DIY Solar Boombox / GhettoBlaster




Introduction: DIY Solar Boombox / GhettoBlaster

You can construct a solar powered boombox for as little as $75

Combine a small, energy efficient digital amplifier, cheap bookshelf speakers, batteries, a small solar panel, and your MP3 player as a source.

Fasten everything together, add a handle, and take it on the road!

This project makes for a fun, easy solar project, that will help you learn about how solar panel, and audio systems operate.

Assembly has been simplified as much as possible, with a very high quality product as the end result.

Possible applications-

  • iPod or Mp3 amplifier
  • "Off grid" remote or cabin audiophile system
  • Third world use
  • Eco friendly sound system for outdoor events
  • Science fair or educational project
  • Jobsite radio and tool battery charger
  • Laptop amplifier for music and movies
The Sonic Impact digital amplifier has been raved about by audiophiles. It has the added benefit of using less electricity than a conventional solid state amplifier, which makes the battery last longer, and the required solar panel smaller.
It is capable of driving most home stereo speakers, so feel free to try it with any speakers you may have on hand. The results may surprise you!
Some speakers are more efficient than others and will play louder given the same input.

*Sonic Impact fans note*

A Sonic Impact amplifier ($30) will run directly off of a single Harbor Freight car charging solar panel($10-20) without a battery.
I offer no guarantees here, but in July Wisconsin sun, an unmodified SI amp was connected directly to the solar panel (a stock SINGLE Harbor Freight unit) and speakers. I did this repeatedly with no problems, other than that the music stops when clouds interfere, or the panel is shaded.


The reason this is remarkable is that the voltage of the panel is over the maximum the amp is supposed to take. The load presented by the amp, draws the voltage down before the amp is damaged.
I have tested this extensively, but you try this at your own risk!

A more powerful panel, such as the double unit we use on the DelSol will be more likely to produce enough current to damage the amp.
I later modified the amplifier to improve the bass, and it required more current than the single panel provided.

Add a battery, and you have a more functional simple system.

See ELECTROVOX.COM for more info, links, and advanced systems.

Step 1: Parts, Sources and Tools

Most components are available via Parts Express, but I list multiple options for some components.

Amplifier options -
Dayton amp - $45
(This amp should be functionally identical to the Sonic Impact amp mentioned throughout this instructable)

An alternative amplifier is sold on Ebay by a seller in China. Shipping will take a while, but the basic amp board is only $25 shipped. Using this amp is a slightly more advanced project, and may require some additional parts. Go to and search for TA2024
Parts express now carries this amplifier as well-

Solar Panel- -$10-19 Your Local Harbor Freight will match website sale prices if you print out the web page and take it into the store.


White indoor/outdoor speakers shown on intro page - $24
I Highly recommend recycling some old speakers here. Car speakers can be used if you provide an enclosure. Use high quality bookshelf speakers if you're an audiophile.


DC Plug - $2.79/2
plug from Parts Express two needed

DCjack - $2.79/1
DC jack option 1 from Parts Express
DC jack option 2 from Parts Express

or extract similar parts from broken electronics. /free


5.0 Ah battery from parts express
Battery - 12 Volt battery SLA (sealed lead acid) get a 2.5-12 Ah capacity one, pay $13-25.00 Shipped
I recommend using a 2.5-5 Ah SLA battery for most people. A 12 Ah battery is quite large and heavy.

bag phone battery charging clip
bag phone battery These can be found for a lot less sometimes.

Cordless drills can be a battery source if the voltage is under 13.6 volts

Optional-get 8-10 AA NIMH 2400mAh or larger. Eight fit in the SI amp, but building 10 into a custompack will play louder than even the lead acid batttery!
I don't provide instructions for these options yet, however.


Wire is mostly recycled, but silicone wire is recommended for connecting the battery to its plug. Cheapskates can try lamp cord here, but please be careful. and read the warnings on the next pages.

