# Lithium 1.5v rechargeable batteries... why not?



## compasillo (Nov 29, 2009)

I've been searching about this subject but couldn't find the reason why. Anybody could explain why there are not 1.5v Li rechageables in the market?


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## csshih (Nov 29, 2009)

chemistry doesn't allow it.


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## ifor powell (Nov 29, 2009)

The chemistry determinse the voltage, and the various lithium recharchable chemistrys all have voltages in of over 3V. It's not somthing you can just arbitarily adjust and tweak the voltage up or down a bit.


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## compasillo (Nov 29, 2009)

However, there are 1.5v lithium (only primaries). Different chemistry then?


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## Conan (Nov 29, 2009)

I used to research this topic too when my AA powered DSLR was new. I just went with NiZn when it came out.


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## Th232 (Nov 29, 2009)

Correct, the non-rechargeables are Lithium, while rechargeables are Lithium Ion.


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## compasillo (Nov 29, 2009)

Is there any chance to develop a 1.5v rech. at a reasonable price or is the chemistry a limiting factor?


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## ltiu (Nov 29, 2009)

Nothing is impossible. 

I am sure there is a chemistry out there that can produce a compatible 1.5v lithium rechargeable. BUT, maybe it is too expensive to mass produce, not commercially viable or unsafe/unstable for dumb consumer use.


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## ltiu (Nov 29, 2009)

Not that simple.

There are some non-rechargeable Lithiums that are 3.7v.

Don't mix em up or you end up like this guy:

https://www.candlepowerforums.com/threads/250219


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## compasillo (Nov 29, 2009)

I know that unfortunate and already posted in that thread...
But I think this is a case of a high grade of irresponsability and not a common story (or I hope). 
Looking for this guy at CPF I realize he's a "special" case and only hope he can learn a bit and keep his family and himself safe...


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## malow (Nov 29, 2009)

how about a li-ion AA sized battery, with a circuit on bottom to reduce to 1.6v~0.9v?


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## compasillo (Nov 29, 2009)

It sounds fine...
I don't know if it's doable, though


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## csshih (Nov 29, 2009)

malow said:


> how about a li-ion sized battery, with a circuit on bottom to reduce to 1.6v~0.9v?


I've heard of those.. but what would be the benefits?


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## XRAYBoY (Nov 29, 2009)

I think that it is possible but not desirable for manufacturers ...
With a battery with that power ... someone else would purchase primary batteries? The ruin for them!


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## malow (Nov 29, 2009)

csshih said:


> I've heard of those.. but what would be the benefits?


get a better rechargeable battery for everything that uses AA for example...


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## Illum (Nov 29, 2009)

csshih said:


> I've heard of those.. but what would be the benefits?


the only benefits I can think off, without high loss at higher current draws, is to create a battery that uses 2x14500 cells in 1S2P configuration and regulate that to 3V output


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## csshih (Nov 30, 2009)

I see that there would be improvements, but at what manufacturing costs?

an AW 14500 is 750mAh -- .75*3.7V = 2.775W
whereas an eneloop is 2000mAh --2*1.2V = 2.4W
(though the AW cell would be more stable at higher current draws due to the regulator?)

assuming the buck circuit is 95% efficient, you'll get a 0.24W gain over eneloops... 
eneloops are roughly 3$ a battery, wheras AW 14500 are 15$ a battery.
cost is rather unbalanced.. and the consumer would also have to buy special chargers as I doubt you would be able to implement a boost charging circuit into the battery.


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## malow (Nov 30, 2009)

*for a battery like*

well, does need to be AW cells? 

looking in a cheaper example, dealextreme have a "good" cell (with protection circuit) for 2,8$ each, and "el cheapo" at 2.4$

and also, the main thing, good li-ion chargers are much cheaper than ni-mh, and a proper circuit in a li-ion cell could make the cell works with current cheap chargers. (well, most of them), 

imagine a world without need to worry about "missed termination", overheat, self discharge (most of it).

of course, this is not the salvation of mankind, but could be a nice addition to existing batteries. as ni-zn batteries does not add more power, but gain a lot of good features, i think still have a "hole" for a battery like this... and of course, who does not like a battery with  feature?


