Have you ever wanted tiny sized power supply that still pack lots of power, here's world's smallest power supply you can make under 6$ !!! Following Features will impress you that's for sure so why not make one ?

# Features

1. 3-25v Adjustable Voltage Output

2. Built in 720mAh Battery Backup

3. 2 Amp Max Current

4. Built in Live LED Voltmeter

5. Built in Voltmeter For Quick Measurement

6. In Built 3.7v Battery Charger

Step 1: Applications

1. Power Supply (OTG) on the go !

2. Measure voltage with it.

3. Do the Job of Many Power supplies 3v, 5v,9v,12v,19v,24v...

4. Charge 3.7v Batteries on the go.

Step 2: You Will Need

★☆★ Buy Parts from your online local store ★☆★

1. 3.7v Li-po Battery http://geni.us/okAOH

2. TP4056 Lithium Battery Charger http://geni.us/f6uQJ

3. Micro Usb 2A 25v Step Up Converter http://geni.us/jbMwyB

4. LED Voltmeter http://geni.us/to6Ap9p

Step 3: Watch Full Tutorial

Watch Full Tutorial Here


Step 4: Making PCB's Compact

LED Voltmeter and Dc-Dc Converter has few leads which may puncture the battery and take up lot of extra space, so use dremel tool or sand paper to make these pcb's flat at the bottom so that battery can be effectively installed here

Or Yo can use flathead pcb wire cutter to do this job , just don't apply too much force otherwise pcb tracks will be damaged.

Step 5: Make the Connections

Make The connections As Showed In This Block Diagram.

1. Connect the tp4056 board to the battery

2. Connect the negative terminal of the battery to the dc-dc converter

3. Connect switch between positive terminal of the battery and dc-dc converter

4. Connect LED Voltmeter at the output of dc-dc converter

Step 6: Stick Togather !

Well Done Your Connections are finished !

Now Stick all the parts togather in a compact form factor as i've done in this picture.

If you like this instructibles ,then check out my Youtube Channel .

Step 7: Some Extra Safety Tips

1. As you are dealing with li-po battery's , make sure not to puncture,smash,tear or casue any kind of damage to the battery it may cause fire hazard. Do it at your own risks.

2. Don't try to measure voltage grater than 24v with this power supply's voltmeter It can damage the dc-dc converter.

3. If you connect any inductive load ,there is chance of causing damage to dc-dc converter , so connect diode at the output. diode will drop 0.7v but save your power supply.

