Is this a capacitor or a battery?

In regards to my "battery free bike light".
  I was told that a dynamo flashlight charges a capacitor.  Is this the case?
Take a look,

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frollard7 years ago
I would be inclined to believe its a small nicad battery - anything but a supercap at that size would light an led for mere seconds, where these generally run for a few minutes.

As kiteman says - its mostly dependent on runtime.  Less than a minute is probably a cap.
cutting off the shrinkwrap will likely yield a result.
I vote nicad also.  Recently I took apart a crank radio that had a very similar nicad battery in it, except no shrink wrap.
Although, rereading the title "battery free bike light" could mean there is no user provided batteries...or that it truly has no batteries total :S

Damn marketing fuzz.
onrust (author)  frollard7 years ago
That is my instructable title!
The instructable has been featured as well and "battery free" is up for question.

frollard onrust7 years ago
Title is fine - just need to include a little disclaimer that its a semantic argument on what a flashlight having a battery actually means - in this case, you don't have to supply any AA's or anything.

its a 3.6V NiMH battery, well as long as its the same one from the instructable.

Also apparently only has a 500 charge life cycle.

see here:

Hope that helps
onrust (author)  smitec087 years ago
  Yes, it seems I'm getting a bit of criticism about my title.  Since the instructable was featured I'm not going to edit it.
  Thanks for the info.   I am most interested to see how long I get out of a "500" charge life cycle. 
Kiteman7 years ago
From the proportions, probably a capacitor.

If it charges to maximum brightness quickly, and if the maximum brightness does not not last a huge length of time, then it is probably a capacitor.

If you don't want to cut the heatshrink off it, try charging it up and then shorting out the connections with a piece of wire - if you get a crack and a spark, it's a capacitor...

...and you may just have wrecked it...