BLF triple 21700?

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Tom E
Tom E's picture
Last seen: 10 hours 5 min ago
Joined: 08/19/2012 - 08:23
Posts: 14626
Location: LI NY

Seems to have turned out triple 21700's are slightly larger in diameter than quad 18650's, 51.8 mm vs. 50 mm.

The 3x21A will be my third triple 21700 light - Haikelite HK90, WildTrail WT90, and the more affordable 3x21A.

I do like the form factor - still comfortable to hold, plenty of power, both for max amps and/or runtime.

Lightbringer's picture
Last seen: 1 hour 44 min ago
Joined: 08/30/2016 - 14:12
Posts: 15492
Location: nyc

Make the body an empty can at 52mm or so. Keep the same contact ring on the head/driver. All parallel, so who really cares how they’re situated?

A cheap “speedloader” that’s got a cross or trefoil cross-section in the middle to keep the 4 18650s or 3 21700s upright, and a bottom-with-springs that would have the springs make contact with the cells on one end and with the body on the other end.

One for 3×21700 (shorter springs) and one for 4×18650 (longer springs).

Nb: I don’t mean a full cell-holder or carriage that’d make the assembly any wider, but just a disc-with-springs at the bottom and central spacer/form to just keep the cells upright. Kinda like a big-ass thumbtack but with cross/trefoil pointy-part.

Then you can have the same light take both configs, 3 or 4 cells.


Eg, if I’m remembering right, the SD01 with its 1pc body, has the cloverleaf-shaped insert-with-springs just drop in and snap-fit to stay, vs the Q8 where the cap unscrews and the PCB-with-springs is hard-mounted inside. The former is so much simpler and cheaper, and works just as well if not better (loses both threads and O-rings, as well as another potential for water-ingress).

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