Standardizing on 18650 or 18500 cell?

[etc]

I have a couple of 2x18500 lites with Malkoff, as well as 2x18650 bodies.

Recently I saw a Surefire 6P body bored out to take 1x18650. That's neat as it would be compatible cell-wise with the bigger Leef 2x18650 unit. Then I would only worry about 18650 cells without having to deal with both 18500 and 18650 cells. Then 18500 cells could be cut out entirely, as I wouldn't need them.

Plus 1x18650 should be more EDC-able. The current 18650 from AW is rated at 2200 mAh but I hear there is a 2500 mAh version coming. While 2x18500 combined are 3,000 mAh. So there is a drop, but how much is runtime affected?

Also I presume that a 6P bored out to take 1x18650 would have to have Malkoff M30, due to low voltage.

So my goal is to have 2 18650-based lites:

1. Leef 2x18650 with M60 for serious work and better runtime, especially loaded with 2500 mAh cells, for pretty decent runtime.

2. For EDC, 6P bored out to take 1x18650. It would have to have M30 in it. Only problem is, I couldn't use primaries in it. But it would be compact. I hear 2 hours of runtime.

 

[yellow]

same "problem" like You have, but that Inova T3 I want to mod will only take 2 18500s, so I might give them a try...

the 18650 for sure is the Li-Ion cell to base power on, at least it is the cell for camcorder and notebooks. They will remain and also see improvements, the 18500 seems more as a by-product.

PS: I have an 18650 modded 6P. Watch carefully while milling and dont put too much force at the back end when using the light, it is just a tiny bit of metal that remains for the body (at the cutout of the o-ring)

 

[etc]

Do you think Leef 1x18650 body is better than bored out 6P, quality-wise?

 

[Agent_Jaws]

I think you're right with needing the M30 if you're only going to run 1 x 18650, or at least it being a better option on a single battery.

Looking at what you're proposing I think in addition to eliminating the 18500 battery you'd also be eliminating your ability to use primaries in a pinch, unless you've got a spacer on hand. I'm not sure if that was a concern for you or not, I know it was for me though so I thought I should mention it.

I get stuck sometimes on wanting to run higher capacity cells in my primary light, right now I've got it set up to run either 2 x 18500 or 3 x primaries without worrying about the emitter. I keep having to remind myself that I am only running an M60L though, and that I am already looking at 4+ hours on rechargeables and closer to 7 hours on primaries, so runtime isn't really an issue for me. If I were to step up to the 2 x 18650 set up I could probably get closer to 7-8 hours from the rechargeables, but then that creeps into the realm of having a dong-light instead of a flashlight.

I can understand your desire to consolidate your batteries but if you do go that route I'd recommend picking up a spacer cell too so that you can run primaries in an emergency.

 

[Sgt. LED]

The spacer cell is very cheap and lightweight.
I have an orange 4 CR123 battery caddy and 1 of those slots has a spacer cell in it. When my 18650 cell runs out I can easily swap in a primary and a spacer cell and keep moving, it's a little dimmer but it's ok with me.
Eventually I will buy some more 18650's and pack those around.

 

[Sgt. LED]

Do you think Leef 1x18650 body is better than bored out 6P, quality-wise?

Yes

 

[donn_]

While 2x18500 combined are 3,000 mAh.

2x18500 cells in series give you double the voltage, but the mAH stays at 1500 (actually, less than 1500).

 

[kramer5150]

..dont put too much force at the back end when using the light, it is just a tiny bit of metal that remains for the body (at the cutout of the o-ring)....

This is a little concerning... IMHO. I for one would not be willing to sacrifice durability for run time, as frequently as I drop my lights. Then again I don't mind reloading fresh cells as needed.:twothumbs The Leaf body seems like a safer alternative to a modded 6P.

 

[etc]

Looking at what you're proposing I think in addition to eliminating the 18500 battery you'd also be eliminating your ability to use primaries in a pinch, unless you've got a spacer on hand. I'm not sure if that was a concern for you or not, I know it was for me though so I thought I should mention it.

