Introduction: Emergency USB Charger V1.0

Picture of Emergency USB Charger V1.0

It is a device that will charge your phone & other other devices that plugs into a USB to charge.

Make it and enjoy.

It can charge your phone up to five time in one full charged battery.

You can charge 4*3 Volt battery with your Nokia mobile charger. It will take time to charge.

Ones it is charged it is ready to charge your phone 5(approx) times. :)

Step 1: Requireed Items

Picture of Requireed Items

You will require:

  1. LM or MC 7805 +5VDC Voltage Regulator
  2. Heat Sink(Optional)
  3. Type-A Female USB Port
  4. 100uf Electrolytic Capacitor 10-50V
  5. 0.1-0.5uf Capacitor 6-50V (any type would do)
  6. 100-160 ohm Resistor
  7. 12(4*3)V Battery(Series Connection)
  8. 2.2V 20mA LED color of your choice
  9. Bread board
  10. Pref Board
  11. 3 Pin Switch...etc which are present in picture

Step 2: The Circuit Diagram (Simple)

Picture of The Circuit Diagram (Simple)

The following picture shows the sketch diagram of Circuit which we want to make.

Step 3: Attaching the Components

Picture of  Attaching the Components

First attach all the components on Bread Board and check the output(O/p) is 5V by Multi-Meter or we have 5V O/p Checker. Then Place it on PVC Board and solder it with the help of soldering components Like the picture.

Step 4: Adjustment

Picture of Adjustment

Do some holes in the box for switch, Charging Point and USB Hub. Do some adjustment in your box and make it fixed with the help of Hot Glue Gun.

Step 5: Done! ;)

Picture of Done! ;)

Now that you've finished building your own USB charger, all you have left to do is to put batteries in box and use it.

Remember when you add batteries in series then it will give you sum all voltage and if you connect all batteries in parallel then it will give you sum of all Amp. .

Ones it is charged it is ready to charge your phone.... ;)

Step 6: Demo!

Check It out...... It's Working Properly....

Step 7: Ugrade

Picture of Ugrade

In this step you will see a how to upgrade you USB Charger..

Since when you insert your charger and switch is not on then charger LED and capacitors are taking voltage from your battery.

So we put a Zener Diode or an Ideal Diode to save your battery. Here I used Zener Diode of 12 V.

Now question Comes What is an Ideal Diode and Zener Diode??

An Ideal Diode is a diode which allows current to flow in the forward direction but not permits it to flow in the reverse direction.

A Zener diode is a diode which allows current to flow in the forward direction in the same manner as an ideal diode, but also permits it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, "Zener knee voltage", "Zener voltage", "avalanche point", or "peak inverse voltage".

Do connection as like in picture first........


shivraj.singh.965 (author)2015-02-01

Awesome Job.... Bro.

Tech Works (author)2015-01-28

Please Vote me... With your help it may be possible that i win the contest....PLZ

mrcaderly (author)2015-01-27

Great idea! Thank you for creating and sharing this instructable.

Tech Works (author)mrcaderly2015-01-28

Please Vote me...PLZ

Tech Works (author)mrcaderly2015-01-27

there were lot of project like this i just made a change little bit. hope you like it. :)

MsSweetSatisfaction (author)2015-01-27

Wow I love the idea of this, it's so useful in the modern day and age. Seems like my devices are always dying... Awesome job showing each step!

Please Vote me...PLZ

I'm glad you liked my work and I appreciate your confidence in me.

rodski (author)2015-02-05

The 90% value is = 0.9
The 80% value is = 0.8
This value were derive from "how the battery generates its preserve power.The formula can be found on
Yoobao FAQ site
(powerbank manufacturer in China).Hope that clarifies your querries.

Tech Works (author)rodski2015-02-05

Thanks a lot man i will remember the calculation...

What do you think if i add 3 more batteries of series connection in parallel to other three then the O/p comes 12V and 7000mAp. can we do this to charge any phone more times.

rodski (author)Tech Works2015-02-05

Glad it helped you understand what i mean...Yes you can do that as long as your DIY board can handle it,as far as i know LM7805 regulators generate heat.(advice add holes on your plastic case for ventilation).You can add 3 batteries in series parallel to that 3 pre installed before.But the downside here,it would be a bit bulky.I suggest you use three 18650 Li-ion batteries with higher mah(ex 3800 mah) wired in series and do it as you planned to double it.

Anyways,you did upgraded your DIY & that's good.Now it's more appealing than before...Cheers!

rodski (author)2015-02-04

As a fellow DIY maker i just make inputs here,not to degrade your project or anyone.,I create & build & shared it here,& im open to any comments made on my ibles.,you should be open to any discussion specially if we are discussing your DIY.As im saying i make QUERRIES!Peace!

Tech Works (author)rodski2015-02-05

your are right as a fellow DIY maker you may just make inputs here, I appreciate that you are giving attentions on my project. I'm ready to answer all of your queries.

