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Hi All,

2 Months back I had custom built a portable multimedia speaker for my friend. It had everything that he needed, MP3/ FM / USB/ SD card/ Aux in / IR remote and external bluetooth

It had few issues

  • AC powers connection,not 100% portable
  • External Bluetooth needed power source
  • Lithium Ion batteries are expensive

In this instructable, I will share how I fixed these problems

Features of the final built

  • True Portable
  • Lightweight
  • 6W / 80DB output
  • Mp3/FM/USB/SD/ Aux
  • IR Remote
  • External Bluetooth
  • 6000 mAH battery / 6 to 7 hrs of life with bluetooth
  • Battery charging LED indicator
  • 5V USB output, can be used for mobile charging too

Step 1: What Do We Need ?

Material

  • Portable Multimedia speakers
  • Ols laptop battery
  • TP4056 with battery protection
  • 3.7 to 5 V DC Step up convertor with USB
  • Switch

Tools

  • Dremel
  • Wood Saw
  • Wires
  • Soldering iron
  • Hot glue gun
  • Black OIl paint and brush

Step 2: Extract Lithium Ion Batteries

We all have at least a laptop at home for years and know that the laptop batteries do not last over 2 to 3 years. I had a bad laptop battery, which I have used for the build

  • Using Screwdrivers, break open the outer case
  • Extract batteries and separate them from any connections or circuit
  • Test individually for voltages ( between 2.5 to 3.7V can be reused)

Put these batteries for charging using TP4056 and measure voltage (open circuit ) should be around 4.2 V.

Few batteries will not detect or charge, You should discard the faulty ones with proper care and as per guidance / regulation followed in your country

Warning: Always use TP4056 or good charger because cheap chargers may over charge your batteries, which could lead to battery explosion

Step 3: Preparing Battery Pack

The Batteries I extracted were of LG 3000mAH. I connected two of these in parallel and left it for 4 to 5 hours

Even though the batteries were fully charged, they can carry slide variations in voltage. Leaving them connected for few hours balances them.

Donot not overheat the batteries while charging.....

I am using Electrical tape to hold them together and for covering metal connectors

Step 4: Back Panel

Since my speakers ran on AC power, it had holes supporting the cables etc. I needed to replace it with a new panel, with holes for

  • Bass tube
  • A switch
  • USB out
  • Micro USB charge
  • LED Indicator

LED Indicator : I used a transparent PVC / plastic stirrer, which my son likes to collect. I fixed a about 1 inch piece over TP4056 so that it can refract light from LEDs on TP4056

Step 5: Connections

Make the following connections
  • Batteries are connected to TP4056 at the B+ and B-
  • Out+ and Out- of TP4056 via switch connected to step up convertor
  • Output of step up converter to MP3 Module and PAM8403 Amp
  • Output of PAM8403 to speakers

Test the circuit at each connection. make sure the polarities are correct and not short circuits due to soldering or overheating

Step 6: Closing It

Fix the USB output and micro USB in as shown. close the back panel. Test all features works

Leave batteries to recharge.

Step 7: Enjoy Music

Features of the final built

  • True Portable,
  • Lightweight
  • 6W / 80DB output
  • Mp3/FM/USB/SD/ Aux in
  • IR Remote
  • External Bluetooth
  • 6000 mAH battery / 6 to 7 hrs of life with bluetooth
  • Battery charging LED indicator
  • 5V USB output, can be used for mobile charging too

Once done enjoy the portable and loud music

Please share your comments and suggestion

<p>Can this speaker charging while playing ? or during charging the won't have the output power from TP4056 ?</p>
yes, we can listen to music and charge at same time.
What is the rating of the Speakers?
these are 5w 4ohms each... the amplifier is Pam8403, which gives 3+3w output<br><br>good for small room

About This Instructable

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Bio: I am IT professional, living in Bangalore, India. As new gadgets come out everyday, we indulge in spending significant time and money on these gadgets ... More »
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