Do 18650s rattle in 21700 lights?

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Bort
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Do 18650s rattle in 21700 lights?

Something i have been wondering, since i don’t currently have any 21700s if i buy some lights that use them and put my 18650s in them for now will they rattle/flicker?

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zoulas
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18650 is shorter and thinner than a 21700. Without some tube or o rings it will definitely move around or probably won’t work at all.

ggf31416
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18650 work fine in my Convoy S21A.

lumenzilla
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It will rattle because 18650 is smaller, use rubber ring to fill the gap.
Something like this.

I tried 18650 on several 21700 flashlights and it worked well because (in my case) they have springs on both ends.

crn3371
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Theoretically a 18650 battery is 3mm thinner and 5mm shorter than a 21700 battery. They certainly will rattle, and most likely won’t work without some type of spacers.

mattlward
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All of my 21700 lights work with 18650 flat tops. I use o-rings or a factory tube to center the cell. If you lights do not have springs on both ends, it is likely you will have issues with the shorter flat top cells.

EDC rotation:
FW1A, LH351D 4000k (second favorite)
FW3A, LH351D 3500k
FW3A, SST20 FD2 4000k
FW3A, Nichia 4000k sw40 r9080 (favorite light!)
FW3A, Cree XP-L Hi 5A3
Emisar D4V2, SST20 4000k
S2+, XM-L2 T6 4C

Bort
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I am considering the Convoy M21B and i have UR18650FM 18650s and some Samsung ICR18650-28As.
I have no idea if it comes with centering washers, though its not mentioned so i am leaning towards no.

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

CR888
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Use factory tube and put a rubber band around it so it doesn’t slap up and down, or some electrical tape. Or even better just run a 21700, cells are cheap & the 21700 hold moer powa’s.

CR888

Bort
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CR888 wrote:
Use factory tube and put a rubber band around it so it doesn’t slap up and down, or some electrical tape. Or even better just run a 21700, cells are cheap & the 21700 hold moer powa’s.

I do plan to get some but at the moment i don’t have any. And they are not easy to get in Canada, plus the current shortage.

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

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I think you’ll find most lights that are 18650 and 21700 compatible may have a little bit of rattle to them when running 18650 cells, but they should be tested to ensure no breakage of circuit continuity. Besides, very easy to slip over a few O-rings on the 18650 to help with the centering.

Bort
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xevious wrote:
Besides, very easy to slip over a few O-rings on the 18650 to help with the centering.

Where do i get some?

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

TIFisher
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Bort wrote:
xevious wrote:
Besides, very easy to slip over a few O-rings on the 18650 to help with the centering.
Where do i get some?

Should be able to find some at your local hardware store or building center. 18mm inside diameter/ 21mm outside diameter. Walmart.com has listings for 10 packs for $5.49US. Not sure what access you have to that up in Canada (you are in Canada, right?). Amazon.CA probably has something close.

Dalamar
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My fireflies 21700 adapters cause rattle, but you can just stuff some TP or something in there.

I only like high CRI. Collection:

Fireflies NOV-MU 21 4500k E21A

Fireflies ROT66 219B SW45 D220

Fireflies E07 Copper 219B SW45k? (odd/higher lumen bin with lower r9 and higher cct?)

Fireflies E07 219B SW45k

Fireflies E07x Pro sst20 FA4 4000k 

 

Varmint removal:

Convoy M21A C8 ver SST20 4000k (5a)

Convoy S2+ SST20 4000k  FB4 (3200ma)

Memes:

BLF GT94

Emisar D18 660nm SST20 

 

 

CRI test dump https://drive.google.com/drive/folders/1kcl_uOhgfpR4RSsa8F4b-UUVP9mkL6Cr...

Bort
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TIFisher wrote:
Bort wrote:
xevious wrote:
Besides, very easy to slip over a few O-rings on the 18650 to help with the centering.
Where do i get some?

Should be able to find some at your local hardware store or building center. 18mm inside diameter/ 21mm outside diameter. Walmart.com has listings for 10 packs for $5.49US. Not sure what access you have to that up in Canada (you are in Canada, right?). Amazon.CA probably has something close.


If anyone has some Canadian links or model numbers that would be nice, i don’t recall most washers having their inner and outer diameters stated.