Tech Works (author)Tech Works2015-02-05

let's remove the topic of how many times it can charge your phone. i took my word because i can't prove you anything with pictures and video. I'm unable to understand charging formula but I think you are telling me from so much confidently that's why i removed the charging limit's from project 3 day's ago. But i want to learn all the details about the formula... the calculation part

rodski (author)2015-02-04

Pls..,Read my comments carefully before you respond.

•Why 90%? Assuming the power bank is well maintained in good working condition and can conserve up to 90% power)
•(Why 80%? An estimate of 20% power is consumed during the charging/ discharging process)

Because you ask for it!

Tech Works (author)rodski2015-02-05

As i said i can't understand the calculation part. Please provide me the full calculation portion .90% of V or amp and 80% of V or amp


rodski (author)2015-02-04

If your still not convince,just ask me,& i will give u the site that gave the formula how powerbank works..,peace!

Tech Works (author)rodski2015-02-05

my friend please provide me the site where you get the formula because i'm unable to under stand what are the values of 90% and 80%

rodski (author)2015-02-04

My friend,no offense,thats not my formula,as i said,i got it from a powerbank maker site from China,& indeed work.Second thing,you havent answer my question,HOW DID YOU WIRE YOUR BATTERIES?,,3rd thing is i said 1 time ,because that
.77 left wasnt good enough to charge your phone in full..4th Never drain a lion battery,believe me,or it wont charge at all.Now tell me,if you wired it in series,to gain 12vdc.,then how come your battery becomes 3.5Ah when it shows that its only 1.5 Ah!
& DIY PROJECT should be discussed because you shared it here,& i make queries.,Right?

Tech Works (author)rodski2015-02-05

in answer of your second question, i put batteries in series and it is gives output 13.65V and 3.5Amp

Now you are agreeing that to never drain a lion battery that's way i said when .77 left it may charge your phone fully.

As i said in last comment it is showing 3.5 Amp. because it is a chiana battery

rodski (author)2015-02-04

One last thing-as you said on your comment
"4th thing"

"So from my calculation it will charge your phone approximately 5 time."

-how did you CALCULATE IT? Can you elaborate it!,
-hoping you answer all my questions here!Thanks

rodski (author)2015-02-03

Calculating the number of times a powerbank can charge a phone.
Example:(in my case using iPhone 4 with my DIY 6600 mah PBank)
-Powerbank: 6600mAh (full at 90%)
-iPhone4 Battery: 1420mAh
= 3.34 = 3 times
(Why 90%? Assuming the power bank is well maintained in good working condition and can conserve up to 90% power)
(Why 80%? An estimate of 20% power is consumed during the charging/ discharging process)
•i closely monitored & record notes these for me to see if the Formula is accurate.
•Got the formula from a well known Powerbank manufacturer in china(that i cant remember the name & url)and Yes,this FORMULA was accurate.
•now in your case:
Lets assume same phone is used:
Powerbank: 3500mAh (full at 90%)
-iPhone4 Battery: 1420mAh
= 1.77= 1 time only

Tech Works (author)rodski2015-02-03

*First of all my friend i want to tell you I'm unable to understand your FORMULA..I want to know what is 90% and 80%..

*Second thing is in my case my phone will be used. My phone battery having 1020mAh

*Third from your Calculation value comes 1.77 that means 1.5 times even more than it. So do calculation properly. we take majority part to go with round figure.

*Fourth thing is every time you will not drain(use full battery until your phone will automatically switch off). So from my calculation it will charge your phone approximately 5 time.

*Fifth thing is I was using the power bank which i made regularly from 3 times.

*Sixth thing is In this project I'm teaching to make this item not to discuss how many times it will charge your phone....


rodski (author)2015-02-02

Thanks for immediate respond & resolving the diagram error.,but as far as i know 1.5 Ah = 1,500mah wont charge a smartphone 5 x with that battery,.

Tech Works (author)rodski2015-02-03

try it...... i said approximately

picture is showing battery amp. is 1.5 but those batteries are from china and they are showing 3.5Amp.

rodski (author)2015-02-02

Thanks for correcting the diagram.

rodski (author)2015-02-01

Can you elaborate which one is correct here..(on your STEP #2

Tech Works (author)rodski2015-02-02

there is little bit problem in it....when i draw the circuit diagram i'm thinking about LM7805 terminals that's way i made a silly mistake....

But i solved it..... you can check and this diagram is correct

rodski (author)2015-02-01

But if you wired it in Parallel then yes,all their 1.5Ah will sum up to 4.5Ah and their voltage stayed at 4vdc then.,can you clarify that.,it's a bit confusing & uou didnt mentioned how you wired it.

Tech Works (author)rodski2015-02-02

Sorry about it.. I have made some mistakes but now i solved every thing and clear all procedure.

rodski (author)2015-02-01

How did you wired your battery?,is it in Series to produce 12vdc?,then the battery amp of 1.5Ah wont increase

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