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Memory Effect Discovered In Lithium-Ion Batteries

samzenpus posted about a year and a half ago | from the a-little-less dept.

Power 157

rwise2112 writes "Lithium-ion batteries have long been thought to be free of the memory effects of other rechargeable batteries. However, this appears to be not the case. Scientists at the Paul Scherrer Institute PSI, together with colleagues from the Toyota Research Laboratories in Japan have now discovered that a widely-used type of lithium-ion battery has a memory effect."

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paywall derp (5, Informative)

SpaceManFlip (2720507) | about a year and a half ago | (#43453705)

shit's paywalled man, no good for Freedom Internets

Re:paywall derp (4, Funny)

Vanderhoth (1582661) | about a year and a half ago | (#43454319)

It's ok, No one here needs to read the article anyway. I kid of course ;)

No Shit (2, Insightful)

Anonymous Coward | about a year and a half ago | (#43453727)

This has actually been theorized for a long time by people that use Li-On batteries and have to charge them frequently. But they've been told 'nope impossible' by the people who make and research Li-On batteries the whole time. To me this is just like the pharmaceutical industry pushing the next opiate as 'non habit forming' and 'extremely safe' only to have it turn out even more addictive and deadly than the last iteration...time after time.

Re:No Shit (-1, Troll)

Anonymous Coward | about a year and a half ago | (#43453747)

Man ... living in your head must be terrible, in a world so full of daemons and enemies constantly conspiring against you. No wonder you are a bitter AC.

Re:No Shit (3, Informative)

kelemvor4 (1980226) | about a year and a half ago | (#43454147)

Man ... living in your head must be terrible, in a world so full of daemons and enemies constantly conspiring against you. No wonder you are a bitter AC.

To my knowledge, both his assertions are accurate. One of them is supported by TFA.

Re:No Shit (0)

Anonymous Coward | about a year and a half ago | (#43454555)

His other assertion is in regards to heroin in that it was suppose to be less addictive than morphine.

In case anybody was wondering.

Re:No Shit (0)

Anonymous Coward | about a year and a half ago | (#43455857)

or Oxycontin or dilaluid or...

Re: No Shit (1)

Anonymous Coward | about a year and a half ago | (#43456169)

...The cure to opiate addiction Suboxone (buprinorphine) has recently shown to be much more addictive and difficult to discontinue than many of the original opiates patients were on to begin with. FDA intervention required the manufacturer late last month to release its patent to two other companies so they may begin producing to keep up with the sudden onslaught of demand. For a drug meant to get people off drugs. Substituting one for another and making quite the profit as average cost is 250 USD for 30.

Just something I've come across in my work and a growing concern among my coworkers.

Re:No Shit (4, Informative)

thaylin (555395) | about a year and a half ago | (#43454401)

Well from the article it is possible to cause it to "forget" the memory so it is understandable why some people see it and others dont see it at the same time.

Re:No Shit (5, Interesting)

BitZtream (692029) | about a year and a half ago | (#43456143)

No one with any actual understanding of batteries said Li-Ion does not have memory.

What was said is that: From a practical perspective, Li-Ion memory is not an issue to worry about.

The article is basically someone who just did a study to confirm what probably every battery manufacture on the planet knew about Li-Ion at least 15 years ago. Longer I'm sure, I just have no experience before that.

What they did was took something they interpreted incorrectly, and then did a bunch of research to disprove some statement they misheard.

This is roughly like me telling you the surface of the earth is flat when you're building a small house, and then having a bunch of morons who overheard our conversion from 3 tables over do a study to determine that no, infact the Earth isn't flat. Of course its not flat, but from a practical perspective to the man building his home, its flat.

Re:No Shit (5, Interesting)

Tobia Conforto (2818827) | about a year and a half ago | (#43456225)

Yes shit. People who "use Li-On[sic] batteries and have to charge them frequently" are simply incurring in an unfortunate characteristic of Li-ion batteries, namely that they have a finite number of recharge cycles, or equivalently, that each recharge cycle diminishes the total charge the battery can hold.*

This has nothing to do with a memory effect.

For comparison, Ni-Cd batteries (as seen for example on power tools) have a strong memory effect, meaning that if you plug them in before they are exhausted, they "remember" the smaller capacity you've used them for, and it takes a number of complete discharge and recharge cycles to restore their full capacity. Of course, all that's needed to fully utilize Ni-Cd is a slightly more expensive charging circuit that fully discharges the battery before switching to recharging, which is why they are widely used in professional applications.

_____________
* Battery-savvy users always keep their mains plugged in on Li-ion devices such as laptops, so that the battery undergoes few recharge cycles and still performs as if it were new when they need it to, even after years of usage. But not after too many years, because Li-ion also have a limited timespan, or equivalently, the total charge they can hold diminishes every second since they leave the factory. Yes, it's a complex world.

Electric Cars (0)

Anonymous Coward | about a year and a half ago | (#43453731)

How will it affect Tesla & other mfgs using li-on as their battery system.

Re:Electric Cars (1)

viperidaenz (2515578) | about a year and a half ago | (#43455303)

It won't, because they're not using iron cathodes.

Re:Electric Cars (1)

WindBourne (631190) | about a year and a half ago | (#43456503)

Tesla uses a different chemistry, so this does not impact them. However, it WILL impact most of the others.

According to TFA... (0)

Anonymous Coward | about a year and a half ago | (#43453749)

Lithium-ion batteries actually have a worse memory effect than Ni-Cad batteries, exhibiting the change after just one partial-discharge/recharge cycle.

