LiPo to MicroUSB Adapter

About: I make things occasionally.

In anticipation of my Raspberry Pi arriving I have created a LiPo (Lithium Polymer) to Micro USB adapter. This adapter converts the power from a 2s – 4s LiPo to a regular 5v. This is then outputted through a Micro USB to be plugged into a Raspberry Pi board. I will be using this to power the Pi when I use it as a ground station for my Arducopter (Which will be a whole new Instructable).
Unfortunately due to the frustration of my PCB etching attempts failing I forgot to take build photos. I only took a few once I was finished, hopefully it will be enough. I hope you all can figure out how it all fits together from the diagrams and photos. I have tried my best to explain what I did.

Please let me know if there is anything confusing you.

Step 1: What You Need

Parts that you need:
  • 1x veriboard/perfboard
  • 1x 7805 Voltage regulator
  • 2x 25v 10uf electrolytic capacitors
  • 1x Micro USB cable
  • 1x Deans Plug (Whatever Plug you use on your LiPo’s)
  • 1x Small cable tie

  • Side clippers
  • Soldering Iron
  • Heat source to shrink the heat shrink (I used a hair dryer)
  • Solder
  • Hack saw to cut the board down to size

Step 2: Failed PCB's and Schematic

My original plan was to print my own PCB and use that but after two failed attempts I gave up and simply build a simpler version on Veriboard. Once I was thoroughly frustrated from my one hundredth attempt at printing my own PCB failing, I drew up a schematic of a very simply Voltage regulator circuit. The capacitors are not strictly needed as this is not rectified AC but it doesn't hurt to put them in.

Step 3: Building

I did not cut the board first which I think made it a lot harder later on. I would place the parts and determine the size of veriboard needed. Cut it first it will make life ten time easier later! I wanted to make this board as small as possible so I place the regulator on the top and the capacitors on the bottom of the board. I put the ground pins for both of the capacitors through the same hole to make it slightly smaller. On either side on the MicroUSB cable I drilled 2mm holes and treaded a small cable tie through. This will prevent the cable from ripping out at any point. 

Step 4: Finishing Up

All that remains is to put heatshrink tubing over the entire board to prevent shorting during use. I used a hair dryer to shrink the tubing, I find it has sufficient heat to shrink all types of heatshrink. 

See the image of the board powering a USB to SATA driver board.

The nice thing about this board is that you can simply replace the MicroUSB cable with a cable to charge your phone or iPod. Meaning you can venture out into the wild and still charge your devices using a large LiPo.

I hope you enjoyed reading this as much as I will enjoy using it! 

If I can get my PCB etching working I will finish building my V2 board which has a voltmeter and an LED on it which will prevent over usage of the LiPo (If it works, a new instructable will be on its way soon).



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10 Discussions


Reply 5 years ago on Introduction

Thank you! The best thing about it is when I go fly I can easily charge my dead phone! I have changed this since, rather than the USB-B I now have a female USB so that I can plug in any USB charging cable.


Reply 5 years ago on Introduction

No no no, you can't charge the LiPo using this. You need a LiPo charger for that! You will blow the regulator and then explode your battery so I would seriously not advise trying. A 7805 is not a bidirectional device.


Reply 5 years ago on Introduction

Duh, I'm so stupid!

Yeah you would have to connect a smart charger either way, it's still pretty cool!

Thanks for the info!


6 years ago on Introduction

Greeting! Great job! My question: how large an intensity current the electronic circuit hands in? Would be good at max 1 ampere and to stabilize.
Than the charger of the phone.


6 years ago on Introduction

Cool idea! But I would recommend replacing the two caps with some 100 nF ceramic caps instead - those caps won't do any goog when the wires to the battery pack and the load is so long, but the 100 nF caps will protect the regulator so it doesn't go into oscillation. Also, remember "smothering" anything with thermal paste is a really bad idea, as thermal paste is an incredibly bad conductor of heat, only surpassed by air. The right way is direct contact from heat source to heat sink - the thermal paste is only to fill the minute voids and scratches there is on the interface on the two devices, so the layer of paste should be paper thin. not a lot of people know this though...


6 years ago on Introduction

This is very clever, I like the idea that it can be used to power/charge multiple different devices.

1 reply

Reply 6 years ago on Introduction

Thank you, I was thinking of putting a plug instead of a MicroUSB cable to allow for interchangeable cables and possibly even a splitter to enable charging/powering of multiple devices at once. Just beware when powering more than one thing or even one for that matter. The 7805 regulator can only handle around 1A, just check the maximum currents of all of your devices before you plug them in! One other thing is that When drawing 1A the regulator will without a doubt need a heatsink. What I would do in that case is flip the regulator over and bolt a heatsink on and smother it in thermal paste too as you will not have any air flow.