Instructables
Construct a small, portable solar panel that will charge two AA rechargeable batteries in a day or two. Use the batteries to make any battery-powered device solar powered.
 
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Step 1: Introduction

Construct a small, portable solar panel that will charge two AA rechargeable batteries in a day or two. Use the batteries to make any battery-powered device solar powered. Or use the panel to directly power small DC electronics.

The panel consists of eight 1"x3" solar cells wired in series with a blocking diode mounted on a board and protected by clear plastic. In this configuration the panel provides about 250 milliamps at 4 volts, which will charge two batteries in a day or two, depending on the weather and the batteries' capacity. Other solar cell configurations are possible to provide more or less power to, for instance, directly charge a 3.6 volt cell phone battery, or to provide a faster charge to AA batteries.

There are a number of off-the shelf small solar panels available on the web, but building one yourself gives you the flexibility to configure it to provide exactly the voltage and amperage your project needs. And it could be cheaper.
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pauly9911 months ago
How might solar cells be constructed so they provide heat? I'm talking about a string of cells that might allow certain substances to stay above 32 degrees fahrenheit?
webgiant pauly997 months ago

The best, most expensive solar cells only convert 22% of the solar light to electricity, which is an incredibly inefficient method of making heat from solar energy.

You'd be much better off using the direct heat of solar light to heat a thermal mass (a bottle of water painted black is the cheapest, though sand in the bottle can do as well), then the combination of solar heat and thermal mass heat will keep something heated above 32 degrees Fahrenheit. There are analog valves which will let out some of the heat should the temperature rise too high, and you can make it even more geeky by using an Arduino and temperature sensors to keep the substance at a certain temperature.

