Hi,
How do the various rechargeable battery chemistries ("consumer cells") fare wrt long term storage in "less than ideal environments"? E.g., put some in such an environment, then try to use them (charge) at some later date and expect "reasonable" performance from them (not "ideal" -- goal here is to be able to NEGLECT them for long periods while still retaining
*some* usable capacity)
My guesses are lithium-polymer (with, probably, great variation from brand to brand), and sealed lead-acid.
I'm mostly going by gut feel, plus a little bit of experience as a 'lectric RC flyer who abuses his flight batteries horribly.
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
"consumer cells" -- e.g., AA, D, C, etc. (I can't recall ever seeing an SLA "AA" cell). Lithium< I htink, is too funky (cell voltage) for most COTS kit (at least, the sorts that have removable batteries)
What sorts of times are you willing to "ignore" them? E.g., a year or more at a stretch? (I'm looking to select cells for the devices in my bugout bag -- they don't need to RETAIN a charge but I'd like to be able to charge them when they are eventually *used*)
Eneloops, been using then ( and not) for the past few years. They are very good at holding a charge. Can't copare them to anyother chemistry.
Cheers
NiCd. NiMH suffer from discharge, but are good otherwise. Lead acid is terrible for surviving when left not charged.
NT
You'd have to define "long term" and "less than ideal."
If you mean "survive and retain the ability to accept a charge"
12 months, NiMH is fine.If you mean the same + "hold part of a charge," low self-discharge NiMH or LiIon (but they may die if you let them go flat).
I have ~100 10yr+ LiIon cells, still good, still hold a charge several years before the pack electronics drains them.
Dunno how LiPo's hold up--they might tolerate going flat better.
Cheers, James Arthur
Panasonic (was Sanyo) Eneloop. I think they only come in AA, but you can get spacers/shrouds/sabots for them to make them fit where a C or D cell would go. You want the plain old Eneloop, not the Eneloop Pro or Eneloop Light.
I have a set of 8 AAs (2000 mAh nominal) that I bought in early 2011, and they seem to do what they say on the tin when I use them in my digital camera. I have some other NiMH AAs; when I charge all my AAs periodically (about once every month or two), on the same charger, the Eneloops always take less juice to fill back up to 100% than the other NiMH batteries that have been sitting.
I usually store my Eneloops in the living area of my house. Sometimes I store them in a vehicle that is parked outdoors, but not for extended periods of time - not more than a week or so.
Other companies have introduced low-self-discharge NiMH since Eneloops came out, but I don't have experience with them.
You can get an SLA "D" cell, Enersys Cyclon. 2.5 Ah, 2.0 V nominal. It has tab terminals rather than a flat end and a bumpy end, though. They don't make them any smaller than "D" size. (These used to be made by Gates, then Hawker, then Genesis.) It doesn't solve your problem but it exists in the world. :)
Depending on the device, and how many cells you require for other purposes, it might not be insane to select alkalines, and then just swap them for new ones every X months (X > 3 or so). That's basically what I do for the portable radio I have. Most of the time I run it on the wall wart, but I also keep good D cells in it, which I end up replacing once every couple of years. I also have a couple of LED flashlights I run with alkalines.
Standard disclaimers apply: I don't get money or other consideration from any companies mentioned.
Matt Roberds
Presumably, this is about sealed lead-acid; liquid lead-acid, with the sulphuric drained for separate storage, has very good shelf life.
But that just reflects how well they hold charge. I don't care if they hold a charge -- I expect them to be "flat" by the time I use them.
What I am interested in is how well they will *accept* a charge, after having been in storage in a less than ideal environment (e.g., garage).
(And, of course, that assumes that they will hold that *new* charge for *some* useful amount of time :> )
E.g., the two 2/3AA NiCd's in my "crank radio" no longer accept a charge. But, I don't have to rely on them as the "crank" is an acceptable source of power. (I'm tempted to add a take off tap so I can use the radio to power other things of similar voltage)
These are for use in my bugout bag(s). I'd like to be able to just ignore them, in the garage, until I *need* (hopefully never) them. Then, have the cells *in* the devices contained in the bag(s) -- even if flat -- so all I have to do is recharge them just prior to use (solar charger, automotive battery, etc.)
OK. :>
The devices that see regular use, here (cameras, flashlights, etc.) typically use NiMH cells. I keep a couple of sets in a charger and just swap them out as need be.
I'd not be happy having to routinely empty the devices in the bugout bag (even yearly!) just because the cells lost the ability to *accept* charge.
(I also need to knock together a battery-powered battery eliminator :> for the times when the cells just *won't* hold a charge!)
Most long shelf life batteries are not rechargeable. For example, the sliver-oxide-zinc batteries used in torpedoes, zinc-air for hearing aids, and various "dry charge" batteries which are activated by adding electrolyte.
SLA/VRLA self discharge too quickly and need to be regularly topped off. You can leave them sitting around for a long time, such as in burglar alarm systems, but you can't run them down to total discharge and expect to have anything useable left when you try to recharge them.
Lithium-Ion sucks because it hates sitting around fully charged:
However lithium thionyl chloride will go for 10 years but is not rechargeable:
However, your rather odd description indicates that you wouldn't mind having the battery go completely flat after some unspecified time, as long as it were possible to successfully recharge it. Offhand, I don't know any rechargeable battery that fits that description. Those that I can recall will all corrode themselves into useless oblivion if left in a discharged state for too long.
For a tolerable compromise, I would recommend Eneloop NiMH, as others have suggested. Just don't let it drop to total discharge.
