Small Solar Panel

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.

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.

Comments

[dinesh007]

it's nice to improve the science knowledge

[the dashing hero]

dude, how did you do that!

[smallsolarpanels]

 This is a great instruction set.  I have some videos showing how to construct small solar panels

[Colonel88]

Nice job the adhesive looks like nose drops tho lol.

[mastover]

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".

[stevenh429]

well if you buy solar panels... there is no point on how to make them...

[ZOOBREAK]

that looks really cool,but where do you get the solar cells?

[CommanderBob]

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.

[Ausi319]

reverse diodes will make them so they dont drain into the panel.

[r.abdou]

How Old are you?

[Zimmerman]

You will need to add something to keep the batteries from over charging.

[Ausi319]

where do you buy a reverse diode?

[forte1994]

good instructible! but would you get more power if hooked up in parallel?

[Berserk87]

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.

[forte1994]

ok thanks

[hobbles]

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.

[hobbles]

(removed by author or community request)

[ElectricMan1]

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?

[FaqMan]

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.

[Tobita]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

cool, but either way, unless i move back to saudi arabia for good, i think this will stay as a novelty item xD

[kadris3]

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]

yeap!

[numenius]

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]

yeah, solar panels are really expensive in the uk. Might try ebay.

[stevezone]

seller fred480v on ebay sells the individual solar cells that you can inexpensively make your own solar panels with.

[Ausi319]

yea you can make your own. i'm looking for a seller that will sell me some for a good price. (and that i can just send the money in the mail or something.) But how do you know how many milliamps you are getting? i know the volts. But how do you know how much your panel is putting into the battery(milliamps) at a time?

[frontier]

http://www.allelectronics.com/index.php?page=search&search_query=solar&x=0&y=0
thats the cheapest place in the internet i've found for small solar panels anyway, i dont know about bigger ones :O

[claire!]

this is great, but how big is each cell?

[kadris3]

here i am running my keyboard, and failing to complement the author. i am sorry. this is exactly the thing which will free us from foreign oil. neither right away nor overnight, but every time we succeed in less oil generated power being used we contribute to moving away from this house of cards. we will win. it will be the students experimenting after school, the self directing mad scientist in his garage or basement, or the tinkerer in his shop that will eventually free us. keep up the good work. thank you.

[eggplanthunter]

If I use 3v@200mA panel with a 1N5819 diode(drop=.34v@100mA), can I charge 2 AA NiMH(1.2v@2800-2900mA) batteries? Or will i need to go to a higher voltage, ie. 3.6v@200mA to charge the AAs.