Instructables

Solar Charged Stereo Cooler

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This instructable outlines a portable solar charging station, stereo, and LED light that is built into a playmate cooler. It is an all-in-one portable unit, as you can charge your phone or tablet with solar power, fill a room/beach/field with music, and also have an area light.

You can set this up at your home for everyday charging of your devices, and easily bring it with you for a day on the beach, on a camping trip, or anywhere else. It can be very useful during power outages, or even be a prime source of power in an off-grid cabin or home.

The design of this unit is very flexible, and you can choose features or expand on this to meet your specific needs. You can also take advantage of using scrap parts for its construction, with old car audio components, scrap wood, and spare wire that you might have lying around. I've found that you can borrow from a lot of "car accessories" that are 12V DC powered, or even use a small inverter for AC loads, to use this solar power for a wide range of devices.

 
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Step 1: Parts

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Cooler:

I chose the 16 Quart Igloo Playmate cooler for this build, since it's big enough to hold everything, but still small enough to carry with one hand. The roll top is also quite useful, and makes access to everything very easy. (~$20, Target/elsewhere)

Faceplate:

I used an scrap laminated bookshelf to mount everything on. I've used thin plywood for this before, but a thicker piece of wood makes the acoustics much better. (free/scrap)

Stereo:

Any standard 12V auto/marine stereo deck will work. I used a basic marine unit, since it somewhat more water resistant than a standard car deck. The cheaper units are "Mech-less" and have no cd-player. You could reuse an old unit, and go pick up a used deck from a junk yard / scrap exchange. ($30+ depending on features, Amazon/elsewhere)

Speakers:

I used a pair of 5.25", 150 Watt, 2-way marine speakers, which fit quite nicely given the playmate dimensions. While you could use regular car speakers, marine speakers are waterproof (in theory) and are usually built to take more impact and abuse. Again, this is a spot where you could pick these up on the cheap as used car parts. (~$20, Amazon/elsewhere)

Battery:

Small 12V AGM lead-acid batteries are very easy to find, as they are used in computer UPS units and fire-alarm systems. Like all batteries, their capacity is rated in Amp-Hours (Ah). Choosing the battery size is a trade-off between Ah capacity and weight, as this is by far the heaviest part. I chose to use two 12V, 8Ah batteries (wired in parallel for a total of 16Ah). At moderate volume, my stereo draws approximately 1 Amp, so in theory I could play music for 16 hours if I drained the battery from 100% to empty. Admittedly, this is overkill, you could get by with 5 - 10 Ah. (~$20 for a 8 Ah battery)

Solar Panel:

Solar panels are getting cheaper by the day, and you can find a small one on eBay or elsewhere fairly easily. Since the battery is 12V, you want a solar panel that is rated for 12V. The "open-circuit voltage" of a 12V solar panel will be around 18V, but the charge controller will prevent overcharging. The size of the panel should depend on the battery size. As a starting point, I would suggest matching the wattage of the panel to the amp hour rating of the battery (10 Ah battery, 10 W panel), but also considering what loads you will have (a stereo will draw 5 - 20+ W). A 10 W panel will have an effective charging current of approximately 0.6 amps (10W / 18V), which will charge your battery from half to full in about 8 hours of full sun light. I used a 10W solar panel, but this will depend on your needs. (~$35 for 10W panel, ebay)

Charge Controller:

If you want to charge the system with a solar panel, you will have to use a charge controller to connect it to the battery. These devices regulate the battery voltage and disconnect the solar panel when fully charged, preventing overcharging and damage to the battery. Find one that has a current rating greater than the "short circuit" current rating of the solar panel (the smallest you will see are typically rated for 5 - 10A). A basic unit will do, but I chose a nicer one that has the PCB sealed in epoxy, making it moisture tolerant.

Some units will have a low-voltage disconnect (LVD) function, which will shut off the loads if the battery voltage gets too low, preventing damage to your battery. ($20-$60, Amazon/elsewhere)

Misc:

- Multiple DC toggle power switches ($5)

- Fuses and fuse holder for different DC loads ($10)

- 12V cigarette ligher socket for accessories ($5)

- Short lengths of wire (scrap/free)

- Drawer handle, to pull the faceplate out ($2)

- LED lights ($10)

Total project costs:

- As built: $250

- Basic components, with same features: $150, (less with used audio parts)

Daft Punk is playing at my house.

Starsword71 month ago

Awsome project, I am definitely voting for you!

jtjaeger (author)  Starsword71 month ago

Thank you!

ibwebb2 months ago

Fantastic! Very easily read, well explained, well thought out, and very well organized! I have been planning to make one of these myself for sometime, but unfortunately I have not acquired the power supply parts (and keep re-working the plans) so it never gets started. You got my votes, favorites, and hope that you inspired me to put all my parts together! Congrats and best wishes!

jtjaeger (author)  ibwebb2 months ago

Thanks! And good luck with you own build!

mcb05012 months ago
Cool
Tabasco432 months ago

Nice!!! I have to make one with bluetooth

jtjaeger (author)  Tabasco432 months ago

I've used one of those aftermarket bluetooth adapters that plug into the 3.5mm aux jack on this system, but it has always been a little finicky with pairing to my devices. If you have the cash to spare, you can get a nicer stereo deck that has bluetooth built in.

SparkyOR2 months ago

can you list source for charge controller,strip LEDs and outlets/switches? What do you think you spent total? thanks, great build. I'm thinking of just doing the basic panel/contoller/output

jtjaeger (author)  SparkyOR2 months ago

I've updated the parts step with approximate costs, as built the total was about $250. I tried to build mine to the full monty, so it could certainly be done for half the cost or less, or even cheaper if you can get your hands on a used stereo deck (or don't use one at all).

I sourced most of the parts from ebay/Amazon (including the LEDs, charge controller, and switches), but shop around if you have any specialty scrap shops or junk yards in your area.

Nemesis2010772 months ago

Great Idea. I've been looking to do something similar for a while. I have an old CD DJ case and loads of SLA's from an old UPS.

Was looking to add USB and cigarette lighter sockets, maybe have a cigarette lighter socket torch stored in there.

Have the option of mains or car charging.

Also might add some lugs to attach jump leads to get the car going.

Slatu2 months ago

Lovely build. I noticed you may have used some Sugru on the corners of the panel. Does the panel fit inside of the cooler for transportation?

jtjaeger (author)  Slatu2 months ago

Good eye, yes, it is Sugru on the panel. The panel that I bought had the standard aluminum frame, and the corners are rather sharp for the the purpose.

Yes, the 10W panel can just barely fit inside the top of the cooler. The sugru addition makes it a little too big, so I'll have to shave it down a tad.

ctx19852 months ago

Awesome build! Excellent and detailed write up as well! Great job :)

MOHD772 months ago
nice & easy ..

This is amazing! It looks fantastic and you did a great job writing it up!

M3G2 months ago
This is awesome! The light is a nice touch.