[HN Gopher] Ode to the AA Battery
___________________________________________________________________
Ode to the AA Battery
Author : Brajeshwar
Score : 136 points
Date : 2026-01-30 13:55 UTC (9 hours ago)
(HTM) web link (www.jeffgeerling.com)
(TXT) w3m dump (www.jeffgeerling.com)
| klooney wrote:
| > run at a nominal 1.2V instead of the 1.5V of alkaline
| batteries.
|
| I've suddenly figured out why so many toys don't work with
| rechargeable batteries
| bux93 wrote:
| You can now find 1.5V Li-on AA batteries with, and that's a
| game changer, built-in charger and a type-C port!
|
| I have one in my wireless mouse. If it dies, I change it to a
| spare and charge it right from my laptop (and the battery that
| was empty becomes the spare)
| ramses0 wrote:
| Came here to post this. I'm 100% agreed with Mr. Geerling.
|
| For a fun challenge try to find a non-built-in-battery arc
| lighter (eg: candles, grills, etc). When I found one I bought
| four (think camping/disaster bag... if everything is AA/AAA
| then having a shelf-stable fire starter is easier/safer than
| lighter fluid).
|
| For a fun sidebar check out the "Panasonic BQ-CC87AKBBA"
| which is effectively a combo "in/out" battery charger OR USB
| battery pack(!). It'll suck in (unfortunately) Micro-USB and
| charge your AA's, then switch a button and it'll spit that
| power back out as a battery bank. When I find one like that
| for USB-C, it's going on my christmas list.
|
| Look up plastic battery holders that hold 8-10 along with a
| 4x charger and I just swap batteries out and recharge them
| into that buffer/holding cell. I'll have to look into the
| Eneloops as I've been working with the Amazon Basics and
| generally have 1-2 batteries fail out every few months (and
| am specifically looking for heat-resistant / outdoor
| applications).
|
| Last one: Lots of cheap solar products have cheap
| rechargeable AA batteries inside... you can generally open
| them up and swap the battery out if they're not working any
| more (and/or potentially scavenge the charging panel if you
| think about it!).
| mystifyingpoi wrote:
| I had this charger once! Really cool with the powerbank
| option. Although, these days, 5V@1A with no PD is probably
| something to use maybe in emergency, it's too slow for
| modern devices.
| Rediscover wrote:
| The NITECORE UM10 is an "in/out" charger too - it handles
| various sized LiIon batteries one-at-a-time. A switch on
| the end determines if it is charging or discharging. Their
| site says it's discontinued, but I thought I recently saw
| them at a shop in Seattle. Time to pick up a spare.
|
| https://charger.nitecore.com/product/um10
| oskarkk wrote:
| I haven't used them, but IIRC they maintain a constant
| voltage until they're discharged, when it instantly drops to
| 0. That may be a problem, because if your device has any
| battery indicator, it will show the battery as full until the
| end. Nothing will tell you that you need to replace the
| battery before the device powers off. That's why I decided
| not to buy them. My mouse knows when my alkaline AA battery
| is low and gives me a warning.
| eisa01 wrote:
| You can get them with different voltage drop-off curves
|
| E.g., this battery is 1.5V for ~70% of the capacity, before
| it gradually reduce to 1.0 V
|
| https://www.xtar.cc/product/xtar-1-5v-aa-clr-3300-lithium-
| ba...
|
| edit: And one with USB-C and linearly decreasing voltage
| curve https://www.xtar.cc/product/xtar-aa-lithium-
| lr-2000mah-usb-c...
| Marsymars wrote:
| I use rechargeable CR123 batteries in my August smart lock
| that face this issue. The solution is to have a spare set
| and rotate/charge on a fixed schedule before they die. I
| have a quarterly calendar reminder to do so.
| jchw wrote:
| I believe I have zero Alkaline batteries left in my house and
| I'm relatively surprised that pretty much everything works
| fine. If anything, I suspect the only problem is that some
| devices have an inaccurate account of how dead the batteries
| are. But I use Eneloops on everything, even things surely not
| designed at all to run on them. (And I reckon you could
| probably make more devices work if you really wanted to; adding
| an additional cell or two in series would surely give you a
| voltage that's in range, if you can figure out a good way to do
| it.)
|
| Of course not all rechargable batteries are the same; there are
| a few different rechargable battery chemistries in the AA form
| factor. I like Eneloop Pros, though; they've been very reliable
| for me. I've been using them for years and I've never had to
| throw one out yet; supposedly they last over a thousand cycles
| with most of their capacity.
| zabzonk wrote:
| I think I have only one device that uses AA - my central
| heating's radio thermostat. This thing has caused me untold
| hassle, which is only partially down to the batteries, but
| still...
|
| Totally OT, but does anyone have a good link on how the
| thermostat gets paired with the boiler? I'm thinking of
| getting replaced and would like to talk to the gas fitter
| from a vaguely informed point of view.
| ghaff wrote:
| Personally, I keep things simple. Got a new (pretty basic)
| Honeywell thermostat after a kitchen fire; thermostat was
| pretty old anyway. For wiring, you mostly have 2-wire and
| 3-wire although there are a lot of variations as you get
| fancier: https://nassaunationalcable.com/blogs/blog/a-full-
| guide-to-t...
|
| Number of zones in the house may affect things as may
| boiler only or AC being in the picture as well.
| bluGill wrote:
| > good link on how the thermostat gets paired with the
| boiler?
|
| You should have a book with the boiler that says how your
| system is setup. They nearly always include schematics and
| are very helpful. Typically you can open a cover and see
| the wiring details as well.
|
| Forget about web sites, there are too many different ways a
| system can be setup, so even if they are not slop they can
| still be inapplicable for you. Once you know what you are
| looking at you can sometimes get useful information from
| the web, but until then you can't sort out what is useful
| for you.
| ghaff wrote:
| Yeah. Have your manuals handy if you get a furnace
| guy/electrician in. My electrician actually wired up my
| thermostat wrong when I got a new thermostat in.
| zabzonk wrote:
| Thanks, and to the other guys. But I am asking about a
| remote wireless thermostat. How does it know to talk to
| my boiler, and not her next door's?
|
| As I said totally OT, and I do have a couple of good C/H
| firms I can get in to sort it.
| ghaff wrote:
| Sounds like an awful idea in general. Think KISS concept.
