# Sanyo Harmolattice Low Capacity NiMH AA Cell - A Comparative Abrams Tank?



## Bones (Jul 24, 2009)

As noted in a prior thread, minimig recently posted these images of a 1000mAh low self-discharge Sanyo cell which appears to be a genuine sibling to the Eneloop:






I can't help but think this new cell is probably built like an Abram's tank, and should be capable of withstanding far more abuse than virtually any other NiMH AA cell out there.

In addition to its advertised use in low drain devices such as remotes and mice, could it also be a viable replacement for ni-cads in solar powered garden lights and constant charge devices such as electric razors and toothbrushes?

As well, it seems an ideal cell for use with relatively low-powered solar chargers far from the beaten path.

Or it already obsolete...?


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## Black Rose (Jul 24, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH Cell - A Comparative Abrams Tank?*

I wouldn't mind getting my paws on some of those to try.

A lot of the NiCads in my solar lights are failing this year - would be worth trying out to see how these ones work compared with another set of NiMh cells I have in some solar lights.

EDIT: This super-lattice alloy is not new...found a Sanyo article from 2003 that talks about it. The Sanyo 2700 mAh cells use it.


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## Bones (Jul 24, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH Cell - A Comparative Abrams Tank?*

As noted in its initial press-release back in November of 2005, the super-lattice alloy is also used in the the Eneloop Black Rose:



> The synergy of the following proprietary technologies of SANYO in developing high capacity products has made the successful development of ‘eneloop’ possible:
> 
> 1. High-performance negative electrode ‘superlattice alloy’.
> 2. Make-up of battery material and battery plates.
> ...


It's hard to believe that the Eneloop has been on the market for almost four years now.

Anyway, the Eneloop's proven durability with its 2000mAh capacity utilizing Sanyo's super-lattice alloy should bode well for this new low self-discharge cell, especially with its mere 1000mAh capacity.


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## lrp (Jul 24, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*

Thanks for sharing, I didn't know they even existed, I will have to try some for sure, as I like the Eneloops more than any other NIMH cell!


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## swiftwing (Jul 24, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*

Like i mentioned in the energizer thread, i've seen these locally for quite awhile now but have not been able to find any information about them.

They cost the same as the chinese GP Recykos (and hence just slightly less than eneloops). So i'm not inclined to get them until further study is made of them.


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## Beacon of Light (Jul 25, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*

Are these not available in the US or something? I have never seen them. Same goes for the GP Recyco. Never seen or heard of these outside of this forum. 

ps. Recyco is that pronounced RE-psycho or RE-sicko? Either way it is an odd title for a battery, conjuring up disturbing mental images.


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## Mr Happy (Jul 25, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*



Beacon of Light said:


> Are these not available in the US or something?


As far as I can tell they are only available in Malaysia and Singapore (and Japan?). Maybe they will become more widespread in the future.

Recyco is meant to remind you of recycle of course. They also are rare in the US, but I saw loads of them in England.


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## Beacon of Light (Jul 26, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*

So it IS pronounced RE-PSYCHO. How disturbing... Norman... this is your mother..... stab stab stab....


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## Sugarboy (Jul 26, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*

i've banned all GP batteries forever due to its irresponsible manufacturing process which have already poisoned a lot of its staff (something to do with the chemicals):thumbsdow:thumbsdow:thumbsdow

they're super cheap & are in nearly *every* supermarket/drugstore here in Hong Kong..

most people here buy Eneloops AFAIK, which is around US$10 for a pack of 4AA/AAAs~~


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## Bones (Jul 26, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*

I've been digging around for a little more information on this cell, and determined that Sanyo has also released an 600mAh AAA version.

As shown on this chart from Sanyo.com, it bears the model number HR-4UQ, whereas the AA cell bears the model number HR-3UQ:








Incidentally, after almost having an accident when I first noted the 6000mAh capacity of the last model listed on the chart, I realized it was the Eneloop D-cell.


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## Bones (Jul 26, 2009)

Oops...


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## Bones (Jul 26, 2009)

As with the Eneloop, Sanyo is publishing reams of information about their new Harmolattice.

