474Views8Replies

Author Options:

Is this a capacitor or a battery? Answered

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,
Thanks

Discussions

0
None
frollard

Best Answer 8 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.

0
None
Re-designfrollard

Answer 8 years ago

I vote nicad also.  Recently I took apart a crank radio that had a very similar nicad battery in it, except no shrink wrap.

0
None
frollardRe-design

Answer 8 years ago

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.

0
None
onrustfrollard

Answer 8 years ago

That is my instructable title!
The instructable has been featured as well and "battery free" is up for question.

0
None
frollardonrust

Answer 8 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.

0
None
onrustsmitec08

Answer 8 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. 

0
None
Kiteman

8 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...