DIY Solar Garden Light Hack - Solar Battery Charger

[@TheDoItYourselfWorld]

*Read the full article with details here:* www.thedoityourselfworld.com/articles/article.php?id=11504

[@trevorcarreon]

The Do It Yourself World maybe it was taken down but the website doesn’t work! I just needed a better view of the diode. I think I can grab the one from the chip but i want to make sure what I think is a diode actually is a diode.

[@trevorcarreon]

But this is really cool.

[@davidhadden4578]

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[@TheDoItYourselfWorld]

Wow, lots of questions. I wanted to go off the grid to show people they can do it and to see how it would feel if society broke down and I was on my own. I started in May 2012. It was a scary move at first, but its so awesome to have done it. I am single, this is my only place, and I rent the land I am. I have a day job, which pays the bills and keeps the car on the road. But ads from my website help too. I highly recommend everyone trying to become somewhat independent for the peace it gives

[@TheDoItYourselfWorld]

Thank you. Watch for the updates in the next couple weeks. I will add a voltage switch, maybe more solar cells and a USB connector to charge my cell phone. I am also looking into control circuitry to prevent over charging of the batteries if I forget to watch them.

[@jessedeleon4200]

i want to build a cellphone charger with this method, how did yours turn out?

[@billyjoegilmour5222]

@@jessedeleon4200 it's the voltage is good but the ampere is bit too low it take about 1 full day in the sun to get 3% very hour so it takes about 93hours in the sun so about 4days

[@TheDoItYourselfWorld]

Yes, I will be making some upgrades for this soon. Keep watching. The batteries get warm when they are finished charging. Most charge controllers sense the temperature. This is such a low current tho that I do not think they would explode, but I would not leave them on for days after the are full

[@Jon6429]

For a small array like this one you could use a 1N4148. Larger ones where you have solar cells in series & parrallel to give the voltages and current needed to charge say a car battery you'll need something like a 1N4001. For kit with internal batteries like smartphones or 2way radios a proper fixed voltage regulator like a 7805 (5v/USB) or 7812 (12v) will be required instead of a diode and there is a 7818 so you could charge a laptop directly by solar.

[@TheDoItYourselfWorld]

Thanks for the comments. The meter is a cheap no name $5 thing. You can sometimes find them on ebay. Think mine were on sale because I cannot find any meters below $10 now.

[@TheDoItYourselfWorld]

Yes if you leave them on too long. Just figure about 25 ma per solar cell and how many ma your battery needs to charge. A few hours give or take will not harm a thing due to the lower current

[@TheDoItYourselfWorld]

Any rectifier or schottky diode will do. A 1n4007 or 1n4001 will work. The Radio Shack part # is 276-1653 for a 25 pack.

[@TheDoItYourselfWorld]

Yes, if it has one. Most do not but only have a little transistor or small circuit in them. But if you have a diode in there, yes it will work fine.

[@TheDoItYourselfWorld]

Thanks. You can actually use a USB cable to charge a normal cell phone. All you need to do is set up the solar cells to put out 5 volts. You can have various voltages from the same solar cells depending on how you hook them up.

[@TheDoItYourselfWorld]

Normally the transistor acts like the one way switch. There is not normally a diode on the board, but depending on your particular circuit I could be wrong. It is hard to tear one of these apart, but once you start making things with them, it get easier and so much fun. These little lights can be used for so many cool projects. I will be uploading more projects later.

[@leightonwestbury92]

The diode usually serves to stop the stored energy in the battery going back into the solar panel, where it would get used by the panel which can act as a crude LED

[@TheDoItYourselfWorld]

Yes, but the commercial chargers do measure the temperature. As the batteries charge up, they get warm. I will be making the circuits later and showing how.

[@TheDoItYourselfWorld]

For larger batteries it takes about 2 full days of summer sun. In the winter about 3. But I use 2400 mah batteries. They are quite large.

[@Darryl603]

It seems that it made more sense to face the wires from the solar cells toward the batteries, so the wires would reach. Is there any danger of over charging (or battery damage) if you leave the batteries in the charger too long? Thanks for the great ideas!

[@TheDoItYourselfWorld]

Thanks for the comments. Yes, the diode is a necessary evil. You could use a schottky diode for lower voltage drop. But in the long run, it shouldnt matter too much with these smaller batteries.

[@TheDoItYourselfWorld]

I use the positive side. The band on the diode is negative, so make sure its installed right.

[@TheDoItYourselfWorld]

It exists and its called a MPPT controller. Multi power point tracking solar charge controller. It used both a buck (reducing) and boost converter to get the best charging curve out of your solar panels. In full sun they put out about 18 volts and in low sun maybe 9 to 10 or so. The MPPT controller matches the battery voltage to the solar panel voltage, increasing the charge over all sunlight levels.

