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.
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 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.
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.
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
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.
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.
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.
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.
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.
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.
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.