| But you'd have to look at manuals. There's probably no
| single answer. (I was thinking of wireless control of the
| thermostat itself.)
|
| I'd add that, where I live (New England), furnace
| failures can be basically catastrophic so any theoretical
| convenience advantages just aren't worth it.
| zabzonk wrote:
| Wireless thermostats are really common in the UK. I don't
| know about elsewhere. I'm interested how they pair (like
| Bluetooth) with the boiler.
|
| Basically, the thermostat is in a living area and you set
| the temperature(s) to what you want, it senses them, and
| then talks to the boiler (in my case in the roof-space)
| to heat up (or not, via radio) the water in the radiators
| to satisfy that. It's a feedback loop.
| ghaff wrote:
| I'm maybe just a fuddy duddy but relying on wireless tech
| for critical systems unnecessarily seems like asking for
| trouble. Running wires to a boiler isn't generally that
| complicated and it's just one less point of failure.
| bluGill wrote:
| That depends. Sometimes because they have encryption. It
| isn't hard to have shared keys of some sort. If there is
| no internet connection on the link (which is possible -
| I've never seen where both systems connect to wifi, but
| if they do worry!), and so you don't have to worry about
| malicious hackers and in turn the encryption is good
| enough even if done somewhat wrong.
|
| Sometimes they are just send a radio signal and hope
| nobody else in range is using that frequency.
|
| So again, there are too many different ways this is done
| to guess. Unfortunately they probably don't put this in
| the manual.
| quickthrowman wrote:
| Thermostats (aka space temperature sensors) can have
| between two and eight wires. A boiler will usually have
| three: 24V power, call for heat, and common.
|
| If your boiler has inputs on the terminal block for a
| thermostat, I would highly recommend buying a wired one,
| the 24V constant power removes the need for batteries.
|
| If you can provide a link to your boiler's installation and
| operations manual, I can tell you.
| bxparks wrote:
| Three things prevent me from eliminating all alkalines:
|
| * smoke and CO detectors with low-battery voltage sensors
| calibrated to alkaline
|
| * some older electronics (e.g. multimeters) using 9V
| batteries
|
| * my non-contact voltage tester refuses to turn on using
| NiMH, for safety reasons presumably
| rini17 wrote:
| There are 9V NiMHs, too. They just need dedicated charger.
| bxparks wrote:
| Yeah, most of the devices using 9V are smoke/CO detectors
| which only accept alkalines. I don't use the few
| remaining 9V devices enough to justify buying a new
| charger.
| accounting2026 wrote:
| I have a weather station that takes two 1.2 V. The LCD screen
| is a bit dim compared to when used with fresh 1.5 V
| alkalines. Other than that, most things take the 1.2 V well.
| But they better do because alkalines reach 1.2 V with >50%
| capacity left.
| dragontamer wrote:
| That's not the reason.
|
| Alkaline batteries only have 1.5V for a short time. In
| practice, toys are designed to opeerate off of 1V to 1.5V,
| because Alkalines vary _wildly_ in voltage during use.
|
| NiMH at 1.2V _STAYS_ at 1.2V, even when drawing 1Amp or more
| (under these conditions, Alkaline would have long dropped below
| 1V).
|
| EDIT: This is also a problem because "nicer toys" will measure
| the voltage assuming an Alkaline is "full" at 1.5V and dies at
| 1.0V. However, NiMH starts at 1.35V, then "plateau" at 1.2V,
| and stays there for most of its life, before rapidly falling
| off to 1.0V or .8V like a cliff at the end of its life. So NiMH
| life "cannot be predicted" by any simple metric.
| jonpurdy wrote:
| I had an issue with the original Apple Magic Mouse that would
| not work correctly with NiMH batteries but work fine with
| disposable AA. The mouse would be fine for a few days then
| randomly stop working; using fresh NiMH would revive it
| again. I assumed it was due to 1.2v vs 1.5v but perhaps that
| particular mouse (or all Magic Mice) was just bad.
| joecool1029 wrote:
| I have an acurite 5in1 weather station running on
| eneloops/laddas. It whines about the batteries being low
| but runs for about a month in any conditions. I just rotate
| and recharge them at the start of the month.
| Zak wrote:
| Looking at the discharge curve for an alkaline, much of the
| energy is below 1.2V even under light load. A device that
| works with alkaline and not NiMH due to voltage is broken
| as designed.
|
| https://lygte-
| info.dk/review/batteries2012/Duracell%20Ultra%...
| ahartmetz wrote:
| If you need 1.5V / 3V for some reason, you could maybe
| insert a tiny boost converter from AliExpress (1EUR, less
| than 1 cm in all dimensions). I have done that for a
| string of fairy lights.
| direwolf20 wrote:
| If they don't work at 1.2V they weren't very good quality to
| begin with. AAs are dead at 1.0 or 0.9V.
|
| There are a lot of low-quality toys.
| c0nsumer wrote:
| A weird flipside is things like... the IKEA Zigbee devices.
| Many of these do not work right at all with 1.5V batteries and
| basically require rechargables.
| Insanity wrote:
| Can't exactly relate to the post. I never had a device die on me
| like that. All my devices with Li-ion batteries are "daily
| drivers".
|
| I do tend to keep charge between 20-80% where possible, and
| fortunately haven't seen significant battery degradation.
|
| I'm on a 4 year old iPhone and even that easily gets me through
| the day still on 80% charge.
|
| My only AA device is my HHKB keyboard and I wish it had a USB-C
| rechargeable battery instead.
| amelius wrote:
| Speaking of which, I really hate those chargers that force you to
| use two batteries instead of one. I get that it is cheaper to
| design it that way, but come on.
| dragontamer wrote:
| NiMH chemistry allows for safe overcharging though. If the
| chemistry allows for it, why not take advantage of it and have
| cheaper chargers?
|
| The downside is that "save overcharging" only works at very low
| charging rates. That's why the double-charger designs all have
| 10+ hour charge times (mine actually has a 20-hour charge
| time).
|
| But in practice? Its cheaper to buy 4 extra AA NiMH batteries
| to keep charged rather than upgrade to the faster chargers. So
| just keep some spares topped off and you should be fine.
| amelius wrote:
| Sure, but those NiMH have the same form factor by necessity,
| so it is confusing.
