Making a handcranked flashlight with a supercapcitor

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Discussion Overview

The discussion revolves around the construction of a handcranked flashlight utilizing a supercapacitor for energy storage. Participants explore the feasibility of using supercapacitors versus batteries, the specifications of the components involved, and the necessary circuitry for the project.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant seeks advice on the type and number of capacitors needed for a handcranked flashlight project using a geared DC motor and LED light.
  • Some participants assert that supercapacitors cannot be made from regular capacitors and emphasize the need for specific electronics to manage their low voltage and charge/discharge cycles.
  • Another participant mentions seeing videos where supercapacitors were made from multiple lower voltage capacitors, suggesting a possible method.
  • There is a suggestion that using lithium cells might be more effective for energy storage than supercapacitors, especially given the project constraints.
  • Concerns are raised about the power output of the proposed motor and whether it can adequately support a 10W LED, with suggestions for alternative components and configurations.
  • One participant expresses frustration about being restricted to using supercapacitors due to school guidelines against batteries.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to the project. There are competing views on the use of supercapacitors versus batteries, and differing opinions on the feasibility of achieving the desired power output with the selected components.

Contextual Notes

Participants note the limitations of using supercapacitors, including the need for additional circuitry for effective charge and discharge management. There is also uncertainty regarding the actual power output achievable with the specified motor and LED combination.

Who May Find This Useful

This discussion may be useful for students or hobbyists interested in DIY electronics projects, particularly those exploring energy storage solutions and the practical challenges of using supercapacitors in applications where batteries are not permitted.

Milo08821
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TL;DR Summary: I want to make a handcranked flashight with a supercapacitor, I need some help and thoughts about what type of capacitor do i need and how many to make suppercapacitor.

the dc motor im going to use is a geared motor which is;
DC Gear Motor 12V 250RPM- SGM25-370
Specifications:
Operating voltage: between 6 V and 18 V
Nominal voltage: 12 V
Free-run speed at 12 V: 250 RPM
Free-run current at 12 V: 50 mA
Stall current at 12V: 1200 mA
Stall torque at 12V: 38 kg.cm
Gear ratio: 1:35
Reductor size: 21 mm
Weight: 85 g

and the LED light im going to use is aroung 10w, i just ripped it off a bike light

Im also using 4 1N4007 diode for a bridge rectifier
 
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You don't "make" supercapacitor from normal capacitors, you buy one.

They are not trivial to use, they have a specific, low voltage (around 2.7 V for fully charged), so they require quite a bit of electronics/regulators for both loading and recovering the charge.
 
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Borek said:
You don't "make" supercapacitor from normal capacitors, you buy one.

They are not trivial to use, they have a specific, low voltage (around 2.7 V for fully charged), so they require quite a bit of electronics/regulators for both loading and recovering the charge.
but some videos i saw, they make a supercapacitor with normal capacitors, no? I saw a video making a supercapacitor with 10 2.7v 3.3F capacitors
 
Milo08821 said:
3.3F capacitors
Those 3.3F capacitors are super-capacitors.
They were probably being connected for greater voltage.

For energy storage, you may do better using a lithium cell than a super-capacitor.
 
Baluncore said:
Those 3.3F capacitors are super-capacitors.
They were probably being connected for greater voltage.

For energy storage, you may do better using a lithium cell than a super-capacitor.
if I could, I would've done it by now, but my teacher doesnt allow us to use batteries, thats why im opting in using supercapacitors for me to handcranked it and let it store power to light up the LEDs for an amount of time
 
Milo08821 said:
my teacher doesnt allow us to use batteries
Thread moved to the schoolwork forums. :wink:
 
Milo08821 said:
Free-run speed at 12 V: 250 RPM
Free-run current at 12 V: 50 mA
Stall current at 12V: 1200 mA
I would be really surprised if you could get more power from that than 2-5W. For a few seconds, at best. And you have a 10W lamp...

A supercap is a terrible idea. Either a battery or a standard cap would work to some extent with minimal electronics, but supercaps ... nope. You would need multiple DCDC conversions at least: but proper charge/discharge circuitry is recommended.
10W from any cheap(ish) supercap is also quite a hassle as I recall.

So, my suggestion: use a small, standalone white LED with a cheap drive circuit: with a standard big cap: and a less dramatic generator.

Maybe you could look around first that how it is done?
 
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@Milo08821 I am wondering how far along in school you are.
 

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