The proliferation of affordable lithium batteries has made modern life convenient in a way we could only imagine in the 80s when everything was powered by squadrons of AAs, or has it? [Ian Bogost] ponders whether sticking a lithium in every new device is really the best idea.
There’s no doubt, that for some applications, lithium-based chemistries are a critically-enabling technology. NiMH-based EVs of the 1990s suffered short range and slow recharge times which made them only useful as commuter cars, but is a flashlight really better with lithium than with a replaceable cell? When household electronics are treated as disposable, and Right to Repair is only a glimmer in the eye of some legislators, a worn-out cell in a rarely-used device might destine it to the trash bin, especially for the less technically inclined.
[Bogost] decries “the misconception that rechargeables are always better,” although we wonder why his article completely fails to mention the existence of rechargeable NiMH AAs and AAAs which are loads better than their forebears in the 90s. Perhaps even more relevantly, standardized pouch and cylindrical lithium cells are available like the venerable 18650 which we know many makers prefer due to their easy-to-obtain nature. Regardless, we can certainly agree with the author that easy to source and replace batteries are few and far between in many consumer electronics these days. Perhaps new EU regulations will help?
Once you’ve selected a battery for your project, don’t forget to manage it if it’s a Li-ion cell. With great power density, comes great responsibility.
I really think we should have invented standard caps and wrapping for 18650 cells to let them be used replaceably like 20 years ago. Maybe key the caps by chemistry or something so they can’t be mixed or misused without modification.
I’ve been using 18650 cells in my flashlights for the last 15 years. They do have standard sized button tops for use in battery holders. I just wish more devices would use replaceable, cylindrical lithium cells instead of custom pouch cells.
18650 cells are somewhat big for many applications though, especially when you also consider the battery holder around it. They use pouch cells because they’re flat, so they fit in.
But does everything HAVE to be so thin?
I remember in the days of Nextel brick phones (I didn’t like flip phones, too fragile).. I was already trying to get my phone’s java api dev kit running. I wanted to make my phone into something similar to what smartphones became later. I also used to tether it via serial cable to a laptop. Yes, it was slow but it was fast enough to browse with the images turned off and worked just fine for an ssh terminal.
But I never thought once… if only this thing were thin. That didn’t matter to me and really still doesn’t.
lol; the power of marketing. The vogue used to be (pre-camera era) to make them as tiny as possible. It seemed you could wear them as earrings at one point. I suspect the change to thin (and increasingly large) was motivated by the smart-phone era, that benefits from ever increasing screen sizes.
i remember being obsessed with how thin calculators could be way back in the early 1980s. but i agree; fundamentally it’s a useless parameter.
I’ve always wished that smaller cylindrical lithium cells would’ve caught on as a standard – they’re not as ubiquitious as 18650s, but they’re certainly mass produced.
I assume that it didn’t happen because no open standard could overcome the general obsession with thinness, vendor lock-in, and safety concerns.
This.
I have a lot of 18650 that I salvaged from old notebook batteries that my colleagues threw into the trash. They’re still good for many years.
I have not only flashlights that take 18650 cells, but also powerbanks, soldering irons, powertools, and even a DAB radio. Also, a lot of devices actually have 18650 cells inside, that are easy to replace, if you know how to solder.
I wish everything would use them.
The tricky part is you may need to integrate battery management circuits.
That actually isn’t tricky – there are 18650 with battery protection integrated. They are few mm longer than the usual ones. I used two of those in parallel instead of main battery of battery powered wifi router. Lasted VERY long time. (Charged also very long time. I stopped using it, when I switched from 3g to 4g modem, because there was not enough power on the usb port for the modem).
I have been quite happily migrating all of my home devices to eneloop (or the japan-made cells at ikea which are relabeled eneloops) Ni-Mh and couldn’t be happier.
With a pair of AA and AAA on the charger and a drawer of spares, I haven’t had to buy a battery in years.
The ‘disposable’ li-ion devices however, are a giant pain in the arse as sourcing replacement cells in a ‘close enough’ shape takes so bloody long, its a job to replace and resolder them, and I constantly worry and have to keep searching to make sure I don’t have an old device swelling up into a great fire hazard in a closet somewhere.