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## tsmith35 (Nov 30, 2009)

A web search finds the average voltages for some various battery chemistries:

LiCoO2 (lithium cobalt oxide) 3.7V
LiMn2O4 (lithium manganese spinel oxide) 4.0V
LiFePO4 (lithium iron phosphate) 3.3V
LiNiO2 (lithium nickel oxide) 3.6V
Li2FePO4F (lithium iron fluorophosphate) 3.6V
Li(NiCoMn)O2 (aka lithium NCM)(lithium nickel cobalt manganese oxide) 3.7V
Li2S8 (lithium sulphur) 2.1V
NiCd (nickel-cadmium) 1.2V
NiMH (nickel-metal hydride) 1.2V

More chemistries are being developed every day. How about LiNi0.8Co0.15Al0.05O2 (aka lithium NCA) (lithium nickel cobalt aluminum oxide) at 3.7V?

It would be nice if some organization introduced a standardized battery charge profile system. This system would take into account the ideal charge profile for each type and size battery, as well as max. temperature, max. voltage, max. charge rate, etc. Digital chargers could provide the manufacturer-recommended charge parameters based on the assigned number.

For example, drop in a NiMH and type in the number "29245537" and it would charge it properly. Put a LiCoO2 and type in the number "93563072". Or maybe the ID could be integrated into the cell in such a way that it could be retrieved when the battery is queried using a preset string of pulses. No more guessing.

Hmmm... looked this idea up and it is similar to one patented (in 2002) on patent #6479962. Wonder if we'll ever see that patent in action?


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## Marduke (Nov 30, 2009)

*Re: for a battery like*



malow said:


> well, does need to be AW cells?
> 
> looking in a cheaper example, dealextreme have a "good" cell (with protection circuit) for 2,8$ each, and "el cheapo" at 2.4$
> 
> ...



Can't have all of them. A "good" Li-Ion charger is MUCH more expensive than a "good" NiMH charger, before you even get into the discharge/analyze features. A basic "good" Li-Ion charger that does nothing but charge like the Pila compares in price more to the much more feature rich Maha C9000.

A reliable protection circuit that would be safe enough for the average Joe to use would not be the "cheapies" you point out on DX, but at AW price _or higher_. 

But no matter how much protection you give them, if it fails, you don't have to worry about missing terminations, but missing fingers...


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## Morelite (Nov 30, 2009)

What would really be nice to have available is a AA (14500) that is a 3.0v Lithium primary just like the CR123 but in a AA size. I know Lisun made them a few years ago but I haven't seen them for awhile.


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## malow (Nov 30, 2009)

*Re: for a battery like*



Marduke said:


> Can't have all of them. A "good" Li-Ion charger is MUCH more expensive than a "good" NiMH charger, before you even get into the discharge/analyze features. A basic "good" Li-Ion charger that does nothing but charge like the Pila compares in price more to the much more feature rich Maha C9000.


well, keeping the DX example, a good charger (simple CC/CV charger that end at 4.2v, nothing else) can be found for 13$ free globe shipping. as is 2 slots only, 2 of them is still cheaper than a sony BCG-34HRMF i bought locally. even as this cheap, it can charge amazingly.



> A reliable protection circuit that would be safe enough for the average Joe to use would not be the "cheapies" you point out on DX, but at AW price _or higher_.


i pointed a protected cell just because they already have a circuit on it (cheap, of course). obviously, when we imagine a circuit on battery to stepdown voltage, we imagine one that is capable of do a cut-off "decently". as aim a average Joe, i don´t consider everything that is cheap, a danger, cause everything i have is the cheapo version, and all works fine, including protection circuit in my trustfires from DX 




Marduke said:


> But no matter how much protection you give them, if it fails, you don't have to worry about missing terminations, but missing fingers...


yes, like everything that have li-ion on it. no matter if is a nokia cell phone, or sony laptop 

not everything must be expensive to be good, but, of course, most crappy things are the cheapo ones 

but we must imagine that a big company can make something good and cheap.


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## ltiu (Nov 30, 2009)

Morelite said:


> What would really be nice to have available is a AA (14500) that is a 3.0v Lithium primary just like the CR123 but in a AA size. I know Lisun made them a few years ago but I haven't seen them for awhile.



I got some from taking apart primary CR-V3 cells. Each CR-V3 has two AA primary 3.0v inside.

You typically find these CR-V3 on-sale. I got mine before Circuit City closed down for $1.99 for a pack of 2 CR-V3. That's 4 AA per pack, $0.50 per 3.0v AA. Great deal.

