Fun with supercapacitor: an usb rechargeable LED flashlight
So it was a long time since i wanted to play with a supercapacitor. I found a good deal on ebay for some 4F, 5.5V capacitor.
The first thing i made is a micro flashlight. It's basically a single super bright (i think 10k mcd) LED with a 660 resistor, a custom USB plug for recharging, and a small switch to turn it on and off.
I made this to see how much juice these supercapacitors could hold. Well, the final result is: a lot :) Powering it for a two or three minutes will keep the led at good brightness for a couple of hours, after that it starts to fade but it's still "light" for more hours, gettin dimmer and dimmer :)
It turns out it's quite a useful flashlight :) with the usb port it can be recharged almost anywhere, the capacitor doesn't have memory effect or loss of capacity over time like batteries, so it's just "plug" at any time without worrying and use it :P
All considered, a funny project :)
image:
image:
@ Wed, 2010-12-29 10:05
Cool idea!
Very cool thing, the usb charching function is very handy. I would like to make a similair thing. But then
something that charges itself with a solarpanel. Wouldn't that be a great idea?
@ Thu, 2010-10-28 17:30
Great idea! Could you please
Great idea! Could you please make a schematic of your setup? Thanks
@ Thu, 2010-10-28 15:16
italians light it better
italians light it better :P
have you the opportunity to test your supercap with a pager motor? do you think that is suitable for power a small robot?
can you provide infos about charge and discharge current of your cap?
@ Thu, 2010-10-28 15:40
LOL :Pthe specification are
LOL :P
the specification are these (i'm not good enought to understand all :P ):
Specifications:
Rated voltage: 5.5V
Rated discharge capacitance: 4F
ESR (mΩ, 1KHz, 25℃) : 120
DC Imp (mΩ, 0.1A, 25℃) : 180
Work temperature range: -25 to 70 Degree Celsius
Storage temperature range: -40 to 85 Degree Celsius
weight: 6.8g
Size (ΦD*L): 24.9*6 mm
Pin configuration: vertical
Long life time : more than 100, 000 times
Maintenance-free operation
Environment-friendly, RoHS compliant
I haven't tryed with a motor yet, but i've tryied to power an arduino with a buzzer and it worked. I don't know for how long :)
@ Thu, 2010-10-28 16:19
ok thankyouDC Imp (mΩ,
ok thankyou
DC Imp (mΩ, 0.1A, 25℃) : 180
this wah the parameter i was searching for. I think it's ok to drive a small motor
@ Thu, 2010-10-28 16:38
care to explain what does it
care to explain what does it mean ? :)
@ Thu, 2010-10-28 17:35
big capacitors have big
big capacitors have big equivalent series resistance compared to standard capacitors
this is an issue because it limit the max current that the cap can supply
@ Thu, 2010-10-28 12:44
Do you limit the charging
Do you limit the charging current?
@ Thu, 2010-10-28 13:08
absolutely not, the
absolutely not, the capacitor is connected directly to the usb port
@ Fri, 2010-10-29 12:55
So it charges almost
So it charges almost instantly (a few ms)? Nice :)