Does anyone know at what rate the Energizer L91 lithium AAs will self discharge if left in storage or used very rarely? The L91 datasheet http://data.energizer.com/PDFs/l91.pdf says they have a shelf life of 12 years, but doesn't say if they lose any of their capacity if stored for that long.
Energizer L91 self discharge rate
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Mr Happy
Flashlight Enthusiast
Yes, they lose their capacity gradually during storage. I can't remember the exact figures, but after 12 years it may be down to 75% of the original capacity or less. This will depend somewhat on the storage conditions: lower storage temperatures will usually extend the shelf life of batteries.
There's a golden rule with batteries: buy them fresh and use them fresh. Don't put them in long term storage and expect to rely on them when you need them. This is just as bad as putting dried food in the back of the cupboard and forgetting about it.
If your batteries are for emergency backup purposes, make a note in your calendar and use them and replace them on a yearly cycle, so the batteries in storage are never more than a year old.
There's a golden rule with batteries: buy them fresh and use them fresh. Don't put them in long term storage and expect to rely on them when you need them. This is just as bad as putting dried food in the back of the cupboard and forgetting about it.
If your batteries are for emergency backup purposes, make a note in your calendar and use them and replace them on a yearly cycle, so the batteries in storage are never more than a year old.
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Actually, it says "Shelf Life: 15 years at 21°C".
The datasheet for the previous 8X version said "Shelf Life: 15 years at 21°C (90% of rated capacity)".
EDIT: Batteries can be a couple of years old on the store shelf. The "best before" date is marked on the battery.
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I did a search and this old thread seemed most related to my situation. A couple of months ago I decided to get a couple of AA LED lights. I bought the Nitecore EA81 and put in eight brand new L91 Lithiums. I ran the light briefly to test it out and then stuck it in my nightstand drawer. I have now purchased some LSD AmazonBasics Eneloop knockoffs and placed the barely used L91 lithiums into a container for storage.
My question is, have I effectively screwed up the 20 year shelf life of the L91 lithiums and might as well just use them up now or can I reliably store them as backups in a BOB for say five years without worrying about them going dead during that time?
Thanks for any insight and/or experience you may have.
My question is, have I effectively screwed up the 20 year shelf life of the L91 lithiums and might as well just use them up now or can I reliably store them as backups in a BOB for say five years without worrying about them going dead during that time?
Thanks for any insight and/or experience you may have.
ChrisGarrett
Flashlight Enthusiast
I was looking at them on Ebay last night and the oldest/, 'farthest in the future' expiry date I saw was 2035. I'll assume that they were at least made in 2016, so that's 19 years. They keep increasing it, like with Eneloops, Mountain House FDF and LifeStraws.
An 8 pack can be had for ~$14 delivered, so I wouldn't put too much worry into the issue. Store them, use them, as it probably doesn't matter much? When the zombies invade and you get 'Abrahammed, or Daled,' it won't matter, since you can't take them with you. Always try and rotate your stocks and stagger your purchases. If you don't need 100 of something today and you know it will still be produced two years down the road, perhaps wait until then?
I've been using a single L91 in my rotary fish feeder for a couple of years. I'll go for one week to three weeks a couple/few times a year and it's still over 1.7v, IIRC.
It's a low drain device, pretty much.
Chris
An 8 pack can be had for ~$14 delivered, so I wouldn't put too much worry into the issue. Store them, use them, as it probably doesn't matter much? When the zombies invade and you get 'Abrahammed, or Daled,' it won't matter, since you can't take them with you. Always try and rotate your stocks and stagger your purchases. If you don't need 100 of something today and you know it will still be produced two years down the road, perhaps wait until then?
I've been using a single L91 in my rotary fish feeder for a couple of years. I'll go for one week to three weeks a couple/few times a year and it's still over 1.7v, IIRC.
It's a low drain device, pretty much.
Chris
iamlucky13
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The question as I read it is whether the shelf life of lithium primaries is affected by not being stored at full charge.
As far as I can tell, no. Supposing you drained 5% out of these batteries, maybe after a decade or two the slightly used batteries are at 90% of original capacity, while an unused set is at 95%. I can't find any information suggesting there's any detriment to storing partially discharged lithium primaries.
A couple minor side notes on this topic: Energizer claims 20 year shelf life for the Lithium "Ultimate" but only 10 year shelf life for the Lithium "Advanced." Not that most people will ever notice.
Also, the shelf life rating for their lithium batteries is based on 95% of original capacity remaining, while for alkalines, it is based on 80% of original capacity remaining. Lithium iron disulfide really do store incredibly well.
As far as I can tell, no. Supposing you drained 5% out of these batteries, maybe after a decade or two the slightly used batteries are at 90% of original capacity, while an unused set is at 95%. I can't find any information suggesting there's any detriment to storing partially discharged lithium primaries.
A couple minor side notes on this topic: Energizer claims 20 year shelf life for the Lithium "Ultimate" but only 10 year shelf life for the Lithium "Advanced." Not that most people will ever notice.
Also, the shelf life rating for their lithium batteries is based on 95% of original capacity remaining, while for alkalines, it is based on 80% of original capacity remaining. Lithium iron disulfide really do store incredibly well.
etc
Flashlight Enthusiast
That's not always possible as by definition, the cells are stored for an emergency situation.
L91 is the better choice for such an event, even better than 123 cells through it's close.
