Dream Battery: 18350 IMR

[GreyShark]

I have no ability to manufacture batteries so I'm just sort of throwing this idea out there in the hopes that it somehow someday develops into a real product.

Lately I've been intrigued by the possibilities of the 1166 incan bulb in FM's D26 G4 Sunlight module. It has great power, great color and decent runtime due to a relatively modest draw all in a light that can be worn in a pocket. Right now I'm driving it off of 3x of AW's 16340 IMR's in a SureFire host. It works great but runtime is under 15 minutes. I really want closer to half an hour to be a practical replacement for my EDC M60. I looked into the possibility of trying to run the bulb on 4x CR123 primaries but after considering the voltage drop from really flogging cells it just didn't look like I'd get much of an improvement in runtime for the greater length. I then considered 3x 18500 in a new host but while the runtime would be fine the light itself would now be four and a half cells long, quite a bit more than my favored 3 cell form factor.

After doing some research I discovered there is an 18350 Li-Ion but it's unprotected and after the draw of around 2 amps is applied I'm not sure how the voltage or capacity would hold up. During my research I read that nearly 5mm of space are taken up by the vent/PTC. It then occurred to me that a safe chemistry IMR cell could handle high discharge rates, wouldn't need a protection circuit and may not need the vent/PTC and thereby regain some of that space to offset losses in power density. Who knows, you might even be able to sneak in an extra mm into the length and still get 3x 18360's into a 2x 18500 host. It would probably be one stompy little cell.

 

[mdocod]

I'd imagine that such a cell would gain ~30% capacity at best... Might be worth it. I bet they would sell well, considering al the 18mm compatible hosts available now 🙂

 

[ElectronGuru]

I just asked AW about 18340's, no go city. Have you tried WA1331, it's my favorite 9P bulb.

 

[GreyShark]

Off the top of my head I believe I've heard that 16340 Li-Ion's get around 750mah. The 16340 IMR is rated at 500mah. Using that relationship as a general indicator I'd then estimate the UF 18350's stated 1200mah capacity to really be closer to 1000mah which would imply an 18350 IMR could have a capacity of 650+ mah.

If the UF 18350's capacity isn't so overstated than that would suggest that the 18350 IMR could have a capacity of 750-800 mah. In other words it would offer all the capacity of the RCR123's but hold voltage much better and handle significantly higher discharge rates, all in a battery that won't make your light grow any longer. Even using the lower figure you're still talking about at least a 25% gain in capacity which would definitely be worth it to me.

I actually did find the thread where AW was saying that he was only finding about a 15% increase in capacity in a standard Li-Ion this size. I would argue that even in this form it would offer better performance under load than any RCR123 but I believe it's the IMR chemistry that would really make this form factor come into its own. I mean the 16340 IMR is a nice little power source in its own right, just imagine upping the ante a little by making it a touch wider and longer. Perfect! If AW doesn't develop the idea I hope somebody else does. Ultrafire already has a battery in this size. A safe chemistry version of it could prove to be a killer app for them.

I haven't tried out a 1331 yet though I may as it seems very similar to my beloved 1166. Based on LuxLuthor's thread it looks like it gets a little more output for a given voltage but loses a little bulb life in the process.

 

[mdocod]

Off the top of my head I believe I've heard that 16340 Li-Ion's get around 750mah. The 16340 IMR is rated at 500mah. Using that relationship as a general indicator I'd then estimate the UF 18350's stated 1200mah capacity to really be closer to 1000mah which would imply an 18350 IMR could have a capacity of 650+ mah.

Many folks may have noticed that in the last few months, since the introduction of IMR16340s, I no longer put forth ANY incandescent recommendation that involves an RCR123.

The reason for this is simple. The protected RCR123 has absolutely nothing noteworthy to gain over the IMR16340 in capacity or performance. 16340 size protected LiCo cells are ~550mAH capacity, into the same loads, so are the IMR16340s. There aren't any LiCo RCR123s on the market that come even close to those label claims of 750-900mAH. The best performers clock in at 600mAH while the worst clock in at 500mAH and there is a direct correlation in many of those cases between how over-sized the cell is from a standard cr123 size. Considering that the IMR16340 is closer to a true cr123 in size (smaller) than almost every LiCo RCR123 out there, and has the same capacity, there isn't any reason to use protected LiCo cells anymore for direct-drive applications. (for buck regulated LEDs on multiple Li-Ion cells a Protected cell is still required).