Industrial Strength Velcro,
glue,and screws to fasten the necessary parts together.
electrical tape or heat shrink tubing

Some kind of handle. Preferably folding.

Sound source such as MP3 player

Harbor Freight has digitalmultimeters for $3 - 10.00 that are very useful, but optional.


Soldering Iron
wire cutters/strippers
needlenose pliers

Step 2: Wiring & Assembly

There are really only a few basic steps here-

1. Remove diode from cigarette plug. (picture 3)

Desolder the diode from inside the Cigarette plug connector that comes with the Solar Panel. The diode prevents the battery from discharging through the solar panel when the solar panel's output is low. The diode must be oriented as shown, with the line away from the solar panel. (see pic 3)

2. Construct a plug/jack passthrough, connect it to the diode and solar panel.

Pay very close attention to wire polarity! You can damage your amp by connecting power backwards! The wire with the white stripe is positive, the black wire is negative. Red terminals are positive, black is negative. Center terminals are positive.

DC jacks often have a switched terminal that we will not be using. It is easy to mistake this for the negative terminal. To find this terminal, insert a plug into the jack and test for continuity. only one terminal will be connected to negative on the plug. The center positive terminal should be obvious. The third terminal is not used, and may be broken off to simplify things.

I created the plug/jack that is attached to the solar panel by bending the terminals on each until they would make contact, then soldering them together and connecting the diode/wires last.
Arrange the parts so that the positive connections have No Chance of coming into contact with the negative. This is very important.
I've had a small battery melt through a small amount of insulation and start smoking. These small batteries pack a lot of juice, and could burn your house down. I'm not kidding. Be sure and do a good job soldering this plug, and on the battery plug. Make sure that soldered connections are solid, and that the bare portions of the wire are kept to a minimum and cannot come into contact with each other. Test all systems in an open area, and don't trust your battery until you've spent some time with it and it hasn't melted anything.
battery meltdown
I now use silicone wire as a result. 14 AWG is a good size.

3. connect a DC plug to the battery.

Wire the DC plug onto the battery wires before connecting the wires to the battery. Center is positive on the plug. Use heavier wire than elsewhere. I suggest at least 16 AWG lamp cord. reread the warning in the above paragraph, and make sure and wire in a fashion so that the bare wires cannot bend and make contact.

4. Test the system prior to assembling the components into a boombox.

Connect amp to the speakers using 22AWG wire. Some speakers have this attached already.
Plug the battery into the solar plug/jack, then plug the solar plug/jack into the amp .
Connect the sound source to the amp.
turn amp on.
turn sound source on.
adjust volume.

I'm not going to go into physical assembly, since everyone's will be different .
Make sure and attach everything together into a solid unit.
Dangly, or loose bits suck.
In this application.

Enclosing everything in a ready made box such as a toolbox or a small cooler can work well, especially if you want to use old car speakers.

Having the solar panel and battery easily removable is very handy. I use Velcro.

Handle options
I've used a bar clamp to hold bookshelf speakers together temporarily.
A wire handle from a five gallon bucket can be fitted.
A handle needs to fold out of the way of a top mounted solar panel. Shading the panel, even a little, reduces its output significantly.

You should be able to add an ipod dock with charging capability by modifying these instructions.

Step 3: Using Your Solar Boombox

Larger solar panels require charging circuitry to regulate the charge current and protect the battery from overcharging. Our solar panel is small enough that a charge controller isn't required.

The battery and solar panel are removable so that you can remove the battery and solar panel and set them outside to charge with less concern for the weather and theft. You could also have two batteries and have one charging outside, while you use the boombox inside, or in shade.

Batteries will last longer if kept in a charged state.
Try to keep lead acid (SLA) batteries fully charged, and never allow voltage to fall below around 9.6 volts (The amp will stop working at around this voltage)
NIMH batteries can be fully discharged without damage, but also should be kept charged for best results.
If your battery will not be used for a while, its charge should be topped off periodically, either by leaving in a sunny spot with the solar panel attached, or by using a wall charger.
I would do this monthly with a SLA battery, and biweekly with NIMH.