PDF specifications for the HR-4UQ (AAA) cell:

http://battery.sanyo.com/en/spec/twicell/HR-4UQ.pdf

PDF specifications for the HR-3UQ (AA) cell:

http://battery.sanyo.com/en/spec/twicell/HR-3UQ.pdf

PDF charts of the discharge characteristices of the HR-3UQ:

http://www.eneloop.info ... discharge.characteristics.3UQ.pdf

As shown in this excerpt, the Harmolattice easily hangs with with the Eneloop insofar as its voltage is concerned:





-


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## Egsise (Jul 26, 2009)

*Re: Sanyo Low Capacity Super-Lattice Alloy NiMH AA Cell - A Comparative Abrams Tank?*



Bacon of Light said:


> Are these not available in the US or something? I have never seen them. Same goes for the GP Recyco. Never seen or heard of these outside of this forum.
> 
> ps. Recyco is that pronounced RE-psycho or RE-sicko? Either way it is an odd title for a battery, conjuring up disturbing mental images.


Try to write it right first lol.... ReCyko.


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## Bones (Jul 26, 2009)

For those who wonder whether their cells will benefit from a 'few' break-in charges, it's notable that for this new cell, Sanyo specifically carried forward and adapted the following blurb from their specifications for the Eneloop:





-


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## Turbo DV8 (Jul 26, 2009)

I notice the package doesn't even try to claim "New & Improved," just "New." The only thought that crosses my mind about these "new" cells is, "What's the point?" It's an answer to a question that nobody asked. And if the relevance of these eludes me, what angle does Sanyo plan on using to differentiate and/or elevate these from Eneloops for the masses? All I can see is getting half the capacity for _perhaps_ just a tiny bit less money. The only advantage I can see over the Eneloop is that they create a "harmonious lifestyle," which I am all for, of course.


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## SemiMan (Jul 26, 2009)

Going to go out on a limb and say these are just "cheaper" Eneloops. "Up To" 1000 recharge cycles is just what it says for Eneloop.

Look at the weight differences between this new one and the Eneloop. The new one is quite a bit lighter.

Hence, I have a feeling, which could be wrong, that mainly these are batteries with less material in them.... perhaps targeted at lights, etc. where the storage needs are not as high.

Semiman


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## wapkil (Jul 26, 2009)

Turbo DV8 said:


> I notice the package doesn't even try to claim "New & Improved," just "New." The only thought that crosses my mind about these "new" cells is, "What's the point?" It's an answer to a question that nobody asked. And if the relevance of these eludes me, what angle does Sanyo plan on using to differentiate and/or elevate these from Eneloops for the masses? All I can see is getting half the capacity for _perhaps_ just a tiny bit less money. The only advantage I can see over the Eneloop is that they create a "harmonious lifestyle," which I am all for, of course.



Well, it's all about "thinking GAIA" - harmony, ecology, CO2 emission reduction, conserving the planet for future generations, nothing else.

I haven't seen these batteries anywhere but I think they will probably cost around half the price of the Eneloops. They will be sold either in the same markets or targeted to developing countries. Sanyo wants their rechargeables to eventually replace dry cells so they need something cheaper than Eneloops. These low capacity models will also be used to fight with LSD batteries sold by other manufacturers.


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## clintb (Jul 27, 2009)

Bones said:


> For those who wonder whether their cells will benefit from a 'few' break-in charges, it's notable that for this new cell, Sanyo specifically carried forward and adapted the following blurb from their specifications for the Eneloop:
> 
> 
> 
> ...


What's even more interesting than the break-in, since we all know it's good, is the Internal Resistance _after discharge to 1.0V._ I've read all through this forum, the ones at rcgroups.com and I don't remember seeing a manufacturer state it so clearly. Is this the correct way to measure IR?


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## lctorana (Jul 28, 2009)

clintb said:


> What's even more interesting than the break-in, since we all know it's good, is the Internal Resistance _after discharge to 1.0V._ I've read all through this forum, the ones at rcgroups.com and I don't remember seeing a manufacturer state it so clearly. Is this the correct way to measure IR?


25 milliohms @ 1.0V is a short-circuit capability of 40A.

I would suggest, on that reading, that
a) these cells should NEVER be flash-amped (not if you value your meter!)
b) they sound interesting for hotwire use...


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## Mr Happy (Jul 28, 2009)

lctorana said:


> 25 milliohms @ 1.0V is a short-circuit capability of 40A.


That 25 milliohms is the 1 kHz AC impedance though. It is likely to be nearer 50 milliohms DC. Even so, that is a pretty good value.


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## csshih (Jul 28, 2009)

lctorana said:


> a) these cells should NEVER be flash-amped (not if you value your meter!)




lucky mine has a resettable fuse!


