higher cap Li-ion batteries

Sony is releasing higher capacity li-ions.
news item is here
Look in particular at the currents obtained with the 18650's, at the bottom of the article /ubbthreads/images/graemlins/cool.gif


Olivier

Interesting. I still have yet to see any compelling advantages to Li-ion over NiMH other than the higher voltage (and even this is almost moot with ultra cheap step-up regulators readily available). Sony's AA Li-ion has a capacity of 830 mAh which works out to an energy capacity of 3.07 watt-hrs. The best NiMH cells have a capacity of 2500 mA which gives us 3.125 watt-hrs, albeit at an average voltage of 1.25 instead of 3.7. The Li-ion costs a lot more as well. It's much lighter than the NiMH, but for most consumer products that really should matter much unless you have a lot of cells. I really don't see that the much higher price buys anything other than less weight.

Size jtr, I thought we were in agreement on refined little things Can't make a compact & potent incandescent throw monster with NiMH (yeah, Ginseng runs 1/2SC's NiMH in a 500lm M*g2C, but even that can be bested with using fewer, smaller Li-Ion cells). I need a impressive flashlight?, that I can whip out of my pocket to show JA when I run across her in the hardware store (ya did read my post in js's M6-R thread, did you not? /ubbthreads/images/graemlins/wink.gif )

Step-up converters, for wimpy outputting LED's; that don't throw or focus/defocus a wide-to-narrow beam? No, that's not a moot point; unless you can point us to a efficient stepup converter that does more than 3amps?

I still don't get it (maybe I'm being dense here /ubbthreads/images/graemlins/smile.gif). I calculated that the best AA Li-ions and AA NiMHs both have nearly the same watt-hours of energy. So what's the difference then besides voltage and weight? Is Li-ion better under very heavy load than NiMH? That still only leaves a few places where it's worthwhile-super heavy duty flashlights and notebook computers (aka infertility machines-check out SR if you haven't already for what I mean /ubbthreads/images/graemlins/wink.gif ). Li-ion have a somewhat better gravimetric energy density than NiMH but the volumetric energy density, which is usually what is relevant for most items, in about the same (so far). When I see Li-ion or Li-polymer AAs with a capacity of maybe 1500 mAh then I'll see a compelling reason for them. But then again we might have 5000 or so mAh AA NiMH by then as well to once again even things out. I'm not sure what the theoretical limits are with either chemistry.

Oh, so that's why you hang out in hardware stores? /ubbthreads/images/graemlins/grin.gif He,he,he. I also loved Ginseng's comment in that thread:

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What is it with you guys and Jessie Alba? Isn't she jailbait or something?


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At least I never took her for jailbait. /ubbthreads/images/graemlins/icon15.gif Now my old g/f from about 22 years ago (the one I've mentioned occasionally on SR), that's another story. At about 4'8" or thereabouts with a thin, completely flat on top build with everything else in proportion to her height unlike many other small people, as well as very refined, delicate features, I wouldn't be surprised if she could still pass for jailbait now (she was about 2 years younger than me, cradle robber than I am /ubbthreads/images/graemlins/wink.gif ). I'm sure you would have liked her but alas I have no pics of her to send you. It was so long ago in a galaxy far, far away, and I don't think I even owned a camera then, nor was much interested in one.

Oops. /ubbthreads/images/graemlins/blush.gif Sorry about taking this so O/T. Weren't we talking about batteries or something? /ubbthreads/images/graemlins/hahaha.gif

Yeah jtr, you are a little dense in catching the innuedo's. 3AA's damn, that's only 3.6v (you're not a hot wire guy, not a 10w HID guy either, not a member of the 500lm club), Now how am I supposed to whip out my flashlight for JA, if it's so damned long cause of the number of NiMH's I need to get to operating voltage (you still haven't supplied me with links to higher amp/voltage efficient step-up converters), that she'll get the wrong 'idea' /ubbthreads/images/graemlins/crackup.gif ...wouldn't want that to happen with Ms aqua GUI, but that's soooo difficult /ubbthreads/images/graemlins/wink.gif.

Is it my fault Ginny watches re-runs of Flipper when JA was 15, on cable TV with his daughter? Oh 'Da weather', and the side-effects, hehe; 5'0", all of 80lbs I would guess...another thread, another forum /ubbthreads/images/graemlins/smile.gif. Didn't you mean habitable vs inhabitable? I still like my idea of having all the testosterone driven males strangling each other to death in the Saudi desert, much better natural selection(hehe, leaves me with all the babes).