Small effect big consequences (4, Insightful)

geoskd (321194) | about a year and a half ago | (#43453753)

The question is: how big is the effect. Even a small effect will cause significant distortions in battery metering, but if the effect is large enough, it will cause the batteries not to last any where near as many cycles as originally believed. This could really suck for electric car owners. Any '07 Roadster owners out there care to share how well the batteries are holding up?

-=Geoskd

Re:Small effect big consequences (-1, Flamebait)

Gothmolly (148874) | about a year and a half ago | (#43453805)

You fail for signing your name to your post.

Re:Small effect big consequences (5, Insightful)

jeffmeden (135043) | about a year and a half ago | (#43453821)

The question is: how big is the effect. Even a small effect will cause significant distortions in battery metering, but if the effect is large enough, it will cause the batteries not to last any where near as many cycles as originally believed. This could really suck for electric car owners. Any '07 Roadster owners out there care to share how well the batteries are holding up?

-=Geoskd

According to what I could read of TFA without paying $32, the memory effect is actually seen just during discharge, as a function of distorting the voltage vs w/hr capacity. The overall w/hr capacity of the battery is not reduced, but the ability to exactly determine SOC is diminished at mid voltage levels.

I am not a chemist, so input from someone with more insight on the exact study would be appreciated.

Re:Small effect big consequences (5, Informative)

Anonymous Coward | about a year and a half ago | (#43454195)

Pretty accurate. They see a small deflection on what was commonly believed to be a smooth curve near the previous peak charge.voltage. It does not affect the overall charge capacity of the battery over time (what people commonly think about when "memory effect" is used), just the ability of the charge/lifetime remaining software to make accurate estimates.

For all examples shown, a user would be told they have significantly more charge remaining until near that point, then immediately after it would appear their predicted battery life would drop dramatically, and then it would stabilize again. It makes sense that this would be of keen interest to Toyota and other electric vehicle manufacturers.

If their graphs are as accurate, noise-free and reproducible as the figures lead the reader to believe... then the good news is, this effect can probably be accurately modeled and compensated for now that we know it exists. In that respect, it is a significant step forward for Li charge remaining prediction software.

Re:Small effect big consequences (1)

jtownatpunk.net (245670) | about a year and a half ago | (#43454503)

I wonder if that's why my G3 ibook battery shit the bed 2 days before I went on vacation that one time. I still got around 4 hours of runtime out of it (I'd checked a couple weeks earlier to be sure I didn't need a new battery) but the charging system suddenly refused to charge it. Of course, it was so old by then that I couldn't even pay full retail for one at the Apple store because they'd stopped stocking them a year or two earlier. I had to suffer without a battery through my vacation and ordered a replacement from Hong Kong when I got home.

Re:Small effect big consequences (0)

tbird81 (946205) | about a year and a half ago | (#43455481)

You could consider not paying the "Mac tax" for inferior hardware and poor support.

Re:Small effect big consequences (0)

Anonymous Coward | about a year and a half ago | (#43456269)

You could consider not paying the "Mac tax" for inferior hardware and poor support.

Is that how you rationalize not forking over the money for the best hardware and best applications in the computing world? (and a pretty good OS)

(Posting AC because I envisage an army of bitter nerds who rationalize in the same way)

Re:Small effect big consequences (3, Informative)

tibit (1762298) | about a year and a half ago | (#43454217)

Voltage monitoring should be just one aspect of charge determination. Properly done charge monitoring integrates the electrical charge actually delivered to or taken out of the battery -- as in taking the time integral of the current. The cell voltage should only used together with other indicators (cell temperature!) to determine each cell's health and charge/discharge endpoints (fully charged and fully discharged). The cell voltage should not figure in normal battery "% remaining" indications -- those solely base on the charge taken out of the battery, and the estimation of the 100% charge capacity.

Re:Small effect big consequences (0)

Anonymous Coward | about a year and a half ago | (#43454327)

The question is: how big is the effect. Even a small effect will cause significant distortions in battery metering, but if the effect is large enough, it will cause the batteries not to last any where near as many cycles as originally believed. This could really suck for electric car owners. Any '07 Roadster owners out there care to share how well the batteries are holding up?

-=Geoskd

According to what I could read of TFA without paying $32, the memory effect is actually seen just during discharge, as a function of distorting the voltage vs w/hr capacity. The overall w/hr capacity of the battery is not reduced, but the ability to exactly determine SOC is diminished at mid voltage levels.

I am not a chemist, so input from someone with more insight on the exact study would be appreciated.

Actually, it's seen during charge -- discharge proceeds normally, so determining SOC from voltage during discharge is just fine.

Also, please stop saying w/hr when you mean Wh. If you must use busted units, at least use whr, w*hr, or some such notation -- it's multiplication, not division, so there's no sense putting a / there!

can be fixed with software change (1)

Chirs (87576) | about a year and a half ago | (#43453999)

According to the first link the issue can be fixed with a software change, and can also be worked around by a full discharge followed by letting the system rest. Doesn't say how long a rest is needed though, depends on the implementation I suspect.

Re:Small effect big consequences (5, Informative)

Anonymous Coward | about a year and a half ago | (#43454289)

The question is: how big is the effect. Even a small effect will cause significant distortions in battery metering,

True, and this is what is seen.

but if the effect is large enough, it will cause the batteries not to last any where near as many cycles as originally believed.

Rubbish. It doesn't diminish the battery's capacity, just changes the q-v characteristic DURING CHARGING. Even if it were a large effect, it's still not going to effect total capacity, or estimating remaining charge by measuring voltage during discharge.