Use it in my L1D.


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## Marduke (Nov 30, 2009)

The low cost isn't what makes the DX ones junk, the fact that they are junk is what makes them junk. If they were expensive, they would just be expensive junk.

They do not offer the same protection as name brand cells (such as AW's). The chargers are also much more dangerous. Just because YOU have not had issue when them doesn't mean they are acceptable for general (non-enthusiast) use. 

There is a whole forum dedicated to "incidents", of which the junk (which just happens to tend towards the "cheap" side) has a high proportion of said "incidents".

I highly suggest you actually read up on lithium safety and use, instead of assuming "it worked for me, so it must be fine". There are a lot of fine technical details I am fairly certain you are currently oblivious to.


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## Illum (Nov 30, 2009)

tsmith35 said:


> ```
> LiCoO2 (lithium cobalt oxide) 3.7V
> LiMn2O4 (lithium manganese spinel oxide) 4.0V
> LiFePO4 (lithium iron phosphate) 3.3V
> ...



nicely done! :thumbsup:


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## malow (Nov 30, 2009)

Marduke, im aware of li-ion safety and risks it offers, im just taking a point, that cheap stuff also works, and not forgetting, as your own signature say, even the best alkaline leaks 

of course, statistics does not lie, crap things does blow up gazzilion times more than quality stuff. but it does not stop manufacturers to make cheap stuff that works for "most people", like me. and like me, they still sell a large amount of batteries, because, it works for most people.

im sure that any *****Fire company (note that all "end with fire" :thinking can make a battery this way, and be very cheap, maintaining it's "quality standard" (i mean, keeping the current ratio of blown-up/not blown-up products)

in my country even the junk are expensive, and "hi-quality" products here are only for people with trees that grow money. AW here for example, not even in the "wildest dream" :mecry:


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## vali (Nov 30, 2009)

Keep in mind you are comparing cheap lithium chargers from DX with a brand name charger for NiMH. The fact is you can buy really cheap chargers for each chemistry, but if you want a decent (and safe) one the cheapest to lithium is the PILA and, compared with a similary priced NiMH one, the difference in capabilities is huge.

The problem is if you get a bad charger for NiMH the cells will be damaged, will lose capacity, will develop high self discharge and high internal resistance. If you get a bad charger for lithim you can end burning your house. There are a couple of threads testing, comparing and reviewing some lithium chargers. None of the ones you can buy from DX are safe nor have the recommended charging methods. Most of them trickle charged the cells (and with lithium it means BIG trouble). 

Some time ago I was searching for a lithium charger with a craddle with at least a couple of bays, that can charge cells individually and were safe. The search was fruitless. Asking for things like testing the capacity seems to be science fiction unless you buy a hobby charger (and then you cant get independent charging channels AFAIK) and do some DIY.

In the end: We have good chargers (fairly simple and cheap) that manage safe chemistries and not even a single one safe enough to handle the more dangerous cells...


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## csshih (Dec 1, 2009)

now.. imagine these cells in the hands of a general "stupid" consumer, sticking these batteries in backwards, etc, etc. just how many layers of protection would you need for these cells?


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## malow (Dec 1, 2009)

csshih said:


> now.. imagine these cells in the hands of a general "stupid" consumer, sticking these batteries in backwards, etc, etc. just how many layers of protection would you need for these cells?


well, "a few" for start... and a bunch of "warnings" in big font... like Ni-Zn "high voltage".. as they also can be dangerous... but they do not have the  factor.


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## mfm (Dec 1, 2009)

It is quite obvious why no reputable company wants to do a generic li-ion charger: they have no control over the batteries used.

Remember that the Pila IBC Charger is a charger for "Pila Li-Ion" batteries, not for AW, TrustFire or generic 18650 batteries. If you use it with something else than Pila batteries then you are on your own.

That is why mobile phones and laptops work without incidents, the manufacturer has full control over the battery packs used and can make sure the total solution is safe. If there is a problem then they have to recall all the batteries.

Who will recall all TrustFire-chargers if/when they blow up with some random battery? No one.


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## tsmith35 (Dec 1, 2009)

mfm said:


> ... That is why mobile phones and laptops work without incidents, the manufacturer has full control over the battery packs used and can make sure the total solution is safe ...



