18500 vs. 18650 cells

[etc]

I have been a fan of Malkoff M60 on 3x123 or 2x18500 cells, the latter combo is what I usually use.

But now I see so much development is going towards 18650 cells and none towards 18500 that I am switching to the 2x18650 configuration.
AW just came out with P-18650 at 2600 mAh and there are many good 2800-3,000 mAh cells currently available. I feel left out with 18500, mine are only 1500 mAh. I asked AW if there are any plans on the horizon to upgrade 18500 and the answer is no.

I now have a custom made Malkoff M60 module designed to run on either 2x18650 or 4x123, so it's input is up to 12V.
At 3,000 mAh or close to it, 2x18650 have higher Wh ratings than 4x123 primaries, impressive.

 

[metlarules]

The only thing that I don't like about the 2x18650 combo is length.
At that length I think I would rather a 2 or 3c mag. Bigger reflector for more throw and less expensive.

 

[etc]

The length is really not that bad. It's shorter a bit than 3xAA FiveMega I have. Even *that* is not too bad. The added length makes it easier to hold also.

It's pretty small diameter wise and the ultimate reason is that you can always switch between Li-Ion and 123 primaries. E.g. go on a trip, no recharging, take primaries; in other circumstances, use 18650s.

Also back on topic - it seems 18650 is most popular, by far, among all these Li-Ion cells. So it gets most development and easiest to buy, and most common.

 

[ElectronGuru]

it seems 18650 is most popular, by far, among all these Li-Ion cells. So it gets most development and easiest to buy, and most common.

Most LithIon cells have a natural demand, but with laptop packs produced in the millions each year, 18650 demand is unnaturally high:

http://www.neufeld.newton.ks.us/electronics/?p=149

and it takes the lions share of technical development, adaptation for use, and economies of scale with it.

 

[Kestrel]

For quite a while now I've been using 2x17500 in my SF C3, but with the new 18650's with a single cell having ~20% more stored energy than both 17500's combined, I'm finally getting a 6P bored (custom fitted to my new cells, 0.001" oversized) to take those new big guys. I briefly considered having the C3 bored for 2x18500 at the same time (since the lathe will be already set up and would take only a few minutes more) but I just can't justify it. As you say, 18500 just does not hold any interest for me anymore. Personally, I'm not interested in a light long enough for 2x18650 (although many folks here like this configuration), but I can see a future where 1x18650 replaces 2x17500 & 1x17670 for my user lights. Very impressive cells.

 

[etc]

yeah, same here. One of these new 3,000 mAh cells (or close to it) holds as much as 2 1500 mAh AW protected 18500 cells.

 

[Kestrel]

... for 3.5 cm less total length! I don't mind the length of the three-cell lights, but not if it's not getting me anything extra in capacity!

 

[ElectronGuru]

The advantage with two cells, it seems, is now limited to their higher voltage. My MC-E M60, for example, won't run on a single fully charged 18650. But given the popularity of M30's, we're likely to see a fresh round of low voltage triples and quads. Incans, of course, are another story.

AW stated publically that 18500 would not be seeing bumps anytime soon. I have to expect that innovations created for the 'lead cell' will eventually trickle down (pun not intended). So the next question is, what will the time window be for such passing. I believe 1-2 years is reasonable, 3-5 years is not.

 

[etc]

I have been EDC-ing my 2x18650 Malkoff, it's OK. I don't like the tint as much as on my original Malkoff but it's fine. It just takes longer to discharge. Longer to get to half the charge and from there on longer to get to completely empty. I like that.

And that's with AW's 2200 mAh cells, I cannot image how nice the new 2x18650 high capacity cells might be.

The best things is that if I cannot recharge, I can stick in 4 primaries in it. Nice to have that kind of flexibility.

As for my small stash of 18500 cells, I have had them for 6 months. I will keep using them. But when they die, I won't replace them. They say they should run at least 1 year and then drop in capacity. I don't want to load up on the current 18650 2600 mAh (maybe get 2 sets) as they will likely soon be replaced with even higher capacity 3,000 cells. I am using the principle of:

Use it up,
Wear it out.
Make it do
Or do without.

 

[LEDAdd1ct]

Nice little rhyme; I like it! Good for saving money.

 

[etc]

Need to increase capacity of protected 18500 cells

AW's 18500 cells are still only 1500 mAh which is half that of new 18650 cells which are only slightly longer (Panasonic just came out with 3100 mAh cell, albeit unprotected)

Doesn't make sense to run 2x18500 when 1x18650 will have just as long a runtime, except a little less voltage. Now 2x18650 are vastly superior to 2x18500 and not that much longer. 18500 just plain don't make any sense anymore.

Needs to update them from 1500 mAh to 2,000 mAh cells, get with the times.

