LED TORCH from discarded mobile BATTERY

INTRO

Here I have used a discarded Li-Ion Battery which is no more working in a mobile handset.
This Battery may not work in a mobile set but it has got a lot of juce left in it to run a small poket size rechargeable TORCH with 5 LED's. It gives a very bright light and does not need a recharge for quite a long time.

Step 1: STEP-1

List of Parts.

1.- One PVC flat Box of size 2 x 3 x 1/2 Inches.
2.- One Single pole single throw switch.
3.- Five Very bright White LED's of 5mm size.
4.- One Discarded 3.6v Li-Ion Battery. (Lithium Battery)

Comments

[randulahemal]

hi dipankar.
thats nice thing buddy.very good

[Dipankar]

Thanks Pal....

[nicholasm]

hi Dipankar,
can we use li-polymer 3.6v type CBA-0001003B?

[Dipankar]

Use any type of battery but you should have an appropriate charger for it.

[7600]

Hi Dipankar. Perfect instructable just what i need for my spare mobile phone battery. :)

Just a question, how did you connect the wire ends to the battery contacts? were they soldered?

[Dipankar]

Spot soldered.

[dava_2]

Ok, thank you..

[dava_2]

What is this sing: http://www.kpsec.freeuk.com/symbols/led.gif
Thanks!

[Dipankar]

This is the symbol of an LED.

[imakethings]

can any one post an instructable how to recharge those batteries without the cell phone?

[ironsmiter]

Here is a little shameless self-promotion, and direct response to your request.

I was thinking along those same lines, as I was reading this 'ible.
then I looked in my electronics junk, er, recycle pile, and inspiration hit.

My solution will indeed recharge, even the larger cellphone batteries.... but it'll probably take a LONG time. My palm treo battery has roughly 9 times the mAh rating, and I don't think my converted "toys" do ANY kind of quick charging. I think they are full-time trickle chargers, with a "full battery shutoff" circuit.

[Dipankar]

How to Charge a Li-Ion Battery Most dedicated Li-Ion-charge integrated circuits (ICs) are designed to charge the battery in this manner. The charging of a Li-Ion battery consists of three phases: pre-charge; fast-charge constant current (CC); and constant voltage (CV) termination. In the pre-charge phase, the battery is charged at a low-rate (typical of 1/10 the fast charge rate) when the battery cell voltage is below 3.0 V. This provides recovery of the passivating layer which might be dissolved after prolonged storage in deep discharge state. It also prevents overheating at 1C charge when partial copper decomposition appears on anode-shorted cells on over-discharge. When the battery cell voltage reaches 3.0 V, the charger enters to the CC phase. Fast-charge current should be limited to 1C rate (0.7°C rate) to prevent overheating and resulting accelerated degradation. However, cells designed for high power capability can allow higher charge rates. Rates should be selected so that the battery temperature does not exceed 50°C at the end of charge. The battery is charged at the fast-charge rate until the battery reaches a voltage regulation limit (typical of 4.2 V/cell, but 4.1 V for coke-based anodes Li-Ion battery). The charger starts to regulate the battery voltage and enters CV phase while the charge current exponentially drops to a defined termination level. However, the output voltage regulation accuracy is critical to maximizing battery capacity and improving its service life. Less battery voltage regulation accuracy means to undercharge the battery, which results in a large decrease in battery capacity. The battery loses about eight percent capacity if it is undercharged by one percent voltage. On the other hand, less battery voltage regulation accuracy also means the battery is overcharged, which reduces the battery service life-cycle. To safely charge the Li-Ion battery, it only allows initiating to charge the battery when the ambient temperature is between 0°C to 45°C. Charging the battery at lower temperatures promotes formation of metallic Lithium, which increases the battery impedance and causes cell degradation. On the other hand, charging the battery at higher temperatures causes accelerated degradation because of promoting Li-electrolyte reaction. This presents a market need for more accurate, efficient and safe battery charge for portable devices. By Jinrong Qian, Senior Member of Technical Staff, Texas Instruments

[zwarriorx]

i'm a newbie just trying to grasp basic electronic concepts ....

.... so you say to connect the LEDs in parallel but mention nothing about using resistors, because this article --> http://www.kpsec.freeuk.com/components/led.htm <-- advises against connecting them in paralel, or at least use a resistor for each LED.

Feedback needed. Thx.

[Dipankar]

Hi zwarriorx, Resistors are only required when the voltage is above the working voltage of the LED's. All the 5 LED's are connected in parellel with a switch to the Battery. LED's are connected PARALLEL because the output voltage of the battery is 3.6 volts and the White LED runs on 3.3volts. So the led's are slightly overrun which will not matter but will give a bright light.