Well, not always... Google search

:naughty:


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## malow (Dec 1, 2009)

http://www.engadget.com/2009/08/03/exploding-ipod-blows-up-in-apples-face/
 
http://www.engadget.com/2007/11/28/korean-man-killed-by-exploding-cellphone/

and a good list of incidents:
http://www.engadget.com/tag/explodingbattery


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## mfm (Dec 2, 2009)

tsmith35 said:


> Well, not always... Google search
> 
> :naughty:



And I thought writing "If there is a problem then they have to recall all the batteries." after it would mean that I didn't have to write "safe" instead of safe, but I guess not.



malow said:


> http://www.engadget.com/2009/08/03/exploding-ipod-blows-up-in-apples-face/
> 
> http://www.engadget.com/2007/11/28/korean-man-killed-by-exploding-cellphone/
> 
> ...



I see that you are arguing against yourself. 

It can still happen when the manufacturer have full control over both batteries and charger (and yes they will be recalled if they explode). It would be thousands of times more common with random chargers and random loose cells in them.


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## malow (Dec 2, 2009)

mfm said:


> I see that you are arguing against yourself. It can still happen when the manufacturer have full control over both batteries and charger (and yes they will be recalled if they explode). It would be thousands of times more common with random chargers and random loose cells in them.


sort of. my point is, even being a "dangerous" thing (li-ion with circuit to reduce to 1.5v) it wold be just "more" dangerous than what we have today. wold not be something "astronomical" dangerous.

if we consider that every user will do stupid things with a product, nothing is safe. we must rely on "user brain" to use it correctly.

anyone can put ni-mh on a ni-zn charger. anyone can drop a quality li-ion cell on the floor. anyone can put a 14500 cell on something and forget it is 3x more voltage than a "normal AA". anyone can put a li-ion cell in the pocket and forget that a metal key-chain can cause a short-circuit. a li-ion cell does not come with a 3 sheet manual with everything that you should "not do". "don't wash it - don't trow on fire - don't eat it".

any crap manufacturer can make this battery and say: "use specific charger - don't trow away - don't short circuit". them, sell together with a charger for it. that's it. if it catch on fire wile charging, and blow up your house, "sorry". if you use incorrectly and also blow up your house, "sorry". this is the kind of safety we already have on most generic brand products. 

if you can get something with quality, good. if you get a cheapo product, good luck and better you be smart on how to use it.


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## bikelunatic (Feb 9, 2013)

ifor powell said:


> The chemistry determinse the voltage, and the various lithium recharchable chemistrys all have voltages in of over 3V. It's not somthing you can just arbitarily adjust and tweak the voltage up or down a bit.



Sorry for butting in. New to the forum
So are you saying, companies/manufactures design produces to the battery specifics 
and not the other way round?>


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## Russel (Feb 9, 2013)

bikelunatic said:


> Sorry for butting in. New to the forum
> So are you saying, companies/manufactures design produces to the battery specifics
> and not the other way round?>



He is saying that physics determines the voltage of lithium ion rechargeable cells. The cell voltage of any given battery is determined by it's chemistry.

Do you realize that this thread is several years old?


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## Norm (Feb 9, 2013)

bikelunatic said:


> Sorry for butting in. New to the forum
> So are you saying, companies/manufactures design produces to the battery specifics
> and not the other way round?>



Yes

Norm


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## StorminMatt (Feb 10, 2013)

I realize this is an old thread. But I thought I would throw in my two cents worth here. It is entirely possible that a lithium chemistry could be found that would allow for a 1.5 volt rechargeable battery. But the BIG question is whether such a battery would REALLY be better than what we already have (ie NiMH). Consider the Energizer L91/L92 lithium primaries. These exist because they serve a definite purpose. Namely, they give consumers the option of a primary battery that remedies many of the shortcomings of alkaline batteries. These shortcomings include low current capability, excessive voltage sag under a load, terminal voltage which drops drastically as the battery is discharged, and drastically reduced capacity at higher loads. When you consider these things, the advantage of L91/L92 primaries is that they behave more like NiMH batteries compared to alkalines.