No trip to IKEA is complete without picking up a few more packs of LADDA rechargeable batteries. I’m convinced they are relabeled Eneloop or Eneloop Pro cells at a great price.
Can’t speak for those – it’s been a while since I was in an IKEA – but I recently picked up a pack of rechargeable AA & AAA cells at Costco, the kicker being that they have USB-C sockets in the actual cell. Simply plug in a USB-C cable and boom (ok, unfortunate choice of word there…) it’s recharging.
OK, the more cynical take is that the product combines the limited capacity of NiMH cells with the end-of-life e-waste of Li-Ion…!
The 9V batteries with the USB charging port are great. I run those in all of my Fluke handheld meters. About once a year I remove them and charge them up.
We use those in one of our products at work; but unfortunately they’re not truly 9V, but a little less, even when fully charged.
They’re OK for stuff like that, but I got a couple to run some old transistor radios (that would have originally used larger, obsolete 9V batteries) and the interference caused wiped out any signal being received. I’m guessing that was because of the circuitry required to get the voltage up to 9V?
I have been using Eneloops for ages and now some of those Costco Coast “Zithion” cells so I don’t need a special charger. The Eneloops have been great and the shelf life of a charge is excellent.
These days I get chargers that can run from USB and a small portable fold out solar “tablet”. Same for simple power banks. It gives lots of options on a long power outage.
to be fair a standard battery is easier to recycle than assorted batteries sealed in dead devices. or they would be if we actually did that. batteries with usb ports seems like an over complicated kludge. id like to see a single chip solution that covers battery management, buck regulation to a constant voltage (eg 1.5v), and recharging. all with only 2 terminals. if it detects a higher voltage at the positive terminal, it disconnects the cell and connects the battery charge circuit with a separate cccv regulator. stick this all on a single pcb and crimp that right to the top of the connector. recycling would involve cutting below the crimp seal, removing the power electronics terminal “plug”, and dumping out the jelly roll (use the tesla tabless config). you can then recycle the cans, the electrodes, the electrolyte, and maybe the power electronics (if they still test good, reuse them).
On that point, alkaline batteries don’t contain chemicals that are particularly harmful or hard to recycle in the first place. It’s zinc, manganese and potash. All easily recoverable and not that harmful even if they end up in the environment.
In a way the recycling of alkaline batteries can be seen as a form of charging. CAAS (Charging As A Service): buy charged batteries, use them and put them in the battery bin at the store and buy new ones.
I’ve got some of those AAA lithium cells. They are much better than NiMh, even though the capacity is about the same.
The lithium cells maintain the output voltage at about 1.5V. The NiMh cells don’t – it starts at 1.4V and drops as the cell discharges.
Battery operated devices stop running on the NiMh cells because the voltage drops too low. The devices have a “low battery” detector designed for alkaline cells. The trigger level is too high to work with NiMh.
In other words, the devices stop working on NiMh while there’s still charge in the cells.
The lithium cells maintain that 1.5V right up until they are drained. The devices run longer.
I use the lithium cells in an SPO2 monitor. It is designed for alkaline cells.
With NiMh cells, it stops running after just a couple of hours.
With lithium cells of about the same nominal capacity, the SPO2 monitor will run for over 10 hours.
Could be a good idea. But everytime I see a test of those on internet, the result is always the same : Those are crap
you end up with a good alkaline replacement and a bad lithium ion battery. every time you have a regulator you lose efficiency. and since you regulate twice, once to go down to aa voltage and once in the device inefficiency stacks.
standard lithium cells, and you can get them in common sizes, can be used to make devices less disposable, but the device has to be designed to use it. then you have the problem of people putting them in devices that take alkaline batteries, potentially destroying them. i suppose you could put a buck-boost regulator in all the devices so it can take either battery type, but you need industry wide agreement on that, and legacy devices that dont can still get fried.
I picked up some of those in CR2 for my Minolta maxxum 5. They seemed like the perfect solution, even if they didn’t last very long a could just keep a pair charged. But it wouldn’t load film with them. I think the winding motor was tripping a current limit? Oh well
There are a few versions, but apparently the LADDA that come out of the Japan factory are the same cells.