There are many practical uses for this. Doing a DIY project while watching the how-to video?
eyesee1 year ago
good
eyesee1 year ago
good
Schmidty162 years ago
How many wats or volts does it produce
dinesh0075 years ago
it's nice to improve the science knowledge
y0!-bReaKdAncE.gif
dude, how did you do that!
 This is a great instruction set.  I have some videos showing how to construct small solar panels
Colonel885 years ago
Nice job the adhesive looks like nose drops tho lol.
mastover5 years ago
Nice Job! I love the idea!
You can get nice cheap solar cells at the electronic goldmine http://www.goldmine-elec.com/. I just ordered 4 of their small cells last week and they are in perfect condition even though it states "may have chipped edges".
stevenh4295 years ago
well if you buy solar panels... there is no point on how to make them...
ZOOBREAK5 years ago
that looks really cool,but where do you get the solar cells?
Nickle metal hydride batteries can take up to 1/10 of there mAh rating and safely dissipate this as heat. This is the minimum and I am sure that if your batteries were charged and you left it there for say an hour, nothing would happen. Now if your batteries are lithium than it is a different story.
reverse diodes will make them so they dont drain into the panel.
How Old are you?
Zimmerman7 years ago
You will need to add something to keep the batteries from over charging.
where do you buy a reverse diode?
forte19945 years ago
good instructible! but would you get more power if hooked up in parallel?
parallel would give you more amps. a lot of the solar cells ive been looking at are 0.5V output and 50-200mA output. so hes probably getting 4V @ 200mA. or around there.
ok thanks
hobbles5 years ago
Im gonna invest in getting better cells, you should make another panel and put it in series and it should cut the time in half. Im gonna try buying some from http://www.quadmodsusa.com/solarcells.html but i dont know how reliable they are.
Didn't your solar cells break over time because, like its already hard to solder them correctly, how do you put them in a plexiglass container without them breaking?
FaqMan5 years ago
This ible would help with our economy actually buying millions of none rechargeable batteries will pollute the Earth while rechargeable would not really. This can be the start of a cleaner earth.
Tobita6 years ago
hello, i am kinda of new to solid state electronics and learned most of what i know now from my grandpa, and i was wondering, if i had solar cells connected in series, and they charge a bank of capacitors (also in series) and i have a switch separating the wire that connects the +and- sides of the capacitors, and i have a transformer on there to regulate it, will i be able to sustain a charge long enough for say charging and operating a notebook?
kadris3 Tobita6 years ago
probably not. charge and use batteries. it's much simpler. a laptop requires about 18 or 19 volts. 12 for some systems, and 5 for the others. its a dual voltage menace. some use a single battery so make up one to parallel the internal system in your laptop. watch polarity to save your electronics. good luck.
Tobita kadris36 years ago
oh my, dual voltage cells? well, if the problem would be shorting my battery or not having enough/too much voltage/amperage what if i simply connected the charging cable, if i stay in the operating amperage and voltage, i SHOULD be able to charge it, even for the smallest moment, right? if not, i could simply be the most hopeless person at this =P
kadris3 Tobita6 years ago
the internal battery cells usually aren't dual voltage. they are higher than the 12vdc systems available everywhere. the computer breaks the voltage down for the various systems it requires. if you are building a system for running the computer, you need two in series: a 12vdc jell cell and a 6vdc gel cell to give you the 18vdc that the computer uses. charge the battery array with about 20 vdc at low amperage. watch polarity carefully. a starting point would be to measure the dc voltage on the output of the 117 vac charger that came with the computer. this will tell you the charging voltage. this is what you will need from the solar array. you can then design the solar array to charge the internal battery. you can then run it from the charged internal battery or the outboard 18 volt jell cells you made up. when charging it might be better to have the computer off to prevent an over voltage as the cells get near full charge. the other alternative and much simplier is use an inverter on a 12 vdc system to provide 117 vac to the charger which came with the computer.i have done this in the truck when i have been on the road and it worked well. i used a 140 watt msw inverter from harbor freight $17.xx on sale. a 70 watt unit as available from wally world for $14.xx and this also worked as well. i also did cell phones and electric razors in the manner. if you need more explanation please feel free to contact me directly to save bandwidth. go to unclecytheledguy.com and click on the contact uncle Cy. i will be happy to provide any electronic help i can at no cost to you. good luck
Tobita kadris36 years ago
cool, but i am gonna keep most of my project for the winter months when it's too cold to go outside and have nothing else to do :D but hot damn, i can't wait !!!!
kadris3 Tobita6 years ago
good for you. many of us northerners do the same. i have several radios to build and i pile them up until winter. lots of projects: electronic and otherwise. i meant to mention earlier, a transformer is for alternating current, but a solar panel generates direct current. you might be successful at charging some capacitors but they would only provide tiny amounts of current. you need much more than that for the needs you described. good luck with your project
Tobita kadris35 years ago
it's winter now! and i put away most other things waiting for this one, first i need to reformulate the goal (charge things using the classic 2/3 prong North America plug) the power source (solar) and storage (pending, worst case is some capacitors in series with a high-end resistor at the end (i wouldn't do that)) so, if i get everything on paper/wetware/digital, i could start an instructable if i had someone capable of fixing the errors and putting things into effect (short on cash since a while, bought a tad too many gifts) then it doesn't seem too mind-meltingly massive.
kadris3 Tobita5 years ago
with average intelligence, which you have already demonstrated, getting wired is no problem. as i have said before, forget capacitors. they will not work. get a couple of golf cart batteries at wally world. they are deep cycle 6vdc and more amperage than three trolling motor batteries. series up the two batteries for the 12vdc you need. keep everything on 12vdc and use an inverter to charge the computer. automotive lights(12v) work well and you don't need to convert anything. RV lights from an old RV, junk yard, RV store are easy to get, and work well. heed the cautions above and go for it. good luck.
Tobita kadris35 years ago
i think now i would need to get the solar panels, but if we could use something that could diffuse the sunlight for more exposure and mount it on the panels it should chare faster, correct? and, when i visit saudi in march, should i dare attempt to bring it in the plane? xD (i wasn't serious, i would mail it instead)
kadris3 Tobita5 years ago
incorrect. diffusing sunlight cuts down on your output from the cells. this is especially true for crystalline, or polycrystalline. slightly less true for amorphous silicone. there are some semi bullet proof(i.e. well built) panels out there but they are expensive. D.I.Y. is the only way to go if you are broke. if all you are doing id recharge a laptop, you may be able to go directly to an inverter and forget the battery bank. you need enough power to drive the inverter, so there is a downside to everything. have a safe trip.
Tobita kadris36 years ago
cool, but either way, unless i move back to saudi arabia for good, i think this will stay as a novelty item xD
kadris3 Tobita6 years ago
that's o.k. too. even casual use may save a drop or two of foreign oil. as the whole nation does it, these little drops add up. besides being fun to play with, you have a back up system when the power fails. let the experiments begin.
Tobita kadris36 years ago
yeap!
numenius6 years ago
This looks useful. I have a boat which has various battery needs so this would be a good soloution. Ready made panels seem overpriced here (UK) How much did this particular project cost?
liam01 numenius6 years ago
yeah, solar panels are really expensive in the uk. Might try ebay.
seller fred480v on ebay sells the individual solar cells that you can inexpensively make your own solar panels with.
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