[nikki1920]

does anybody kows the importance of IC in mobile phone battery? what is the diffirrence of double IC to single IC? please i need quik reply. thanks.

[Dipankar]

Hi nikki1920, Sorry , could not follow your Question. There are no IC in a mobile phone battery.

[cpotoso]

Does anyone know how to charge one of those batteries safely (without using the original cell phone)

[Dipankar]

Hi cpotoso, Buy a Lithium Battery Charger which charges many types of lithium batteries.

[cpotoso]

Most cell phone batteries have 3 connectors. Do you know what they are? Thanks for the answer, especially the answer to "imakethings". Good instructable, btw.

[Dipankar]

Yes cell phone batteries have 3 connectors.
Right side is (-) Left side is (+) marked on the battery

The MIDDLE connection is for the CHARGER, it decides what type of charge to give to the battery at what time. It reads the condition of the battery.

SEE ----------- How to Charge a Li-Ion Battery.

[DIY Dave]

I think you could use the cellphone charger without the phone.

[Dipankar]

NEVER USE THE CHARGER WITHOUT THE PHONE. Where will you get the third logic connection? It is in the cell Phone.

[cpotoso]

Isn't the charging logic (described by Dipankar in the answer to imakethings) contained in the cell phone rather than the "wall wart"?

[Dipankar]

YES - The charging logic is contained in the cell phone itself. Special types of Charger are there to charge LI-Ion Batteries.

[collard41]

to be on the safe side i would add a resistor in there to. As you can soo from the photo on the last step it says DO NOT SHORT CIRCUIT. Connecting the LEDs to the battery like that is practically making a short circuit.

good idea though

[Dipankar]

Dear collard41, LED's are diodes which are a one way street, Resistors NOT required.

[qs]

The LEDs will draw about 250-300mA with a freshly charged battery (which is about 4.2v). This current is safe for the battery, but might shorten the life of the LEDs quickly if used for long periods of time. The diode in the circuit below cuts down the excess, and gives you about 2x the run time. A push button switch will let you go "High" when you need to. You can add one more diode in series to cut down the brightness even more, and extend battery life even longer! The addition of a 10k resistor (anything from 5k to 50k is OK) gives you a 'night-light' feature too.

[Dipankar]

Hi qs, I tried Using a IN4001 and the light became so dim that it was useless as a torch, please advice.

[qs]

The diode protects the battery from being drained below 3-volts. First, make sure the battery has 8-10 hours of charging! Then, if you have access to a DC-voltmeter, turn your lamp on and measure the voltage across the + and - of the battery - if it is under 4-volts then the battery is dying and cannot be properly recharged any more.

[Dipankar]

Hi qs, Will it help if I use 5, 150-Ohms resistance to each of the LED's, to keep it simple. Please Advice.

[qs]

If the Lithium is 4.2v; and you want to run the LEDs at 3.3v at 20mA, the proper R is: (4.2 - 3.3) / 0.02, or 45-ohms per LED. Anything from 39 to 56-ohm should work fine.

[collard41]

the diode will only cut down the voltage a bit. using V=IR you'd want about 20-30mA of current through the leds, at 4.5V and a voltage drop of 2V with the LEDs you would need about 400ohms resistance in series with the LEDs.
this will make the leds go miles higher and with no noticeable difference of brightness.

[qs]

Your numbers are off: White LEDs have an operating range of 3.2 to 3.6v. Silicon rectifier diodes like the 1N4001 will drop around 0.65v. A properly charged Lithion battery is 4.2v If you use the diode to remove 0.65v from 4.2v, it will bring the voltage to within the LEDs safe operating range. This has the added safeguard of preventing the Lithium battery to be drained below its recommended level of 3-volts.

[disturbedreaper]

leds last a very long time like a few solid years of on so i wouldnt mind even cutting that inhalf to make it a bit brighter

[qs]

That's why there is a switch for 'regular' brightness. If you run 25mA LEDs at 60mA, they will be noticeable dimmer in a few weeks. At 150mA they will die in minutes. Also, LEDs efficency goes down as you increase the current (it also becomes real purple-y) - you get way less than double the light when you double the power. So it's a no-win to over-drive LEDs.

[disturbedreaper]

it is a nice idea and if im gana make this ill probaly use the switch

[Dipankar]

Dear qs, I am really thankful to you for your advice, that is why I always refer my Instructable to you. Thanks again.

[ta-tommy]

how can you short a bulb?

[rimar2000]

Dipankar, Wednesday I disassembled an old mobile telephone, I think the battery is good. I will do your project. Thanks.

[Dipankar]

Hi rimar2000, Happy hunting, You will love the Bright light.