid those with USB-A head.

My friend has 18650 batteries with usb-c port, it have come bit loose but still works after 1,5 years of use ( he use them on vape so he charges them regularry)




Only Tools Matters

[old Lefty]

I went the rechargable way just a fortnight ago.
This after always relying on batteries.
I needed max. power in smallest possible size and that pushed me over.
Eventually I chose the Nitecore TM12K. I've used it according my original use case, it does what it says on the tin and so far I haven't even charged it yet.
So, happy camper me, guess we will see if that stays the same in the coming months and years.

Lähetetty minun SM-T515 laitteesta Tapatalkilla

[Antti Lammi]

I went the rechargable way just a fortnight ago.
This after always relying on batteries.
I needed max. power in smallest possible size and that pushed me over.
Eventually I chose the Nitecore TM12K. I've used it according my original use case, it does what it says on the tin and so far I haven't even charged it yet.
So, happy camper me, guess we will see if that stays the same in the coming months and years.

Lähetetty minun SM-T515 laitteesta Tapatalkilla

That is awesome small powerhouse and looks great but also pricetag is awesome.


Only Tools Matters

[old Lefty]

That is awesome small powerhouse and looks great but also pricetag is awesome.


Only Tools Matters

True dat. Somehow I ended up paying quite a few euros more than I originally thought I'd be spending. Luckily that normally never happens in this world of SAK's etc.

Lähetetty minun SM-T515 laitteesta Tapatalkilla

[Sos24]

True, those are handy but rechargeable AA usb-c also have bad habit to die, without warning since it gives from start to end 1,5v current (thanks to current regulator) if there isnt something to show capacity from that we come to capacity  what is smaller than regular chargeable AA and depening quality of battery (what company made them) real capacity might be much smaller than stated.

Real advantage comes from steady current from start to end (even if they die suddenly) meaning devices like flashlight, light doesnt fade but keeps it same amount lumen all the time until battery dies.
Like Sos24 mentioned those are handy on a trips where you can charge them allmost anywhere (if you have cable with you) and home if you have misplaced batterycharger.

I have used these kind but those broked after 2 months, then i used batteries lot and thought those would come handy, first those were handy but some of those are badly made and usb became loose until it was point of break. Whole usb part wobbled and didnt charge anymore. So avoid those with USB-A head.

My friend has 18650 batteries with usb-c port, it have come bit loose but still works after 1,5 years of use ( he use them on vape so he charges them regularry)

(Image removed from quote.)


Only Tools Matters

I have the ones with the port built in.  The Acebeam 14500 and Fenix 16340 have worked well for me. 

I have also used Pale Blue Earth AA and AAA for about a year. Originally they had usb-micro ports but switched to usb-c not that long ago.

[Antti Lammi]

I have the ones with the port built in.  The Acebeam 14500 and Fenix 16340 have worked well for me. 

I have also used Pale Blue Earth AA and AAA for about a year. Originally they had usb-micro ports but switched to usb-c not that long ago.

I may need to try those usb-c Pale Blue AA batteries, i could use those on console controller batteries ( i have rechargeable batteries in those but its diffrent kind)


Only Tools Matters

[Sos24]

I may need to try those usb-c Pale Blue AA batteries, i could use those on console controller batteries ( i have rechargeable batteries in those but its diffrent kind)


Only Tools Matters

They work great for that.  I have four of the old micro usb rechargeable ones I’ve been using for just that purpose.

[nate j]

The numbers (21700 vs 14500) refer to the physical dimensions of the battery, correct? I don't need to worry about "picking" the optimal one, I just use the one that fits?

I’d say this is partly true, as many of the batteries are physically different sizes and many of the numbers do refer to physical dimensions.  However, there are some important caveats.  First, it is always wise to consult the owner’s manual for your device to determine what batteries are acceptable to use in it.  For example, AA and 14500 batteries are basically the same size, but because the voltage is different, AAs shouldn’t be replaced with 14500s unless the device is designed to handle the higher voltage.  Second, even with a specific battery size, there are different options:  protected vs. unprotected, energy capacity, rated cycles, rated shelf life, etc.

P.S.  I agree with those who have pointed out that batteries with built-in charging ports are more convenient than needing a separate charger, but my real preference is USB-C charging built into the flashlight.  No messing around with separate chargers or proprietary connectors, easily available spares/replacements, fast charging without even needing to open the light…

[Antti Lammi]

I’d say this is partly true, as many of the batteries are physically different sizes and many of the numbers do refer to physical dimensions.  However, there are some important caveats.  First, it is always wise to consult the owner’s manual for your device to determine what batteries are acceptable to use in it.  For example, AA and 14500 batteries are basically the same size, but because the voltage is different, AAs shouldn’t be replaced with 14500s unless the device is designed to handle the higher voltage.  Second, even with a specific battery size, there are different options:  protected vs. unprotected, energy capacity, rated cycles, rated shelf life, etc.