Hi. Thanks for a brilliant instructable.. This can be used to charge bose speaker. It's battery needs 20 volt output.
<p>If you use a 3 wire voltmeter, the output can go below 3V</p>
<p>bptjr The tp4056 charge board comes stock to current limit at 1 amp . Is this too high current to charge the battery you describe ? Or did you change the current limit resistor on the board ? Great project I plan to build one Thanks</p>
<p>can I use this power supply to charge my laptop?</p><p>Input : 100-240V ~ 1.8A</p><p>Output :19V - 3.42A</p>
are those components available in ebay.in??
<p>Made it. Fun, cute and somewhat useful. I was not expecting the ugly waveform when I looked at the output on an oscilloscope. Set to 12.0V, and looked at the 'ripple' on the output line with no load. See photo below. There is an average noise of about 1.3V p-p distorted saw-tooth waves riding on the 12V level with irregular jumping levels. I presume an applied load would lower that amplitude some. I strongly recommend a heavy filter capacitor to smooth out some of that noise/ripple.</p>
Nicely done! I made almost exactly the same here https://m.instructables.com/id/Portable-Variable-Voltage-Power-Supply/, but it has a few extra features and the lithium cell is much bigger (taken from a defective portable charger) so the size is much bigger, but the main components are the same. For those interested in knowing if a bigger size cell works on the same charger,the answer is &quot;yes&quot;. I have been charging and using it for about 4 or 5 months now.
<p>Love it. As an alternative to flat-sanding the board, you could press it into a slab of Sugru, and shape it around the Li-po for a nice finished look. </p>
<p>1) does the battery get automatically disconnected from the circuit when the 'high power' USB input is used?</p><p>2) using just the battery, what output current is available from the circuit (at 5V, or at 12V)?</p>
in high power mode battery is disconnected since we're keeping battery switch off, and @5v 1.2amp @12v 500 ma.
Thank you for answering my questions. Nice project.<br>When I build it I'll have to be careful about keeping the switch off when using external power.
<p>Is that small battery to be used for the charging circuit or is it for whatever I am turning on? Can I replace that small battery with a large 5,000 mAh battery? Will the 2 amp charger be enough to charge it&gt; Hope someone answers me.JR</p>
There's no problem keeping Tp4056 as chaging circuit with bigger battery,but if battery is higher capacity then use high power handling dc converter.
<p>No. This will handle single cell lipo batteries. Charging a large lipo (multi-cell) battery requires a balancing charger to keep the charge rate under control.</p>
<p>He wrote nothing about using more than one cell, so &quot;no&quot; is premature and incorrect. There are ~ 5000mAh Li-Ion cells and you could use as large a cell as you want providing there is no minimum charge rate specified by the manufacturer.</p><p>Yes a 2A charger would, in most cases, be enough to charge a 5Ah battery, but the charger is not 2A, it is 1A max, but the input is USB so your source could be even lower at 500mA.</p><p>Even as low as 500mA could work but it would seem undesirable to have to wait that long so I would recommend that you find an alternate power source and charger capable of more than 1A, which will raise the build cost a little but so does the 5Ah battery.</p>
how to adjust voltage.....?
with the potentiometer on dc-dc converter
Is it possible to use this power supply as a battery backup with continue connection to USB power?<br>
Yes its possible to continue use with usb input.
<p>Yes but that would be foolish, to bother with a charging circuit and battery at all when you could eliminate both and just use a 5V step up power supply. There is a narrow range within which you could have more current for a short period from the battery but since the USB input is the limiting factor and that in a power outage you are presumably using some OTHER battery to power the USB, it would make lot more sense to just use a different boost or buck power supply to convert the larger input battery to the output voltage and current level needed.</p>
<p>@shaheed.</p><p>The little square blue component with the tiny screw head is a potentiometer (variable resistor). Looks like that is how you adjust the voltage.</p>
Actually it is a dc-dc step up converter .
<p>do you need to adjust the voltage everytime you turn it off and on again? Or do you get same voltage from before?</p>
You get the same voltage seted before.
<p>Hi,</p><p>very useful and clever power supply.</p><p>I've just one question, do you think it's possible to use the output power of the DC/DC during battery charging ? or it's not recommended ?</p><p>Thanks in advance for your help.</p><p>Regards</p><p>Erix</p>
Hi , Erix<br> Yes power supply can be used during charging with no problems.
<p>Nice project, i go to make also one.</p>
<p>At 3v vs 25v, qhat is the amp dra?</p>
25v @ 500ma<br>3v @ 2 Amp
<p>Compact. Great ideas. Thanks</p>
Very nice.... ?
Great instructable! So the voltmeter can measure other voltages but the source itself?
With new shipping restrictions imposed on Lithium Cells, is it difficult to get Lipos shipped to the USA from China?
<p>If you go through HobbyKing you can get Lithium batteries from their stateside outlets. I buy my lipo batteries from them all the time. Can not beat their prices</p>
<p>Work for Raspberry Pi? Can it be configured to power the Pi in a power outage on just the builtin battery with minimal power loss (Pi continues running in a power failure) and signal the Pi to shutdown before the onboard battery fails?</p>
Good idea, But 2A wouldn't be enough for 99% of my projects :)
This is really cool! Do you connect it to the circuit third through spare wires or the USB??
i used wires to connect them.

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