[@TheDoItYourselfWorld]

A Schottky diode would be best due to a lower voltage drop, but almost any diode (non zener) will work in this case because it is only blocking the voltage from flowing out of the batteries and into the solar cells when a cloud passes over.

[@TheDoItYourselfWorld]

Please do share your experience if you have seen these go bad. In my studies and experiments, I have made many solar panels out of smaller solar cells. Solar cells are strung up to make larger voltage solar panels. Then you can string up your solar panels to make higher output or current. Yes, there should be diodes on each one, with larger panels. These little solar cells do not put out much voltage or current though. I have multiple cells in order to overcome the voltage drop and still work

[@Totogita]

This video is responsible for the solar setup I have now. I saw it in 2012 and that peeked my interest

[@TheDoItYourselfWorld]

That is cool :)

[@TheDoItYourselfWorld]

Sometimes Westinghouse brand has the AA or AAA. A lot of these are now coming out with the 2/3 AA. But you can use the solar cells from the dollar store path lights and get a battery socket at Radio Shack.

[@TheDoItYourselfWorld]

1n4001 or 1n4007 work fine. Basically any sort of rectifier diode will do. Its just a blocker to prevent the battery from discharging back through the solar cells.

[@TheDoItYourselfWorld]

In between the panels and the batteries either on the positive or negative side. Just make sure you get the polarity of the diode right.

[@TheDoItYourselfWorld]

Series increases voltage. Parallel increase current. The solar cells are each meant to charge a 900 mAh battery in a full day. So you can charge two of them in this setup in half the time. Or a pair of 1800 mAh batteries in a whole day.

[@TheDoItYourselfWorld]

These put out about 3.5 to 4 volts with no load. They drop down to about 1.5 to 1.7 volts per panel with a load, which is the right voltage for charging AA and AAA batteries.

[@TheDoItYourselfWorld]

Yes, you are correct. I wanted to quickly get the video done and show it working before it got dark out.

[@TheDoItYourselfWorld]

Yes, AA and AAA batteries. All you need is the right socket. You could actually charge your cell phone with the right voltage and power connector on it. I will do an update on that soon. I am ordering some USB connectors from China.

[@TheDoItYourselfWorld]

Thanks for the compliment. You can modify this in many ways. I will be adding to it later when I get time.

[@TheDoItYourselfWorld]

These are usually a single transistor based boost converter. They step up the voltage from 1.2 volts to about 3.2 volts to run a white LED. You could use them for anything that runs in that voltage range and current. At some point tho, you will find its highest current limit and fry one. Keep track of what burns it out so you know your limits. They will charge anything within their voltage range as well. The 2.3 volt cells should happily accept the voltage, yes.

[@TheDoItYourselfWorld]

Yeah, its cool soldering off the grid. Actually everything is cool. I cut my own hair with a electric clippers and use an electric razor on my face every day. My panels are about 250 - 300 watts total. Nothing huge, but it does the job. I am comfortable. No fridge yet tho. My aunt was proudly showing me how she is using solar path lights for emergency night lighting in the house. They are very versatile.

[@TheDoItYourselfWorld]

That is fine. You can use the same diode with multiple cells.

[@TheDoItYourselfWorld]

No problem. Please let me know how it goes.

[@TheDoItYourselfWorld]

1N4001 or 1N4007 work fine. But a low power Schottkey is the best due to its lower voltage drop. Sorry dont know a number, but you can ask them.

[@TheDoItYourselfWorld]

A standard battery charger puts out about 80 to 120 mAh into the AA or AAA batteries for a slow charge. A fast charger will put out about what you have. I prefer the slow charge for longer battery life though. Please come over to thediyworld forum and let me know how it goes. Please upload some pics when done.

[@TheDoItYourselfWorld]

If you left it for many days, yes it would. With smaller batteries you should pull them off the charger after a day. With larger capacity batteries it will take a few days to charge them.

[@TheDoItYourselfWorld]

I am sorry, but I am not sure what you are asking. What do you want to do with the strip lights. What about the solar panel with the male connector?

[@christo930]

You might want to attach a couple of mirrors that will bounce more light onto the solar cells. It shouldn't heat them up very much while getting more watts per solar cell. This would really only work when the sun is rising or setting and in the winter, but you can get some really cheap mirrors.

[@TheDoItYourselfWorld]

Yes you can. Anything that can sense the strength of the sun's intensity will work. Just set up a circuit that is triggered at a certain voltage level. More sunlight equals higher voltage output from the cells. Less light equals a lower voltage. Hook one up to a volt meter and play around with it. Hold it in different angles to the sun. Try it at dusk and dawn. It will work.

[@TheDoItYourselfWorld]

Sorry, for the delay in my answer. Was in Canada. Any sort of blocking diode will work. Radio shack or ebay. 1n4007 or 1n4001 are good.