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## clintb (Jul 28, 2009)

lctorana said:


> 25 milliohms @ 1.0V is a short-circuit capability of 40A.
> 
> I would suggest, on that reading, that
> a) these cells should NEVER be flash-amped (not if you value your meter!)
> b) they sound interesting for hotwire use...


Guess I should have clarified how I'd do the testing; I have 2 x iCharger 208B hobby chargers and a PLD IRM. No DMM usage for this test!


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## lctorana (Jul 28, 2009)

That's a subtlety that's so far eluded me. But now you force me to think about it, some questions natuarally occur.

What does the AC impedance mean in practice?

And why does the value differ from DC - is is a polarization thing, or is there a capacitive or inductive shunt reactance?


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## lctorana (Jul 28, 2009)

You know what I'd like to see now?

A toe-to-toe test against a 1Ah Sanyo CadNica AA.

Same brand, same capacity, two different chemistries. Would make fascinating reading, particularly at very high discharge rates.


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## Mr Happy (Jul 29, 2009)

lctorana said:


> That's a subtlety that's so far eluded me. But now you force me to think about it, some questions natuarally occur.
> 
> What does the AC impedance mean in practice?
> 
> And why does the value differ from DC - is is a polarization thing, or is there a capacitive or inductive shunt reactance?


I am far from expert on this, but I think that the AC impedance is quoted because it is easier to measure using standard test tools.

And I think the AC impedance is lower than the DC internal resistance because the equivalent circuit for a NiMH cell contains some capacitance.


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## swiftwing (Jul 29, 2009)

wapkil said:


> Well, it's all about "thinking GAIA" - harmony, ecology, CO2 emission reduction, conserving the planet for future generations, nothing else.
> 
> I haven't seen these batteries anywhere but I think they will *probably cost around half the price of the Eneloops*. They will be sold either in the same markets or targeted to developing countries. Sanyo wants their rechargeables to eventually replace dry cells so they need something cheaper than Eneloops. These low capacity models will also be used to fight with LSD batteries sold by other manufacturers.



That's the problem, they don't. They are only slightly cheaper than the Eneloops, and its not a shop trying to rip people off thing since Sanyo controls prices pretty tightly over here, every single place sells eneloops at the exact same price.


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## wapkil (Jul 29, 2009)

swiftwing said:


> That's the problem, they don't. They are only slightly cheaper than the Eneloops, and its not a shop trying to rip people off thing since Sanyo controls prices pretty tightly over here, every single place sells eneloops at the exact same price.



I thought that these batteries are not really present on the market yet. They are practically absent on-line, even Sanyo web pages don't advertise them. Maybe when (and if) they are fully available the pricing policy will be different. I have no idea what can be the reason to offer them with the price close to that of Eneloops which seem to be a clearly superior product.


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## vali (Jul 29, 2009)

Maybe they are as tough as Nicads.


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## minimig (Jul 30, 2009)

I've seen these cells in only one shop, it is a specialty shop that sells batteries. They priced these cells exactly half the price of Eneloops.

Miguel


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## Jumi (Jul 30, 2009)

Miguel 
So how much did they cost in USD?

They should sell these with solar charger.

Juha


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## wapkil (Jul 30, 2009)

Mr Happy said:


> I am far from expert on this, but I think that the AC impedance is quoted because it is easier to measure using standard test tools.
> 
> And I think the AC impedance is lower than the DC internal resistance because the equivalent circuit for a NiMH cell contains some capacitance.



The impedance or resistance is usually mentioned in the datasheet but I remember only Energizer mentioning them both. I don't know enough about these values but the relation between them seems to highly depend on the cell size. For AAs the resistance can be ~2.5x higher than impedance but for Cs it can be only around 1.2x. 

The values highly depend on the state of charge. I think that most manufacturers show the (lower) values for charged cells while Sanyo data is for discharged ones - I believe the difference is quite large (2-3 times?). To make matters worse, some manufacturers write "resistance" when they mean impedance...


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## Black Rose (Jul 30, 2009)

lctorana said:


> You know what I'd like to see now?
> 
> A toe-to-toe test against a 1Ah Sanyo CadNica AA.
> 
> Same brand, same capacity, two different chemistries. Would make fascinating reading, particularly at very high discharge rates.


Do they still make those?

I had several sets of CadNica AAs in the mid 80s that I used in my Sanyo "walkman". I still have the charger for those.


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## minimig (Jul 31, 2009)

Jumi said:


> Miguel
> So how much did they cost in USD?
> 
> They should sell these with solar charger.
> ...