Read this instructable for some basic solar battery charging information.

Putting a bead of silicone caulk around the glass on your solar panel is recommended to help weatherproof it.

Different audio sources have different output levels. If you feel your box is too quiet, the source may not put out strong enough of a signal.

You should be able to turn the amplifier nearly all the way up, and control the volume with your source, assuming it has a volume control. You can experiment with different combinations with the two volumes in order to get the best sound.

Keep the solar panel oriented towards the sun, and not shaded for best charging. Even a small amount of shade negates its ability to charge the battery.

I get 6 hours playback from a fully charged 2.6 Ah battery at top volume, and 10+ hours at normal listening volumes. This is with the solar panel disconnected. YMMV

Sonic Impact amp specs-

The TA2024 is a 15 W/ch continuous average two-channel Class-T Digital Audio
Power Amplifier IC using proprietary Digital Power Processing� technology.
Class-T amplifiers offer both the audio fidelity of Class-A/B and the
power efficiency of Class�D amplifiers.

�· Battery Powered System
�· Optional AC Adapter for 12V DC power source
�· No heat sink required up to 15W per channel
�· Intelligent short circuit protection
�· Connects to any passive 4/8 Ohm speakers
�· Takes standard audio line input from any sound system

�· Fully integrated solution with FETs
�· Easier to design-in than Class-D
�· Reduced system cost with no heat sink
�· Dramatically improves efficiency versus Class-AB
�· Signal fidelity equal to high quality linear amplifiers

�· Class-T architecture
�· Single Supply Operation
�· â��Audiophileâ�� Quality Sound
0.04% THD+N @ 9W, 4 Ohm
0.18% IHF-IM @ 1W, 4 Ohm
11W @ 4 Ohm, 0.1% THD+N
6W @ 8 Ohm, 0.1% THD+N
�· High Power
15W @ 4 Ohm, 10% THD+N
10W @ 8 Ohm, 10% THD+N
�· High Efficiency
81% @ 15W, 4 Ohm
88% @ 10W, 8 Ohm
�· Dynamic Range = 102 dB
�· Mute and Sleep inputs
�· Turn-on & turn-off pop suppression
�· Over-current protection
�· Over-temperature protection

Harbor Freight solar panel specs

Model 44768
22.5 VDC open circuit voltage
14.75"L x 6.5"W x .875"Thick
91" cord
weather, shock, rust, UV resistant frame

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    9 years ago on Introduction

    wouldn't the solar panel's efficiency drop like 66% if it has that much shading from the handle on it?


    9 years ago on Introduction

    wouldn't the solar panel's efficiency drop like 66% if it has that much shading from the handle on it?


    10 years ago on Step 2

    Hello, does this wiring set up charge the battery while its plugged in and run off battery while its not plugged in or if the solar panel isn't generating power?


    Reply 10 years ago on Step 2

    This design is not set up that way, but it could be.


    10 years ago on Introduction

    Hey I was wondering...if I did everything you did, except used:

    2 25W RMS speakers,

    this amp:

    and an ipod dock to charge my ipod, would 1.5 W be enough?

    btw thanks so much this is a great instructable!


    Reply 10 years ago on Introduction

    also, sorry for bothering again, but is there a way to plug an ipod dock into external speakers?


    10 years ago on Introduction

    Hey I am putting my boombox together. I'm using the recommended amp. First off can you briefly explain to me the series/parallel relationship between the three parts (battery, panel, amp)? Just one more thing. I'm using the led acid 12V 5.0 Ah battery. The recommended charging voltages for the battery says around 14-15V, but the panel puts out around 24V. Should I knock down the panel voltage or does it not matter?


    Reply 10 years ago on Introduction

    The fifth picture under "Step 2 Wiring and Assembly" shows a simple schematic.
    You don't have to worry about the higher voltage of the solar panel, if it isn't significantly larger than the one I used (1.5 Watts). Just don't connect the solar panel to the amp without the battery being connected first.
    The battery will draw down the voltage of the panel, A small solar circuit such as this one can get by without a charge controller.
    Good luck!


