Battery Discharge / Wasted Batteries

[blinkjr]

Hi all! Newbie here who really doesn't understand all of this battery technology. I'm lucky to understand the different sizes, much less all of the alkaline/nimh/lithium/lion formulas and the inherent complexities brought on with the proper care and feeding of rechargables. So I come to you experts for some help.

I have always been under the idea that once a battery (carbon-zinc/alkaline/whatever non-rechargable) is first used, even if it is then set aside and not used any more, it will begin to discharge at a faster rate than if it had been left on the shelf. Is this correct? If it is, my assumption was just use the battery as soon as possible. Otherwise you are just wasting a perfectly fine battery.

If this is correct, does it also apply to lithium (CR123s/AAs) batteries? My thought is having a car flashlight that uses this type of battery that I don't have to worry about being dead when I need it. But if I use it once, is it going to retain its energy for an extended time? Or will it speed up its discharge?

My questions are thus: 1) once initiated, do batteries natural self discharge speed up?; and 2) if so, how much is this process speeded up?

My thanks to all of CPFers! You all are a wonderful font of knowledge. :twothumbs

 

[ltiu]

I have always been under the idea that once a battery (carbon-zinc/alkaline/whatever non-rechargable) is first used, even if it is then set aside and not used any more, it will begin to discharge at a faster rate than if it had been left on the shelf. Is this correct?
:twothumbs

No.

 

[blinkjr]

Itiu - is that a blanket no? Self discharge rate is constant, whether or not they have been used at all?

Thanks!

 

[JBorneu]

I have always been under the idea that once a battery (carbon-zinc/alkaline/whatever non-rechargable) is first used, even if it is then set aside and not used any more, it will begin to discharge at a faster rate than if it had been left on the shelf. Is this correct?

Yes.



Well, to be honest, I'm not sure, but I've read about it here on CPF in CR123 safety threads. Two new CR123's in a light, light is used for 10 minutes and stored a year and the two cells degrade faster and at unequal rates, making them two cells with different states of charge after one year, making one of the cells vent with flame when the light is used again.

Again, I'm not sure if it's true, but I use primaries as a backup only so I treat 'em like it's true. Once I have used them a little bit, they are used up in my EDC lights and recycled.

Lithium primaries are great backups, perfect for a car light which is not used, but they all cost a lot, and with CR123 cells you have to make sure you're only using USA / Japan made perfect matches (same brand, same manufacturing date, same state of charge ...) in a light which takes multiples. I wouldn't put them in a user, that's just throwing money away, god created LSD NiMH's for that purpose. If you're a newbie and want to use high-power lights without spending a fortune on batteries, get a couple good LSD NiMH cells (sanyo eneloops, duracell precharged with white tops if you can find them) and a decent charger (one which terminates the charge at the right moment, usually says delta V somewhere on the packaging). Alkalines will leak when they are stored in your light (and outside of a light, but you'll be a lot more annoyed if it happens in a light), use them as backups stored outside the light or use them up in a couple weeks.

NiMH AA's won't explode unless you really try to, they are very resistant to abuse, and a cheap backup is available in any store. And, best of all, a LOT of GREAT lights run on them!

Cocnlusion: You need a car backup and an EDC which both run on AA's, put lithiums in the car light and LSD NiMH's in the EDC and use the EDC when possible. When you've used your car light, put new cells in it and use the used cells up in your EDC, that way your backup always has full cells.

 

[TooManyGizmos]

Multi-cell lights using un-matched (equal voltage) Lithium CR123A batteries , can be hazardous .

Whether I'm on topic - or not .
.

 

[Illum]

I have always been under the idea that once a battery (carbon-zinc/alkaline/whatever non-rechargable) is first used, even if it is then set aside and not used any more, it will begin to discharge at a faster rate than if it had been left on the shelf. Is this correct? If it is, my assumption was just use the battery as soon as possible. Otherwise you are just wasting a perfectly fine battery.

Short answer, no

Long answer, theres several variables you have to hold constant, some of the more common factors are expanded as follows:
[1]-Enviroment temperature: If the outside temperature is too cold/too warm, or otherwise outside the cell design temperature, the self discharge affect may be reduced or propagated.
Usually the colder it is the less it goes, but this varies with chemistry and whether that chemistry is rechargeable or not.