Here is a good reference if you’re hunting for comparables, but for as long as this list is, I have only seen/used the original ones, Ikea branded, and the Fujitsu ones.
https://eneloop101.com/batteries/rewrapped-batteries/
I’ve been slowly migrating from Eneloops to Tenavolts Li-Ion AA and AAAs. The .3v difference between NiMH and Li-Ion starts to become a problem when a device is using AA’s in series for an expected 12v. None of my trailcams will run on NiMH.
Have you tried NiZn?
I’m a huge fan of the “AA” cell for bulk vs capacity of modern chemistries we now have. Loved the Eneloops, but dang they’ve gotten pricey.
I bought a few NiZn recently, in “AA” size. A shorter run time but they’re a nice bump for my (4 level) lumintop single “AA” lights, when you want the high setting for a few mins.
I don’t have much need to run the high setting, but nice to have the extra umph of the higher voltage cell.
Some of the vendors ship a rechargable lithium cell with the light, But I’m a bit concerned with life span of the LED when running that hot.
I had found some NiZn some years ago and liked the better performance in cameras also. Glad to the Ni-Zn showing on the market again. The 1.6 volt played a little better with the camera cut-off points.
Super-zinc was the brand name, back then.
Just wish there some 4-slot smart chargers (for the Ni-Zn) cells, with single slot charging (vs paired cell only types)
That are mains powered, rather than needing a cord and a USB cube to keep up with.
And can we please stop putting the prongs in the back of the #&*!ing chargers, which makes them block an entire mains receptical.
I’ve never liked using the ports on my computors as a charging port. Sockets are always too flimsy for it
Eh, I tried them and they die as fast as other Nimh batteries. Got a few which stopped holding charge within months.
i also worry about the fire hazard from liion and i have a bit of anecdata…
usually they swell when they are deep discharged. so i have a pile of abandoned laptops and as a rule of thumb every one of them will swell given enough yeras, and i have had to remove the battery. but by the time they swell, they’re dead, they’re discharged, and they aren’t a hazard. i wanted to know for sure so i cut them open and nothing happens.
the ‘spicy pillow’ happens when you try to recharge them. that’s when they get spicy. i had a device that i left on a charger forever, and it had a bug in the firmware or bms where it would stop charging the battery and then deep discharge it while connected to power! and that was really concerning because it was still on the charger! but luckily, it never attempted to recharge it after making the upillow.
Surprised they don’t mention a place where they’ve definitley gone too far… The diposable vape!
At least the devices on the list have some capability for recharging even if I generally agree with the sentiment and would rather have replaceable (preferably also rechargeable) AA or AAA batteries for a lot of them.
Absolutely, but the problem there is the perverse incentive for the manufacturer to not add the hardware to recharge the otherwise perfectly rechargeable Li-Ion battery. That would just increase the price, and they couldn’t sell nearly as many pens.
Some vapes are rechargeable, but not refillable.
If you’re pondering “what?”, it means the manufacturer can use a smaller battery. So rather than use it and throw it away like you’d normally do, you recharge it a few times and then throw it away.
The world of saving a few cents is very odd indeed.
For those that salvage these, you gain a USB-C charge circuit but lose out in battery capacity.
Exactly. Disposable vapes should be nuked from orbit. I don’t care how it gets done, just figure out a way. Just start smoking again ffs
Apparently those batteries in disposable vapes may be ones which failed checks and aren’t good to recharge? Think HaD had an article on vapes last year.
There are also disposable lithium cells. They can have double the capacity, but can’t be recharged without setting them on fire.
Ahh, crap. I’ve been salvaging vape batteries and have a small stock pile for an ESP project. Glad I found this out so I can dig into discovering exactly what I have.
They don’t use disposable lithiums in vapes – too expensive.
Definitely bad for the environment, but I personally quite like them: asked a few friends to not throw ’em away, and now I have a lifetime supply of batteries and chargers for small battery-powered projects (in case some of you don’t know, even in the cheapest ones that microphone-like thingy can charge batteries if you connect +5v to the blue wire that usually goes to the coil).
I’ve got NiMH rechargeable in all my calculators, which I don’t use often, and when I need the said calculators months later, the NiMH are invariably dead. I’ve had to put a Li-Ion battery in my HP 48SX due to shattering the battery tray when “opening” it to fix the usual dead top keyboard row of keys, and if I ever need it even months later, I know that I can always count on the battery being strong.