The issue is therefore how a 1.5 volt rechargeable lithium battery could be better enough than NiMH batteries to justify their development. And I can't see how you could improve much on NiMH. NiMH already has the ability to deliver high current with little voltage sag, and deliver a very constant voltage during discharge. Capacity also drops little as discharg current increases. And because the elctrolyte is aqueous, NiMH is a very safe chemistry. Some make an issue of the 1.2 volt nominal voltage. But this is FAR less of an issue in practice. And if this is REALLY a problem, further development of existing technologies like Ni-Zn would be FAR more cost effective. Of course, if a rechargeable lithium battery with all the virtues of NiMH could be developed which has drastically greater capacity than NiMH, that might be another story. But I don't see this as likely.

In the end, NiMH is awfully hard to beat, especially given the REALLY good, low cost LSD options available today. Any rechargeable lithium batteries of similar nominal voltage would have to be FAR superior to existing NiMH and cost effective in ordr to be successful. And THAT'S a tall order.


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## Shadow352008 (Jun 6, 2013)

I realize that this is an old thread, but it addresses a question that I've been wondering about. It's said here that the 3.7 volt batteries are Lithium ION types and the non rechargable types are just Lithium, and the chemical listing was very nice, but doesn't list what is in the 1.5 volt lithium types?


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## Russel (Jun 10, 2013)

http://batteryuniversity.com/learn/article/lithium_based_batteries


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## Paul_in_Maryland (Jun 10, 2013)

For now, the PowerGenix nickel-zinc AA cell comes closest to your 1.5V ideal rechargeable: 1.6 to 1.8V under load, outstanding safety, great cold-weather performance, and cheap. The main drawbacks are: fickleness (failing at an unusually high rate when overdischarged), a self-discharge rate that's higher than most of us would like; lowish amp-hour capacity (better than 14500, but worse than NiMH); and they require their own charger. Oh, and they're no longer made; when they're gone, they're gone.


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## wadesrc (Sep 25, 2013)

I have been waiting for a battery like this too!!!

http://www.aliexpress.com/item/8-pc...13802224.html&cv=11032041&af=cj_3836173&vd=30


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## ALW248 (Oct 7, 2013)

Paul_in_Maryland said:


> For now, the PowerGenix nickel-zinc AA cell comes closest to your 1.5V ideal rechargeable: 1.6 to 1.8V under load, outstanding safety, great cold-weather performance, and cheap. The main drawbacks are: fickleness (failing at an unusually high rate when overdischarged), a self-discharge rate that's higher than most of us would like; lowish amp-hour capacity (better than 14500, but worse than NiMH); and they require their own charger. Oh, and they're no longer made; when they're gone, they're gone.



Other brands still offer NiZn.


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## Frog_Botherer (Nov 24, 2013)

wadesrc:

I've seen those batteries too, and while the idea is exciting I'm not going to go out and buy those particular ones. I don't exactly trust a manufacturer who prints "mWh" on their batteries when they mean "mAh". If they can't keep that straight, what other corners are they cutting? That said, if someone braver than me wanted to buy these and run some tests on them that would be wonderful.

A AA-sized LiPo rechargeable with a step-down circuit to 1.5V would be a really neat thing though, and those batteries seem to imply that it's on the horizon. If the idea is a feasible one then hopefully we'll see better manufacturers coming out with batteries like that in the near future. If they can keep the energy density higher than LSD NiMH while fitting in the step-down and protection circuit, and if they can manage to keep the current capacity reasonably high, they could be a real step forward. It's probably a matter of technology rather than physics – packing a step-down-and-protection circuit in there that is robust, efficient, small, and has high current-carrying capacity is no trivial thing but with the right electronics it sounds doable.

They'll probably always be a bit more expensive and lower energy-density than normal 3.6V LiPos because that step-down circuit is going to take up space and increase the price, but there's just so much gear out there designed for 1.5V AAs, and AAs are so easy to come by (you can always find a crappy Alkaline at the corner store in a pinch) that I would love it if something like this became common and high-quality. Another advantage I could see is that the step-down circuit would work as a built-in voltage regulator, so that you would have a nice 1.5V output right up until the end (followed of course by a very sharp cutoff, but that's why we carry spares for critical applications, right?).

1.5V rechargeable AA lithium batteries may well be the next step forward in the evolution of rechargeables. If you ask me we're probably not quite there yet (unless somebody knows of a source of high-quality ones that's already out there) but maybe we will be soon.