Notes regarding this:
1. This effect is shown in LiFePO4, which is commonly marketed as a "safe" chemistry Li-ion. Laptop and mobile phone batteries almost universally use LiCoO, which is not, AFAIK, addressed in this research. The Tesla Roadster also uses either LiCoO or LiMnO (I've seen conflicting reports -- probably because these two have similar electrical characteristics -- and both have much better energy density than LiFePO4), so your plea to Roadster owners seems a little odd...
2. This effect is caused by starting with discharged battery, charging partially (greatest effect for charging ~50%), discharging completely, then recharging completely. During the final (complete) charge process, the voltage starts at baseline (i.e. full-discharge/full-charge cycle, at the same % charging), increases slightly faster than baseline, so that the voltage difference over baseline peaks at 50% (or whatever state you partially charged it to), then increases more slowly than baseline to arrive at the same voltage when fully charged -- so capacity measured while charging will be overestimated. On the subsequent discharge, however, the q-v characteristic conforms to the baseline -- so capacity remaining will be measured accurately when a device is in use.

Re:Small effect big consequences (1)

bluefoxlucid (723572) | about a year and a half ago | (#43455275)

The real question is: is the effect real? NiCd and NiMH batteries don't actually have a memory effect; that's not a real thing, it's just folklore.

NiCd batteries, for example, experience a memory effect if discharged to the same exact level +/- 3% repeatedly MANY times, where the output voltage is not below roughly 1.0V, and the maximum charge is below or exactly 100%. If the batteries are charged with full overcharge or the level of discharge between charges varies by more than 3% or goes below 1.0V, memory doesn't happen at all in any way. Laboratory conditions. Essentially, a memory effect on a NiCd isn't a real thing; you'll never get there without sensitive metering equipment and very deliberate action.

Re:Small effect big consequences (0)

Anonymous Coward | about a year and a half ago | (#43456175)

I kind of wish that you had provided the NiMH example, because my first thought was, "I bet my camera shuts itself off at about the same voltage every time." Also, wireless game controllers are probably fairly consistent about how low they will go, so I would suggest that the number of batteries which see repeated discharges to the same level is, well, a big number.

Re:Small effect big consequences (0)

Anonymous Coward | about a year and a half ago | (#43456311)

Back when I still had a wireless mouse, I used NiCd and NiMH batteries, and both do have memory effects. At first the battery would last weeks but after a while a battery would last less than a day and would need to be replaced. This was using a standard battery charger with built-in discharger. But I guess an optical wireless mouse qualifies as sensitive metering equipment.

Re:Small effect big consequences (3, Informative)

wildsurf (535389) | about a year and a half ago | (#43455405)

Any '07 Roadster owners out there care to share how well the batteries are holding up?

My '08 Roadster (there are no '07 roadsters) has 33k miles on it, and after 4 1/2 years, its battery capacity has been reduced about 8%. I now get 225 miles on a full charge, down from 244 on day 1. That's even better than Tesla's initial projections, actually.

Re:Small effect big consequences (1)

BitZtream (692029) | about a year and a half ago | (#43456047)

Thats because you aren't driving it. You're basically treating the batteries in the ideal way judging by time and milage. You'd probably get slightly worse than that if you didn't drive it at all.

Tesla doesn't use LiFePO (1)

YesIAmAScript (886271) | about a year and a half ago | (#43455673)

And besides that, if you look at the charts, this doesn't cause a loss of capacity, even an apparent loss of capacity. Instead the voltage just reads high during charging. It appears it can foul up capacity remaining estimates, but not actually change the capacity remaining.

Re:Small effect big consequences (0)

Anonymous Coward | about a year and a half ago | (#43455681)

Any '07 Roadster owners out there care to share how well the batteries are holding up?

Well, the Roadster came out in '08 not '07. But mine has over 80,000 miles on it now. My range seems around 90% of what it was when it was new.

The Roadster batteries are Lithium-Cobalt, though. The article was about Lithium-Iron-Phosphate (like the Volt).

Graphs in linked article show minor effect (2)

WillAffleckUW (858324) | about a year and a half ago | (#43453781)

In the source article, I notice it's only about a 4 percent total effect on total charge.

So, while not "no memory effect" it's not as bad as the impacts on the other types of battery storage.

Even storage devices like compressed air (PHES) for wind and solar PV systems have only a 70 percent efficiency, so it's still way better than that.

And that type of battery is.... (4, Informative)

DigitAl56K (805623) | about a year and a half ago | (#43453801)

LiFePO4.

Cliffhangers in the summary now?

Re:And that type of battery is.... (4, Interesting)

afidel (530433) | about a year and a half ago | (#43453845)

And I wouldn't call LiFePO4 "widely used", it's hardly used at all in the west due to extremely high royalty rates charged by the patent holders. I'd actually love to use LiFePO4 cells for my camping solar setup but the only ones I can find are dodgy Chinese imports with questionable charge controllers.

Ping Battery (2)

Slashdot Parent (995749) | about a year and a half ago | (#43454243)

I'd actually love to use LiFePO4 cells for my camping solar setup but the only ones I can find are dodgy Chinese imports with questionable charge controllers.

I can't really vouch for their quality because I am far from a battery expert, but Ping Battery [pingbattery.com] is very highly respected among DIY electric bicycling enthusiasts.

Definitely place them in your category of "dodgy Chinese imports", but anyway they're considered to be very reliable among that particular category!

