Ode to the AA Battery | Hacker News Reader

Ode to the AA Battery

jeffgeerling.com

162 pointsBrajeshwar174 comments

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.

> 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.

I have a mix of eneloops and Amazon Basics, they seem pretty equivalent

Up until 2-3 years ago, the Amazon Basics NiMHs were just rebranded Eneloops.

Any new "Made in Japan" NiMH cell is an Eneloop since that's the only NiMH factory left in Japan. E.g. IKEA's LADDA are still Eneloop.

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.

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.

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.

BTW the Ikea rechargeable AA and AAA batteries are whitelabel Eneloops.

Someone tested them and they're practically identical in performance to actual Eneloops, just a lot cheaper.

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.

>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.

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.

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.

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.)

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.

I actually can't think of anything besides smoke detectors that I'd use these for, of which my house has 10 or so. Not having to replace those yearly would be worth it. I use Eneloop NiMH or Li-ion rechargeables just about everywhere else.

If I had a dollar for every device that I've seen ruined by leaking alkaline cells, I could buy a palletload of lithium cells.

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.

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?

The comment above is about non-rechargable lithium-metal batteries. You are thinking of rechargeable lithium-ion batteries.

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.

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.

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.

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.

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.

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.

I don't know what to tell you. I'm older than you. I've seen it happen 20-30 times in my life. I've seen batteries leak in flashlights, clock radios (the backup battery), wall clocks, calculators, cameras, remote controls, thermostats, wireless mouse, and so on.

A few years ago, I had an unopened pack of 8xAA Duracell alkalines. They had expiration dates on them, and had 2-3 years left. Two of the batteries were leaking in the pack.

Over the past 15 years, I have gradually migrated almost everything to NiMH. I don't see leaking batteries anymore in my house. But go to a thrift store, e.g. Goodwill, and open up the battery compartments of things. Many of them will have been destroyed by the leaking batteries.

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.

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.

Lithium primary cells have a shallower discharge curve than alkaline, but not completely flat; measuring state-of-charge is essentially trivial for any competent design engineer. Medtronic specifically recommend FR6 lithium cells in their insulin pumps.

https://data.energizer.com/pdfs/l91.pdf

https://www.medtronicdiabetes.com/sites/default/files/librar...

While the Medtronic pump has a setting to toggle between "Alkaline" and "Lithium" to adjust how it reads the battery percentage, the Dana i is primarily calibrated for Alkaline (LR03).

So your mileage may vary...

> there's basically no reason you'd ever want an alkaline battery except cost

Rechargeable batteries are much cheaper than disposable single-use batteries.

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.

> 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.

I have seen panasonic cells around my area advertised as leak-proof (or was it leak resistant?). I wonder the effectiveness.

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.

> 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...

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.)

I can't think of too many places I'd use Li-FeS2 other than maybe in smoke alarms. They're available in 9-volt form factor. I use NiMH or Li-ion pretty much everywhere else these days.

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…

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.

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)

Pish, what's the worst that could happen when rusted steel and aluminum are kept in a sparky environment?

In chunks like that, with such little metal total? Nothing. Even if you sabotaged it to heat indefinitely the plastic around it would burn and leave the aluminum unreacted.

> 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.

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.

A standard that works something like nvme drives would be neat. Room for a longer flat battery, cool use a full size. Don’t have one? That’s fine a short one will still work.

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.

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.

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.

They say 3.7v, so probably the wrong kind.

That's smart. It's not perfect, as you say, but at least it's trying to play nicely with the other kids.

There's some flashlights which take either 14500s or AAs. Seems like it'd be pretty handy as a backup (iirc the AAs can't put out quite as much instantaneous juice)

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.

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...

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.

> 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.

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

And, if you use good quality 2500mAh rechargeable AAs, those controllers go forever between charges.

> those controllers go forever between charges.

In my experience - about a month. Less if you play more often.

Ditto for the Nintendo Wii Remotes and the Balance Board --- I still have a set of rechargeables from that setup.

I believe some 8bitdo controllers have this as well.

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.

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.

Mentioned this above - so happy we went with Eneloops. Our battery waste is nearly 0, and no leaking..

I've been using NiMH AA batteries for over 20 years. I've never had one leak. It's not unique to Eneloop.

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?

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.

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.

If it runs on 3 AAAs you could also hotwire it to use 1 lithium ion (choosing a model with builtin protection).

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.

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.

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)?

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.

You can get replacement parts for PS controllers, although they can be rather fidgety to open up.

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.

> 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

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)

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!).

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.

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

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.

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...

That's cool, thanks for the links.

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.

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.

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.

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.

> 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.

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.

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.

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.

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.

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.

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.

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.

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

There are 9V NiMHs, too. They just need dedicated charger.

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.

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.

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.

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.

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.

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%...

If you need 1.5V / 3V for some reason, you could maybe insert a tiny boost converter from AliExpress (1€, less than 1 cm in all dimensions). I have done that for a string of fairy lights.

Apple sold their own NiMHs (actually rebadged Eneloops) along with their own AA charger to go along with the Magic Keyboard/Mouse, so my bet would be on a faulty device. https://en.wikipedia.org/wiki/Apple_Battery_Charger

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.