OK, I get it now. /ubbthreads/images/graemlins/tongue.gif That's what working through the night thinking about taxi lights does to you.

No, I don't think efficient step-up converters which can handle tens of watts or more with an input voltage of 1V or so exist in small sizes. I can build one with a TO-263 size MOSFET and a huge inductor which might get into the low 90s efficiency-wise but it wouldn't be very good for your JA special. More like a Pamela Anderson limited edition instead. As you might know step-up converters get less efficient at low input voltages because current input increases. This means more I²R and switching losses in the MOSFET and the inductor.

Your population control idea is certainly interesting although don't think for one moment that males have a monopoly on violence. You just haven't met my sister yet. /ubbthreads/images/graemlins/grin.gif Good thing firearms are hard to get here in NYC because I've seen her do a fair approximation of Clint Eastwood's last scene in "Unforgiven". So much for male-only violence. /ubbthreads/images/graemlins/crazy.gif

Speaking of lumens, I have an old 120V, 1000W halogen bulb that I found by the curb many years ago. Still works, too, and gives you a nice suntan. Now I just need to find a portable 120V power source delivering about 8.33A and I'll best everything you guys have done by raising the bar to 25,000 lumens. /ubbthreads/images/graemlins/buttrock.gif

Another viewpoint:
You have compared AA Lion vs. AA NiMh, which is kind of exotic for LiIon (and therefore not highest energy density).
If you compare LiOn vs. NiMh for the 18650 form factor you get up to 2400mAh for LiIon, while NiMH is in the 4500mAh range=> LiIon has an advantage of >50%

another LiON advantage... it was the only cell available with enough power to operate my current design. a LiON can out put 1.5W comfortably with an AAA, NiMH can do a watt and Alkaline, 1/2 a watt.. so when smallest and brightest counts, so does LiON.

-awr

LiIon wins a lot in my book just by not having terrible
self-discharge issues...

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andrewwynn said:
another LiON advantage... it was the only cell available with enough power to operate my current design. a LiON can out put 1.5W comfortably with an AAA, NiMH can do a watt and Alkaline, 1/2 a watt.. so when smallest and brightest counts, so does LiON.

-awr

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awr,

The energy density of a battery is one thing, but the power output (in watts) is another.

Li-ion wins for energy density (big time) but at the moment, NiMH wins for sheer wattage via the high current regiem. A KAN 1300 AA NiMH battery, for example, can easily deliver 10 amps at 1.1 volts. This is far higher than a watt. In point of fact its 11 watts, and this isn't even close to the limit.

Anyway, these new Li-ion's are also much SAFER than currently available Li-ions due to a different chemistry, and that's the best news of all.

single cell li-ion use has huge advantages over nhm. when you are trying to achieve the smallest form factor and still deliver high lumens w/long runtimes. single cell li-ion is the only way to go.

multi-cell li-ion packs I don't like. requires protection circuits to prevent reverse discharge. charging li-ion packs presents another set of problems. much prefer to charge single cells.

I would have to concur that for multi cell packs nmh is the way to go. eliminates a host of problems related to running li-ion packs.

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js said:Li-ion wins for energy density (big time) but at the moment, NiMH wins for sheer wattage via the high current regiem.

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Li-Poly are not bad either. A 18650 Li Poly can deliver some 20A at ~3.3V.

And I agree with cy above, Li Ions are best in in single cell (or maybe parallel) configs.

What the heck are you guys talking about?! What do 4'8" women and Pamela Anderson have to do with Sony's higher-cap 18650's!? /ubbthreads/images/graemlins/smile.gif

Seems like this topic can be boiled down to a few simple points:

1) Volumeteric energy density is about the same but NiMH trade voltage for capacity and Li-Ion are just the opposite.
2) In general, Li-Ion batteries will allow for a much brighter and smaller flashlight.

Is there anything the size of a Strion (or smaller) that uses NiCad or NiMH technology and runs as long or as bright?

Jon

Sorry StoneDog, jtr is known for being the OT master on another forum, so to get the gist would require intensive reading, and 6 degrees of separation....snoooze /ubbthreads/images/graemlins/smile.gif Li_Ion = Foghat's "Slow Ride" song innuedo analogy, via 6 degrees of separation...Ah, never mind, too obscure a reference /ubbthreads/images/graemlins/smile.gif.