|
| I would be surprised if the extra costs for the electronics
| for charging an extra cell are more than a few dollars.
| dragontamer wrote:
| NiMH cells are like $1 each. Seriously, Amazon.com is
| quoting me $18 for 16 cells, AA Amazon Basics NiMH.
|
| As I said earlier: it's likely a better strategy to buy 4
| extra cells and keep them pre charged / topped off, rather
| than spending a few dollars on a better charger.
| D13Fd wrote:
| I'm not sure that's true in practice. Chargers are often
| shared in a household and you may not have control over
| people putting things back on the charger. My preference
| is to have something that charges more quickly, rather
| than a bunch of spare batteries.
|
| Plus if you leave batteries on the overcharge-style
| charger for long periods of time, I'm pretty sure they
| just dissipate the extra charge as heat, and that charge
| is applied indefinitely. They essentially turn into
| little electric space heaters, sending that energy down
| the drain.
| dragontamer wrote:
| Don't leave them in the charger! You precharge and then
| store for a year+. Modern NiMHs only need topping off
| once per year or less.
|
| So you have two piles. Good charged NiMHs and uncharged
| depleted NiMHs. While(uncharged.size() >= 2) put them in
| charger.
|
| Then once per year, do a refresh charge on all the NiMHs.
| Easy-peasy.
| BeetleB wrote:
| I think what he is referring to is this:
|
| If one battery is 50%, and the other at 70%, and you put both
| in, one will end up at 80% and the other at 100%. When one is
| full, those cheap chargers stop charging the pair.
| alnwlsn wrote:
| Speaking of which, I have yet to see a consumer battery charger
| that isn't incredibly cheap feeling. Even ones for charging
| different chemistries or that let you set current rates are a
| mess of low-quality molding and cryptic button presses.
| bombcar wrote:
| This is expensive but so far pretty nice. It's about the size
| of a console, though.
|
| https://www.amazon.com/OLIGHT-Exclusively-Rechargeable-
| Batte...
| jasomill wrote:
| I've never had a problem with the basic 4-cell chargers that
| Panasonic includes with their Eneloop starter kits, other
| than the mildly annoying fact that they cover more than a
| single plug on a power strip.
|
| Build quality seems fine, and I've been using them for
| decades without a single failure, so I've never seen any
| reason to even investigate alternatives.
| jasona123 wrote:
| Panasonic does have one that charges over USB (micro-USB
| input though) so you can use an old 5V Apple brick and only
| take up one spot. It also supports USB out via a full-size
| USB-A port. Picked one up since I liked the idea of being
| able to use AAs in a pinch for recharging.
| iberator wrote:
| Build one. Great, ambitious but doable newbie electronics
| project :)
| conception wrote:
| The Xbox 360 was the most gamer friendly console (play your open
| music during games?!?) but one feature i loved was the battery
| packs. Your controller died? Just swap a pack - two seconds. And
| the packs could be rechargeable or AA so you could have a bunch
| of rechargeable AA for a fair price and never get bogged down
| waiting for anything to charge.
| coldpie wrote:
| Series X controllers still work this way. Takes standard-ass AA
| batteries, including rechargeables; or you can buy a bespoke
| charge pack[1] which actually supports charging while in the
| controller.
|
| [1] https://www.xbox.com/en-US/accessories/batteries-
| chargers/pl...
| jon-wood wrote:
| I really wish more devices went this way. In devices these
| days the thing that will fail first, long before other
| components, is usually the battery. It seems disingenuous of
| manufacturers to claim that rechargeable batteries are good
| for the environment and then ship devices without user
| replaceable battery packs.
| coldpie wrote:
| > I really wish more devices went this way.
|
| It's a shame Xbox Game Studios is run so badly, because
| pretty much everything else about Xbox is genuinely better
| & more consumer-friendly than what PlayStation & Nintendo
| are doing. But the main thing that matters is the games,
| and they just don't have 'em over at Xbox. Oh well.
| hn_acc1 wrote:
| Hey, they're just as good for the environment as all that
| plastic that we can, "honestly, for sure, 100%, totally"
| recycle almost all of it. /s
| pdpi wrote:
| And, if you use good quality 2500mAh rechargeable AAs, those
| controllers go forever between charges.
| BeetleB wrote:
| > those controllers go forever between charges.
|
| In my experience - about a month. Less if you play more
| often.
| WillAdams wrote:
| Ditto for the Nintendo Wii Remotes and the Balance Board --- I
| still have a set of rechargeables from that setup.
| Lutzb wrote:
| The best thing about Eneloops do not seem to leak. I can just
| leave them in rarely used electronic devices without worrying.
| They might discharge, but so far this has never been a problem.
| ahartmetz wrote:
| I don't think that I've ever seen any NiMH leak. If you look at
| teardowns - it's maybe not even possible. They look rather dry
| inside.
| hn_acc1 wrote:
| Mentioned this above - so happy we went with Eneloops. Our
| battery waste is nearly 0, and no leaking..
| BeetleB wrote:
| I've been using NiMH AA batteries for over 20 years. I've never
| had one leak. It's not unique to Eneloop.
| alnwlsn wrote:
| Designers have a choice in lithium-ion though. 18650 is is pretty
| large cell but there's 14500 which is AA sized or 10440 which is
| AAA sized. They make versions with the usual battery "nub" rather
| than the flat faces for spot welding, and built-in protection
| circuitry to prevent over-discharging. You probably would want to
| use ones of a different size than normal 1.5v cells though. A
| personal favorite of mine is RCR123A/16340.
|
| Even many of the pouch cells come in "standard"-ish sizes. An
| 803860 is nominally 8.0mm x 38mm x 60mm, but I am seeing more
| custom sizes recently.
|
| Meanwhile, alkaline batteries can go to hell. You might as well
| plan on one leaking in the battery compartment. My favorite non-
| rechargable 1.5V AAs are Li-FeS2, which never leak and have
| spectacularly low self discharge (especially good for multi-year
| ultra-low-power projects), but are dammed expensive.
| everdrive wrote:
| >Meanwhile, alkaline batteries can go to hell. You might as
| well plan on one leaking in the battery compartment.
|
| On the other hand, alkaline batteries never burn your house
| down.