Using the latest conversion rate US$1.00 = PHP48.105

Eneloop PHP720.00 or US$14.97 (4 pack AA)

Harmolattice PHP360.00 or US$7.48 (4 pack AA)

And they give away a 4 pack of Sanyo AA Neo Super manganese cells for evry 4 pack of AA Eneloop or Harmolattice. :thanks:


Miguel.


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## Bones (Aug 1, 2009)

minimig said:


> Using the latest conversion rate US$1.00 = PHP48.105
> 
> Eneloop PHP720.00 or US$14.97 (4 pack AA)
> 
> ...



Thanks for this Miguel.

It really does appear that the Harmolattice was primarily intended as cost competitor:







At least there is now have a lower cost alternative to the Eneloop for devices which utilize a constant charge or a very low rate of charge, as well for ultra low-drain devices which tend to subject cells to extended periods under 1.0 volts.


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## Black Rose (Aug 1, 2009)

I am hoping these will hit the North American market at some point.

Once my supply of alkaline AAs are used up in clocks and remotes, it would be nice to be able to have a rechargeable solution that is geared towards that particular type of drain.


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## GarageBoy (Aug 2, 2009)

So they're a TAD cheaper than Eneloops, half the capacity?
What's wrong with just using Eneloops in your remotes, etc?


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## Black Rose (Aug 3, 2009)

Battery operated clocks are known for sucking every last ounce of energy out of a battery. Not the type of low drain environment you want to subject your better quality NiMh cells to.

I do use Eneloop AAA in my Harmony remote, as that thing eats 4 AAA cells in about 2 months.


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## condor11 (Aug 3, 2009)

GarageBoy said:


> So they're a TAD cheaper than Eneloops, half the capacity?
> What's wrong with just using Eneloops in your remotes, etc?



Here's my theory. Manufacturers, including Sanyo by now realized that Eneloops were just too good. They last forever in clocks, smoke detectors etc. and they don't cost a lot. This erodes their bottom line. So what they'll do is sell Harmolattice for almost the same price as current Eneloops and it will be targeted as a replacement of regular AA alkaline. Then they'll increase prices for Eneloops and target them to hobbysts (Radiocontrol stuff, Digital Cameras).

Kinda like Ford that makes Focus for students and Mustang for for post-menopausal wealthy men


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## wapkil (Aug 3, 2009)

condor11 said:


> Here's my theory. Manufacturers, including Sanyo by now realized that Eneloops were just too good. They last forever in clocks, smoke detectors etc. and they don't cost a lot. This erodes their bottom line. So what they'll do is sell Harmolattice for almost the same price as current Eneloops and it will be targeted as a replacement of regular AA alkaline. Then they'll increase prices for Eneloops and target them to hobbysts (Radiocontrol stuff, Digital Cameras).



I don't like this idea - sounds bad enough to be true. Harmolattices will still be half the price of Eneloops but it's not exactly the way I wanted them to be. I hope the pressure from other LSD cells manufacturers will make Sanyo reject your advice


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## Turbo DV8 (Aug 3, 2009)

condor11 said:


> They last forever in clocks, smoke detectors etc.


 
The next best thing to having no smoke detector, is using rechargeable batteries in a smoke detector and expecting them to "last forever." When a nearly-depleated rechargeable hits that "knee" voltage, drops off and rapidly dies, you better hope you aren't away for the evening or weekend and miss that low-batt chirp.


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## condor11 (Aug 3, 2009)

Turbo DV8 said:


> When a nearly-depleated *alcalines* hits that "knee" voltage, drops off and rapidly dies, you better hope you aren't away for the evening or weekend and miss that low-batt chirp.



I replaced one word in your statement, now how is it different? Noone expects Eneloops to last forever, but they will last as much as alcaline.

As for my theory, I may be playing devil's advocate a bit but given today's alcaline battery prices (how much are 4 AA Energizers, like $4 in Canada) I would expect anything from battery industry. They aren't stupid to shoot themselves. Competition, some say? AA alcaline Energizers, Panasonic and Duracells all cost a lot! And what's funny even with dollar stores selling 4AA for a dollar for the last 5 years the brand names still don't drop their prices!


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## TorchBoy (Aug 3, 2009)

1. I really don't know about having "harm" in the name of a battery.
2. Is there any evidence it's super rugged? Are there claims it can take constant trickle charging or withstand repeated overdischarging? It _does_ claim to be LSD, though.
3. It looks rather light weight. I'm with SemiMan in thinking part filled.
4. Those voltage curves don't look good to me, compared to Eneloop. For any given current their performance is lower than Eneloop, so I don't think they'd be particularly good for hotwire.
5. Without having a price significantly less than Eneloop there wouldn't be much point in using them where I wouldn't want Eneloops tied up doing not much (eg, TV remotes). I guess we'll wait and see on this one.

