Introduction: EMERGRNCY LIGHT With Mobile Phone Battery

Picture of EMERGRNCY LIGHT With Mobile Phone Battery

There were a few Discarded Mobile Phone Batteries lying around the house, so I was thinking how to use them as they had plenty of juice left in them to run something.

This is how I could find a use for them by making an Emergency LED light.

Step 1: Parts You Will Need.

Picture of Parts You Will Need.

33 LED’s of 5mm.

One LED 1 watt.

A thin PVC sheet to fix the LED’s.

An old PVC light case.

3 Discarded Mobile Phone Batteries of 3.6 volts each.

1 single pole double throw switch. (SPDT)

Wires, solder etc.

Step 2:

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Fix the LED’s to the PVC sheet in 3 rows of 11 LED’s.

Check the polarity of the LED’s.

Step 3:

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Wire the LED’s, Batteries, and Switch as shown in the Circuit diagram.

No resistance or Capacitor have been used in this project. 

Step 4:

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All the 3 Batteries should be connected in parallel, so that the voltage remains 3.6 volts at all times.

Charging the batteries should be done separately one after the other.

Never charge the Batteries all together because they are Lithium-Ion Batteries and may EXPLODE by using unregulated battery charger voltage.

Step 5:

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Your Emergency LED light is ready.

Switch ON the 1watt led or the 33 LED’s as you wish.

This light is lightweight due to the batteries and can also be used by Kids.

It will give you uninterrupted light for at least 3 hours.


Step 6: Charging the Batteries

Picture of Charging the Batteries

Charging the Batteries with a Li-Ion Battery Charger.


hendrosutono (author)2012-06-12

I thing you can put a mini usb(type b) socket/female connector. That way you can charge the battery using the usb charger, the same one that we use to charge ipod, ipad, iphone, galaxy, etc.

the charging process will much easier.

mjbird (author)hendrosutono2017-07-11

The problem with that is that the cheap phone charger "bricks" only provide the 5v on the USB. If you're lucky it may also current limit to the specification's 500ma. There is no circuitry to stop the charging when the battery is fully charge. Overcharging can cause Li-Ion batteries to swell and explode. You need some circuitry to prevent the overcharge condition.

3d.rashid (author)hendrosutono2012-10-20

ya you are right we can use this connector with diod and a led as a indicator.

kanhatiger252 (author)2016-08-21

my battery is heating up so what should i do?

Dipankar (author)kanhatiger2522016-08-21

How may LED you have used?

RajanR6 (author)2016-02-17

How many 1 w LED i can connect to a Nokia 3.6 V battery?

And, How long the charge will last ?

Dipankar (author)RajanR62016-02-18

One 1 watt LED -2 hours.......

MicoE1 (author)2015-09-05

Can I ask if how many led can do in a 1 mobile battery

Dipankar (author)MicoE12015-09-06

What is the Amp. hour of the battery?

Monster2015 (author)2015-07-02

can we use this type of battery to run circuit???

Dipankar (author)Monster20152015-07-02

Try it.............

narakotch (author)2015-03-30

Instead of throwing away electronics junks which is not too good for our environment, It is good to see you guys recycling it.

How about recycling these abundantly found electronics junks :

1. In many places we come across defective 600VA UPS with 12 volt batteries

2. portable LED lamps (Chinese Made)

Do you guys have any idea how to recycle it, so that these cheap LEDs could be powered by not so healthy 12 volts batteries from the UPS, Also since the Charging section in the UPS are often intact, one could use this to charge the 12 Volt Batteries.

WasiA2 (author)2014-12-10

Hey !

1.By connecting 4 mobile batteries of 3.7 V can i get 12V or high...? can i connect all of them in parallel to get 12V use some thing....

Dipankar (author)WasiA22014-12-11

1. By connecting 4 mobile batteries of 3.7 V in series you get 14.8 volts.

2. By connecting 4 mobile batteries in parallel you get 3.7 volts.

Ashishk003 (author)2014-05-11

Hey Dipankar ! I want to glow Led from a 12 volt Battery. How Many Led i have to use? please guide me the necessary details.

Dipankar (author)Ashishk0032014-05-11

What is the Ampere of the 12 volts battery?

databank08 (author)2014-02-07

Hi All,
I came across similar project that I needed to work on. I ripped off four Li-Ion (falt build) batteries from Sony NP FH100 7.2v pack, pretty similar to 3.6v mobile batteries, (except that these don't have any clothing lol).
What I did was put all of them in parallel and used protection circuit:

And of course as a stable power supply to above circuit I can't rely on anything but DC-DC buck converter. Its just the matter of getting all things together and connecting correctly.

timpowell (author)2013-11-20

Is there anyway to charge the batteries while the light is in use, like would be possible would when the battery is inside the phone?