|
| I also feel like they serve different purposes. Needed for
| long-term storage and only used in an emergency? (eg, a
| flashlight for power outages) You're probably better off going
| with old-fashioned alkaline batteries. Duracell claims they're
| good for 10 years. Needed for day-to-day usage? Lithium might
| be better: you can monitor for swelling, the battery recharge-
| ability is probably more important than any of the downsides
| that come with lithium ion batteries.
| aftbit wrote:
| No, there's basically no reason you'd ever want an alkaline
| battery except cost. For your use case of long-term storage
| or a rarely used flashlight (e.g. in a car emergency kit),
| you'd want a Li/FeS2 as the parent poster recommended, also
| called just a "Lithium" primary (i.e. non-rechargable) cell.
| They have a longer shelf life, don't leak, hold more energy,
| can provide a higher discharge current, work over a wider
| temperature range, and have safety characteristics very
| similar to alkaline.
| jrockway wrote:
| Lithium primaries are great. I use them in my weather
| station. 2AAs have lasted at least 4 years, and still work
| well when it's 0F out.
| js2 wrote:
| Main disadvantage is cost. Looking on Amazon, it's $1.61/ea
| AA lithium vs $0.62/ea akalaline. That's Energizer vs
| Energizer. Amazon Basics AA alkaline are $0.32/ea. (Unlike
| alkaline, knock-off lithium aren't much cheaper than
| Energizer.)
| Dylan16807 wrote:
| Well how many batteries do you need as long term storage
| for emergency use? $10 worth?
|
| Everything else use rechargables for a dollar-ish plus
| charger cost.
| Spooky23 wrote:
| Great point.
|
| I was going to say cost is a really significant factor
| there, but I was thinking convenience retail where they are
| marked up. They are only 3x more on Amazon. Now you're
| guaranteed to damage equipment as the current alkaline
| formulations leak.
| everdrive wrote:
| That's an interesting counterpoint, thanks for letting me
| know. I was really under the impression that lithium ion
| batters discharged more aggressively. Maybe that's just
| more reflective of how they lose capacity over time? Can
| you speak to the fire risk?
| mbrubeck wrote:
| The comment above is about non-rechargable lithium-metal
| batteries. You are thinking of rechargeable lithium-ion
| batteries.
| jandrese wrote:
| There are a handful of applications where alkalines are
| better. IR TV remotes run effectively forever on a couple
| of batteries and the slow self discharge on the alkalines
| makes them ideal for the task.
| SAI_Peregrinus wrote:
| I think you're thinking of rechargeable Lithium-ion
| batteries. GP is talking about lithium primary cells,
| which have even lower self-discharge than alkalines.
| Usually about 1/2 the self-discharge rate of alkalines.
| bxparks wrote:
| Great in theory.
|
| In practice, the Duracell alkaline battery will leak
| caustic fluids inside the remote control and destroy it,
| and you will have to mortgage your house to buy a
| replacement on eBay, if it's even available. (I pick on
| Duracell because they are the worst. They leak if you
| look at them wrong, when they are brand new, inside the
| original packaging, before their "expiration date". But
| all alkalines are bad.)
|
| All my remotes get NiMH batteries, no matter what. I
| don't care if one charge cycle lasts 10 years. It's
| cheaper than having the battery destroy the remote.
| bigstrat2003 wrote:
| I have never, in my 40 years of life, had an alkaline
| battery leak and destroy something. I'm aware that it
| _can_ happen, but in practice it doesn 't happen very
| often.
| quickthrowman wrote:
| I have seen every kind of common alkaline battery size
| leak acid or have corrosion. 9V, AA, AAA, C, D. It helps
| that I used to fix broken things for a living, I guess.
|
| Can't recall if I've seen a CR2032 leak acid or corrode,
| but I think I have.
| vel0city wrote:
| I have many times in my less than 40 years of life. Often
| things that had batteries left in then and forgotten
| about for a few years, and often with the cheap batteries
| something came with. Often with kids toys, TV remotes and
| rarely used flashlights. If you're the kind of person
| that takes batteries out when you put things away or you
| change the batteries somewhat soon after they die you
| likely never had any leak.
|
| I have a Canon AE-1 that takes a 4LR44 to operate the
| light meter. When I got it the battery had deteriorated
| significantly, causing a lot of damage to the battery
| area. I had to remake the battery contacts cutting and
| soldering in new springs and pads as the corrosion had
| practically completely eaten the old ones. That was
| probably the most notable leak I've encountered. But the
| previous owners didn't even know there was a battery in
| it, so it likely had that battery in there for a decade
| or more.
| dfe wrote:
| I've only had batteries leak in remotes left unused for
| over a year. I just pick up Duracell or whatever is at
| Costco.
|
| I've also bought two replacement remotes off of Amazon in
| the past year, one Samsung and one Insignia. I think they
| were $15-20 each, which seemed very reasonable to me.
|
| Generally they won't have the manufacturer's logo, but
| everything else on the outside looks 100% identical, and
| all the buttons worked.
| pimeys wrote:
| There is one very good reason: the discharge curve. An
| alcaline battery loses voltage when it discharges, the
| lithium ones discharge with the max voltage until they
| suddenly stop working.
|
| This is a reason insulin pumps require specifically high
| quality alkaline and lithium is considered a risk.
| Zak wrote:
| Alkaline has a tendency to leak electrolyte when stored in
| devices long-term, especially if used intermittently, even
| more so if the loads are at the upper end of what alkaline
| can handle as they are in many modern flashlights. The
| electrolyte is corrosive and often results in a broken
| device, which is exactly what you don't want in an emergency.
|
| Li-ion's self-discharge is pretty low for a bare unprotected
| cell, and a flashlight with a mechanical switch consumes no
| power when off. One must take care to avoid short circuits
| when handling such a cell, but modern Li-ion flashlights have
| over-discharge protection, so that's the main safety concern
| with a single-cell design.
| D13Fd wrote:
| > You're probably better off going with old-fashioned
| alkaline batteries.
|
| Never. They will leak and die. Alkaline cells always end up
| leaking and dying in my experience, given enough time.
|
| In fact, I do the reverse: If it's something I think will sit
| for a long time, I make sure to put a rechargeable battery in
| it. That way, worst case, it's dead--but it won't be
| destroyed by a leak.
| thinking_cactus wrote:
| I have seen panasonic cells around my area advertised as
| leak-proof (or was it leak resistant?). I wonder the
| effectiveness.
