The Evolution of My Homemade Boombox: From a Car Radio Upgrade to a Mains-Powered Audio System

About five years ago, I created a homemade boombox around a simple car radio. The construction was straightforward, but over time, the whole setup fell apart, and the 12-volt 70 AMP battery lost its original capacity. It was clear that an upgrade was necessary, and in this video, I'll show you how to build a lighter, louder, and more convenient audio system that can be powered by integrated batteries or mains voltage.

The Heart of the New System

The heart of my new system is a pioneering 6600-step car radio, which will be powered by two 12-volt 7.2 amp lead acid batteries. For sound playback, I'll be using salvaged 17 centimeters (40 watt) speakers, one connected to pin B3 and B4 of the car radio clock.

First Test Run

I spun out the first test run according to the standard settings and hooked up a double pole double throw switch with four wires that utilized the opposing terminals of the switch pair. The second switch received only two wires soldered on one switch, which is connected in series to pin A7NF of the radio and acts as the main battery power switch.

Digital Radio Antenna Test

I used an overpriced digital radio antenna to test the reception capabilities, and I found that a short piece of plain old wire works just as well. This was a successful test run, and I'm excited to continue with the next steps.

Powering the Radio with Mains Voltage

To power the radio with mains voltage, I used a 12-volt 30 amp power supply. I hooked up the live, neutral, and protective ground wires and applied mains voltage, setting the output voltage to around 14.5 volts DC. This voltage is necessary for reaching the charging voltage of the batteries and also works as a supply voltage for the radio.

Charging Controller

I connected the output of the power supply to the input of the charging controller, which then outputs to the battery. The charging current would exceed the rated initial current of the batteries if not limited by the charging controller, but this improvement ensures a longer lifespan.

Additional Safety Measures

To prevent over-discharge, I added a voltmeter in combination with a switch to monitor the battery voltage. The radio works with voltages as low as 10 volts, so I set an threshold value of 11 volts for over-discharge. Later, I also edited another switch to connect the speaker terminal, allowing me to hook up external speakers.

Complete Parts List and Wiring

The wiring scheme is relatively straightforward, but I'll be using proper Farrell's and baguette omelette blocks to establish a good electrical connection as well as car radio sockets to remove the radio at any time.

Final Tests and Completion

After completing the wiring, I performed a successful final test, cleaned up the wiring with zip ties, mounted the radio in its place, and added two pairs of magnets to keep the lids properly closed. The project is finished, and I'm excited to enjoy my music up to nine hours continuously, which is not bad.

Conclusion

I hope this project inspires you to build something similar and that you liked it. Don't forget to Like, share, and subscribe, and consider supporting me through Patreon to keep such videos coming. Stay creative, and I'll see you next time!