P.S.  I agree with those who have pointed out that batteries with built-in charging ports are more convenient than needing a separate charger, but my real preference is USB-C charging built into the flashlight.  No messing around with separate chargers or proprietary connectors, easily available spares/replacements, fast charging without even needing to open the light…

That was reason why i recommended that Fenix LD12R. It comes with right battery and if needed can still use AA for backup if forgetted to recharge battery on it. Even better option for usb-c IMHO is magnet charging it eliminates port damages even with cost slower charging.

One good rule is that dont use AA devices with 14500 even those can handle higher voltage since it produces unecessary heat usually.


Only Tools Matters

[nate j]

Even better option for usb-c IMHO is magnet charging it eliminates port damages even with cost slower charging.

I have one or two lights with magnetic charging.  While I agree that they may be more rugged than USB-C, I still feel USB-C is a better option overall…

Magnetic charging cables for flashlights are AFAIK pretty much always proprietary to the manufacturer, and often specific to a given model or even generation.  I’ve only ever seen a single charging cable come with each light, additional cables would need to be ordered from the manufacturer, and they can only be used to charge that specific light.  In contrast, I have a USB-C cable in all three vehicles I regularly drive, plus one on the kitchen counter, one in my bedroom, and probably others stashed around.  In addition to flashlights, they get used to charge cell phones, Kindles, etc.  And, if a USB-C cable gets lost or damaged, a replacement is inexpensive and no further away than the closest gas station, convenience store, or grocery store.

[Damsel]

I have a cheap torch/flashlight that is USB rechargeable and I think it's great. I hate anything battery powered these days because I am always having to buy or charge the batteries. Maybe it's because I'm still using AA's, or it's because my charger is 15 years old and a bit pants, but they seem to take forever to charge.

With my torch i can just connect it to any USB port and it's charged in less than an hour, and it's plenty bright enough for my needs. The flood/throw "zoom" lens is quite handy too. If I ever find the light getting a little dull I just plug it in while on my laptop or watching TV. Green light tells me it's charged.



Danielle

[gustophersmob]

I know I’m in the minority here in this, but I just don’t like rechargeable lithium batteries for flashlights. Even if the chance of thermal runaway is small, it is literally a pipe bomb in your pocket.  They’re sealed tightly enough the best case is it blows out the lens/optic. Worse case is metal shrapnel.

For my needs, I don’t need the additional light output enough to offset the risk. Though, to be fair, my edc light is a AAA fenix ld01 from almost 10 years ago. If it’s ~80lm high isn’t enough, I get my AA zebralight. I’ve never felt like I didn’t have enough light with that.

I never use alkalines. Only eneloops for frequent use lights and lithium primaries for cars, get home bags, etc.

[nate j]

I know I’m in the minority here in this, but I just don’t like rechargeable lithium batteries for flashlights. Even if the chance of thermal runaway is small, it is literally a pipe bomb in your pocket.  They’re sealed tightly enough the best case is it blows out the lens/optic. Worse case is metal shrapnel.

For my needs, I don’t need the additional light output enough to offset the risk.

Of course, you pays your money and takes your choice.

To quantify the risk, though, we’re talking about a catastrophic failure rate of quality Li-ion cells that is on the order of one in ten million.

[gustophersmob]

Of course, you pays your money and takes your choice.

To quantify the risk, though, we’re talking about a catastrophic failure rate of quality Li-ion cells that is on the order of one in ten million.

I agree the risk is probably low overall, but I’d be curious where the 1 in 10 million number comes from. In my experience it seems like it is higher.


There are several consumer devices that have high rates of catastrophic battery failure:  EV batteries, cellphones and laptops (so-called “spicy pillows,” which if happened in a light could be very bad), and battery power tools. All of these are cells using smart charging and various kinds of protection.

I’ve personally had a work laptop go “spicy pillow” and have had a dewalt li-ion rechargeable battery vent.   

[GearedForwards]

I agree the risk is probably low overall, but I’d be curious where the 1 in 10 million number comes from. In my experience it seems like it is higher.


There are several consumer devices that have high rates of catastrophic battery failure:  EV batteries, cellphones and laptops (so-called “spicy pillows,” which if happened in a light could be very bad), and battery power tools. All of these are cells using smart charging and various kinds of protection.

I’ve personally had a work laptop go “spicy pillow” and have had a dewalt li-ion rechargeable battery vent.