| hn_acc1 wrote:
| It's gotten worse over the course of my life, IMHO.
| Costco's Kirkland batteries 15 years ago rarely leaked -
| now they do it in months sometimes. We had leakage a bit
| back when I was a kid (80s) but I honestly don't remember
| it happening as often.
|
| It's one of the things that pushed me all-in on Eneloop. We
| were throwing away 10-20 AAs/month at one point (wife likes
| electric candles). Recently, it's been 2 or 4 as we
| discover old remotes or something we hadn't replaced yet.
| And we have 8-20 AAs and 2-4 AAAs charged and ready to go
| at any point. Swap, and put the empty ones in the charger
| is now the standard process at our house.
| js2 wrote:
| > My favorite non-rechargable AAs are Li-FeS2
|
| Lithium Iron Disulfide. For those looking for a brand name,
| that's what these are:
|
| https://energizer.com/batteries/energizer-ultimate-lithium-b...
| ploxiln wrote:
| I just worry that the voltage of these is a bit too high, if
| the device takes 3 or 4 in series. They tend to be around 1.8
| volts per cell, significantly higher than a fresh alkaline AA
| at around 1.6 volts, and even after half the energy is
| discharged, if the device is off for a long while, the
| initial voltage for next turn-on creeps all the way back up.
|
| (The price doesn't bother me ... it's worth the much lower
| chance of leaking than alkaline, if you leave it in a remote
| or gadget for years. But I've come to think that rechargeable
| NiMH like eneloops are a better idea due to the voltage.)
| Scoundreller wrote:
| I'm visiting some family and I'm a hero for fixing a couple
| devices that stopped working from alkaline batteries by using a
| bit of foil paper to overcome the corroded contacts.
|
| Maybe not great in the long run (steel and aluminum don't like
| eachother)... maybe I should have put on some grease...
| sowbug wrote:
| I swab the corroded contacts with white vinegar from the
| kitchen. It turns the white gunk into a foamy blob, and I
| assume it etches off enough of the corrosion to restore
| conductivity. I wipe the foamy part with the dry side of the
| cotton swab, and the device usually works again.
|
| I started doing this as a kid, reasoning that the white gunk
| looked like baking soda, which is fun to combine with
| vinegar, so let's see what happens. I just looked it up, and
| it appears that the process is legitimate and safe. The
| vinegar turns potassium carbonate into potassium acetate,
| also producing carbon dioxide.
| bluGill wrote:
| That is step one. However that is rarely enough: the
| corrosion eats through the chrome plating on the steel
| (chrome is a good conductor, steel makes a great spring),
| and that rusty steel is a poor conductor. Even if you
| polish the steel, it will rust again soon. (chrome plating
| requires nasty chemicals, not something to attempt at home
| - I suspect you could silver plate at home for cheap enough
| but I haven't tried it)
| Dylan16807 wrote:
| > Designers have a choice in lithium-ion though. 18650 is is
| pretty large cell but there's 14500 which is AA sized or 10440
| which is AAA sized. They make versions with the usual battery
| "nub" rather than the flat faces for spot welding, and built-in
| protection circuitry to prevent over-discharging. You probably
| would want to use ones of a different size than normal 1.5v
| cells though. A personal favorite of mine is RCR123A/16340.
|
| But other than 18650 you can't expect to find a lot of devices
| using any particular size.
|
| We should strive for a couple blessed sizes that a lot of
| devices will stick with, where all cells include a nub and
| protection circuitry.
| cogman10 wrote:
| The form factor I'd like to see standardized would be a flat
| pack like the Nokia phone battery.
|
| Not saying the cylinder doesn't have it's place, but so many
| of my devices would like a flat pack.
|
| If that happened, it'd have the added benefit of being able
| to standardized a bms protocol for the packs. Hard to have
| control pins with a cylinder.
|
| And if you were super clever, you'd make those packs
| stackable so they could be charged and discharged together.
| sowbug wrote:
| I love the 14500 except for its footgun shape. 6 x 14500 is at
| least 21 volts, which won't play nice with a device that wanted
| 9 volts. I used to try to keep the 14500s far away from the
| AAs, but there's no stopping a kid in a hurry who wants to play
| with a toy or musical instrument.
| Pxtl wrote:
| I've taken the approach of electrical-taping my USB-
| chargeable 14500s each to a dummy-battery, since the things I
| put them in have 2 adjacent slots for series AAs. The voltage
| is still high (3.somethingV instead of 3V) but they seem to
| work.
| Dylan16807 wrote:
| Are those LiFePO4 batteries that cap around 3.6V, or normal
| lithium ion that cap around 4.2V? I'd be cautious with
| either kind but especially with the latter.
| MarkusWandel wrote:
| Am I courting disaster by reviving won't-charge pouch cells by
| just manually running a bit of current through them until they're
| nonzero volts and then a normal charger will do the rest? So far,
| in the maybe half dozen times I've tried it (rectangular battery
| blocks for old digital cameras, the pouch cell inside a long-
| disused Kobo Reader) it's worked. They charge right up, they
| don't swell, and they still have decent capacity.
|
| I'm running at the hairy edge and only high quality safety
| engineering is protecting me here? Or these cells can take a lot
| more abuse than they're given credit for?
| creaturemachine wrote:
| I've jump-started my share of batteries this way. Such a deep
| discharge might affect lifespan but it's typically old devices
| we do this to anyway.
| vladak wrote:
| Cool. I have a modern (not smart) body weight scale and it
| regularly ruins this way at least one of the 3 GP NiMh
| rechargable AAA batteries I put in it, so I wanted to hear
| some ideas what could be done with them given they have been
| through only bunch of charge cycles.
| Dylan16807 wrote:
| If it runs on 3 AAAs you could also hotwire it to use 1
| lithium ion (choosing a model with builtin protection).
| RankingMember wrote:
| I've thought before that it'd be nice to have some kind of
| device that would do this in a safe(r) fashion wherein you'd
| connect the 2 charging leads to the dead battery plus a temp
| sensor pad and it'd slowly bring the charge up to the minimum
| required for charging by a regular charger.
| Zak wrote:
| Over-discharged Li-ion cells can grow metallic lithium
| dendrites that result in internal short circuits. Charging them
| again following over-discharge does create a risk of
| fire/explosion.