Re:And that type of battery is.... (1)

UberChuckie (529086) | about a year and a half ago | (#43454261)

LiFePO4 batteries are starting to be used in motorcycles. I have a Shorai branded one in one of my bikes. Compared to a conventional lead-acid battery, it is smaller and much lighter. It also has a very limited self-discharge rate which means I don't have to charge the battery when the bike is stored during winter. I do disconnect and bring inside the battery due to the cold weather and parasitic draws.

The downsides that I knew about are that they don't work as well in colder weather and they're not compatible with all battery chargers. Battery chargers with a de-sulphate mode cannot be used.

I wonder what the impact of this discovery is on motorcycle uses. The battery is really only discharged when the starter is engaged. The rest of the time, the alternator is keeping the battery charged and whatever parasitic draws when the bike is parked is minimal.

Re:And that type of battery is.... (2)

Rich0 (548339) | about a year and a half ago | (#43455609)

I'd actually love to use LiFePO4 cells for my camping solar setup but the only ones I can find are dodgy Chinese imports with questionable charge controllers.

Hey, they could come in handy if you ever run out of tinder and kindling!

Re:And that type of battery is.... (2)

afidel (530433) | about a year and a half ago | (#43456021)

I've used the 9V and pot scrubber trick to start a fire when both my lighters failed on a camping trip (I wasn't going far enough away from society to pack the parafin encased bluetips which are my backups when my life depends on fire).

Re:And that type of battery is.... (1, Interesting)

GameboyRMH (1153867) | about a year and a half ago | (#43453935)

Which is actually a very uncommon form of li-ion battery. Military drones use it, the batteries are taken out of service after just a few charge cycles.

Re:And that type of battery is.... (1)

hey! (33014) | about a year and a half ago | (#43456297)

Thanks for spoiling the story for me. Now I guess I'll have to read something else.

Wrong description (5, Informative)

folderol (1965326) | about a year and a half ago | (#43453815)

I do wish people would stop calling it a 'memory effect'. It's probably the least descriptive term your could apply.

I don't know about Lithium batteries but NiCad cells exhibit a second plateau which gradually gets more difficult for the charge system to punch through. The usual cure is a couple of heavy charge/discharge cycles.

Don't think I want to try that with Lithium though!

Re:Wrong description (1)

thaylin (555395) | about a year and a half ago | (#43454485)

Actually it is very descriptive. It remembers the last charge cycle and begins to memmic it which is different from the system just plateauing.

GODDAMNIT DURACELL (0)

Anonymous Coward | about a year and a half ago | (#43453823)

Fuck you, Rabbit!!!

Re:GODDAMNIT DURACELL (1)

noh8rz10 (2716597) | about a year and a half ago | (#43453895)

umm, the rabbit was energizer. Still going! nothing outlasts energizer.

Re:GODDAMNIT DURACELL (1)

Anonymous Coward | about a year and a half ago | (#43453987)

nope, it was first introduced by Duracell and then re-used by Energizer, and only in the US at that. In Europe we've only had Duracell's.

Re:GODDAMNIT DURACELL (-1)

Anonymous Coward | about a year and a half ago | (#43454199)

nope, it was first introduced by Duracell and then re-used by Energizer, and only in the US at that. In Europe we've only had Duracell's.

See, the problem is that you're European. Europeans are all faggots who suck each other's dicks and take a nice shot of cream up the ass (properly stretched, of course).

Re:GODDAMNIT DURACELL (2)

Vicarius (1093097) | about a year and a half ago | (#43454083)

http://en.wikipedia.org/wiki/Duracell_Bunny [wikipedia.org]

The Duracell Bunny campaign was launched in 1973 and predates the Energizer Bunny, which was created in 1989.

Re:GODDAMNIT DURACELL (1)

noh8rz10 (2716597) | about a year and a half ago | (#43455011)

from your link:

In Europe & Australia the term "Duracell Bunny" has entered the vernacular as a term for anything that continues indefatigably while in North America the term "Energizer Bunny" has a similar connotation.

Never heard of the duracell bunny, so I guess it's a US/EU thing. this is one of the biggest dichotomies on slashdot, not apple/google/MS. Speaking of dichotomies, US Customary Units 4evah!

Laptop batteries, anyone? (4, Interesting)

toygeek (473120) | about a year and a half ago | (#43453831)

I've always wondered why they say that Lithium Ion and Lithium Polymer batteries don't have a memory effect, when even laptop batteries based on those technologies die after several years, and NOT because of charge cycles. I'm talking about the ones that stay plugged in most of their lives, charging. Maybe its the lack of charge cycles that kills them? But to say Lithium batteries have no memory effect has always been ludicrous to me.

Re:Laptop batteries, anyone? (1)

Anonymous Coward | about a year and a half ago | (#43453885)

Batteries should be stored in a cool location. Keeping a battery in your notebook for long periods of time when running off of AC subject it to high temperatures and a shortened lifespan.

Re:Laptop batteries, anyone? (2, Interesting)

Anonymous Coward | about a year and a half ago | (#43454067)

"
Batteries should be stored in a cool location. Keeping a battery in your notebook for long periods of time when running off of AC subject it to high temperatures and a shortened lifespan.
"
Nope, that's not the reason.

Typically, a new laptop owner does the following.
Buy new laptop
Install battery (if it's not already)
Place on desk.
Plug in to AC power.
Use for 5 years or less, and never move it from that spot.

In other words, the battery is NEVER used.
I've seen it personally with the last 3 business laptops I've had (hp, lenovo, dell) as well as the past four personal laptops i've sold to people. Those that actually use the battery down to zero at least once a month? Batteries last forever.
Batteries never actually used, but the laptop runs on AC power with the battery sitting there doing nothing? 100% of them will not hold a charge of any kind after 12 months of this "non-use".