*If* it was on topic, since when did alkalines in low drain devices have a knee voltage? Could you start a thread explaining that one?


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## Mr Happy (Aug 3, 2009)

Eneloops are still sold at a premium price: I saw some over the weekend priced at $15/4, and this has always been more or less the normal price for them in shops. If the Harmolattice cells are sold at half the price, e.g. $7.50/4, then they would be useful for lower drain devices that don't need the expense of an eneloop, like clocks and remote controls.


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## Linger (Aug 3, 2009)

Bones said:


> for ultra low-drain devices which tend to subject cells to extended periods under 1.0 volts.


I read this, then looked back and saw the icon of a flashlight (end of the row) and thought it had no business being there what so ever.


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## condor11 (Aug 3, 2009)

Mr Happy said:


> Eneloops are still sold at a premium price: I saw some over the weekend priced at $15/4, and this has always been more or less the normal price for them in shops. If the Harmolattice cells are sold at half the price, e.g. $7.50/4, then they would be useful for lower drain devices that don't need the expense of an eneloop, like clocks and remote controls.



To that point one "advantage" of Eneloops or any other LSD is that they are sold as "pre-charged". That means customer expects to buy them and start using without the need to charge first. But if the battery has been on a shelf for 2-3 years retailer would want to get rid of it because in 2 years it certainly lost some charge. And this is the time many retailers blow them out at half price or less. At least in Canada we have our famous drug mart chain blowing Duraloops twice a year for $6.88 per 4AA or 4AAA.


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## Bones (Aug 3, 2009)

I continue to view the introduction of the Harmolattice as decidedly positive development.

With the Eneloop, Sanyo really did engineer and produce a NiMH cell that's clearly in a class by itself.

Yet, not only does the Eneloop have to compete against regular rechargeables in a market where capacity is usually the primary selection criteria, but also against other, significantly inferior low self-discharge cells that are churned out by the gazillions in China.

Except for the enthusiasts that belong to this and other venues where these cells are subjected to independent testing and ultra-critical long term scrutiny, I doubt there are very many consumers who are aware of just how superior the Eneloop is proving itself to be.

Accordingly, when faced with a selection of low self-discharge cells, some bearing well-known brand names, and no understanding of the distinctions between the Eneloop and its competitors, it only seems logical for the average consumer to choose based on price.

Assuming that Sanyo manufactures the Eneloop in Japan primarily to protect is formulation and production processes, it seems to me they only had two real choices to become more competitive cost-wise.

Either comprimise the Eneloop by using less costly ingredients and/or crank up its production lines while letting quality control slide a bit, or design and build a lessor capacity, less costly cell which is at least equivilant to the Eneloop in self-discharge, quality and durability.

Obviously, the quality and durability have yet to be proven, but considering that Sanyo's had almost four years since the Eneloop was introduced to tweak it's formulation and production processes, and considering the lessor trade-offs against its capacity, I'm reasonably confident that this new Harmolattice really will prove itself to be even tougher and more durable than the Eneloop.


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## TorchBoy (Aug 3, 2009)

How long to get some to SilverFox?


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## Turbo DV8 (Aug 4, 2009)

condor11 said:


> I replaced one word in your statement, now how is it different? Noone expects Eneloops to last forever, but they will last as much as alcaline.


 


> Manufacturers, including Sanyo by now realized that Eneloops were just too good. They last forever in clocks, smoke detectors etc.


 
First, I don't know of any smoke detectors that use AA cells, but since you seem to know of some and feel Eneloops "last forever" in them, I thought it would be wise to warn "unenlightened" folks the risk of using rechargeable batteries in general in smoke detectors. Let's just suppose Sanyo introduces a 9 volt LSD NiMH that would fit right into a smoke detector. That doesn't mean a smoke detector would be a suitable application. I used the term "knee" voltage in parenthesis as a way to help visualize the difference in the discharge curve of an _alcaline _(_sic) _and a rechargeable, whether NiMH or NiCd.