[@TheDoItYourselfWorld]

The price for 4 solar cells at a dollar each is $4. You can get diodes free anywhere, sometimes in the solar lamp. And its fun. And you cannot get cheap solar panels here. The shipping to bring one over here is more than the panel. Over here for a 5 watt panel plan to spend about $30 to $60.

[@TheDoItYourselfWorld]

Yes, you can connect them to get 14 volts to charge a battery. But the current is very low. Better to charge smaller batteries and use LED lighting to save energy. It would take months to charge up a car battery with these tiny solar cells. I got a bunch of dollar store LED flashlights I am converting to run off my solar charged batteries. They are very bright and run off AA or AAA batteries. String them together for best results. At least its free lighting for life.

[@gregoryfaith4303]

I've got several of these solar lights under several inches of snow that I bought as Christmas decorations. Now I know what to do with them when they are uncovered after this spring. Thanks!! Ex Navy electronics technician looking for a new electronics re purposing project!!

[@TheDoItYourselfWorld]

Its AWESOME. It gives a sense of freedom, accomplishment and peace. And I never loose power.

[@TheDoItYourselfWorld]

You could do it, but it would take some time. The current output from one cell is about 50mA. In a 10 hour day you get about 500mA from one cell. Two of these gives you an amp in 10 hours. The voltage output is about 2.5 to 3 volts per cell. Put them together to get what you need. Check the original charger output for the proper voltage.

[@techcheck5019]

Each little panel usually produces around 20mA at best, so you are looking at 80mA (but I would say around 70mA on average). So if you have a single 1000mAh AA battery then it will take 14+ hours to charge. But it is interesting trying to re purpose these small panels, it's a fun thing to do. It could be handy for charging those 300mAh AA batteries in timely fashion.

[@TheDoItYourselfWorld]

Works for all batteries but yes, best results for smaller ones.

[@erfquake1]

How does the circuitry handle these hacks? I'm looking into a 100mm x 100mm panel to charge 2 or 3 AAA batts so the light will hopefully stay on all night. As it is , my Home Depot 14w light sputters out by 7:30pm. But I wonder what the limiting factor here might be: draw (unlikely), supply, storage, or circuitry.

[@TheDoItYourselfWorld]

Yes, sort of. They put out very little current. It would be a trickle charger to maintain its charge, rather than top off a battery. It may prevent a battery from discharging over time. I have been thinking about putting one together. You need 18 volts on the solar panel, no load. String them up in series to make 18 V. Then put groups in parallel to get more current.

[@TheDoItYourselfWorld]

I had to learn on my own by reading and taking things apart. Either way, it is good to know how things work. I have a lot of plans for these little lights in the near future. So many ideas, so little time...

[@albysHub2006]

There's power were you are? Why you are using an inverter?

[@TheDoItYourselfWorld]

Yes, actually the unmodified dollar store path light will charge batteries just about double the capacity of the puny ones they ship the lights with in a day with no problem. Some people add larger batteries to make them last longer each night.

[@TheDoItYourselfWorld]

Yes, where you can buy dollar solar path lights to do these experiments. Its a great site.

[@TheDoItYourselfWorld]

That is cool. When I lived in Brooklyn, NY I used a 12 volt alarm system battery to power a battery operated 12 volt fluorescent lamp in the bathroom. The ones found in most hardware stores sold as closet lights. I had a shower room and a separate bathroom. Had a lamp in each. Saved some money on lighting that way.

[@TheDoItYourselfWorld]

1N4007 or 1N4004 are both fine. Just about any blocking diode will do.

[@TheDoItYourselfWorld]

Yes, that is a relatively untouched area. They are very fine boost converters, but noone really knows what to do with them. I sadly have no 3 volt devices, so I cannot use them. But they may be good for running some LED flashlights. You could even theoretically string a bunch of the circuits up to run higher powered LED bulbs, such as a 1 W LED. Now that would be an accomplishment.

[@TheDoItYourselfWorld]

It can if you leave it too many days in the sun. I am working on a charge controller but it adds a lot to the cost of the charger.

[@TheDoItYourselfWorld]

Yes, you would need 8 or even better, 10 of the cells. With 10 you can get charging with a bit of overcast as well. Your cell phone and some other devices have a built in charge limiter in the device. Otherwise, the circuitry gets a bit complicated with the need for a voltage monitor on the output of the solar panels which can shut off the output to the device when the voltage reaches a certain level.

[@TheDoItYourselfWorld]

There is normally only a transistor on the board, which acts like a diode sort of. Place a diode anywhere between the plus on the battery and the plus on the solar cell output. I can fully help you if you come over to thediyworld forum and post a photo. I can then see what parts are on your board and help you get it going.