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## ginbot86 (Nov 26, 2013)

Frog_Botherer said:


> wadesrc:
> 
> I've seen those batteries too, and while the idea is exciting I'm not going to go out and buy those particular ones. I don't exactly trust a manufacturer who prints "mWh" on their batteries when they mean "mAh". If they can't keep that straight, what other corners are they cutting? That said, if someone braver than me wanted to buy these and run some tests on them that would be wonderful.
> 
> ...



I think the mWh versus mAh rating is just to make the numbers look bigger. mWh = mAh * 3.7 volts, in the case of a Li-ion cell. I've been waiting on a 4-pack of the AA sized batteries since early October, and they haven't arrived yet. As for the regulator, I doubt that it'd be able to hold a steady 1.5 volts over a large current range. We'll just have to find out when/if I receive them.

I saw a chart outlining the discharge current and voltage and the plot is rather interesting. (Image re-hosted from my personal blog)






EDIT: Note how there is no real current data as for each load line. Without any data to correlate current and voltage, this graph isn't exactly helpful...

My whole blog post talking about this cell is available here: http://ripitapart.wordpress.com/201...hium-polymer-aa-battery-what-sorcery-is-this/


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## StorminMatt (Nov 26, 2013)

ginbot86 said:


> I saw a chart outlining the discharge current and voltage and the plot is rather interesting. (Image re-hosted from my personal blog)



At what kind of discharge current was this made? Without any indication of discharge current, this is pretty much meaningless.


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## ginbot86 (Nov 26, 2013)

StorminMatt said:


> At what kind of discharge current was this made? Without any indication of discharge current, this is pretty much meaningless.



That's what I'm saying. The lack of actual current information means that the sales page image has pretty much no useful data.

My blog post talks about the graph in a bit more depth. That said, the forum and blog posts were done in the early hours of the morning, so my apologies if the postings are a little rough around the edges.


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## HKJ (Nov 26, 2013)

StorminMatt said:


> At what kind of discharge current was this made? Without any indication of discharge current, this is pretty much meaningless.



Because the NiMH and alkaline has about the same capacity, it has to be at a fairly low current, maybe 100mA.


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## glire (Nov 26, 2013)

A TPS54719 could draw some current and still be efficient at light loads.
But it would be strange to put 2-3-4 AA in series that, each, downs to 1.5V from 3.7V...
Or only one down to 1.5V then pushed to ~3.2V to drive a LED.

IMHO the question is not "why not rechargeable 1.5V AA" but "why is still AA alive at 1.5V" ?
HMDI replaced old fashion video connections thanks to industry agreements. I wish the same for cells, a standard prismatic cell of about 50x20x8mm embedding 5Wh of energy at least would be nice.


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## Frog_Botherer (Nov 26, 2013)

Well I think it's just because 1.5V AAs are so damn ubiquitous and so much pre-existing gear runs on them, and devices that run off of other battery types are not backwards-compatible. With HDMI it was only a matter of replacing one or two pieces of equipment, and for a long time televisions and the like were backwards-compatible and would work with either the old connectors or the new (and some still do).

If 1.5V AAs disappeared a lot of people (including a lot of hardcore battery nerds, even) would suddenly have a lot of non-functioning gear that would need to be replaced, which would be annoying to say the least. And 1.5V AAs are perfectly fine for many applications (my wireless mouse will run for about a month on a pair of them, for instance) so that would mean that people would have to replace a lot of equipment that was otherwise perfectly good, just because the batteries to power it had become unavailable.

That said, better batteries (and gear that runs from them) are becoming gradually more common. 3.6V 18650s and the like have already mostly replaced AAs (or maybe it would be more appropriate to say that they've replaced C and D cells, which were what we used to use when we needed more capacity) in high performance applications like powerful flashlights and electronic cigarettes. And various custom-form-factor LiPo batteries are ubiquitous in stuff like cameras and phones where space and power are at a real premium.

1.5V AAs are probably here to stay for the foreseeable future, though. Perhaps something like a 14500 or a standardized prismatic will eventually replace them, but it will be a slow phase-out and AAs will stick around for a long time so that people can continue to run low-performance gear that works perfectly satisfactorily on 1.5V AAs. In the meantime, it will only be a good thing if manufacturers can continue to push the capacity and performance envelope for that battery type -- a lot of that technology (not all of it, but a lot) will carry over to other types of batteries, improving things across the board.