So if you think NiMH are better than Li-Ion, fine but I disagree. I tend to use NiMH in devices where I don’t want to use alkalines, not because of cost but because those are devices I really don’t want to have some alkalines leaking into (e.g. calculators). Things I don’t use much and of low value, I don’t mind using alkalines, I’ve got a list of the “best before” dates and check once in a while. If I’m getting rid of something (e.g. sale or charity shop), I just swap batteries with the oldest ones on my list.
I’ve also got some HP48 calculators that have been carefully opened up to repair that bad keyboard connection. Good idea to hide a small lipo cell in the battery compartment. Nearly a perfect voltage match to the 3 1.5V AAA cells and like you said, no leak risk and very low self discharge rate. Great way to keep that magnificent calculator going a few more decades.
Actually, put a large Samsung device (don’t know what, comes from the recycle bin at work) battery in the expansion card compartment :) I’ve had 48s since the 90s and never had a card, so don’t mind sacrificing the slots. Battery actually takes one slot, so I may still be able to use one of the slots if the need ever rises (which is highly unlikely!).
Go one step further and use those QI coils you plug into phones to convert them to wireless charging.
I never do wireless charging, I find it very inefficient and way too slow to charge.
Good for you. But for a tool like a DMM or calculator that might only need charging once a year, work for me.
Are you using LSD NiMH or just regular ones?
My guess is that either you aren’t using LSD or the other models of calculator have some bad battery management and are draining them more than they should.
I believe there is indeed a battery management issue as this happened with non-rechargeable too (happened on at least the TI-89 and HP-50g, I haven’t checked the nSpire and TI-84 but I did put NiMH in those too). I guess the Li-Ion has so much capacity that it just lasts way longer regardless. In fact, on alkaline batteries, I used to switch off the HP48 with ON+Space to disable the clock and save battery, with the Li-Ion I don’t even bother.
That makes more sense because LSD NiMH are rated to hold like 80% charge from full over 10 years sitting.
So it would be far more likely to be bad behaviour on the device than just self-discharge.
Nah, that’s 85% for a single year.
I have a slew of AA/AAA rechargeables. They have saved me probably several hundred dollars over the past five years, as opposed to buying Energizers. Got a little “battery box” (those and every other battery I might have). I grab “fresh” AA out of the cases I keep in there, drop the old ones in the box. When it seems there’s too many, I get my Bonai 16-bay circular charger out and run an overnight recharge. I’ll never go back to disposable AA/AAA. (I even have some USB-rechargeable 9-volts for the smoke detectors!)
A smoke detector is probably the one place I would stick with a standard alkaline battery and do the standard practice of replacing it yearly. I would not want to chance that a rechargeable goes flat without notice.
How long do the smoke detectors go on them? 9V alkalines last many, many years in ours.
I’ve gotten Alkaline AA’s for as little as $25 for 100 cells at the local Fry’s before it went out of business.
The only thing I’ll add here is that NiCd and NiMH are not great for direct drive motor applications such as electric toothbrushes, shaver/trimmers, etc. Because their “full charged” voltage is only 1.2v, your motor speed is that of a partially dead alkaline battery at best
Same with my HP-41cx (since someone mentioned the HP-48 above). My 41 shows “Low battery” at 1.2V. I replace the alkalines as soon as the indicator comes on, not waiting even ten minutes, as I want to make sure I have neither leakage nor lost memory. I’ve had my most-used programs in it continuously for 25 or 30 years.
Nonsense. You can connect them in series and they don’t need balancing like Li-ION. I have have a shaver and a tooth brush and had them for years. They run just fine with NiMH.
18650 cells provide higher output current than alkaline batteries or nickel-based rechargeable cells can manage, and this does indeed make flashlights in particular better (because brighter). so they may not be the best example here.
ya, as someone who’s used 18650 flashlights, i cant go back to anything that takes AA batteries.
get reusable protected 18650s, and they’re just as reusable than a rechargable AA cell
They’re pretty good. Only problem I’ve found is, the protection circuit makes the cell slightly bigger than standard and it fits too tightly in some battery holders, and the little circuit board gets damaged somehow and stops working.