Back in the 90's, there was Windows (3.11, wfw, NT, win95, win98) software available to exercise the battery while it was plugged into AC power. Such software allowed even ni-cad's to last for years without developing "memory" or losing run time. It allowed you to schedule a full discharge of the laptop battery weekly or monthly. Such software was also available for UPS's at the time. (Remember those UPS's that actually would run a computer for hours instead of minutes, yeah, those ones)

Since then, all such software has disappeared, and what do we have? Completely useless batteries in both laptops and UPS's, in under a year.

It's the same trend as printers and power tools. Consumables must cost more than the original unit and/or fail every year, minimum. Inkjet cartridges? Check! Power drill batteries? Check! Color laser printer toner? Check! Laptop batteries? Check!
When things in the PAST are worse than things in the PRESENT, and they perform the same task, it's not the advancement of technology that is to blame.
It's sociopath-run businesses wanting to turn everything into a service with an annual fee. Go-go-gadget free market consumerism!

My personal experience with laptop batteries has been that if they are fully/completely discharged to zero at least once a month, they last forever, regardless of all other usage patterns, elevation, humidity, temperature, make, model, or cell count.

Re:Laptop batteries, anyone? (1)

Anonymous Coward | about a year and a half ago | (#43454173)

I've seen it personally with the last 3 business laptops I've had (hp, lenovo, dell) as well as the past four personal laptops i've sold to people. Those that actually use the battery down to zero at least once a month? Batteries last forever.

That's true for older technologies, but not true for lithium-ion. They will lose capacity no matter what you do. They'll lose it faster when fully charged and at higher temperatures, but they'll always lose capacity.

Re:Laptop batteries, anyone? (1)

mikael (484) | about a year and a half ago | (#43454313)

The battery is used. If there's a power blackout, the laptop keeps on going. The desktop, DVD player, cable box, satellite box, and plasma TV have all gone out and go back into their respective boot-up sequences.

Re:Laptop batteries, anyone? (1)

Immerman (2627577) | about a year and a half ago | (#43454345)

What? AC is completely correct, and you failed to even address their comment in any meaningful way, except that, yes, I too have noticed occasional deep cycling seems to help preserve battery capacity.

Heat deteriorates li-ion batteries - and being in a laptop with a cpu, HD, etc all running at max because they're on AC subjects them to lots of heat.

Being held at 100% charge also wears out li-ion batteries, there's a reason that a Prius strives to keep it's batteries between 40 and 60% charged most of the time, the further you get from half-charged the faster the battery degrades, and those suckers are under warranty.

My latest laptop battery has held a far more stable capacity since I adjusted the power settings to stay in battery-saving mode even when plugged in to AC, I rarely need the extra performance anyway, and can adjust the settings on the rare occasions when I do. As an added benefit the decreased heat and fan noise is more pleasant for me as well as for the battery. I just wish there was an option to not charge it beyond maybe 80% under normal circumstances.

Re: Laptop batteries, anyone? (0)

Anonymous Coward | about a year and a half ago | (#43454477)

my cheap crappy atom net book has an option to not charge beyond 80%. On the other hand it does need all the performance I can wring out of it...

Re: Laptop batteries, anyone? (1)

Immerman (2627577) | about a year and a half ago | (#43454897)

Seriously? Sweet! What brand? I may have to look to them next time I need a rechargable gadget of some sort.

Re: Laptop batteries, anyone? (0)

Anonymous Coward | about a year and a half ago | (#43455799)

I know at least the Samsung Series 5 Ultrabooks have that.

Re:Laptop batteries, anyone? (4, Interesting)

Maximum Prophet (716608) | about a year and a half ago | (#43453943)

With any battery technology, it's almost never the "Memory Effect", but simple overcharging. If your laptop batteries are always hot just sitting there when the laptop is plugged into the mains, they won't last as long as ones that are properly charged and left alone until they are needed for discharge. With cheap cordless drills and other tools, simple putting a timer on the charger will greatly increase the number of cycles you can get out of the batteries.

Re:Laptop batteries, anyone? (1)

sunking2 (521698) | about a year and a half ago | (#43454063)

The overall Works Like Crap Effect is still the same for the consumer. Semantics of the cause doesn't make the user any better off.

Re:Laptop batteries, anyone? (1)

Anonymous Coward | about a year and a half ago | (#43454301)

I'll put it simply the designers are too cheap to simply put a timer circuit/code in place to stop charging the damn battery because it's already as charged as it's going to be....

Re:Laptop batteries, anyone? (2)

The Wannabe King (745989) | about a year and a half ago | (#43454249)

High battery temperature and a high state of charge is a killer combination for Li-ion batteries. This is exactly what happens in a laptop that is plugged in and running. An electric car, on the other hand, usually avoids this. My Nissan Leaf charges to 80 % SOC, unless I explicitly ask it for a full charge, and even then it will not allow the batteries to reach the real 100% SOC. (Just like the batteries aren't really empty at 0 % SOC.) The advice is not to leave the batteries at full charge for more than a few days, and preferably only a few hours. The Leaf does not have active cooling (but the Model S has) which is not a problem in most climates. The batteries are still cooler than the laptop batteries that are stacked next to the CPU, at least in my laptop. The exception here is Arizona, as some Leaf owners have been unfortunate enough to discover. No problems after 21 000 km in Norway, though... there is still snow on the lawn!

