# This thing says I have to use Energizer E91 AAs. Why?



## williaty (Jan 20, 2013)

So I got a new smoke alarm and it demands that I use Energizer E91 AA batteries in it (even though it ships with copper tops). Why? What's special about the E91? As far as a I can tell, it's just a generic AA alkaline battery with no special features. Given that a smoke detector must be a low current application, why not shove some lithium AAs in there to get a longer service life and less risk of the attack of the green goo?


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## Timothybil (Jan 20, 2013)

What was the exact wording? Did it say 'only' or 'recommend'? I'm guessing they don't want you to use 10 cent carbon zinc AAs and stuff like that. As long as the AAs produce 1.5v and last a reasonable time (like six months to a year or more) you should be good with any alkaline or lithium cells. How many AAs does this alarm take. ALL of the smoke detectors I have ever used used 9v batteries.


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## williaty (Jan 20, 2013)

They said only. No others to be used.

2 AAs. That was one of the selling points to me, along with the fact that it's a dual-sensor (which ALL detectors should be, really).


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## StarHalo (Jan 20, 2013)

[see below] You can use any AA cell, just be aware that modern alkalines do tend to leak over a long enough timeline, so keep an eye on them.


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## lwknight (Jan 20, 2013)

It has been my experience that the high $$ lithium AA calls are no better than the $0.50 alkies in low drain devices like smoke detectors
except for the slight leakage risk in alkies. Anything that gets several months out of a battery will work just as good with alkaline as lithium cells


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## williaty (Jan 20, 2013)

StarHalo said:


> E91s are not alkalines at all, they're lithium


Energizer's own literature clearly states the E91 are alkaline.


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## lwknight (Jan 20, 2013)

Maybe what they are really saying is that the detector requires 1.5 volt batteries.
As in liken to nimh would not work because the voltage is lower.

So many manufacturers do not give true technical info. Their info is geared to the simple minded people.


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## GunnarGG (Jan 20, 2013)

williaty said:


> Energizer's own literature clearly states the E91 are alkaline.



I first thought you were completely wrong, but of course you are absolutely right!
Everytime a read anything about Energizer _91 I think lithium.

E91 is alkaline
L91 is the lithium battery.
Somebody had a similar question a year ago at some other forum:

http://www.city-data.com/forum/house/1484287-carbon-monoxide-detector-use-only-energizer.html


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## StarHalo (Jan 20, 2013)

williaty said:


> Energizer's own literature clearly states the E91 are alkaline.



Ah, you're right, I'm thinking of L91s; which makes even less sense, because why would you use the product code for a common alkaline battery?! You'd think detector designers would make it a point to keep things simple for the end user..


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## Lynx_Arc (Jan 20, 2013)

Yes the E91 is an alkaline if I remember correctly and nothing special about it as there are other brand cells that are equivalent to it. Whoever wrote the manual probably has energizer data sheets and was told by some engineer the battery the device operates on is an alkaline one so they looked it up and wrote that down and put.. "use this only" thinking people shouldn't use heavy duty or nicads in it.


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## Yamabushi (Jan 20, 2013)

It's possible the smoke alarm manufacturer is protecting itself against claims. It tested the device with specific battery brands/models to get UL and FM approvals. If you use something else and someone gets hurt because the alarm didn't go off, they're off the hook.


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## Lynx_Arc (Jan 20, 2013)

Yamabushi said:


> It's possible the smoke alarm manufacturer is protecting itself against claims. It tested the device with specific battery brands/models to get UL and FM approvals. If you use something else and someone gets hurt because the alarm didn't go off, they're off the hook.


I think the fact they say use only energizer batteries and sell it with duracells clue you into the fact that someone wasn't thinking when they made the manual IMO.


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## StandardBattery (Jan 20, 2013)

Lynx_Arc said:


> I think the fact they say use only energizer batteries and sell it with duracells clue you into the fact that someone wasn't thinking when they made the manual IMO.


* +1* And I'd recommend you keep using Duracells because my experience on the US east coast is the energizers are more prone to leaking. Has any one else made tests of just what the best Alkaline battery is in terms of non-leakage?


