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.

THIS MAKES A GREAT DEMONSTRATION!

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.

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bobert6101 year ago

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

bobert6101 year ago

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

liquidflorian2 years ago

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?

pekar (author) liquidflorian2 years ago

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

Athelestan2 years ago

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

2 25W RMS speakers,

this amp: http://www.amazon.com/gp/product/B0049P6OTI/ref=ox_sc_act_title_6?ie=UTF8&m=AZ7YIJX32M70J

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

btw thanks so much this is a great instructable!

Athelestan Athelestan2 years ago

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

Diygai2 years ago

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?

pekar (author) Diygai2 years ago

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!

dinyoclese2 years ago

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.

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

pekar (author) dinyoclese2 years ago

It's a 1N4001 type.
Available here-
http://www.adafruit.com/products/755
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!

dinyoclese3 years ago

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.

pekar (author) dinyoclese3 years ago

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

BuildHomeSolarPanel3 years ago

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.

marrilia4 years ago

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
http://www.amazon.co.uk/Duracell-Supreme-2450mAh-Rechargeable-Batteries/dp/B0031OE6LG/ref=sr_1_1?ie=UTF8&qid=1288354114&sr=8-1
or should i get a lead acid one like this
http://www.amazon.co.uk/NP3-3-12-Ultramax-Rechargeable-Lead-Acid-Battery/dp/B002TW74P6/ref=wl_it_dp_o?ie=UTF8&coliid=I20SQT4IMYV1A6&colid=SO6O03Z0DRVD

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

Marrilia

pekar (author) marrilia4 years ago

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-
http://www.maplin.co.uk/Module.aspx?ModuleNo=31427&OrderCode=RK45Y
-if building the pack is too much trouble.

Good luck!

marrilia pekar4 years ago

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.

cheers

pekar (author) marrilia4 years ago

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

x-Shakey-x4 years ago

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.

elSquish4 years ago

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.

pekar (author) elSquish4 years ago

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.
http://www.allelectronics.com/make-a-store/item/SPL-61/SOLAR-CELL-60MM-X-60MM-X2MM/-/1.html
http://www.jamestowndistributors.com/userportal/show_product.do?pid=52241&familyName=PowerFilm+Rollable+Solar+Chargers
http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/424480/377%20710/0/solar/Primary%20Search/mode%20matchallpartial/0/0?N=377%20710&Ne=0&Ntt=solar&Ntk=Primary%20Search&Ntx=mode%20matchallpartial&Nao=0&Ns=0&keyword=solar&isLTokenURL=true&storeNum=5002&subdeptNum=9&classNum=592

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!

the_shazz4 years ago

as an fyi, parts express does sell a solar charger similar to the one specified (www.parts-express.com/pe/showdetl.cfm) but its twice as expensive. however, if you pick up the amp and batteries from parts express too you can just make the $100 free shipping, but the increase in price almost cancels it out. check the prices and figure out which is cheapest with shipping

k_man935 years ago

saying "audiophiles" makes it sound dirty...

3VIL G3NIUS k_man934 years ago

ROFLMAO!!!

rdmoreno25 years ago

I love this idea for our RV trips. I was wondering if a 12v auto plug (male) could be added and used with a Car battery. I have a 12v outlet (female) on the outside of my trailer and it would be nice to be able to hook up while outside in the evening. Would a 12v deep cycle marine battery cause damage to the amp (dayton) and if so what would be needed to protect it. If anyone has any ideas I would appreciate a scematic of some sort as I am a little green to electornics.

maxwelltub5 years ago

why do you need a plug/jack? couldn't you just have the plug hooked up to the battery and solar panel? is the the jack just extra in case you want to charge it through other means?

pekar (author) maxwelltub5 years ago

Yes, it also allows you to use multiple batteries. Personally, I find it most convenient to be able to separate the battery, solar panel, and boombox. This also allows me to charge the battery without having to leave the boombox out in the weather. You can hardwire everything, but I think most people will appreciate being able to separate the components. The plug/jack also helps avoid the possibility of connecting two power sources in series and frying the amp.

Da Nugesta5 years ago

where did you get those particular speaker drivers that were shown in the first image ? cheers

pekar (author) Da Nugesta5 years ago

Those are Aurasound NS3-194-8E featured in my Delsol speaker project here:
http://www.diyaudio.com/forums/showthread.php?s=f0de12f6e2b099494dc6bc2d1bfe5c7a&threadid=90212&perpage=10&pagenumber=1
Sadly no longer available.