Re:Laptop batteries, anyone? (0)

Anonymous Coward | about a year and a half ago | (#43454315)

So why don't the charge controllers handle this? Would it be that much more expensive? Do the designers want the battery to fail earlier so they can sell a replacement?

Re:Laptop batteries, anyone? (2)

tibit (1762298) | about a year and a half ago | (#43454321)

With modern charge controllers, there is no overcharging of any sort -- a charged battery pack is not being charged anymore, that's it. Only after it self-discharges a bit -- enough so that it's detectable -- will it be topped up. The problem you have of course is that the battery pack is still treated as a whole and while charge controllers in mobile device battery packs will detect voltage on individual cells, still very few have the electronic bypass switches needed for cell charge equalization and cell bypass. Never mind that most power supplies are not designed to properly work with a battery that has a dead cell in it -- even if it's entirely technically feasible.

Re:Laptop batteries, anyone? (2)

Ecuador (740021) | about a year and a half ago | (#43454079)

I don't see how plugged-in laptop batteries dieing has anything to do with a memory effect. Lithium-Ion batteries when stored lose capacity depending on how much they are charged and how high the temperature is. At the relatively high temperatures of a laptop and kept at near 100% charge they can lose as much as 40% capacity per year. This is a known fact and has nothing to do with what is called memory-effect. The summary talks about a specific (and not widely used as I understand it) kind of Lithium battery which has a memory effect (in addition I assume to the effect I described that kills Li-Ion batteries).
If you want to make sure your Li-Ion batteries won't go bad, when you don't use charge (or discharge) them to 40% capacity and put them far from heat.

Re:Laptop batteries, anyone? (3, Informative)

Firethorn (177587) | about a year and a half ago | (#43454159)

Okay, first up let's define memory effect: Memory effect is NOT a battery dying. Memory effect is the tendency for a battery to stop charging/discharging at a set level if you regularly fail to completely charge/discharge it. It develops a 'memory', and thus falsely acts as though it's fully charged or discharged before it actually is.

While this can ruin a battery, a number of techniques have been developed to rehabilitate such batteries to restore full function.

However, batteries don't just wear from charge/discharge cycles. They age over time as well. Alkaline and Lithium primary cells are especially resistant to this, but until very recently LiIon rechargeable cells were very, very vulnerable to this, losing 10% or more of total capacity just sitting on a shelf in a cool warehouse at 70% charge(the ideal situation for them).

Sitting in a hot laptop being kept at 100% is much worse than ideal, you could be losing 30% or more per year in that scenario.

Re:Laptop batteries, anyone? (1)

mybecq (131456) | about a year and a half ago | (#43454365)

being kept at 100% is much worse than ideal

This is at the heart of my laptop battery experience. My laptop is rarely off AC power. When I had the charger set to stop charging at 100% (and to recharge when 90%), my battery life greatly improved. OId battery dropped 60% in reported capacity in less than 2 yrs; new battery is barely down 30% in the following 4 years.

I call it Chinese electron torture for your battery -- drip, drip, drip.

Re:Laptop batteries, anyone? (1)

Firethorn (177587) | about a year and a half ago | (#43455719)

The new battery might be using the improved technology as well, but you'd probably save even more life if you can set the charger to recharge at 60% and stop at 80%.

After that it's a fight against heat. Keep the battery under 70F and you'll slow it's degradation even more.

Then again, 30% in 4 years might be slow enough for your purposes.

Re:Laptop batteries, anyone? (2)

tibit (1762298) | about a year and a half ago | (#43454257)

The problem with most batteries is that the designs are cheap and the cells are not individually controlled with bypass switches. Then you have a pack with just one bad cell and the whole pack is "bad". All the rechargeable battery pack failures I've seen were of this kind: one weak cell with all the others having lots of life in them. The bad cell issue is self-exacerbating: as soon as a cell has higher internal resistance than the others, it will always get overcharged and over-discharged, accelerating the deterioration that leads to further raise of internal resistance.

Re:Laptop batteries, anyone? (1)

bluefoxlucid (723572) | about a year and a half ago | (#43455399)

Holy shit someone is wrong on the Internet.

Each cell supplies a certain amount of voltage. Lead-acid, carbon-zinc, and alkaline batteries supply 1.5V per cell. Remove a cell and the voltage potential drops, which plays hell with electronics not ready for that big of a fluctuation. For example, when a car battery loses a single cell, it usually can't start the engine--it definitely can't when it's cold. Sensitive electronics may have some very odd issues with different input voltages. It's possible to compensate--worksite CD players run on 12.5-24V battery packs (as in the same exact model has ports for any of these and will compensate with fancy integrated circuitry). Usually computer equipment is prepared for this over a 5% deviation.

Re:Laptop batteries, anyone? (0)

Anonymous Coward | about a year and a half ago | (#43454409)

First, laptops don't use LiFePO4 which this paper concerns, so GTFO.

Second, not every form of battery deterioration is "memory effect", so you're full of horseshit. Educate yourself, then you'll understand what's going on. (Hint: laptop batteries mostly die because of because you're roasting them alive in a hot laptop.)

Re:Laptop batteries, anyone? (1)

jittles (1613415) | about a year and a half ago | (#43454551)

I've always wondered why they say that Lithium Ion and Lithium Polymer batteries don't have a memory effect, when even laptop batteries based on those technologies die after several years, and NOT because of charge cycles. I'm talking about the ones that stay plugged in most of their lives, charging. Maybe its the lack of charge cycles that kills them? But to say Lithium batteries have no memory effect has always been ludicrous to me.