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## RCM (Jan 20, 2013)

Duracell 9 volts are better in terms of not leaking. We just had a detector replaced because it wouldn't shut up! They are hardwired with a backup battery....the battery I found in it was an energizer alkaline I almost couldn't get it out because it was swollen so badly! The new one recommended to use lithium or carbon-zinc! All over the others have rayovac alkaline...


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## StarHalo (Jan 21, 2013)

I've had an alkaline 9V pop open inside a smoke detector before, a pair of the AAAA cells inside were wedged all the way up against the other side of the battery compartment. Still not paying for a lithium 9V just to sit in a smoke detector though..


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## Lynx_Arc (Jan 21, 2013)

StarHalo said:


> I've had an alkaline 9V pop open inside a smoke detector before, a pair of the AAAA cells inside were wedged all the way up against the other side of the battery compartment. Still not paying for a lithium 9V just to sit in a smoke detector though..



I too still have a hard time justifying paying 3-5 times or more the price for lithium batteries in stuff that a leakage is more of a nuisance than critical. I would probably never use lithium 9v because their 4x price with perhaps 2x runtime it is IMO wasting about 5 dollars of your money for a slight risk of ruining a ~20 dollar smoke alarm. Perhaps they will one day figure out how to make a smoke detector that will run 5 years off of a pair of 2032 batteries. I would be tempted then to pay twice as much and replace them so as to not have the expense of $2.50-$3+ 9v alkalines


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## Timothybil (Jan 21, 2013)

They are now selling 'lifetime' detectors that never need battery changing. They come with a lithium built-in, and are guaranteed for I think 10 years. Since that is the expected lifespan of the detector, when the battery goes you just buy a new unit. Haven't been out more than a year or two so will see how they do in the Real World.

http://www.amazon.com/dp/B0009RWK52/?tag=cpf0b6-20


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## SaraAB87 (Jan 21, 2013)

I just got one of the kidde talking dual carbon monoxide/smoke detector combo and I put 3 ray o vac alkaline AAA's with a date of 2017 in it and its working fine.i have like 6 smoke detectors in the house and it would be very costly and probably not justified to purchase lithium for this use. Also I live with grandparents and the fire dept here gives free detectors to everyone over 65 or something like that so I am set if any of them decide to start leaking I can probably get it replaced for free.


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## Lynx_Arc (Jan 21, 2013)

Timothybil said:


> They are now selling 'lifetime' detectors that never need battery changing. They come with a lithium built-in, and are guaranteed for I think 10 years. Since that is the expected lifespan of the detector, when the battery goes you just buy a new unit. Haven't been out more than a year or two so will see how they do in the Real World.
> 
> http://www.amazon.com/dp/B0009RWK52/?tag=cpf0b6-20


lifetime for what? A dog? I don't think I would want to spend money on new detectors every 10 years myself


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## SaraAB87 (Jan 22, 2013)

Um you are supposed to replace your detectors every 7 years or when the package says to anyways since they are only good for that long, if you don't replace them they may not sense a fire or carbon monoxide. It could be very dangerous if you don't replace them. The newer detectors will chirp when their lifespan is up to let you know to change them out. That is the point of a lifetime detector, it has a sealed battery inside so when the life of the detector is up the battery will be dead and then it's time to buy a new detector.


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## Yamabushi (Jan 23, 2013)

Yamabushi said:


> It's possible the smoke alarm manufacturer is protecting itself against claims. It tested the device with specific battery brands/models to get UL and FM approvals. If you use something else and someone gets hurt because the alarm didn't go off, they're off the hook.



I was right. I checked UL Standard 217. For certification, the manufacturer must test 6 sets of each make/model of battery under specified conditions for a minimum of 1 year. The manufacturer can only supply or recommend makes/models of batteries that have tested satisfactorily in their alarm.

The fact that the instructions specified "only Energizer E91" but the alarm shipped with Coppertops probably means that the Coppertops were certified after the instructions were printed.


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## Wiggle (Jan 25, 2013)

GunnarGG said:


> I first thought you were completely wrong, but of course you are absolutely right!
> Everytime a read anything about Energizer _91 I think lithium.
> 
> E91 is alkaline
> L91 is the lithium battery.



Probably confused the E91 with the EA91. The EA91 is a budget lithium cell from Energizer.


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