I don't think I've ever heard of a torch exploding like you describe, I'm... not even sure that's possible?

But I do notice some stuff about your examples:

"spicy pillows" - Arguably the most notable here is the Samsung Galaxy Note 7, it was a failure of the battery manufacturers (there were two, with different problems), but it wasn't a problem of battery chemistry. Phones and laptops are arguably the most problematic here because of their form factor and the intense heat they can, very easily, be subjected to.

EV batteries - As far as I'm aware, EV batteries are like old laptop batteries, basically just a big ol' case full of smaller Li-ion batteries. I'm going to assume that this makes the failure rate more complex when each EV has however many individual hundreds/thousands of cells within it.

As a bonus I'll throw bike batteries in here because a common issue is a combination of using the wrong charger and people wanting an E-bike cheaper, so getting something with too many load-bearing corners cut.

In use in a flashlight there doesn't really seem to be an issue at all.

And some quick research shows that lithium primaries seem to be the more dangerous of the two anyway?

I've owned and used Li-ion cells in lights now for over a decade and I've never experienced a failure, catastrophic or otherwise, and all the cells are actually still in useable condition. If the risk were really anywhere significant, it would not only be more talked about, the tech wouldn't be so wide spread. I'm going to go out on a limb and say that the likelihood of death through car accident and flying are probably higher.

[gustophersmob]

I don't think I've ever heard of a torch exploding like you describe, I'm... not even sure that's possible?

But I do notice some stuff about your examples:

"spicy pillows" - Arguably the most notable here is the Samsung Galaxy Note 7, it was a failure of the battery manufacturers (there were two, with different problems), but it wasn't a problem of battery chemistry. Phones and laptops are arguably the most problematic here because of their form factor and the intense heat they can, very easily, be subjected to.

EV batteries - As far as I'm aware, EV batteries are like old laptop batteries, basically just a big ol' case full of smaller Li-ion batteries. I'm going to assume that this makes the failure rate more complex when each EV has however many individual hundreds/thousands of cells within it.

As a bonus I'll throw bike batteries in here because a common issue is a combination of using the wrong charger and people wanting an E-bike cheaper, so getting something with too many load-bearing corners cut.

In use in a flashlight there doesn't really seem to be an issue at all.

And some quick research shows that lithium primaries seem to be the more dangerous of the two anyway?

I've owned and used Li-ion cells in lights now for over a decade and I've never experienced a failure, catastrophic or otherwise, and all the cells are actually still in useable condition. If the risk were really anywhere significant, it would not only be more talked about, the tech wouldn't be so wide spread. I'm going to go out on a limb and say that the likelihood of death through car accident and flying are probably higher.

Yes, as I said, the risk is low. But not low enough to be worth it to me. I’ve never had occasion when using my couple hundred lumen zebralight and thought, “you know, I really need 600lm right now.”  Obviously everyone’s risk tolerance and use cases are different.

Do you have any info on lithium primaries being more dangerous? I’ve not heard of cr123s or energizer lithium aa’s and aaa’s venting with flame or exploding.

[nate j]

I agree the risk is probably low overall, but I’d be curious where the 1 in 10 million number comes from. In my experience it seems like it is higher.

I’ve seen it referenced in multiple articles by “experts”:

https://cen.acs.org/articles/91/i6/Assessing-Safety-Lithium-Ion-Batteries.html

https://polarium.com/insights/safety/

https://batteryuniversity.com/article/bu-304a-safety-concerns-with-li-ion

[gustophersmob]

I’ve seen it referenced in multiple articles by “experts”:

https://cen.acs.org/articles/91/i6/Assessing-Safety-Lithium-Ion-Batteries.html

https://polarium.com/insights/safety/

https://batteryuniversity.com/article/bu-304a-safety-concerns-with-li-ion

Thanks for the links!

I’ll preface this by saying this quickly goes beyond my knowledge and is about things I haven’t researched in depth in almost 10 years.

Those articles all seem to be talking about lithium ion batteries which, along with lithium polymer, are rechargeable batteries. Non-rechargeable lithium primaries like cr123 and energizer lithium AA and AAA are based on Lithium Manganese Dioxide chemistries.

My understanding is that the Lithium Manganese Dioxide chemistry is more stable and the fact that it isn’t being subjected to the stress of charging cycles make it less likely to self vent or combust.

I do like that the last article makes the distinction between  normal defect rates per million product and the more special case type failures. It is my belief that both types of batteries probably see similar manufacturing defect rates, but the combination of a more volatile chemistry and the stress inherent in recharging make lithium ions more likely to exhibit a catastrophic failure.

Again, I know this is a small number overall.