21700 battery case
- Thread starter MarkJ
- Start date
Stuart France
Well-known member
Well of course Fenix sells excellent head torches that use 2x21700 5AH batteries but whether you can get the waterproof case alone as a spare part only is doubtful and whether you'd want to is another matter as the enclosure contains circuitry and has a flimsy built-in cable. I have one of these lights which is great for cave photography but I'm concerned about its cave-proofness.
www.aliexpress.com
As it happens our old friend Ali now sells one and two 21700 sprung battery holders literally for pennies which reduces your problem to finding a plastic or metal box to put the whole battery assembly into. You then just have to sort out your own cave-proof socket or a flying lead and plug and of course some way to charge two Liion batteries in series unless you use a multipole socket that allows them to be charged in parallel but used in series to get ballpark 8 volts.
I've used 2x18650 cells in series as caplamp batteries housed snugly in an extruded alu box made by Hammond for years (these have solder tags so there is no plastic holder between the cells and the outer alu box) and would like to upsize to 2x21700. I'd prefer a plastic sprung holder as it is easily replaced and modular. I've had several tagged 18650 cells de-tag themselves in use, I suppose due to cumulative helmet clonking around caves, and it is quite alarming for my light to go out or flash when I put my head at a particular angle and the welded tag joint temporarily comes apart.
New Arrived ! 21700 Case 2 Slots 21700 box 21700 Battery Holder 21700 Battery Box With Line /With Pins Series/Parallel - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
As it happens our old friend Ali now sells one and two 21700 sprung battery holders literally for pennies which reduces your problem to finding a plastic or metal box to put the whole battery assembly into. You then just have to sort out your own cave-proof socket or a flying lead and plug and of course some way to charge two Liion batteries in series unless you use a multipole socket that allows them to be charged in parallel but used in series to get ballpark 8 volts.
I've used 2x18650 cells in series as caplamp batteries housed snugly in an extruded alu box made by Hammond for years (these have solder tags so there is no plastic holder between the cells and the outer alu box) and would like to upsize to 2x21700. I'd prefer a plastic sprung holder as it is easily replaced and modular. I've had several tagged 18650 cells de-tag themselves in use, I suppose due to cumulative helmet clonking around caves, and it is quite alarming for my light to go out or flash when I put my head at a particular angle and the welded tag joint temporarily comes apart.
Last edited:
MarkJ
New member
Thanks, though my use case is slightly different, it is just for storing them in my caving bag as spares when caving. I have a Fenix HM70R so just a matter of taking the dead battery out and putting a fresh one in when needed.
Ali was a good idea though as I'd not checked there. Found this and just ordered the 2x 21700 option:
https://www.aliexpress.com/item/1005012794083065.html
Will see how good it is!
Ali was a good idea though as I'd not checked there. Found this and just ordered the 2x 21700 option:
https://www.aliexpress.com/item/1005012794083065.html
Will see how good it is!
Cantclimbtom
Well-known member
If this is cheap, light, less robust for a caving suit pocket... You might find googling 21700 battery storage box gets you something, which can be put inside a seal strip bag. If that's all you're after rather than something more solid and serious
MarkJ
New member
Thanks, yes, this would be a good lighter weight solution, and hopefully what I have ordered for Ali Express will be be a more robust solution for when needed (though who actually knows with Ali Express)
alanw
Well-known member
Four x 18650 fit nicely in the internal diameter of 50mm pipe, however the minimum length using the endcaps and coupling I've got for drill bits would be about 2 x 80mm = 160mm, more than twice the length of the cells.
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