If you want more specific recommendations, kindly supply some numbers and specs as to times, capacity, discharge rate, charging method, environment, cost, etc.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
You can Always freeze Li-ion batterys to extend their life. I have a portable HDTV with a Li-ion or Poly battery that just sits in the freezer until its needed. I check it every year and after a thaw it charges fine.
Cheers
How about a super capacitor pile? The supercap pile can be discharged to zero and survive nicely. They self discharge fairly rapidly, but do meet the aformentioned criteria. They also lack energy density, so you'll need lots of them. Also, they're kinda pricy.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
As far as I can tell, one of the things that NiMH cells don't "like" is being stored at a low or zero state of charge. If you charge them to
100% before you store them, the low-self-discharge cells avoid this problem by not discharging themselves that far when sitting around.Sanyo/Panasonic claims 65%-70% charge retention after 5 years for late- model Eneloops. I don't *know*, but I *suspect* it's easier to get a NiMH cell to take a charge if it's been sitting around at 65% charge, than if it's been sitting around at 5% charge or less.
The first poster in this thread bought some Eneloop AAs that were new in August 2006 and sat until about December 2007, and he says they seemed to take a charge OK. Small sample size, earlier version of the product, disclaimer, disclaimer.
My experience so far is that you can't ignore rechargeable batteries, if you want them to be there for you later.
As a wise philosopher once said, "You can't always get what you want."
I sort of have that, in the form of a couple of automotive-12V to 3/4.5/
6/7.5/9 adapters. I can run those from the car, or from a couple of loose 12 V AGMs I keep around, or (if I have to) by stealing the AGMs out of my computer UPS.Matt Roberds
Ditto for SLA
Then it becomes a problem of deciding how long (and in which environmental conditions) they'll hold onto their charge "enough"
If it takes *longer* to take the charge, that's OK. If the 5% cell will never take more than a 50% charge, that's not quite as nice.
My concern is the garage as storage venue. I suspect it's never below
25C even in *winter*! And, even with an insulated door, it tends to get pretty warm during the other 11 months of the year! Batteries much prefer cold to heat.That's encouraging!
Yes. And, in most uses, they aren't left unused as most folks put them
*in* something that they intend to use. E.g., I have to periodically remember to drag out the GPS's and recharge them (as they rarely find any use).Yes, but I'd be happy to "get what you need"! ;-/
I figure I have to address three scenarios:
- shelter in place I've got all the kit in the BoB's available along with everything that's already in the house: UPS's for short term power; genset for longer term; propane and briquettes after that
- drive out Throw ALL the BoB's in the car (no time to see what *else* might be of use). Have car battery for short term power; engine/alternator for prolonged use
- walk out Carry the "bare essentials" on two (or one) back
I've tried to find items that run off 12VDC so the car battery option has more appeal (ditto batteries pulled from UPS's, etc). But, there are some (small) things that really prefer to operate on lower voltages, smaller cells (AAA), etc.
I considered keeping "fresh" (or "freshly charged") cells someplace "convenient". But, that's one more place to look, thing to retrieve (in an "emergency"?).
I also considered a harness for a modest SLA battery (12V). It could power any of the 12V devices -- via a tether. And, with a little switcher, even the devices that operate on ~6V. Not as convenient as having the batteries *inside* those devices. But, more compatible with the idea of using the car battery as a source in the drive-out and shelter-in-place scenarios.
Dunno. Of course, the underlying hope is that all of this is a colossal waste of time. OTOH, folks in NOLA probably wouldn't think so!
Also Tenergy Centura, the off brand version I believe. Probably others.
I have some in my camera: with infrequent use, they go for months without a charge. Way, way better capacity for infrequent use than the common "maximum capacity" (but horrific self discharge) NiMH.
Tim
-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
On a sunny day (Fri, 15 May 2015 02:14:51 -0500) it happened "Tim Williams" wrote in :
The Eneloops work, I have those in almost everything that takes AA or AAA. Charging is critical, if you charge too much the Ri goes way up and stays that way,. You need to monitor temperature really.
What so far surprizes me is LiFePO4. I got some like this (different seller):
Don't the Energizer lithium AA cells claim long shelf life?
I'd second the notion that rechargeables may not be the best choice if you REALLY, REALLY need them to work.
The whole idea of being prepared is to "be prepared".
Separate rechargeables from devices and recharge them periodically. Put lithiums in one flashlight so you can see to put rechargeables back into the other stuff.
Nickle-iron ("Edison" or "NiFe") cells are practically bomb-proof, some have been revived to full capacity after decades of lying around idle in all states of dischrge. They tend to be used for industrial emergency lighting and as float-batteries on D.C. supplies, so the cells are rather too large for your purposes.
It's a pity there aren't any consumer-sized versions for specialist applications.
-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
On Thu, 14 May 2015 19:56:12 -0700 Don Y wrote in Message id: :
Check out the page 2 of this pdf for SLAs
a) Why not let them go flat? Unscientifically, I've had new NiMH and NiCd cells flat for years and years. Most (80%?) worked fine. Dehydration through the seals seemed to be the main limiter--some types leaked and died, other mfrs lived 100%. (These were OEM AA cells, not consumer-branded.)
b) RayOvac has low self-discharge NiMH too, and they're quite good. They keep changing the product name though, so you have to look on the back of the package for the graph showing superior charge retention.
c) For a no-hassle BoB, ordinary alkaline primary cells now store for a decade, & lithiums store for two.
If Don really wants rechargables, LiIon (or LiPoly?), IME, could be left charged two or three years before needed attention, but exceed that, drop too low, and they go hi-z (they eat their own electrodes).
Cheers, James Arthur
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.