question on Battery Options

caveeagle

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Sep 5, 2014
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I have been playing around with ideas for a dive light and was wondering why the 18650 battery seems to be so prevalent for battery packs vs some similar like 22650 or 26650?

The Idea I have in might will probably use just 4 cells, and there would not be much penalty for a wider26.5mm cell vs a smaller 18mm cell.

on a similar thought path, I currently use Dive Rite BX-1 lights for back ups and they use a delrin sleeve to space out a 18650 battery. It seems like a 22650 battery would fit in there just fine. I might email DR to ask, but I don't see any reason this would not work, as both batteries are 3.7v.
 

Str8stroke

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I like 26650 cell lights. Possible draw backs on individual cell use (not a battery pack): Size, weight, availability and price. They are larger so the light has to be larger. They don't fit in all chargers. The light is hard to pocket. They weigh more. There are less models to choose from and they are a little more expensive. If I wanted a long run pack and size didn't matter, I would go that route for sure.
I built one for my neighbors bike. He had a cheap ebay China bike light. It had a 4 cell 18650 pack. The original cheap pack lasted a month. I built him a new pack out of four KeepPower 5200mAh Protected cells. The charger takes a while to charge it. But he is happy.
 

caveeagle

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In my existing Dive Rite BX-1 backup lights, they require a sleeve for the 18650 battery. That sleeve is nearly the exact same size as some other spacer I bought that say they are to adapt 18650 to 22650 application. So why not just use the 22650 in the BX-1. Honestly, these lights are pretty great. Ad work well as primarys for short cavern/wreck dives. So a little more battery life, would be great.

I have been bouncing around ideas for a Custom HH Primary light. I want to be able to use 4 individual cells, vs a battery pack to avoid hassle with air travel. The battery container I have in mind would need to be spaced down for an 18650 cell anyway, so why not just run a larger 22650 or 26650 in the first place ? ..no reason that I can think of.
 

DIWdiver

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I think the reason the 18650 is so popular is that it's so popular.

That may sound facetious, but since they are (or at least were) used in nearly all laptop packs, they were made in much higher quantities than any other single size. Thus you get the most bang for your buck. This is also true of the AA size in alkalines and NiMH.

It isn't inherently better, just cheaper and more available. That said, my lights are all 26650 now.
 

caveeagle

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That's what I was suspecting. I think I might pick up a couple to try out in my BX-1. FWIW, they run a Cree XML2-U2
 

Lynx_Arc

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I think the reason the 18650 is so popular is that it's so popular.

That may sound facetious, but since they are (or at least were) used in nearly all laptop packs, they were made in much higher quantities than any other single size. Thus you get the most bang for your buck. This is also true of the AA size in alkalines and NiMH.

It isn't inherently better, just cheaper and more available. That said, my lights are all 26650 now.

Right now a 26650 is about twice the volume of an 18650 but doesn't have near twice the capacity. The advantage of 26650 is ability to put out higher current more easily which in order to get the same current out of an 18650 you would have to drop capacity to probably less than half of a 26650 battery. I see a continuing trend on more lights using the 26650s due to the market wanting uber high output lights 2000+ lumens where current creeps upwards of 4-5A and those higher currents the higher capacity per volume 18650s start having problems that alkaline batteries do compared to nimh chemisty as current increases.
 

caveeagle

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Any danger in running the higher capacity 26650 battery to a Cree XML2-U2? I might send an email to Dive Rite on this. For some reason they only mention using the 3xAAA pack or an 18650 in their info card.
 

Lynx_Arc

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Any danger in running the higher capacity 26650 battery to a Cree XML2-U2? I might send an email to Dive Rite on this. For some reason they only mention using the 3xAAA pack or an 18650 in their info card.

I've read somewhere that some of the 26650 batteries can put a lot more current than an XML2 can handle you may want to get a driver for the LED to throttle it back and also allow you multiple output levels too.
 
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