The problem is non-compliance with the standard: protected batteries are sold everywhere should have a different number because they have a different size
There is no standard for the physical size of the protection circuitry, so there’s no “number”. It varies from one manufacturer to the next. Sometimes they fit in, other times they don’t.
With this article, I was wondering if the rechargable Lithium cells ran oversized.
That’s long been a pet peeve with the re-chargable “AA”s, running just large enough that if you drop or bump the device, the cells can slip back from the device contacts and then stay hung there. Thus your gadget goes dead.
Also sucks when rechargeable cells get hung up inside of your flashlights!
The rechargeable 18650 cells work great for say robotic projects. But for smoke alarms, thermostats, garage door openers, etc. standard non-rechargeable AA, AAA, or 9V square work fine. I use rechargable NiMh AA battery backs for my R/C transmitter. All depends on where used.
While NiMH has gotten better, they still haven’t quite solved the self-discharge issue, and the fact that they have a lower voltage so devices built for alkaline batteries stop working before the cell is empty, and the high capacity cells don’t get very many discharge cycles before they start degrading.
Also, with low drain devices such as remotes and wireless keyboards, alkalines have vastly superior capacity over NiMH. The main drawback of alkalines is their slow rate of reaction and high internal resistance, but that is not a problem if you’re drawing less than milliamps of current. The efficiency of the cell goes way up and it goes for ever and ever.
I had to make that call with a device that had to work for a year on a set of six cells. The NiMH cell would lose 15% in a year, more if it got hot, and then the voltage would be lower so it would cut out another 15-20% sooner. That meant an alkaline cell of the same nominal capacity would go for 40% longer, but we were pleasantly surprised to find that in testing even the cheap shop brand batteries would actually exceed that.
Another point is, since the device would only see less than 10 sets of batteries in its life, the alkaline cells would actually cost the same or less than the NiMH cells if you buy them in bulk.
That’s why I was slow to go to rechargeable bicycle-light batteries. I don’t ever really plan to ride in the dark, but there have been a few times over the decades that it was inevitable, for example a time I rode into the mountains, and soon after I turned around to come home, traffic was being stopped because one of these hot-dogger motorcyclists who’s always taking the turns too fast had wiped out, and police had stopped traffic until they could get the guy airlifted out and clean up the bazillion motorcycle parts that were strewn all over the road. By the time they let us go, it was getting near sunset, and I had about 25 more miles left to go to get home. I had my lights in my seat bag, ignored for many months if not a year or more, with alkaline batteries, and they worked at full brightness. If I had had rechargeable batteries, they would have been dead. Now lithium batteries are much better about that.
the initial jump to generator-powered bicycle lights is large and expensive, but once you’re there your lights are always ready to serve without any doubt, any modern ones will be plenty bright enough to make riding in full dark entirely doable, and the ongoing costs are zero.
What if you don’t want to? A hub generator adds weight and a little bit of drag even when it’s not operating.
certainly nobody’s forcing you. personally i’ve never noticed the added drag when it wasn’t operating (and, logically, it can’t be much more than 15-20 watts or so even at max output), and i’m not athletic enough to notice or care about the added weight. the convenience of always having good lighting available without needing to worry about batteries outweighs those factors, to me. your literal mileage is definitely allowed to vary, though!
to me, the main drawback is the expense. a hub generator by itself can be $hundreds, and then you need to (pay someone to) build a wheel around it as well, so…
I gather that some people turn their nose up at the old tire rubbing dynos.
But keep it set/adjusted for a light pressure and it’s not that noticeable.
I always felt just 6~7 psi drop of tire pressure felt more noticeable than the dyno, if it’s set up right.
pretty handy for no drag until you need the light. Last time I needed a new light, I went for the rear wheel mount, rather than the old, front forks mounting.
but you trade off for having the wire (carefully) routed along your frame and thus one more thing to need mechanical protection.
And on a personal note, Can we stop with the strobes on bikes already? In heavy traffic, it makes it much more difficult to pick you out from the random glints of of a thousand shiny surfaces that are also creating random flashes.
I watched a guy turn on blinky lights on his bike, then he put on a helmet with blinking lights around it.
Then he put in the earbuds and blithely rolled off into sunset time traffic. Six lanes of traffic at this intersection.