More importantly than Sony's Li-Ion 18650's of 2550 vs 2400ma, which is not that much of a percentage increase; for the near future, the driving force of the cell phone battery tech industry; should bring improvements in Li-poly or other chemistries to trickle down applications that will work for flashlights.

But exactly, I agree with your succinct analysis (and BTW, I made no mention of Pam Anderson, or 4'8" women, that was all jtr's /ubbthreads/images/graemlins/twakfl.gif doing /ubbthreads/images/graemlins/wink.gif, see my avatar, see the 'JA Special' reference). It's all about voltage when you are looking at higher output incandescent lights. Either you use one or a few Li-Ion (not sure what js is referring to as being safer now, other than JSB's protected Li-Ion R123 cells, which do not work so well with incandescent lights, or maybe Pila?); or many, many NiMH cells.

To get a smaller light using LED or incandescent, you need either higher voltage Li-Ion technology, or pitifully low capacity, excessively small, multiple micro-sized NiMH cells. For the much larger multi-cell applications that js deals with(no Ginseng's 1/2subC NiMH powered ultimate high-output EDC of shorter duration will not compare to truly thin small Li-Ion powered lights), NiMH has a slight current capability advantage (hehe, except if you know which Li-Ion 1200ma 18650's can do 10a comfortably with less true useable capacity losses than NiMH, again at 3.7v vs. 1.2v for NiMH).

KAN 1300aa AA NIMH, or for that matter the better CPB 1650ma AA NiMH, do 10a; umm for Andrew's light or any other 1 or 2 cell light those NiMH would be a flash in the pan, wham bam thank you mam type of not particularly useful lighting, using only one or 2 NiMH 1.2v cells, don't you think? 1300a NiMH rated capacity is for what current draw? Many of these smaller NiMH, like the KAN AA 1300a will do 1.1v, at lower current draws, like an 5w LED would require and meet the rated 1300ma capacity. But at 10a, the runtime would be a few minutes, and true useful capacity would drop to less than 1300ma under such a load. I would rather rely on one or 2 Li_Ion cells working, than 3-4 times as many in a multi-cell NiMH batterypack. NiMH might make sense in a 'gas-guzzling' SUV sized Surefire M6-R, short duration 500lumen light (there you go StoneDog, another analogy both you and jtr might agree upon /ubbthreads/images/graemlins/wink.gif ); but this is a rather narrow application. Li_Ion of smaller than 18650 size as in keychain sized lights powered by next years higher efficiency LED's , or even the 18560 size; fit far more practical, longer runtime applications than which js is used to employing NiMH's in. Some of us like thin/slim/sexy small lights with some 'legs' (endurance-amongst other things); others are happy with big, bulky, 'quickie' runtime thrills, flame throwing lights /ubbthreads/images/graemlins/grin.gif StoneDog, both jtr and js are well aware of our particular favorites; it's a never ending debate /ubbthreads/images/graemlins/smile.gif

[ QUOTE ]
StoneDog said:
What the heck are you guys talking about?! What do 4'8" women and Pamela Anderson have to do with Sony's higher-cap 18650's!? /ubbthreads/images/graemlins/smile.gif

Seems like this topic can be boiled down to a few simple points:

1) Volumeteric energy density is about the same but NiMH trade voltage for capacity and Li-Ion are just the opposite.
2) In general, Li-Ion batteries will allow for a much brighter and smaller flashlight.

Is there anything the size of a Strion (or smaller) that uses NiCad or NiMH technology and runs as long or as bright?

Jon

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udaman said:(hehe, except if you know which Li-Ion 1200ma 18650's can do 10a comfortably with less true useable capacity losses than NiMH, again at 3.7v vs. 1.2v for NiMH).

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These are the Li-Poly cells I mentioned above. Readily available and not even expensive.
Anybody interested in a datasheet?

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...driving force of the cell phone battery tech industry; should bring improvements in Li-poly...

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Do they need that high power capability in cell phones? I have the impression that capacity at lower loads is more important now. LiPoly is easier for difficult shapes.

the highest capacity R123 (650 mah)I'm aware of is offered by S2K.

these were unfairly tarred and feathered in another post. I've been running these thru the paces with no problems.

These 650 mah R123 drive 5watts the best out of all the R123 li-ion cells I've tried.

for 2x R123, go with JSB protected cells, but for single cell app's I've been using bare R123 with no problems.