Parts Express has some similar Tang band drivers.

whizbo5 years ago

Check out the Amp 6 here http://www.41hz.com/
I used it to build a similar portable system. Works great

hispanickausinpanik6 years ago

Wondering why I couldn't use a small (25 w.p.c. or so) car amp or eq/ booster to push a pair of 6x9's. I would of course use a 12v s.l.a. battery and a solar panel to recharge. Would either amp or eq be too inefficient voltage wise???

pekar (author) hispanickausinpanik6 years ago

This will work, but is less efficient and would be better paired with a larger battery and solar panel. The beauty of my system is that the energy efficiency of the amplifier allows you to use a smaller solar panel/battery and still have a powerful system in a small package. I encourage you to experiment with whatever is on hand!

hispanickausinpanik pekar6 years ago

Pekar, one more question for ya. Just about got my system built, but I wanted to see if a piece of plexiglass layed over a solar panel for protection would do more harm than good ? Will it reflect light enough to not let the panel be as efficient as it would without it? Thanks for your reply.

pekar (author) hispanickausinpanik6 years ago

It shouldn't reduce the panels effectiveness by much.

hispanickausinpanik pekar6 years ago

Thanks for all the help, Pekar.

rocketman2216 years ago

you should add a 7805 voltage regulator and connect it to a usb cable so that you can charge your mp3 player over the usb connection.

sunworks7 years ago

Have wanted to do this for some time, so appreciate your work on this. I have the T-Amp and two Polk Audio DB650 car speakers which are very efficient and nice sounding. Also have a Creative MuVo2 FM 5gb which requires a 5v input In order to power the system for a good (long) amount of time at volume and under less than ideal solar conditions, I want to upgrade the solar panel and battery. Am looking at a 12v, 10W panel charging a 4.5ah lead acid 12v battery. Will I need a solar controller for this? Can the T-Amp run directly off the battery or is some sort of voltage regulator needed? Finally... can somebody suggest a DIY design for the car audio speakers to "tune" the sound? I'd like to make this enclosure from balsa wood backed by XPS (Dow Styrofoam) insulation with the balsa on the inside. Any thoughts/ help is appreciated!

rocketman221 sunworks6 years ago

a solar panel that large would overcharge a small battery very fast. so you will definitely want a charge controller. I would also suggest a larger battery 7 - 12 Ah. make sure that the output current from the panel is not over the max charge current of your battery.

pekar (author) sunworks7 years ago

Batteries can take up to 1/10 of their mAh rating and safely dissipate this as heat. In your case a solar panel could put out a maximum of 450 ma without requiring a charge controller. Your 10 watt panel is probably too large for that small battery.

sunworks pekar7 years ago

Thx 4 the info. I want a system that can cleanly handle less than full sun. Ur in Badgerland, which has pretty much the same climate as me in Gopherland (MN.) When those big cumulus clouds come and go, I still want the tunes. I hooked up a solar panel in my Jetta (VW) and I've got a VW solar panel in there. (Max Power: 3.2 watts, Voltage @ Max Power; 18.8 Volts, Current @ Max Power: 170mAmps, 42 cells) Virtually every panel I've seen listed as 12V has 36 cells. This one has 42. When I plug the T-amp into this panel and turn the amp on, there is 1/2 second of sound, then nothing. This happens repeatedly. I'm thinking the voltage is too high and causing the T-Amp to clip out. When I put 8 NiMh AA cells in the T-Amp, it cranks out the sound. That's 9V. This is a lot more. I'm driving Polk Audio DB650 car speakers. Do you see any way to make this particular panel work? Could I hook it up to a 4ah battery and then plug the T-Amp onto the battery posts? Or will this setup end up with premature battery/equipment failure? The Harbor Freight panel is not for me. I don't like amorphous cells and cannot accept dead silence when there are clouds. Thx for the help! Clinton

pekar (author) sunworks7 years ago

You can connect your VW panel directly to the 4.5 ah battery without any charge controller.
I suspect your VW panel might not have enough voltage to power the amp directly. A solar panel's voltage drops dramatically when you place a load on it. You would probably need to connect two VW panels in parallel to produce sufficient juice. You then risk overpowering your amplifier. Putting a battery in the circuit regulates the voltage and prevents damage.
Read here for a good description of running on minimum voltage-
http://www.diyaudio.com/forums/showthread.php?postid=1214804#post1214804
A 41hz.com amp6basic kit amplifier has built in voltage regulation and is a nice upgrade from the SI T-amp.
Ultimately, if you don't want to experiment, but just want solar powered tunes, use a battery in the circuit, and consider adding a second VW panel in parallel for quicker charging.
enjoy,
Pekar