Dozens of cars turning in and out of the street. Even with knowing he was there, I lost him in the sea of other intermittent light glints.
Ride safe guys and catch few bugs in the face, for this old boomer with trashed knees.
I did have a generator on the bike in the 1970’s, when battery-powered lights were really lousy, to say the least. The generator drag slowed me down quite noticeably, and without any battery of any kind, the light would be dim when going uphill (because of the reduced speed), went completely out when you stop, and going fast would blow out light bulbs, due to lack of a regulator.
@adobeflashhater again: Riding with earbuds is illegal, at least in California; and then I see riders and joggers with their earbud music turned up so loud I can hear it from as much as 40 feet away! (Getting way off topic, I wish the law required them to ride with a mirror too. It’s required on all other vehicles, including convertibles with the top down where you can hear all around you. Putting the mirror on the glasses works best, by far, although it takes some learning.)
I keep a little 15 lumen “ring light” in my bag. It runs off of two coin cells and it straps around the handlebars. It’s just enough to see the road a couple feet ahead so you don’t run into a pothole, though mostly it serves as a warning light for cars. Unless you’re literally in the sticks, there’s always enough light coming from distant street lamps and other stuff to see where you’re going – it’s the other people who won’t see you coming.
My latest bike also has a built-in lamp in the front reflector. I’ve never replaced the batteries – I couldn’t figure out how to open it without unbolting it from the bike and taking it apart completely. There’s no obvious battery door or latch, or charging port of any kind. It has yet to run out of power.
With my previous bike, I tried having an aftermarket generator powered light, but somebody stole the lamp. They didn’t take the generator because the wheel was chained to the bike rack. You can’t really leave any sort of accessory on a bike because the kids will nick it. Cellphone holders, rear lights, a fancy seat… if you park in the same place every day for a couple months, it’s gone.
I tried using rechargeable NiMH batteries for years. They’re terrible., mostly because they will readily discharge on their own but also because … at least in my experience … they simply go bad pretty soon and won’t accept a full charge anymore.
A very big advantage of Li-ion batteries over alkaline and even NiMH batteries is that Li-ion can produce a lot more current … something that is essential for many appliances including high power flashlights.
So no, Mr. Bartz, Li-ion and its cousin LiFePO4 are here for a reason.
One of the problems with NiMH is that it’s very difficult to judge when the cells is “full” when charging. The voltage goes up, then there’s some weird chemical reaction and the voltage dips down and the temperature starts going up, not necessarily in that order. When to stop charging depends on all sorts of factors which are hard to track, so most consumer chargers apply some dumb cut-off point and either don’t charge the cells completely, or they cook the cells to death after a few cycles.
Also, the behavior is different between “normal” NiMH and the “LSD” variety like the Eneloops. The latter do not tolerate overcharging well, so they basically need their own special charger – at least if you want a fast charge. For slow charging over 10 hours or so, it doesn’t matter.
To complicate matters, this action had a dance with temperature. We made a thing that was used by the pushback tugs at airports which push the airliners away from the terminal. When they weren’t in use, they were to sit on the charger on the tug; but sometimes that would mean being in the sun, and other times in the shade, moving in and out of shade frequently. The solution which worked well was just to go back to a D-sized 2V lead-acid cell.
Temperature, current, the age of the cell, the SoC where you start charging from…
A NiMH battery develops hydrogen gas internally, and there’s a catalyst to recycle it back to the electrolyte, so the charging profile and trickle charging rate has to be matched to the catalytic reaction to keep it healthy in the long term. Different cells from different manufacturers obviously behave differently, so it’s difficult to design a charger that would keep them all in good condition.
Why is it that portable devices like vapes, laptops, and phones, which can be powered by lithium batteries, are required to include the batteries themselves instead of just featuring a connector like USB-C? With the introduction of Power Delivery (PD) communication, it should be possible to accommodate a variety of shapes, sizes, and attachment options for lithium batteries that could be reused even after the device is discarded.
With the AA batteries, the device has an instant refill. Just swap the discharged batteries with fresh ones !
18650 holders have this feature in addition to extra power density, low price, easy fix, device durability and easier disposal.
In time they insure capacity, power, performance improvement and availability.