| accounting2026 wrote:
| About 15 years ago I was writing software for an embedded
| device made by another company, and they sent us a unit for
| testing. It had a small rectangular rechargeable lithium
| battery that was charged via a DC jack.
|
| At one point I hadn't kept it charged, the battery went
| completely flat, and after that it would no longer charge at
| all. When I called the company, they said the battery was now
| too deeply discharged and required an "intelligent" charger to
| revive it. They sent a charger with a slot for the bare
| battery; some LEDs blinked in various patterns for a while, and
| eventually normal charging resumed.
|
| I've always wondered what that charger actually did, that the
| built-in charger was not capable of. Was it performing some
| kind of analysis to decide whether the battery was safe to
| recover (e.g. after deep discharge), or was it simply applying
| some initial charge ignoring the battery's protection circuitry
| (and at what risk)?
| InsideOutSanta wrote:
| My Xbox 360 controllers are still in use. Meanwhile, I've
| resigned myself to never using any PlayStation controllers for
| more than three or four years.
|
| AA and AAA batteries are great. I wish using them weren't
| considered a negative by many hardware reviewers.
| Cthulhu_ wrote:
| You can get replacement parts for PS controllers, although they
| can be rather fidgety to open up.
| InsideOutSanta wrote:
| Yeah, I tried fixing the wand controllers for PSVR, ordered
| batteries from AliExpress. It took an hour to get everything
| done, and I was constantly scared I'd break something. That
| was a few years ago. Now they are back to not working; I'm
| not sure if I can even still get the batteries.
| jmclnx wrote:
| I did something similar with my old 286 system. The CMOS battery
| failed and I rigged up a replacement using velcro and 4 AA
| batteries. Worked great.
|
| Sadly I had to toss that system when I moved to a smaller
| apartment :(
|
| Looking back, tossing it was a huge mistake.
| embedding-shape wrote:
| > Looking back, tossing it was a huge mistake.
|
| On the other hand, being afraid of ending up with similar
| feelings like you, I keep stuff.
|
| So I sit here in a room where I'm probably one or two arms-
| length away from VGA and DVI cables and other relics, "just in
| case".
| bluGill wrote:
| If it makes you feel better, I just bought a used zoom h4 for
| cheap - it still works, but it uses mini-usb and I long ago
| toss those cables because I didn't have anything that used
| them. (I have a full audio workstation with a 18i20 interface
| in my office, but sometimes I want something portable)
|
| Which is to say those might become useful someday again...
| Are they worth storing is a different question - since I'm
| looking for the cables anyway - both of the cables you
| mentioned can be bought for $5-$10, and the mini-usb I need
| is as cheap as $3. It will cost more more in shipping than
| the cable. (though I will likely look for something else I
| need to get free shipping)
| jasomill wrote:
| I also have a hard time letting go of expensive cables merely
| because they were expensive. For this reason, I probably have
| as many parallel SCSI cables as I do USB cables, despite not
| having used a parallel SCSI device in years, including
| several 15+ meter HD68 cables that only work with high-
| voltage differential SCSI, despite owning exactly one HVD
| device.
|
| OTOH, it's a large, loud, heavy, and ugly IBM 3590 tape drive
| that I'd rather not need to have at arms length to use.
| timc3 wrote:
| If it makes you feel any better I've had to buy back cables
| that I have thrown away because I hadn't used them for 15
| years - and then found a project where I need DB9, SCSI,
| FireWire 800, Component to VGA converter or some relic.
|
| Another reason they call me the cable guy at home ( though
| mainly because I probably have at least 800 cables in my
| studio )
| bombcar wrote:
| Ebay has various 286s for about $200, some even working!
| palmotea wrote:
| > It would be faster to leave the batteries in my tools, but over
| 40 years of sacrificing devices to alkaline cell leakage, it's my
| habit not to. So far I've never had leakage problems with the
| eneloops, but old habits die hard.
|
| I've gotten burned by that too, but I just try to remember to
| take out the batteries before I put something into storage.
|
| BTW, I think the old-style "heavy duty" batteries and lithium AAs
| don't have a leakage problem. Though lithium AAs are now
| _ridiculously_ expensive. I think they went from $1 a cell to $2
| in cell in a Sam 's Club 18-cell bulk back over a couple of
| years.
| voidUpdate wrote:
| Whats the energy/volume comparison between standard AA batteries
| and li-ion batteries?
| Zak wrote:
| Highly variable based on load and the specific batteries
| involved. Alkaline will almost always have more capacity for
| something that takes more than a day of continuous operation to
| drain the battery, and NiMH will almost always have more for
| something that takes less than four hours.
|
| Here's a tool you can use to compare different batteries at
| different loads, graphing voltage vs Amp-hours. The individual
| battery tests have more detail and graphs of voltage vs Watt-
| hours, which is often a more useful measurement.
|
| https://lygte-info.dk/review/batteries2012/CommonAAcomparato...
| cbdevidal wrote:
| I invested a few hundred dollars into Eneloops, but they kept
| disappearing. Turns out my kids were throwing them away, thinking
| they were disposable (cry).
|
| I've since trained them and rebuilt my stockpile but that was
| painful, at what was then $2 a cell. (Now $3-4.)
| jopsen wrote:
| IKEAs rechargable batteries are great.
| gralab wrote:
| According to what I've heard, IKEA rechargeables are
| rebranded eneloops.
| orev wrote:
| I have a bright label on each saying "Do not dispose".
| Hopefully it's enough to at least get someone's attention to
| read or ask further before throwing them out.
| Marsymars wrote:
| Training for kids here is that batteries never go in the trash,
| since they all go to the same recycling place.
| ocdtrekkie wrote:
| 100%, I am a huge fan of actual detachable batteries and I also
| store most electronics with them removed. I generally consider
| any rechargeable battery a risky thing to store. (Some explode.)
|
| One thing I really love is power tool systems though: I have some
| Ryobi tools that are over 20 years old and they work with
| batteries sold in stores today. (The battery tech has changed but
| as long as your charger is for your battery tech, the tools are
| all good.) I rarely use a given tool enough to justify replacing
| batteries in it every 2-4 years, but I use one of my Ryobi tools
| or the other frequently enough to justify keeping a couple good
| batteries available at any given time.