Dipankar (author)timpowell2013-11-20

Do not charge the Battery when in use....

krisley (author)2013-03-28

Sweet. I built myself an electronic cigarette. It's a basic circuit that connects 4-AAA battery pack to a dead man's switch and a cartomizer. Think it'd be safe to switch out the AAA pack for a cell phone battery?

Dipankar (author)krisley2013-03-29

Yes use 2 Mobile Phone Batteries in series.

krisley (author)2013-03-25

Are using phone batteries as simple as utilizing the positive and negative pins?
I have three Li-Ion batteries from HTC, used in the G2 phones. They have four contacts, the positive and negative being the furthest left and furthest right pins.

Do the middle contacts have no bearing to using the batteries as a power source?

Dipankar (author)krisley2013-03-26

It is only inside a mobile phone that the 2 contacts other than the positive and negative comes into play. If you using the batteries outside the mobile phone then use only the positive and negative contacts, for use to light an LED or while charging.

ramizsattar (author)2012-04-12

Please check.

This circuit has LEDs is series. Battery voltage is 3.6v and LEDs asking for 33v???

LEDs chould be in paralell and must have a current limiting resistor or LED driver.

Dipankar (author)ramizsattar2012-04-13

SORRY I have uploaded the wrong circuit Diagram, thanks for pointing it out to me. THANKS....................

satpathi (author)Dipankar2012-11-01

Pl post the correct circuit diagram?

Dipankar (author)satpathi2012-11-01

Already posted in step 3........

Dipankar (author)ramizsattar2012-04-16

Dear ramizsattar,
I have changed the Circuit diagram, please check it out. A current limiting resistor is not required here.

ramizsattar (author)Dipankar2012-04-16

Dear Dipankar

Its ok now.

As LED temprature rises when it glows, its current will also increase (I checked it myself), what will happen, LED taking 20 mA current will start taking more current and its life will direase. Its always better to limit the current.

I am using two 1 W LEDs (with current limiting) for fish equarium, they are constantly running since two years (with 3 to 4 hrs rest per day 14600 hrs) nothing happend to them.

Dipankar (author)ramizsattar2012-04-17

OK and Thanks.......

tutdude98 (author)2012-04-05

These old phones dont have diode inside (it have diode on charger) so i can charge and use it with this cable

Dipankar (author)tutdude982012-04-05

Yes there are many ways to charge the Batteries, and you can choose to do it your way, the main thing is to charge the batteries.

tutdude98 (author)Dipankar2012-04-06

no i mean with this cable i can use battery :D so i just need put phone inside and connect it to leds and leds will work
I dont need to solder battery

ray_Bond (author)2012-04-05

Hi Dipankar bhai its really nice and very simple upload. Keep it up bro its really simple one. You make it really simple and easy to made. The only one thing i would like to add here is that; these batteries are rechargeable so just add cheap mobile charger to it and make it more valuable. There is no need to pull out the batteries separately and charge them. What is required;is that you put simple mobile charger which connected in parallel to all the batteries and of course it will take time thrice as com paired to that off single battery.............................
Thanks bro to upload such good things

rimar2000 (author)2012-04-01

This seems very useful, Dipankar. Thanks for sharing. Electronics is my pending subject, but this project is very simple.

Dipankar (author)rimar20002012-04-01

I only make simple projects so that any one can make it without difficulty.
Thanks pal.

samalert (author)2012-03-29

Great Dipankar, i did one which was very small to keep not a very large scale one and tat 1watt led is so bright must say tat single led is enough for me :P
Thanks for the instructable

Lastly since you soldered the wires to the battery it is very difficult to remove solder > charge > solder again

tutdude98 (author)samalert2012-03-31

make some battery holder :D

Dipankar (author)tutdude982012-03-31

Easier said than done, can you give me an idea?

tutdude98 (author)Dipankar2012-03-31

make holder from plastic and where are terminals put some metal and solder on that metal so you can put battery in that case and later remove it and charge

Dipankar (author)samalert2012-03-29

They are not soldered but twisted and taped for removal and charging the batteries.

rocketman221 (author)2012-03-31

How do you charge it?
You might want to add a lithium battery charger from sparkfun so it can be charged from a USB port.

Dipankar (author)rocketman2212012-03-31

The Positive terminals of the three Batteries are soldered to the batteries and clipped on the other side. when you want to charge, take out the positive wires from the clip and charge each battery separately. The negative terminals can be together, no problem.

About This Instructable




Bio: Now I am a retired person, who enjoys life and making small things to pass the time keep myself busy.
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