    10 years ago on Introduction

    Do you know what type of diode came with the solar panel you used? I bought one but it did not have the diode. I'd like to add it but I'm not sure what type to use.

    BTW - these plans are awesome! I have been enjoying the boombox I built with your help!


    Reply 10 years ago on Introduction

    It's a 1N4001 type.
    Available here-
    Most electronic devices have these inside, if you want to salvage one.
    Just pick one that looks like the picture, don't worry about exact part number.
    I'm glad you're enjoying the boombox!


    11 years ago on Introduction

    Can you have the battery plugged in at the same time as the solar panel? I want to do this but am afraid it will generate too much voltage.


    Reply 11 years ago on Introduction

    Yes, if wired as described in step 2. Look at the additional pictures on step 2 for exact wiring detail.

    Great invention there. See what imagination can do with solar power? It will be great if more inventions will be made in the near future.

    Great post. Keep Sharing.


    12 years ago on Introduction

    Hello i know this is an old thread but i am building my own solar powered boom-box .
    I am using a Chinese Lepai T2020 amp , a 3w solar panel,pioneer Dual-Cone TS-1001i Speakers .
    will be incorporating a cigarette lighter plug that converts into 2 usb ports to charge phone and mp3 player.

    now all i need is a battery and have been searching around for what type i can use.

    am trying to keep the weight as low as possible so i don't need a heavy car battery but was wondering what is best for my setup?
    want to keep the boom box in the windowsill so i can charge my phone on a daily base .

    am quite capable of soldering etc. .

    so should i go for something like this and wire 10 of them to make my own battery pack
    or should i get a lead acid one like this

    am a bit lost in the whole battery thing so any help is much appreciated.



    Reply 12 years ago on Introduction

    I really like my 10 aa NIMH pack the best. There are tutorials online explaining how to solder batteries together successfully, and assemble them into packs.
    The batteries you've linked to should work fine.

    There's also this holder-
    -if building the pack is too much trouble.

    Good luck!


    Reply 12 years ago on Introduction

    thanks for the advice!just ordered a dozen 2900mAH...another question do you think i need a charge regulator or can i hook up the bateries direcly to the panel?

    there is a diode in the panel so shouldn't drain the batterypack.



    Reply 12 years ago on Introduction

    You'll be fine without the charge regulator. A 3W panel doesn't put out enough current to overcharge those batteries.


    12 years ago on Introduction

    Thanks a bunch for this project. I used the 2x15 amp from Sure Electronics and some 10 watt RMS speakers I found cheap on Ebay. I built a pine box and hard wired it all together. Sure, it ways 30+ lbs, but it's loud. If anybody is just starting this project today (5/8/2010) you can find some Kricket 5" 10 watt RMS speakers on EBAY for about $25.


    12 years ago on Introduction

    I would like to do the same thing here... except instead of building a box i am thinking about using a coleman or igloo cooler... with a Car Battery also using a Car/Marine Stereo and Speakers...  I go on a lot of Tubing Trips in the summer and would like the best possible waterproof setup lemme know if you have any other suggestions as to what i can do.


    Reply 12 years ago on Introduction

    There are other plans for cooler boomboxes online you can look at for inspiration.

    my suggestions-

    1.  Many waterways ban glass. Look for a solar panel with no glass, they are available.  Try marine sources. Some have a metal backing plate, some have circuit board material, some are flexible and roll up.  One cheap source might be to gang together a bunch of garden light solar panels.

    2. You might not need a full size car battery, I'd try a garden tractor/motorcycle battery, or better yet, a large SLA computer power back up battery.  Try Ebay.

    3. Think about how you will use it.  It might be easier to have the battery and solar panel removable so that you aren't leaving your whole stereo out to charge where it could get stolen or rained on.

    I'd love to see a picture of your completed project, good luck!