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

jeff51
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I use a pair of O-Rings from a hardware store. I just looked a the packages and picked ones I thought would work. No rattles. And I like having sir space around the cell. As opposed to wrapping it in cardboard or something like that.
Length wise all seems to be an OK fit. Most of my 21700s are a tight fit length wise.
Seems like I used a magnet spacer in at least one of my lights – but I can’t remember which one(s).
All the Best,
Jeff

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Bort wrote:
If anyone has some Canadian links or model numbers that would be nice, i don’t recall most washers having their inner and outer diameters stated.
I don’t know how remote you are out there in Oh Canada, but if you’ve got a hardware store chain in reasonable distance, give ‘em a call and see. Or, just pop over on eBay. You can get all kinds of cheap o-rings from China on the cheap.
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I’ll check it out next time i get to the hardware store, don’t go there much becasue of covid but when i get there i shall look carefully. Probably ask a helpful associate.

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

raccoon city
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I'm not a fan of trying to find things at hardware stores...

I would just do eBay or Amazon.

Search for:

o-ring 18mm 21mm

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raccoon city wrote:

I’m not a fan of trying to find things at hardware stores…


I would just do eBay or Amazon.


Search for:


o-ring 18mm 21mm


The shipping would cost too much.
I am surprised none of the lights come with spacers, most 26650 lights come with 18650 spacers.

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

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Bort wrote:
The shipping would cost too much. I am surprised none of the lights come with spacers, most 26650 lights come with 18650 spacers.
There’s another thing you can try. Cut some duct tape and fold over into strips, then trim to make into loops secured with tape. Then slide over your 18650 cell. You should be able to fashion a good fit. Just be sure not to let any adhesive residue be exposed that might stick to the inside wall of the flashlight tube.

Otherwise, order from eBay. Often sellers from China offer free shipping, at least to the USA… don’t know about Canada.

ggf31416
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Bort wrote:
I am considering the Convoy M21B and i have UR18650FM 18650s and some Samsung ICR18650-28As. I have no idea if it comes with centering washers, though its not mentioned so i am leaning towards no.

You can buy the M21B with an included battery from the AliExpress Convoy store, apparently they ship to Canada. If the specific model id not available contact Simon or ask in the main Convoy thread. The batteries you mentioned have ~5A CDR so their runtime may be a bit lower than expected in the M21B.

TheIntruder
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First off, not all 21700 lights will take 18650 cells, even with an adapter tube, or shimming to reduce lateral movement.

The Sofirn SP35 has only a single spring in the tail cap, and an 18650 (unprotected flat top 30Q, in my case) is too short to engage both it and the contact pad in the head.

My Sofirn Astrolux EC01 has dual springs, and was bundled with an adapter tube. But there is still slack inside the adapter, and between the adapter and the body, so shake it hard enough and it will rattle. Enough force can still overcome the steadying tension the spring(s) provide and allow the cell to shift.

Scotty321
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My local hardware stores often have rubber O-rings in the isle that they have toilet component parts (like where the tank valves are).

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if you have ace hardware in your area they have drawers of stuff like o rings.
you can test fit on the spot.
and o rings are easy to stash in your battery boxes(you are using them right?)
if you need quick and easy a strip of cereal box wrapped around the cell will do.

CR888
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I wouldn’t bother going to a store to buy something so simple, a folded piece of cardboard will do exactly what any rubber oring will and work just as well. I bet wherever you are right now Bort, within reach is something that can solve your issue. A bit of card or rubber band will work just fine until you get your 21700 cells. If I was in the US Id scoff a Charleston-Chew fold up the wrapper and stuff that in. I can only get Charleston chews at fancy import candy stores which sucks btw.

CR888

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Next problem.
Why are ants going in my flahlight and charger?

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Snakebite, two possible answers: Ants are looking for a warm dry place to build their nest; or they are looking for something edible.

I also have ants frolicing in my kitchen. Some of them like to go into my cupboard where I keep my coffee mugs. I guess they smell residue of milk and sugar in mugs.

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snakebite wrote:
Next problem.
Why are ants going in my flahlight and charger?

I have not owned any 21700 lights so i asked if there would be a problem using an 18650 battery in it.
Not like i asked the meaning of life Facepalm

The Journal of Alternative Facts TM

"It is critical that there is a credible academic source for the growing and important discipline of alternative facts. This field of study will just keep winning, and we knew that all the best people would want to be on board. There is a real risk in the world today that people might be getting their information about science from actual scientists"

 

snakebite
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That was a joke about using candy wrappers for a spacer

CR888
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FWIW even a few ants stuffed in there will work well too.

CR888

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