Most here understand that once a NiMH or NiCd falls to a certain voltage, it then falls at a precipitous rate. On the other hand, an alkaline's voltage will just slowly drop to zero at a fairly constant rate. A smoke detector begins to emit the low-batt warning chirp at a certain cell voltage, and will continue it's intermittent chirp as the cell voltage slowly drops until the cell voltage can no longer power the detector. The gradual discharge slope of an alkaline allows the smoke detector to continue to chirp it's warning for many days and even weeks. The discharge slope of a rechargeable, however, is so steep once it hits that "knee" voltage, the smoke detector may only chirp several times, or for a few hours. If you happen to be out shopping, spending the evening on the town, or you're out of town for the weekend when this happens, you are SOL, because you will get home and never know your smoke detector battery just died while you were out.

Then that night you decide to charge some Eneloops at 200 mA on your v.32 BC-900, it melts down, ignites the pages of your battery spread sheets sitting next to it, the house burns down, and you sleep through it all because your smoke detector didn't work because you didn't know the rechargeable battery in it had died the day before. Then when you pass on to the other side, you realize you have gone to hell, where everyone is banned from CPF.:banned::devil::banned:


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## Mr Happy (Aug 4, 2009)

Although this is a wise caution, I have run eneloops in low drain devices like a weather station and a 24h LED backlight, and they actually continue to power such devices for weeks while at or below 1.0 V. So the knee is much less pronounced with trickle loads compared to power loads.

With smoke detectors I think the best plan regardless of battery type is to press the test button weekly and replace the batteries to a schedule, such as every six months to a year.


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## Beacon of Light (Aug 4, 2009)

BEST POST EVER AWARD GOES TO *Turbo DV8*!!!

I just realized my Lacrosse BC900 IS v.32. Did they ever do a proper recall? Could I have Thomas Distribution send me a v.33 to replace it? Mine DOES get overly warm... Oh dear. I could see a scenario just like Turbo DV8 mentioned happen to me.



Turbo DV8 said:


> First, I don't know of any smoke detectors that use AA cells, but since you seem to know of some and feel Eneloops "last forever" in them, I thought it would be wise to warn "unenlightened" folks the risk of using rechargeable batteries in general in smoke detectors. Let's just suppose Sanyo introduces a 9 volt LSD NiMH that would fit right into a smoke detector. That doesn't mean a smoke detector would be a suitable application. I used the term "knee" voltage in parenthesis as a way to help visualize the difference in the discharge curve of an _alcaline _(_sic) _and a rechargeable, whether NiMH or NiCd.
> 
> Most here understand that once a NiMH or NiCd falls to a certain voltage, it then falls at a precipitous rate. On the other hand, an alkaline's voltage will just slowly drop to zero at a fairly constant rate. A smoke detector begins to emit the low-batt warning chirp at a certain cell voltage, and will continue it's intermittent chirp as the cell voltage slowly drops until the cell voltage can no longer power the detector. The gradual discharge slope of an alkaline allows the smoke detector to continue to chirp it's warning for many days and even weeks. The discharge slope of a rechargeable, however, is so steep once it hits that "knee" voltage, the smoke detector may only chirp several times, or for a few hours. If you happen to be out shopping, spending the evening on the town, or you're out of town for the weekend when this happens, you are SOL, because you will get home and never know your smoke detector battery just died while you were out.
> 
> Then that night you decide to charge some Eneloops at 200 mA on your v.32 BC-900, it melts down, ignites the pages of your battery spread sheets sitting next to it, the house burns down, and you sleep through it all because your smoke detector didn't work because you didn't know the rechargeable battery in it had died the day before. Then when you pass on to the other side, you realize you have gone to hell, where everyone is banned from CPF.:banned::devil::banned:


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## clintb (Aug 5, 2009)

Mr Happy said:


> With smoke detectors I think the best plan regardless of battery type is to press the test button weekly and replace the batteries to a schedule, such as every six months to a year.


While I agree with Turbo DV8 to an extent, this line from Mr Happy is, what I consider, the most important part of the entire smoke detector battery equation.

Lucky for me, the smoke detectors used in our house are wirelessly tied to the alarm system, which is monitored and has police / fire / emergency backup assistance. They're powered by CR123's.


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## vmaldia (Dec 15, 2009)

these are for some reason 50% more expensive in the philippines

~650 pesos for 4 eneloop AA's versus ~ 450 pesos for 2 of these


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## mfm (Dec 16, 2009)

These cells are not available in Japan, so they are probably just budget cells for poor countries.


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## CdBoy (Mar 27, 2011)

Linger said:


> I read this, then looked back and saw the icon of a flashlight (end of the row) and thought it had no business being there what so ever.


 
yes you are right it has no business in being there.


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