But I completely get the point. Old cells have diminished capacity.
I have a bunch of L91s, the expiration date is 2021-22 and 2024.
A lot of 123s, with the expiration date of 2018. So these were made circa 2008 or so.
L91 is the better choice for such an event, even better than 123 cells through it's close.
But I completely get the point. Old cells have diminished capacity.
I have a bunch of L91s, the expiration date is 2021-22 and 2024.
A lot of 123s, with the expiration date of 2018. So these were made circa 2008 or so.
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ChrisGarrett
Flashlight Enthusiast
I don't know if you're an OCDer like me, but you might as well just use them up, buy some fresh ones for the Zombie Apocalypse and call it a day.
You'll sleep better at night, like I do.
Chris
The discharge rate is probably <1% per year.
Meaning the seals of the battery will fail before the energy is dissipated.
Energizer had a white paper discussing the battery, and thought the consumer would not believe a 40 year shelf life.
Meaning the seals of the battery will fail before the energy is dissipated.
Energizer had a white paper discussing the battery, and thought the consumer would not believe a 40 year shelf life.
If it even has half the capacity left after 40 years that is about 1500mah at lower drain rates and could outlive a lot of people especially if they weren't in the crib when the batteries were bought for them.
etc
Flashlight Enthusiast
Does a perfectly new, untouched L91 have any advantages over a slightly used L91? I recently inherited a number of L91s, all with some runtime on them. 100 cells that all measure 1.63-1.65V. I wonder how well do these store, once some have been used a bit?
etc
Flashlight Enthusiast
Yes, I've discharged one that low. Scroll down and look at the chart for L91s and notice the voltage and currents.
http://electronics.stackexchange.com/questions/134143/when-is-the-aa-battery-voltage-drop
You will see that at about 1.4v on a 100ma load you have about 1/6 of the capacity left and at the same 100ma at 1.6v the L91 is about 1/2 depleted. At higher currents the capacity drops and also the runtime drops too.
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etc
Flashlight Enthusiast
I see your point, given 100mAh, 1.4V appears to be the cut off point and 1.6V just about half-way discharged.
I recall that in my Garmin GPS, they discharged to 1.3V if I remember correctly. It also appears to depend heavily on the device what the cut-off point is. I tried some 1.3V alkalines in a xbox one console and it would not fire it up to my surprise. Needing more voltage. I've also had some devices run to 1.15V and below.
I recall that in my Garmin GPS, they discharged to 1.3V if I remember correctly. It also appears to depend heavily on the device what the cut-off point is. I tried some 1.3V alkalines in a xbox one console and it would not fire it up to my surprise. Needing more voltage. I've also had some devices run to 1.15V and below.
Two things to also remember
1) If a battery is allowed to rest it can recover some voltage (goes up). Alkalines are more akin to this behavior than lithiums are but they will recover a little bit even and both will recover if put under heavy loads in use.
2) Voltage without a load doesn't equal voltage with a load especially when a battery has lost capacity in use the voltage can sag more and more.
When an alkaline is 1.3v is it half way used up under light loads I believe and heavier loads more than 2/3rd used. The devices that will run batteries down to low levels often will either run very low voltage levels (under 0.9v) or are rather low loads on the battery. I've got devices that will act up when an alkaline hits 1.3v also which makes it hard to use nimh in. One device a remote thermometer runs about 2 1/2 years on alkaline and only 6-8 months on nimh because when it hits about 1.25v even at low current it gets unreadable (the LCD display) and starts having trouble receiving the remote signal. I have an old caller ID box that craps out at 1.3v too.
In other words the 1.63v lithium batteries may have been used in a device that puts a heavy load on it and started to sag (less bright if a light). I picked up a bunch of L91s in a buy on the CPF market years ago for 50 cents each and of the 60 I bought 3 were less than 1.8v most were 1.80-1.83v but I had one at 1.59, 1.65, and 1.74v. The 1.59v didn't last very long and the 1.65v one lasted about half as long with the 1.74v about 2/3 as long as the ones measuring 1.8v+.
One way to test batteries is a load meter which as batteries deplete the voltage will sag more the closer they are to empty.
etc
Flashlight Enthusiast
It's painfully obvious voltage without load is just a relative guide to where things are, not a really good indication for either L91s or 123s.
You can gauge relative capacity versus other cells, not necessarily put a percentage on it. It does have some juice left for sure. I picked up 124 L91s from a recycling facility, almost all of them at 1.65V with just a few at 1.8V and a couple completely dead.
Free L91s with that capacity is the very definition of guilt-free lumens. Too bad I don't love AAs all that much for torches. Malkoff M61LL or LLL off FiveMega 3xAA being the only exception.
An alkaline at 1.3V is IME 2/3 of the way towards depletion. Point is, L91 graph is different from either Li-Ion 14500 or Alkaline and NiMH.
You can gauge relative capacity versus other cells, not necessarily put a percentage on it. It does have some juice left for sure. I picked up 124 L91s from a recycling facility, almost all of them at 1.65V with just a few at 1.8V and a couple completely dead.
Free L91s with that capacity is the very definition of guilt-free lumens. Too bad I don't love AAs all that much for torches. Malkoff M61LL or LLL off FiveMega 3xAA being the only exception.
An alkaline at 1.3V is IME 2/3 of the way towards depletion. Point is, L91 graph is different from either Li-Ion 14500 or Alkaline and NiMH.
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