WEBVTTKind: captionsLanguage: enAbout five years ago this homemade boombox build around a simple car radio was createdBut over time the whole construction slowly fell apart and the big and heavy12-volt 70 AMP battery lost quite a bit of its original capacitySo obviously it was time for an upgrade and in this videoI will show you how great this new lighterLouder and overall easier to operate in box that can even be powered by the integrated batteries or by mains voltageWhich simultaneouslyCan charge the batteriesLet's get startedThe heart of the new system is this pioneered eh X6600 step car radio which will be powered by two 12-volt7.2 amp our lead acid batteries and for the actual sound playbackI will be using those salvaged 17 centimeters 40 watt speakers. IConnected one of them to pin B 3 and B 4 of the car radio clockAccording to its standard I spin out for first test runThen I hooked up the ground pin of the radio to the negative terminal of one battery and got myselfTo double pole double throw switches which are basically two switches in one packageThe first one received four wires which utilized the opposing of put terminals of the switch pairWhile the second one only got two wires soldered on one switch of the four wireswhich pair is hooked up to pin a7nf of the radio and is also connected in series to the two wire switchWhich acts as the main battery power switch by connecting the positive terminal of the battery to the circuits?After hooking up the overpriced digital radio antenna to the car radio and to the 12-volt power pin FIFIt was time for the first test which turned out to be successful and just in case you're looking for cheap antenna to receive digitalRadio, why not use a short piece of plain old wire. The funny thing is it works just as wellOkayMoving on to power the radio with mains voltage and shot the battery as well. I used the 12 volt 30 amp power supplyI hooked up the live neutral and protective ground wire applied mains voltage and set the output voltage to around14.5 volts DCThis voltage is necessary to reach the charging voltageOf fourteen point four volts of the batteries and does also work as a supply voltage of the radioNext I connected the output of the power supplyto the input of the charging controller and that outputs to the battery and if we are thinking to herself why not just use14.4 volt of the power supply to charge the batteries directlyWell, the charging current of a constant voltage source will most certainly exceed the rated initial current of the batteriesWhich could lead to serious damage?The charging controller however can limit the currents and thus improve the lifespan of the batteriesbut neverthelesslet's finish this test circuits by connecting the remaining switch pair of the four wire switch between the power supplies plus terminal and thePins a seven and a four of the radio this complicated four wire switchBasically cuts off the battery voltage from the radio and replaces it with the power supply voltagethis way the charging controller can charge the batteries withoutinterfering with the rest of the circuits while the radio keeps on playing its music without anyInterruptions and so far this wiring seems to work pretty wellBut later on I also added a voltmeter in combination with a switch in order to keep track of the battery voltageto prevent an over dischargeSince the radio works with voltages as low as 10 voltsBut 11 volts should be the threshold value of over dischargeI also later editanother switch in combination will be speaker terminal in order to hook up external speakers as well aComplete parts list with the wiring scheme and better pictures can be found as always in the video descriptionthe last missing part of my boombox was a wood chest to mount all the components minus dimensions of37.5 by twenty seven point eight by eighteen point three centimeterswould fakeness of around 1 centimeterFirstly I applied a layer of protective oil on the outside and inside of the boxInstalled the mounting processBy marking the location of the speakers on the left and right side of the chest and used the jigsaw to create the circular cutoutsNext I determined the location for the Radio 2 centimeters underneath the upper ledgeMarked the square and cut it out as well with a jigsawThen followed three of five millimeter holes at a level above the radiofor the battery would meet our ant mains operation switch andAfterwards a smaller square underneath or for the voltmeter on the back sideI created square cut outs for the mains voltage sockets the speaker terminal and one additional 5 millimeter hole for theexternal internal speaker switchThe last major cutouts was a hole with a diameter of 2 centimeters in the front left corner of the lid for the antennaWhich I mounted into place immediatelyThen I got myself a 25 centimeter white sheets mark bending edges left and right from the twenty seven point eightCentimeters long main section cut off the excess sheets and finally created a u-shapeAfter removing the protective film I pressed the customized sheets to the bottom of the chest and were two or four millimeter holesThrough the front and back side of the box through the sheets, but before bolting it to the boxI used another sheets to create two more u shapes that came out my batteries to the side of the box as wellwith the help of m4 nuts and boltsI secured the sheets and batteries which will leads the thin bottom part of the box from too much weightBut don't forget the protective conductor which later connects to the PEterminal of the mains inputs because safety firstafterwards, I do all the necessary holes for the speakers and secured both of them woof m4 bolts and nuts as well with theSame tactic. I then mounted the speaker terminal the mains inputs and the handles to the box for the power supplyI firstly created a template for the holes taped that to the bottom drilled the holes and then secured it of em for bulbsNext I press the voltmeter into place and hot glued all the switches to the designated spotsThe almost last step was the wiring which should be pretty self-explanatoryYears since I talked about the wiring scheme at the beginning of the videoonly difference is that now I'm using proper Farrell's and baguette omelette blocks to establish a good electrical connection asWell as to car radio sockets in order to remove the radio at any timeOnce the cable chaos was completeI performed a successful final tests cleaned up the wiring with zip ties mount the radio in its placeAdded two pairs of magnets to keep the lids properly closed and the project was finishedI'm really happy you were power turned out and with an average current draw of roughly 1.6 m/sI should be able to enjoy my music up to nine hours continuously, which is not badI hope you liked this project and maybe it inspires you to build something similar as alwaysDon't forget to Like share and subscribeConsider supporting me through patreon to keep such videos comingStay creative and I will see you next time