|
| I have a modern drill and impact driver because I use them a lot.
| But the handful of couple decade old saws are plenty adequate for
| the very rare occasions I need a jigsaw, circular saw, or
| sawzall.
| briHass wrote:
| This seems like more of a rant about non-replaceable batteries
| (of any type.)
|
| When I buy things like flashlights/headlamps and other battery
| knickknacks, I ensure it uses a 18650 or some other standard
| lithium formfactor.
| wrs wrote:
| Alongside their AA-powered keyboard, Apple sold a little two-cell
| charger with two AA NiMH batteries, which is still what I use to
| charge my Eneloops.
| bluGill wrote:
| I miss the old Rayovac batteries. They had a 10 year no leak
| guaranty, and it was real. I did get some to leak - I found a box
| of gear that I know hadn't been opened in 13 years, and even then
| it was a small leak that wouldn't be hard to clean up.
|
| But Energizer bought the company and changed the formula.
| bityard wrote:
| Were the old Rayovac batteries alkaline or zinc-carbon? Zinc-
| carbon batteries use a "dry cell" chemistry that will never
| leak, have a low self-discharge rate, and are very cheap to
| make and buy. You typically find them marketed as "heavy duty."
| The trade-off with those are that they have a lower energy
| capacity compared to alkaline.
|
| I use NiMH in almost everything but for things like TV remotes
| and clocks that sip power AND you can't be arsed to change them
| all the time, they work great. I buy a pack of 4 at the dollar
| store.
| bluGill wrote:
| Alkaline. Rayovac spent a lot of money making alkaline that
| wouldn't leak (after several years of research one guy's wife
| asked "why don't you encase them in steel" - turns out that
| works, or at least that is how I heard the story). They never
| has the capacity of the more expensive competitors, but for
| my camping stuff I'll take that trade off. (all too often the
| last trip of the year I'm throwing everything in a box in the
| rain, and then it gets stored until next season when I'll
| just put new batteries in if needed)
| accounting2026 wrote:
| At our high school we each had to buy a TI-83 calculator
| kit, and it came with one of those Rayovac alkaline
| chargers.
|
| I also had a Seitek Eco charger that could charge "normal"
| alkalines. But you had to be careful not to discharge them
| too deep. It seemed kind of pointless over rechargebles
| though the capacity of NiCD/NiMH was way lower back then (I
| remember when NiMH AA batteries at 700 mAh were considered
| really high!). And perhaps it some devices it was great
| they held 1.5 V.
| randusername wrote:
| My offshoot rant is that it should be easier hold devices at a
| longevity charge.
|
| I want some gadget that keeps my essential gear in a long-term
| maintenance mode. Oscillate it 20-80% or keep it at 50%, whatever
| is optimal.
|
| Every time I've looked into building something like this it seems
| like there's no standard reporting of charge level over the wire.
| I would waste a genie wish on this to have it in the USB spec and
| widely adopted.
| tom_alexander wrote:
| > it seems like there's no standard reporting of charge level
| over the wire
|
| Isn't that the "Battery_Status" message in the USB PD spec?
| Page 152 in this pdf: https://e2e.ti.com/cfs-
| file/__key/communityserver-discussion...
|
| Combine that with the "Battery_Capabilities" message (page 163)
| to get the total capacity, and you can calculate the charge
| percentage.
| dhll wrote:
| I'm always surprised that camping, and other outdoorsy, tools
| (i.e., flashlights, headlamps, satellite communicators, GPS,
| etc.) are increasingly powered by li-ion batteries. I think it's
| because there is currently an "ultralight" trend going on in the
| backpacking world, but it's still very annoying. When I go out, I
| just make sure everything, except for my Kindle, is powered by
| AA(A)'s. This way all I need is a dry bag with some extra non-
| rechargeable batteries, my battery charger, and solar panel.
| eulgro wrote:
| This makes no sense. With the li-on batteries you would need
| everything you listed, minus the extra batteries.
| incognito124 wrote:
| A 4-pack of Eneloops was my first ever online purchase in life. I
| bought them off eBay, scared shitless I'd get scammed or my data
| stolen (I was very young; the online shopping industry, too). But
| they happily arrived in my mailboz one day.
|
| They were for a Konica Minolta camera and they lasted
| surprisingly long. I think I saved about 30-40% of the price of
| the camera itself in recharging Eneloops, instead of buying new
| AA batteries every now and then.
| m3047 wrote:
| Ahh the Sony Walkman. Yes, still useful. I bought one
| specifically for the AM radio, I use it in conjunction with a
| radio frequency generator (so old it uses vacuum tubes) to trace
| wires. Had to tape gauze over the headphones, the foam is long
| gone.
| brikym wrote:
| Some government needs to force some standards. Power tools are
| the worst. Each company is trying to create a network effect and
| it's anticompetitive.
| tbrownaw wrote:
| Well anything up to 240W can fit into USB-PD.
| bluGill wrote:
| Fortunately you can get adapters to take 18/20 volt batteries
| to any other (18 and 20 volt rechargeable are the same cells,
| but they measure the voltage differently). Likewise most 12v
| systems have adapters.
|
| There are two issues: some manufactures put more smarts in the
| battery than others. So never run the battery completely dead
| which some combinations allow. Never charge the battery with
| other than the OEM charger.
|
| Don't buy the off-brand batteries (which sometimes are
| counterfeit that look like the real thing) since they sometimes
| are not safe.
| bahmboo wrote:
| That would be bad. The reality is that government can't
| micromanage technology. We could be in an alternate universe
| stuck with NiCad battery packs and 6v lantern batteries because
| the laws weren't kept up to date - particularly because the
| NiCad manufacturers and lantern battery manufacturers dumped
| money on politicians to cement their position.
|
| I think the most I could get on board with was the mandating of
| USB C by the EU. You can have whatever connectors you like so
| long as you have the USB C. And then of course we can get lost
| in what "USB C" actually is.
| mrguyorama wrote:
| Government "micromanaging" technology is why you can actually
| plug things into the phone network. Things like modems. For
| the internet. Before the government slapped AT&T, you leased
| the phone and it was wired into the wall and they could take
| you to court for connecting anything "unauthorized" into the
| wall.
|
| It's also why PC compatibles ever happened at all.
|
| It's also why Apple phones finally have a standard port.