Actually overcharging your Li-Ions and Li-Pos is bad news. It shortens the life of your battery. You can't trickle charge them, so as you use the device plugged in, the battery discharges to some threshold, where the battery controller starts charging it again. So even if you leave it plugged in 24x7, if the battery is plugged in, it will discharge and then recharge at some frequency.

Re:Laptop batteries, anyone? (1)

bluefoxlucid (723572) | about a year and a half ago | (#43455345)

Leaving a lithium battery plugged in all the time while in use is actually the best way to damage it and shorten its life span :)

anybody with an iThingie can tell you that (0)

swschrad (312009) | about a year and a half ago | (#43453891)

and I wish you didn't have to hack your way in to replace them.

Re:anybody with an iThingie can tell you that (-1)

Anonymous Coward | about a year and a half ago | (#43454139)

ZomG!!!!? An Apple bash?
 
You sir deserve a cigar for such a feat! You're the shit. No... really, you are. Thanks for bringing your fantastic insights to the table. It's people like you who really make Slashdot worth coming back to.

Re:anybody with an iThingie can tell you that (0)

Anonymous Coward | about a year and a half ago | (#43454231)

and I wish you didn't have to hack your way in to replace them.

lol! Opening iCrap to replace a battery is not hacking. I guess I can understand why an apple user would think it is.

Re:anybody with an iThingie can tell you that (0)

Anonymous Coward | about a year and a half ago | (#43454679)

I dont know. I have had my iphone 4 for around 3 years now and the battery still is good. Even though I mostly get partially charged two times a day to and from work, when I use it as GPS.

Re:anybody with an iThingie can tell you that (0)

Anonymous Coward | about a year and a half ago | (#43455187)

Back when I was in my 20's, unscrewing a device, and lifting a battery to replace it wasn't considered "hacking"...

Ha ha... (1)

UltraZelda64 (2309504) | about a year and a half ago | (#43453903)

It pays to charge your batteries based on your instinct and tradition "just in case" instead of just believing and falling for claims that are only to be proven false later...

Well, I'm set, because I always let my phone nearly die before charging it. That's sure as hell not gonna change now.

Re:Ha ha... (1)

ledow (319597) | about a year and a half ago | (#43454037)

Nice. Because that's the worst thing to do to a Lithium-ion, for example.

Re:Ha ha... (0)

Anonymous Coward | about a year and a half ago | (#43454123)

Seriously? My dad has used the same Li-Ion drill every day at work for over 2 years and only charges it when it's dead. Still runs like the day he bought it, he says. It should be noted that he does not baby his tools, and for anything to last him 2 years is an achievement, let alone a battery.

Re:Ha ha... (0)

Anonymous Coward | about a year and a half ago | (#43454183)

Correct, that's how you should use them if you want them to last forever, regardless of type (ni-cad, ni-mh, li-ion, li-po).

Use it till it's dead, regularly, and it will work just fine forever. I have found this to be true, personally, for 20 years.

Re:Ha ha... (1)

tibit (1762298) | about a year and a half ago | (#43454339)

I have a Makita LXT drill and screwdriver and I've been beating the crap out of them, running the batteries down each time until the performance drops low enough to make me have to switch. No problems so far, even though I've had them 3 years or so. I'm drooling for the new brushless versions, but seriously I have no reason at all to replace what I have -- they work great in spite of using brushed DC motors.

Re:Ha ha... (1)

Immerman (2627577) | about a year and a half ago | (#43454429)

Are you sure? I thought it was letting them *totally* die that was a problem. I've noticed deep-cycling them (to 10%) occasionally, maybe once every month or two, seems to do them good, not that I've done any rigorous testing, just noticing how changing behavior patterns seem to affect them.

Of course the biggest benefit was when I disabled "maximum performance mode" when connected to AC. Battery-saver mode gives me plenty of performance 99% of the time, and the lack of lap-roasting heat and a roaring fan during normal use does both me and the batteries a world of good.

Re:Ha ha... (0)

Anonymous Coward | about a year and a half ago | (#43455245)

that was ni-cad.

Re:Ha ha... (1)

UltraZelda64 (2309504) | about a year and a half ago | (#43454711)

Nice. Because that's the worst thing to do to a Lithium-ion, for example.

You tell that to my phone, which after a full year and a half is still capable of running as long as it could when I bought it. Actually, it was lasting a day or less when I first bought it (largely due to a battery-guzzling bug that I found out how to solve), but now a whopping seven days. Lots of tweaks to reduce power draining too, but it's still running the same stock OS on the same battery it came with.

By comparison, many of my friends leave their laptops and cell phones plugged in 100% of the time there in a nearby outlet... and then after a few months to a year they're having battery problem. It seems that the old "use down to 5-1% power before fully recharging" trick couldn't be working any better. Only rarely does the battery go 100% dead--I figure as rare as that in anyway, it can't hurt anything.

Re:Ha ha... (1)

viperidaenz (2515578) | about a year and a half ago | (#43455159)

The worst thing you can do to a lithium ion battery is to leave it fully charged. That's the quickest way to wear it out. (aside from the obvious over charging and over discharging)

Re:Ha ha... (1)

bluefoxlucid (723572) | about a year and a half ago | (#43455411)

The worst thing to do with a Li+ battery is to keep it fully charged.

No shit Sherlock (0)

Anonymous Coward | about a year and a half ago | (#43454001)

This should have been listed as "from the no-shit-Sherlock dept." I, and numerous others, have been saying for years that all those claims that li-ion batteries don't suffer from memory effect are bullshit. The aftermarket laptop battery market would be almost non-existent otherwise.