 

[mdocod]

Re: Need to increase capacity of protected 18500 cells

AW's 18500 cells are still only 1500 mAh...get with the times.

Little harsh eh?

AW doesn't manufacture cells. He can not just tell someone to make him a 2AH 18500 cell, they have to be able to do it and for a reasonable price, and more often than not, many of the cells he is putting his label and protection circuit on are probably cells that are already part of a regular production line somewhere.

The problem is, 18500s are a tiny fraction of the market. So there is minimal research and development compared to the very popular 18650 size.

Do you know of any manufactures making a 2AH 18500 cell that we could point him to to check out? Keep in mind that most big name manufactures require quantity purchases up around 10,000 units or more to get in the door. Something tells me AW would not be interested in this route. So more specifically, an 2AH 18500 that can be purchased in batches of 1,000 or less?

Eric

 

[etc]

Re: Need to increase capacity of protected 18500 cells

Yeah, that's exactly the point and exactly the reason. Not economically viable to mess with 18500. It's a dead-end. Once he makes his investments, nobody will buy it and will remain on the periphery of things, high capacity or not. 18650 cell is a few mm longer (maybe 10?) but has twice the capacity. There is almost never a need for 18500 when you can have 18650.

If I had 2000 mAh 18500 cells, my Watt-Hours rating would be: 2*4.2*2000 = 16.8Wh, which is greater than 1x18650 configuration, even a high-capacity one is still around 12Wh.

I realize 18500 is not a mainstream cell. I got into it a few years ago when I first started looking at Li-Ion, a neat swap into a Surefire 9P type format. But, 18650 *are* mainstream more or less and they get more development. I run Panasonics and they are phenomenal. M60L just keeps running for what seems forever on them. Plus I have taken apart so many laptop cell packs that I probably have a hundred 18650 cells of various capacities between 2200-2600 mAh, but all charge to 4.2V and all work nicely in the 1x18650 lites. (I had to throw away 100 bad cells, that didn't charge fully, or got hot while charging, or were too deeply discharged)

In an emergency, when you have no other choice, you can use unprotected 18650 cells in a 2x18650 configuration, but then keep track of your runtime as you won't notice as it discharges to 2.5V. Even then, I may not care I paid nothing for these cells. If it discharges that deep and you damage some junky old 2400 mAh cell, big deal. But it's almost never a good idea anyway. I use AW's 18650 cells in 2x18650 configuration. That works fine with the exception that protected cells don't dim, they just go out in an instant. Not a good concept in the field.

 

[jasonck08]

Re: Need to increase capacity of protected 18500 cells

Sanyo, one of the industry leaders in batteries only has a 1700mAH 18500 cell.

As mdocod said, 18500's have a very small percentage of the market.

I'd probably guess that the 18650 size sell 100x as much as the 18500 size, simply because they are used in 99% of modern laptops and millions of laptops are sold each year.

That is why most companies put their R&D efforts into developing higher capacity 18650 cells.

 

[etc]

Re: Need to increase capacity of protected 18500 cells

RE: Sanyo - is it protected? If not, a moot point, as you can get a Panasonic 2000 mAh cell, right here and right now...

 

[jasonck08]

Re: Need to increase capacity of protected 18500 cells

Of course its not protected. No big-name company makes single protected cells.

Also the Panasonic 2000 mAH cell I don't think is mass produced. I can not find the cell anywhere other then Panasonics site.

 

[Kestrel]

Re: Need to increase capacity of protected 18500 cells

I thought we already had this conversation? Why not just bump your existing thread on this topic instead of starting a new thread?

Back in 2009:

But now I see so much development is going towards 18650 cells and none towards 18500 that I am switching to the 2x18650 configuration. AW just came out with P-18650 at 2600 mAh and there are many good 2800-3,000 mAh cells currently available. I feel left out with 18500, mine are only 1500 mAh. I asked AW if there are any plans on the horizon to upgrade 18500 and the answer is no.

 

[mdocod]

Re: Need to increase capacity of protected 18500 cells

I don't think that the Panasonic 18500 with the 2AH rating is an actual product. I tried pulling up the data sheet on the website and even inspected the html on the site, a link to the data sheet doesn't even appear to be there. (I could be wrong on this).

I prefer the 18500 size cell for many incans as it makes for great 2 cell length lights that are more comfortable to handle. I use many 18500s, despite the lower capacity.

Eric

 

[CuriousOne]

Re: Need to increase capacity of protected 18500 cells

18500 cells can be obtained from battery packs for Sony camcorders, NP-F, NP-FM, NP-QM series. Genuine Sony made ones contain 2-4-6 1100mAh cells (or maybe 1600mah). Interesting thing is that unlike laptop batteries, which have clear indication of model like US SF18650GR or whatsoever, these generally are in transparent shrink wrap, and bear only numeric code, without any model or capacity specs.