Yeah, I have come to realize the same thing. I think I am going to stay with the 2x18500 form factor, and have the ability to run 3x123 is sweet.

I admit, M60L *is* tempting. It would get awesome runtime in 2x18650 configuration.

Yet I will probably go with a different module altogether, because I also want 4x123 capability, or if Gene can built an M60* that can handle 13V (Current version cannot of course)

 

[etc]

2x18500 cells in series give you double the voltage, but the mAH stays at 1500 (actually, less than 1500).

But the end result is the same? You don't get more lumens, you get better runtime?

 

[Kestrel]

But the end result is the same? You don't get more lumens, you get better runtime?

The technical term for this behavior is "regulation", the concept appears to be of some interest here on CPF.:ironic:
K

 

[etc]

Yes, buck vs. boot circuit as far as I understand.

 

[dhwfd46]

I honestly don't see a dilema with running 3 primaries in a 2x18650 body tube.

I too have a Leef 2x18650. The li-ions are enroute from lighthound. I've been running it with 3 primaries and a dummy spacer fabbed out of a piece of 3/8" copper tubing with caps soldered on the ends. This is stupid, ridiculous, easy to make and costs all of about $1.00. You can insulate the outside with electrical tape, liquid electrical tape, or heat shrink tubing.

 

[etc]

Well, you can run 3 primaries + dummy cell in 2x18650 body, or for that matter, 2x18500 + dummy, which is what I have been doing (Until I get new high capacity 18650 cells or get primaries and find a module that can take up to 13V)

However, seems like a waste of space. If am going to do that, might as well use a 3x123 or 2x18500 body:

 

[Agent_Jaws]

I think part of your problem etc is that you might have too many options available lol. If you reduce yourself down to 18650 batteries only (or 4 x primaries, or 3 x primaries + 1 spacer), what are you going to do with your 2 x 18500 bodies?

I aspire to have that problem one day, though my wallet still begs me not to. I kinda figured if I wanted a larger capacity cell I may as well try and step up to a 2 x "C" size rechargeable option, something like the BigLeef system. But then I'll have moved way beyond having standard flashlights, and I'm not so excited about that part.

 

[etc]

You know, you are right. Cool thing about 18500 bodies is you can use regular 123 cells in them, wrapped in something so they don't rattle.

As for BigLeef system, don't get me started. I already looked at that and you know where that leads...
If I want serious runtime, I can resort to Mag with Malkoff...

One problem that I see is that I will lose the ability to use 123 cells, and I want retain that ability. It's nice to be able to switch between Li-Ion and 123 cells.

 

[yellow]

You know, you are right. Cool thing about 18500 bodies is you can use regular 123 cells in them, wrapped in something so they don't rattle.

ahhh, sorry but isnt that wrong?
the 18650 is as long as two CR123s, so the 18650 body should give that option
:thinking:


as to strength:
I just measured the original SF body with 19,7 mm and the Leefbody 18650 with 20.05 mm
When milling to ... :thinking: ... 18,5 mm for the 18650, the difference is
Sidewall of 0.6 mm to 0.775 mm. Does not sound to much difference but is 30 % stronger. With that thin material, or possible imperfections while milling ...
As a stand I would not use both lights

... unfortunately with the Leefbody You still need switch (leef is nice) and head (very difficult to get, ime). The G&P head works but is in no way comparable with SF or Leef build quality


PS: my milled 6P survived much use and regularly being clamped to the bars while MTB-trail riding, for over 1 year now.
Here the milling was bad and I am sure to have less sidewall, more around 0.3-0.4 mm. It works, but fore sure I dont drop the light

 

[etc]

Thanks for the report.

 

[Kestrel]

November 20:

I think part of your problem etc is that you might have too many options available lol.

From September:

Of course the array of choices makes my head spin...

 

[etc]

I decided to keep using both 18500 and 18650 cells.