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## Gauss163 (Nov 27, 2013)

*How batteries are designed - a glimpse into the mind of an expert*



compasillo said:


> Is there any chance to develop a 1.5v rech. at a reasonable price or is the chemistry a limiting factor?



A look at future battery chemistries is a nice glimpse into the design decisions involved in constructing a rechargeable battery. It explains briefly how anode/cathode elements are chosen from the periodic table to meet various design constraints (including voltage). The author Yevgen Barsukov is a leading expert in battery technology at Texas Instruments (who did much of the work on TI's widely-used Impedance Tracking battery fuel gauge). The article is part of TI's Fully Charged blog, which contain many interesting, informative entries.


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## ginbot86 (Aug 29, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*

I just bought a 4-pack of these Kentli AAs, along with a charger for it. A teardown and performance (voltage-vs-current, capacity, etc.) analysis will be done once I receive them.

Let's see if it actually _arrives this time_...


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## ginbot86 (Sep 23, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*

After much anticipation, my 4-pack of Kentli AAs and its charger have arrived today! When I get to doing a teardown and analysis on them, I'll make a separate thread for it.


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## Richwouldnt (Sep 27, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*

ginbot86; Glad to hear it. Looking forward to some good analysis and performance numbers. The posted link batteries seem mighty expensive at about $12 per cell. I agree with the earlier post about using watt hours for bigger numbers as the nickel zinc battery makers did exactly the same thing. All a numbers game and DO NOT read the fine print!

The reason for the continued existence of alkaline batteries is that they ARE CHEAP and work fine in most low current demand devices. They are lousy at higher current draws and have a propensity for leaking but for the average consumer the price per battery seems to be the main consideration. After all what is the justification for the continued production and sale of Carbon Zinc batteries with their minimal performance other than they are even cheaper than alkaline batteries to produce so can be sold for less. I have a batch of Panasonic AA Platinum Power batteries coming from Amazon and they claim reduced risk of leakage construction and a 10 year shelf life when properly stored. Pretty good if true at 50 cents per battery including shipping and I have seen alkaline AA batteries going for 25 cents each from some sources. Panasonic is, I believe, now the largest battery manufacturer on the planet.


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## ginbot86 (Sep 27, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*

Yep; I can understand why many other manufacturers don't go with this route of putting a regulator in a Li-ion battery and turning it into a 1.5 volt battery. Paying $10+ for a single cell is pretty steep (and the AAAs are even more expensive).

I can understand why Kentli wants to characterize their cells using mWh rather than mAh (at least from an engineering standpoint). The use of mAh (constant-current modeling) for capacity isn't as accurate when dealing with batteries with a different nominal voltage. The use of mWh (constant-power modeling) allows the batteries' energy to be more accurately represented. Additionally, the use of a switch-mode buck converter in the battery means that the Li-ion cell inside will essentially see a constant-_power_ load, even if the device is drawing a constant _current_ from the 1.5-volt side.

But of course, bigger numbers look better.


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## cenz (Sep 27, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*

I heard this type battery before, but not in flashaholic field, is portable audio field, specially used for AMP/PCM recorder.. here is the link which is a chinese thread that the reviewer use "ear to feel" to test this Kentli with 2 typical Ni-MH brand, he said the bass is more powerful (solid / tight bass?) with Kentli, so the sound is different/enhanced because of high/constant current from the 1.5v li-ion tech.?

He also intro that is type of li-polymer constant-voltage 1.5v


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## Sivy (Sep 27, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*

Can these Kentli batteries be charged in a regular Li-ion charger?


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## HKJ (Sep 27, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*



Sivy said:


> Can these Kentli batteries be charged in a regular Li-ion charger?



There is a problem with the connection, the plus pole need a special shape:


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## ginbot86 (Dec 6, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*

Finally got a teardown finished on this little battery, performance data coming soon!

http://ripitapart.wordpress.com/2014/12/06/teardown-of-kentli-ph5-1-5-v-li-ion-aa-battery/


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## StandardBattery (Dec 7, 2014)

*Re: How batteries are designed - a glimpse into the mind of an expert*



ginbot86 said:


> Finally got a teardown finished on this little battery, performance data coming soon!
> 
> http://ripitapart.wordpress.com/2014/12/06/teardown-of-kentli-ph5-1-5-v-li-ion-aa-battery/



Excellent. Thanks!


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