Question: who here has experience with rechargeble NiZn batteries? They have a nominal voltage of 1.6 (1.8 when fully charged). I’ve been told they have a high self-discharge rate.
“in the 80s when everything was powered by squadrons of AAs” – excuse me? I’m pretty sure the ghettoblasters used something more beefy than mere AAs…
‘C’s and ‘D’s if memory served, and lots of them (about six to eight).
ah yes, those flashlights powered by too many D-cells that were large and heavy enough to beat a wild boar to death with. and, because they ran incandescent bulbs, were still somehow too dim to be really useful as lights.
I have long time held off using any lithium rechargeable chemistry battery in my portable projects due to fire risk and how careful you need to be in using them, but AA and AAA NiMH batteries are do fall short in a few applications like size, output voltage, weight.
I am now experimenting with LiFePo (LFP) batteries, I finally found a source of these batteries in smaller form factors being sold by a company called Soshine. They sell them in AA, AAA and many other form factors. Using AA and AAA LFP batteries introduces the danger of using them (3.2V) where normal NiMH batteries (1.2V) are required, overvolting and possibly destroying the equipment.
After browsing I have settled on the CR123 form factor, also known as 16340. These are bit fatter than AA’s and a bit over half their length, so no danger at all of mixing them up with my other batteries. They have a capacity of 550mAh (sticker capacity) at 3.2V so a bit over double the capacity of a eneloop AAA. Battery holders for this form factor are not as common but available on aliexpress in single and double format, through hole and SMT. The SMT one you could possible fit in a cutout in your PCB to reduce thickness.
Still need to evaluate the form factor and use them in a project but LFP has some advantages for home electronics projects: A bit safer, the 3.2V nominal and 3.6V max voltage matches well with 3.3V microcontrollers, cylindrical cells are easy to replace like AA/AAA, LFP has a higher energy density then NiMH.
the thing about alkalines is they leak some sort of contact-destroying chemical. i thought they were supposed to wait until they died to do that, but i’ve replaced a battery the very day the clock stopped working, and its contacts were destroyed. before i switched to lithium AA/AAA, i literally destroyed every single device that ever touched an alkaline. did alkalines get worse about a decade ago??
the problem with nimh is the capacity is so lousey after only a couple of uses. and one sitting on the shelf is always flat. and they actually aren’t easy to charge. maybe i should invest in a better charger. i use them for my wireless videogame controllers but all around i wish it was lithium.
the problem with lithium AA/AAA (besides being disposable) is that they’re actually garbage. it was an epiphany to stop throwing away every single device because of corroded contacts, but after a few years i wound up throwing away a flashlight, it turns out, because it had destroyed the voltage regulator in one of these lithium batteries! and that was after the struggle to polish the contacts from its earlier lifetime with alkalines. i assume the regulator in the flashlight had a resonance with the regulator in the battery, or maybe it was just a defect. but one way or the other disposable lithium batteries are no panacea.
i have a bunch of devices with built in lithium rechargeable and i’m overall really pleased by them. i’m a little nervous about charging them, i guess. but they tend to have great lifetime both per charge and per device.
i hate the reputable brands of bike lights (cateye, blackburn) because they are so expensive and so incredibly undurable. after decades of poor durability they upgraded them all to be too-bright, but still die immediately. they upgraded the batteries to built in rechargeable lithium but they used standard-defying microusb connectors! and they still die immediately! so on a lark i bought a variety of cheap bike lights on temu. at first i was skeptical because the temu ones had obviously undersized the battery. i mean these lights are tiny and even so you can feel they’re just empty plastic boxes. but they last as long as any light i’ve ever owned per charge, and much longer per device! the lithium revolution has swept chinese manufacturers and it’s amazing.
1) People use crappy chargers and crappy NiMH batteries, and then wonder why they die quickly. NiMH lasts very well if you use even a half decent charger, and is great for lower power drain purposes.
2) Yes, lots of things actually benefit from lithium, including flashlights. Better ones than you usually see people buying can easily draw as much power as a cell can provide, for a limited time before the thermal regulation kicks in. And tons of them do actually use cylindrical cells you can replace – many of those even have usb chargers now, so that you don’t have to understand how to unscrew a cap and put a battery in a charger when it gets low anymore.