The reason that they match*in capacity even though the energy density of the 2 chemistries is different, is because the actual cell sizes under the hood don't match. An IMR16340 is dedicating the majority of that space to a cell. A PCB is pretty much a fixed deal as far as how much space it takes up, so on smaller cells like this, the PCB found on the protected RCR123 consumes a large percentage of available space. In the case of those trustfire cells out there that break 600mAH true capacity, they'd slapped a PCB on a cell that was already a RCR123 size cell before the PCB was installed, result in a cell that is ~3mm longer, and often fatter than a cr123, so they don't fit many flashlights...

The UltraFire 18350s have a true capacity of ~850mAH as tested by CPF members. They are unprotected so there is no space being wasted by a PCB in this case, a similar size LiMn cell would likely come in at ~650-750mAH, same conclusion you were coming to just via different roads. Where in that range would depend on how over-sized the cell was from proper dimensions, especially length.

-Eric

 

[GreyShark]

You know, I never actually stopped to take note of the IMR 16340's relative size before. Holding it up next to a SureFire primary I can see it is almost exactly the same size, it is also a little slimmer than my AW 17670. So yeah, bumping it up to 18350 or 18360 should definitely offer a reasonable boost in capacity. I bet I could get an honest 20 minutes out of a mini 1166/1331. Now if only somebody would build it... :sigh:

 

[ElectronGuru]

An IMR16340 is dedicating the majority of that space to a cell. A PCB is pretty much a fixed deal as far as how much space it takes up, so on smaller cells like this, the PCB found on the protected RCR123 consumes a large percentage of available space.

Awesome insight! :thumbsup:

 

[evenchaos]

+1
I too am really forward to looking for someone to manufacture a reliable 18350/18360. Seems almost a no brainer.

It would also be great for powering some of the high power LEDs on the market in a small formfactor package. Imagine a 18350 MC-E pumping out 700 lumens 😱 /sigh ... one can dream

 

[GreyShark]

Yeah, that would be pretty awesome! If it ever happens we'll have to call it the Noisy Cricket. :thumbsup:

 

[Flashlight Aficionado]

I am patiently waiting for a 10180 and 10280 IMRs. 😗

 

[Kestrel]

I am patiently waiting for a 10180 and 10280 IMRs. 😗

And I am patiently waiting for 16180 IMRs. 😗

At 8C with an estimated capacity of close to 250 mah, that would be a maximum current of ~2.0 amps. Here's one possibility:

E1E: 2.0 amps @ 7.4v = ~15 watts
(with a buck driver, wouldn't it be fantastic to run an MC-E at its full potential in a single-cell host?)
:devil::devil::devil::devil:

 

[buickid]

mdocod: thats a pretty good policy, I think I might have to adopt it :thumbsup:

 

[Moddoo]

bump for any Battery manufacturers out there.

Let's see some 18340-18350 cells

please

 

[fivemega]

[size=+4]18350[/size]

Not IMR

 

[Bullzeyebill]

[SIZE=+4]18350[/SIZE]

Not IMR

+1

Bill

 

[Moddoo]

haha
just found those, and just bought some.
Then found this thread again!

This might be a good cell(s) for some recent multiple LEDs in series concoctions...
lovecpf

 

[GreyShark]

I've been working on some other hobbies lately and only found out about the new 18350 IMR's today. I just wanted to bump this thread to show that sometimes dreams really do come true!!! :rock:

I'll be looking for a way to bore out my C3 to accept these awesome new batteries this week. 😎

 

[Ginseng]

I've been working on some other hobbies lately and only found out about the new 18350 IMR's today. I just wanted to bump this thread to show that sometimes dreams really do come true!!! :rock:

Yep, and sometimes they take a really, really long time. And as you can see in that thread, there were others before us. At last, the eternal quest is fulfilled.

Wilkey

 

[Kestrel]

[...] At last, the eternal quest is fulfilled.

Doesn't that mean that it's not eternal then? 😉

The AW IMR 18350 does sound like a good cell. From what I hear, AW was unsure of market demand on these cells, so let's hope that there is enough CPF demand to ensure future production runs. 🙂

 

[ElectronGuru]

Its still early, but 18350 demand is greater than 16340's and settling in to equal 18500's. I would be surprised if it doesn't end up in the top 5 or even top 3 models (including the 2900).