Rechargeable Emergency LED Light

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Introduction: Rechargeable Emergency LED Light

About: student of ELECTRICAL ENGINEERING

very easy to make.
things you have......21-white led, 1-PCB, 1-330ohm resistance, 1- 1N4007 diode, 1-switch, 1-small red led, 1- small Container box

Step 1: Cut the Container Box Like This...

Carefully cut like this..

Step 2: Make Led Circuit

Step 3: Then..

solder all things.. as per diagram.

Step 4: Small Red Led and Socket

fix socket and red led as photo

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    14 Comments

    what's the config of white LEDs? is it 1w led? or less?

    4 replies

    no its not 1w led ....I think it is lass then 1w

    This is a nice project. The only problem is that you are drawing too much current. If 1 led had a 20mA current draw, then the LED's alone are drawing about 440 mA!! That is very power inefficient. Now if your going to hook your circuit to a 2000mAh battery, the battery will only last you only about 4.5 Hours. You should multiplex the LED's so only 1-3 are on at a time. That will draw less current than powering all the LED's at once. You won't notice the off LED'S because of POV(Presistence of View). Anyways next time you should provide a schematic of any project you publish so that other people could build the projects you make.

    5 replies

    multiplexing the leds will not reduced power. It will reduce the no of wires. Secondly it requires a circuit which is more complex, at least in the terms of fault finding. Secondly, if you are multiplexing 3 leds, then to keep the same illumination you will have to give a pulse current which will be three times dc current. This may affect battery.

    For checking efficiency, you should compare light output to power consumption.

    Wrong. If you power only one third of your leds, you'll get only one third of light, POV has nothing to do with that.

    What makes me perplex is there's no current limiting, current is only limited by internal resistance of the battery, something will break soon !

    First, I said to turn on 1-3 LED AT A TIME. It doesn't mean I couldn't switch the led's really quick so you notice the flashes(that's how you cell phone's screen works). This could be done with an NE555 and a 4017. Second, an LED cant keep drawing current. It only draws only 20mA. It wouldn't keep eating current.

    overcharging lithium will make it die fast or explode..becareful

    2 touch buttons inplace of rocker can be made

    Not bad but soldering technique is not well.