[2]-Battery Chemistry: If treated properly, Lithium primaries such as LiMNO2 [CR123a], Li-SOCl2 [SAFT cells], or Li-FeS2 [Energizer L91,L92] can last upwards of 5 or more years at minimum, rechargeables on the other hand are more variable. Single use cells will depend on how the one way reactions proceed, carbon zinc, etc that uses a liquid [rather than paste like MnO2, or "alkaline"] may corrode the battery as it is being used, and once that reaction is started the only thing you could do is slow it down by lowering the temperature, but even then the function between discharge rate and time is not absolurely linear, just as discharge rate and temperature stored is not absolutely linear. If its reactions like zinc-air cells (Zn(OH)4) where an oxidation reaction occurs for power, then self discharge rate will depend on how well you can seal air out from its environment.

[3] State of charge: IIRC someone suggested here that for NiMH rechargeables to maintain its capacity over long storage times it is best not to have the cells topped off but instead partially discharged [around 40%], which seems to suggest that discharge rate is a function of the cell's state of charge. For LiCoO2 cells [lithium-ion secondary] on the other hand appears to level around 4V/cell indicating a ~20% discharge state to minimize self discharge

As you may have seen, theres more than one kind of Lithium primaries discussed in this forum and several different secondaries as well. Each has its own charge/discharge chacteristics as well as voltage per cell and handling procedures. most cannot be used as an alternative to another's intended products. Aside from LiCoO2, theres also the LiMn2O4, LiFePO4, etc...so its very hard to quantify self discharge when it comes to the extraordinary differences in each respected fields of cells we collectively identify as "Lithium Rechargeables"

For single use batteries, chemistries is discussion would be inclusive of but not limited to: Zinc Chloride, Zinc-manganese dioxide (Alkaline), LiFeS2, LiMNO2, Mercury Oxide, zinc-air, Silver-sinc (zinc oxide)

Just the NiMH discussions on LSD is lengthy enough, and some of its proprietaries I do not yet understand. I'm not a chem major, I'm a user of these batteries just like you...I don't have any noteworthy credentials in this field to examplify my contributions despite my best intentions to summarize the complexities in a credible manner

I'm pretty certain after this is posted the battery experts among us [LuxLuthor, Mdocod, Silverfox...] will be off to their refridgerators to pick up eggs :duck:

 

[blinkjr]

Wow! I knew I would knowledgable answers, but this is great. lovecpf So, for the EagleTac T100C2 I'm getting I should either 1) use primaries as a matched pair and use them up (once turned on, use the flashlight until the batteries are done); or 2) get a good 18650 (or two) and a good charger (any recommendations other than the Pila IBC and the WF-139?) for edc use. Sound right?

And yes, I want to properly care and feed the 18650 . No in my house!

 

[JBorneu]

So, for the EagleTac T100C2 I'm getting I should either 1) use primaries as a matched pair and use them up (once turned on, use the flashlight until the batteries are done); or 2) get a good 18650 (or two) and a good charger (any recommendations other than the Pila IBC and the WF-139?) for edc use. Sound right?

Sounds about right. You don't have to use them up all in one run, but don't let them sit for half a year after they have been used a bit.

About 18650's: They are not very economical if you only use the light 2 or 3 times a year (li-ion cells usually don't last much longer than 3 years and for the price of 2 good 18650's and a charger you can get a nicel supply of surefire CR123's), but if you plan on using it often, then yes, they are the best solution for that light.
For a charger: the Pila IBC is the best plug and play charger, no doubt about it. The WF139 and the DSD charger are both pretty decent low-end chargers (meaning they won't blow anything up and charge your cells if your unit works correctly - cheaply made, not always sure, check it during the first charge) but they are not a perfect charger. another safe option is using a hobby charger, which is only useful if you plan on going a bit further with this hobby and getting lights with a lot of cells / exotic cell sizes / a lot of different chemistries.

If you don't know a lot about li-ion cells I'd advise you to read the link in my signature, it tells you just about everything you need to know to use them responsibly.