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.

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.

> 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.

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.)

IKEAs rechargable batteries are great.

According to what I've heard, IKEA rechargeables are rebranded eneloops.

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.

Training for kids here is that batteries never go in the trash, since they all go to the same recycling place.

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.

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.

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)

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.

I forgot about those, the rechargeable existed too, but their regular non-rechargable were the ones that didn't leak.

> 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.

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.

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.

I'd love to see a new battery standard.

Something future proof for new chemistries, consumer friendly and self protected, able to be series-es and paralleled if needed, etc.

Maybe even designed to be an external part of the case like 2 way radio and tool batteries, with the option of a retaining screw for toys and tamper resistance.

A few different sizes, from keychain up to power tool, and paralleling adapters to go bigger.

The electronics would probably cost pennies in volume, just like the tech that goes into those lithium AAs with built-in chargers and buck converters that are almost really awesome.

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.

This makes no sense. With the li-on batteries you would need everything you listed, minus the extra batteries.

Well, you wouldn't need the sun for one.

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.

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.

Well anything up to 240W can fit into USB-PD.

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.

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.

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.

You are conflating so many things. I was speaking about the "government" (there are hundreds and hundreds if not thousands of them) regulating battery standards for power tools - you address none of that. Yes I made a broad statement about government micromanaging which I stick by even as a staunch pro-regulation power to the people type of person.

Even if the EU (a specific government entity) hadn't stepped in over the USB C thing it would have been figured out eventually we just didn't want to wait.

I don't see how you can use AT&T as an example for your point. AT&T was our US government forcing us under threat of state violence to use what technology they deemed was allowed.

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.

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).

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.)

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

Indeed, that video was half of the inspiration for writing up this blog post (and is linked in the footnotes!). Always amazed by the depth of his tests for videos that are published on a weekly schedule.

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.

I have a head-torch with a pretty good compromise. The bay either accepts the proprietary battery, or three AAA batteries. The supplied lithium battery lasts longer than the AAA, but it's nice knowing the device will outlive the battery

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.

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.

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.

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.

> 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".

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)

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.

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 )

Latest for me was the ill-fated "mini VGA" cable Apple used on like 2 iBooks and the original Xserves... I couldn't find one when I needed it. But now I have like 8 of them, which I got in a box of random old Mac stuff recently!

Ebay has various 286s for about $200, some even working!

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.

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.

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!

Whats the energy/volume comparison between standard AA batteries and li-ion batteries?

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...

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.

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.

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.

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.

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.

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.

So now you have two piles, you come back after a year and then have to figure out which is which. All of this because someone wanted to save a few cents on the implementation of a charger.

The pile with 0 or 1 batteries in it is the one of partially charged batteries.

The pile with 2 or more batteries is the full set of fresh batteries.

Alternatively, buy a Battery Daddy and put +side up when it's charged, and -side up when it's uncharged.

Like the problems you are talking about really aren't that hard to deal with.

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.

That's not how it works at all.

When one is 80% and the other is 100%, the full one enters a state of over charge, reaching 105% or even 110% charge. This is safe.

The H2 reaction then rapidly speeds up, leaking energy in the form of heat. The full battery heats up from overcharge but is otherwise safe.

You end up with both batteries at 100% and maybe 110%, and a day or two later the 110% overcharge settles down to 100% by leaking out.

-------

So you waste a bit of power but as long as the trickle charge is safe and as long as the overcharge is only for a few dozen hours or so, it's fine. In the very long term (if you keep doing this) the NiMH could get damaged. But if we are talking about a once-per-yeqr top off charge, then it's fine.

The problem is like I said before: the safe rate of overcharge is low. This means that these chargers must charge slowly, maybe 10 hours or longer.

Any faster risks blowing through the NiMH innate ability to take an overcharge and convert it into heat. (This results in a forceful vent, a 'pop' sound that permanently damages the NiMH as the H2 gas escapes the safety hatch).

------

Note that these super cheap chargers are simply a glorified 10+ hour timer. They don't even check the state of the AA cells.

So if you stick a 50% full battery in, it will charge the battery to 150%, most likely. (But safely, as the NiMH just leaks out the excess energy as heat, as I said earlier).

I suppose there are lots of different chargers. The one I had made both charging lights turn off when one turned green. Maybe it was overcharging but still showing as red till both were charged?

Ok, but do you agree that in this day and age of cheap electronics, it is really not worth it to even consider all this and it is better to just make a charger that doesn't overcharge and doesn't come with extra instructions?

It doesn't really make sense to buy a $20 charger when you only have $16 or so worth of AA cells (ie: a 16 pack from Amazon Basics). The $10 charger makes a lot more sense.

As for the knowledge problem: that's easily solved. I already told you what to do so you know how to work the $10 charger now. If you still want the $20 charger that's fine, it's your money.

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.

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...

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.

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.

6 inch extension cords are a blessing I didn't know I needed until I had them. Now every charger takes up exactly one outlet.

Build one. Great, ambitious but doable newbie electronics project :)

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