| Which you admit.
|
| Interoperability is not natural, and IP laws make it trivial
| for companies to utterly block as we are dealing with today.
| Interoperability often requires regulation to _force_
| companies to allow people to interact with "their"
| standards.
|
| The government can manage _interfaces_ in a way that enables
| standardization and interoperability without limiting
| capabilities.
| tbrownaw wrote:
| I have some LiPo-based 1.5V AA and AAA batteries that have USB-C
| ports built in for charging. The AAA ones claim 1200 mWh (800
| mAh) and the AA ones claim 3400 mWh or ~2250 mAh. (I say "claim"
| because I bought them off some random Amazon shop a few years ago
| and haven't bothered to actually check.)
| nickcw wrote:
| Eneloops are fantastic. I've been using them for 10 years.
|
| They have very low self discharge so you can keep them on the
| shelf for a year and they will still have 70% charge which is
| very different to most rechargeable batteries.
|
| They don't leak unlike alkaline batteries and you can run them to
| 0% charge without damaging them unlike Lion batteries.
|
| The terminal voltage is only 1.2v so there is the occasional
| thing they don't work well in.
|
| That said my collection of eneloops get much less use than they
| used to as everything comes with built in lithium batteries and a
| usb charger nowadays. That is very convenient until the moment
| the lithium battery dies...
|
| Changing the lithium battery in things sucks. Firstly it's really
| difficult to get a good one and not a crappy knock off. Secondly
| modern stuff isn't meant to be repaired. Every time I pick up my
| kindle I shed a small tear when I see the screen damage I caused
| changing the battery.
|
| So, I buy stuff with AA or AAA batteries if possible and if I
| want it to last for more than 3 years.
| NoImmatureAdHom wrote:
| > Every time I pick up my kindle I shed a small tear when I see
| the screen damage I caused changing the battery.
|
| Don't shed a tear! https://en.wikipedia.org/wiki/Kintsugi
|
| Repairs are beautiful.
| russdill wrote:
| I have a mix of eneloops and Amazon Basics, they seem pretty
| equivalent
| BeetleB wrote:
| Eneloops were huge for use in DSLRs.
|
| And they are overhyped.
|
| Most of them are about 2000 mAh. Other NiMH batteries can have,
| say, 2700 mAh. So even though the latter have a higher
| discharge rate - after 6 months of storage the latter still has
| more juice.
|
| The benefit with the 2700 mAh, of course, is if you're using
| when full, you can use it for much longer.
|
| If they cost the same, I could see the hype. But most people
| are still better off with regular NiMH AA batteries.
| jdietrich wrote:
| Eneloop Pro cells have a rated capacity of 2500mAh.
|
| I can't think of any good applications for conventional NiMH
| cells any more - they're dominated by LSD NiMH cells in low-
| discharge applications, by lithium primary cells in ultra-
| low-discharge applications and by the various lithium
| secondary chemistries in high-discharge applications.
| jasona123 wrote:
| The whole "everything I own just has a built in Li-ion battery"
| thing came to mind when I ordered my first set of Eneloops
| ahead of last week's snowstorm in North America - most things I
| own have their own batteries with a charger (right down to this
| decorative squishy whale lamp), and I can count on two hands
| the things that use AAAs and one hand the things that use AAs.
| It's wild.
| inasio wrote:
| I found a Minidisc player that had been in storage for over 10
| years, probably closer to 15. Runs off a single AA battery; I'd
| left it with a Duracell and it was still running.
| bityard wrote:
| I have a considerable backstock of Logitech Anywhere MX (no
| bloody 2, 3, or 4...) mice in my drawer entirely because they can
| be powered by 2x AA batteries for months at a time. I like these
| because when the batteries die, I just swap them out and keep
| doing work.
|
| I have one of the newer models and when the battery runs out, I
| have to stop what I am doing and charge the mouse. Yes, you can
| get through the rest of the day with a quick 5-minute charge but
| if you're like me, you won't remember to plug in the mouse at the
| end of the day and will have to repeat the quick-charge multiple
| times until I finally remember to plug it in overnight (usually
| by writing a sticky-note). I assume Logitech's answer to this
| would be: buy a second mouse as a backup!
|
| The only major downside is that these older mice don't do
| bluetooth and USB Type-A ports are getting more and more rare.
|
| This has greatly informed my decision to always try to buy things
| that take AA batteries, or at least easily replaceable li-ion
| batteries (at worst).
| oulipo2 wrote:
| At https://infinite-battery.com we're making a repairable battery
| where you can change the cells, because there's no reason your
| e-bike battery should work differently than your remote control:
| when batteries are drained, you can change them!
| VikingCoder wrote:
| I suck at electronics, so -
|
| Could you possibly make a modern cell phone that runs off of
| rechargeable AA batteries?
|
| How many would it take to have roughly the same amount of screen
| time?
|
| ChatGPT says it's a bad idea, but roughly I'd need 10 AA
| batteries and a boost converter.
| catlikesshrimp wrote:
| 4 AA NiMh would get you 5V, the same coming from the slow
| charger. Let's say each AA battery holds 2000 mah. To reach
| 5000 mAH you would need 2.5 AA. Now multiply 2.5 x 4 = 10
|
| The dumb AI read a good estimation.
|
| Carrying 10 AA batteries strapped to your cellphone is not
| sexy. On the other hand, falling phones would land with the
| screen up - batteries down.
| schiem wrote:
| It depends on the AA battery, but you'd need 6 - 8 to get
| equivalent performance.
|
| The Google Pixel 9 has a 4700 mAh battery at 3.9 volts. The
| total energy is around 18.3 watt hours.
|
| A high capacity rechargeable AA battery is 2500 mAh at 1.2
| volts, or around 3 watt hours. If you wired 3 AA batteries in
| series, and then 2 of those series in parallel (for a total of
| 6 batteries), that would give you 3.6v at 5000 mAh. 3.6 volts
| falls within a normal discharge curve for a lithium ion
| battery, so you probably wouldn't need a boost converter.
| vel0city wrote:
| Project Farm has had a number of good reviews on alkaline,
| lithium primary, and NiMH AA batteries. He's tested so many with
| some pretty through tests.
|
| Best AA Rechageable Battery?
|
| https://www.youtube.com/watch?v=-jXQNY6rve8
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