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.
Someone tested them and they're practically identical in performance to actual Eneloops, just a lot cheaper.
Don't shed a tear! https://en.wikipedia.org/wiki/Kintsugi
Repairs are beautiful.
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.
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.
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.
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.
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.
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.
Lithium Iron Disulfide. For those looking for a brand name, that's what these are:
https://energizer.com/batteries/energizer-ultimate-lithium-b...
(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.)
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.
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.
This is a reason insulin pumps require specifically high quality alkaline and lithium is considered a risk.
https://data.energizer.com/pdfs/l91.pdf
https://www.medtronicdiabetes.com/sites/default/files/librar...
So your mileage may vary...
Everything else use rechargables for a dollar-ish plus charger cost.
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'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.
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 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.
Can’t recall if I’ve seen a CR2032 leak acid or corrode, but I think I have.
Rechargeable batteries are much cheaper than disposable single-use 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.
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.
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.
Maybe not great in the long run (steel and aluminum don’t like eachother)… maybe I should have put on some grease…
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.
[1] https://www.xbox.com/en-US/accessories/batteries-chargers/pl...
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.
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?
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)?
AA and AAA batteries are great. I wish using them weren't considered a negative by many hardware reviewers.
I've suddenly figured out why so many toys don't work with rechargeable batteries
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.
https://lygte-info.dk/review/batteries2012/Duracell%20Ultra%...
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)
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...
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!).
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.
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.
Number of zones in the house may affect things as may boiler only or AC being in the picture as well.
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.
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.
As I said totally OT, and I do have a couple of good C/H firms I can get in to sort it.
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.
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.
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.
* 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 a lot of low–quality toys.
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.
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’ve since trained them and rebuilt my stockpile but that was painful, at what was then $2 a cell. (Now $3-4.)
But Energizer bought the company and changed the formula.
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.
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'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.
When I buy things like flashlights/headlamps and other battery knickknacks, I ensure it uses a 18650 or some other standard lithium formfactor.
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.
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.
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.
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.
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.
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.
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.
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).
Best AA Rechageable Battery?
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.
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.
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.
Sadly I had to toss that system when I moved to a smaller apartment :(
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".
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)
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.
Another reason they call me the cable guy at home ( though mainly because I probably have at least 800 cables in my studio )
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.
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...
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.
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.
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).
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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).
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.
I would be surprised if the extra costs for the electronics for charging an extra cell are more than a few dollars.
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.
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.
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.
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.
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.
https://www.amazon.com/OLIGHT-Exclusively-Rechargeable-Batte...