# Charge Your Phone With a Car Battery (6V-24V)

31,285

73

13

## Introduction: Charge Your Phone With a Car Battery (6V-24V)

Charging your smartphone while camping outside is not always easy. I am showing you how to charge your phone by using a car battery and a moped battery. You can also use the gadget with any kind of 6V-24V power source.

### Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

## Step 2: It Is Time to Choose Your Circuit!

You may have noticed that I build 2 cicuits inside this gadget, which basically have the same function. But they have their own pros and cons:

LM7805:

+ very simple, perfect for beginners

+ very cheap

+ useful when you only need a little current

- efficiency is horrible with higher voltages (24V --> 21%--> becomes a heater)

(12V --> 42%--> not nice)

LM2576:

- more complex circuit

- more parts, more costs

+ efficiency is quite good for a DIY phone charger (around 80%)

You can decide which one you want to use or maybe you build both. It is up to you.

## Step 3: The Simple Way: LM7805!

Ebay:

Capacitor Kit:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

Amazon.de:

LM7805: http://amzn.to/1rFtsve

Capacitor Kit: http://amzn.to/1vEZGGc

Amazon.com:

LM7805: http://amzn.to/10pimPw

Capacitor Kit: http://amzn.to/10pis9P

You only need 3 parts for this circuit. If you got all the parts then follow the schematic to create your circuit. Feel free to store your new gadget in an awesome case.

## Step 4: The Efficient Way: LM2576!

LM 2576 (be sure to get the 5V version, there also exists an adjustable one):http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

Capacitor kit:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

Schottky Diode:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

This circuit requires 5 parts. But it is still pretty cheap and creating the circuit should be fairly easy.

## Step 5: Combine the Circuits and Make a Case!

If you decided to build both circuits and you want to combine them in one awesome case like me, then get your parts and follow the schematic.

Rotary switch:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

Green LED 5mm:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

## Step 6: Success!

I hope your new gadgets works great and you enjoyed this project.

Feel free to check out my Youtube channel for more awesome projects.

9 2.9K
30 5.9K
53 7.4K

## 13 Discussions

l was wondering what will happen if we don't use the coil and the schottky diode ? Because when l'm using them my output amp is getting too low around 80mA.And as a second is this safe ?

Take any car adapter for your phone and connect it to the battery and you have the same thing. It will work for 6v-12v

i have no coil / inductor can you give the alternative

Now i made a pcb for that circuit (LM2576 circuit only). I used heatsink with IC & yes...it worked. But there is still problem with inductor.. Although i used an inductor with current rating upto 3Abut it still becomes hot enough to touch..!

(Plz note that i couldn't find the inductor in toroidal form with proper rating that's why i used 3A 100uH inductor in cylinderical form)

Now i made a pcb for that circuit (LM2576 circuit only). I used heatsink with IC & yes...it worked. But there is still problem with inductor.. Although i used an inductor with current rating upto 3Abut it still becomes hot enough to touch..!

(Plz note that i couldn't find the inductor in toroidal form with proper rating that's why i used 3A 100uH inductor in cylinderical form)

I tried one at bread board for testing...though it worked but the problem is my ic 2576 & inductor are heating up. I connected my phone n it started charging. Al most after 15 or 20 min the ic an d inductor became so hot that it was hard to touch them

anyone can tell the reason and suggest any change to make it more efficient

Very nice method. :)
I want to charge my phone using a 6V Lead acid battery (6.8V 5 Ah).
So my question is can I use this switching regulator in case of 6.8 V battery ?