Re:No shit Sherlock (2)

Immerman (2627577) | about a year and a half ago | (#43454483)

Degradation with time and usage != memory effect. Memory effect is a specific kind of degradation due to partial charging or discharging. For example if you recharged a NiCd battery that was only down to 50% charge you would immediately and permanently reduce it's total capacity, hence the tendency of those "in the know" to drain the batteries completely before recharging them.

DUH! I Could Have Told You That! (0)

Anonymous Coward | about a year and a half ago | (#43454185)

Any consumer could have told you that!!! If you haven't noticed your lithium batteries not lasting, not holding a charge then pinch yourself and put down the crack pipe!

Re:DUH! I Could Have Told You That! (1)

viperidaenz (2515578) | about a year and a half ago | (#43455077)

There's a difference between the memory effect and the battery wearing out. It is known that a lithium battery will wear out. They even wear out while in storage. Especially when warm and fully charged.

Just in: Rechargable batteries suck! (0)

Anonymous Coward | about a year and a half ago | (#43454225)

I don't think I've ever owned a rechargeable battery (of any chemistry) that lasted even 10% of the claimed recharge cycles.

Why aren't rechargeable batteries real world tested by a hard core standards body that kicks battery makers in the nuts and berries when 'ideal lab conditions' don't measure up to actual usage?

Re:Just in: Rechargable batteries suck! (1)

BitZtream (692029) | about a year and a half ago | (#43455859)

Because you're treating your batteries like shit.

Lead Acid batteries (like you car battery) are pretty fucking hard to kill outside of the environment your car subjects them too (heat is a bitch), even that, how many times have you warranty replaced your car battery?

NiCads are relatively resilient. You can certainly hurt them, but you have to do 'known bad' things that every manual and charger label probably has written on it. Don't drop them below 1.2v per cell, keep them cool during charging (heating means you're doing it wrong). I've had high quality packs for my R/C cars last 5 years. First year as 'race' packs, then the next several as warmup/fun packs. You're talking 250-500 charge cycles of extremely harsh use. That is at least 10% of the nicads expected life under what most would consider some of the harshest possible conditions for the batteries to be in. High current discharge while basically laying on an asphalt road way in the Florida sun, to be immediately thrown back on a charger for the next round without letting it cool or anything. Not even needed to memory cycle the batteries, my usage patterns were so harsh they didn't have the time to build up memory before they were shot anyway.

My previous laptop was an amazing example of excellent battery in my eyes. I retired it in the middle of last year, almost exactly 3 years to the day after purchase and it was used from full charge to nearly depleted extensively during that period as my workstation. I admit, towards the end it was getting short, but certainly well past the 80% at 400 cycles. My wifes laptop on the otherhand won't hold a charge for shit and its only 2 years old! Of course, its been sitting with a charge connected to it for its entire life time, which is a horrible thing to do to a Li-Ion.

Forget the batteries... (1)

MugenEJ8 (1788490) | about a year and a half ago | (#43454507)

I need science to figure out why my significant other has these 'memory issues' -- I'd like to win at least one discussion in my life...

Discombobulating multiple issues (2)

WaffleMonster (969671) | about a year and a half ago | (#43454943)

First of all of LiFePO4 are not commonly used in any of our portable gadgets.

Second memory effects we are seeing in our gear are illusions based on memory effects in the electronics that help figure out capacity. Deep cycling lion batteries works to clear these effects as what you are actually doing is resetting the "gas gauge" to synchronize with reality of the battery.

Re:Discombobulating multiple issues (1)

BitZtream (692029) | about a year and a half ago | (#43455909)

First of all of LiFePO4 are not commonly used in any of our portable gadgets.

Lithium Ion != Lithium Iron ... i.e. WTF are you bringing up LiFe for? Not part of this conversation.

Second memory effects we are seeing in our gear are illusions based on memory effects in the electronics that help figure out capacity. Deep cycling lion batteries works to clear these effects as what you are actually doing is resetting the "gas gauge" to synchronize with reality of the battery.

Actually, you have that backwards.

The batteries have degradation. The electronics are wrong because they remember capacity based on the charge/discharge cycle of the battery when it was new. Over time it degrades, this is not memory, its just degradation ... wear. When you 'deep cycle' the battery, all you are doing is allowing the device to actually see how the battery is currently performing rather than how it was expected to perform a hundred charges ago.

'Deep cycling' won't fix the issue and make your battery last longer suddenly. It will just cause the gauge to understand that your battery is no longer new and is now rather shitty indeed.

Pitty A123 died then eh? (1)

viperidaenz (2515578) | about a year and a half ago | (#43455033)

Tell me when there is a problem with cobalt lithium batteries.

Memory free batteries don't exist (3, Insightful)

BitZtream (692029) | about a year and a half ago | (#43455727)

And I expect never will. All batteries have various flavors of memory. The only question is, does the memory effect cause enough of a problem to make it worth addressing the issue to extend battery life.

You worry about memory in a NiCad because the process that causes the memory is easily reversible (partially), and the battery itself is still functional.

If the memory effect of Li-Ion only effects ... say 1% of the total capacity before the rest of the chemical processes break down and cause the battery to 'wear out' than it has memory, but from a practical perspective the memory is irrelevant.

There are all sorts of batteries that would appear 'memory less' at first glance, but thats only cause they are so shitty in other ways that you don't get to the point of noticing the processes that cause memory to start happening.

Until a battery is 100% energy efficient, its going to have memory, so never.

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