[@TheDoItYourselfWorld]

Looks good. This has serious potential. These little solar cells can charge an AA or AAA battery during the day, so 3 of them would put out enough for small devices. I am surprised tho that your devices take the 3.2 volts from the boost coverters on the little circuit boards. Most devices these days need 5 volts in.

[@TheDoItYourselfWorld]

Not sure about AAA but I have 1800 and 2000 AA batteries at home. From Radio Shack, Walmart just about anywhere you can get good rechargeable batteries.

[@TheDoItYourselfWorld]

No problem. Please feel free to ask any questions when you make one.

[@TheDoItYourselfWorld]

I have a general idea of the solar cells capacities because of the original batteries that came with them. Mine, for example, were 120 mAH batteries. That gives me about 120 mAH per day of charge per cell. 5 cells gives me about 600 mAH per day of charge. You can also just measure them from time to time. A rechargeable nicad is about 1.2 volts charged. When I get the to about 1.3 then I pull them off the charger.

[@TheDoItYourselfWorld]

Thank you for the feedback. Happy to help.

[@TheDoItYourselfWorld]

Yeah, just go to Radio Shack and ask for a 1n4001 or 1n4007 or equivalent diode. Remember the band on it is negative and the unmarked end is positive. It blocks the flow in one direction but allows it in the other. If your charger is not working the first time, check the diode and make sure its installed the right way.

[@BriannaBeastMode]

Just seeing this video for the first time just now. I miss radio shack :(

[@TheDoItYourselfWorld]

@@BriannaBeastMode I miss them too. Now I have to order everything online and wait for it to arrive.

[@TheDoItYourselfWorld]

Yes, it is. As long as the battery has enough capacity to keep it running, no problem.

[@TheDoItYourselfWorld]

Yes, just make sure you get the right voltage out and you have a solar USB charger. I plan to make one soon.

[@johnarizona3820]

Well done bro! Theres much can be done with these cheap lights. My mom lives in upstate ny and has a very dark stairway so i took one apart, extended the led connector and installed the light above her stairs while placing the solar panel in a fixed spot outside on the roof. Now she always has enough light to see the lights switch at night. I want to build this charger so thanks for the demo. God bless!

[@TheDoItYourselfWorld]

That depends on what type of batteries they are. Can you open the lights and get to the batteries? If yes, then try to charge them with a conventional charger. You can also test the circuit using an outside power source. If you need more details, please come to thediyworld (dot) com forum and I would be happy to help. You can post photos there as well.

[@TheDoItYourselfWorld]

Also at 12:30 in the video is a direct clickable link to the webpage.

[@TheDoItYourselfWorld]

Well, I want to do it asap, but the stuff takes some time coming from China. It will be a couple weeks, but keep watching. Very soon. I have everything in place, waiting for the USB sockets. Of course, you could also remove sockets from an old, broken device that has a USB port on it. I am looking around for something I can scrap out. Watch for the video.

[@TheDoItYourselfWorld]

In theory, yes. But it would take a lot of them to get any serious charging current. They are best used for smaller flashlight batteries.

[@TheDoItYourselfWorld]

Yes, I have tons of them. But they put out way too much current for little batteries.

[@TheDoItYourselfWorld]

You only need to block the power from flowing on one side. It has to flow through the circuit and back again. Blocking it on one side does the job. One diode. The original circuit regulates the on and off based on if the sun is shining or not. This is a battery charger though. No LEDs in the system. Just the solar cells and your batteries to be charged.

[@TheDoItYourselfWorld]

Yes, and I will be doing update experiments soon. Keep watching for them. I will be setting up multiple voltages and a USB adapter, plus control electronics.

[@jasonparrish8488]

Hello friend. I had that very same idea. But at the time I didn't know that I needed a diode. I didn't even have a dial to begin with so that nothing went right. You were very informative I enjoyed your video very much. I hope you have a good day.

[@TheDoItYourselfWorld]

Happy to hear it helped.

[@branchcensus5083]

@@TheDoItYourselfWorld you replied after 10 years Respect+

[@TheDoItYourselfWorld]

@@branchcensus5083 Still going strong. Thanks.

[@TheDoItYourselfWorld]

I plan to make a wood gas generator soon. Hopefully it will work.

[@TheDoItYourselfWorld]

Various dollar stores have them at different times. I go back once a week to each chain to see what I can hack for me newest projects. Keep checking, eventually you will hit the jackpot

[@BrianCaouette]

Wired in series you are increasing voltage. Wired in parallel to increase amps. Depending on your needs and the solar cells being used you may need a combination of the two to get decent charge!

[@TheDoItYourselfWorld]

Believe it or not, with my cell phone. I can hook it to my laptop as a modem. I get pretty good reception, even in the mountains far away.

[@ScottDamery]

So how long did it take to get those batteries fully charged? We need stats...

[@TheDoItYourselfWorld]

1n4001 or 1n4007 work fine. Get them from radio shack or ebay

[@TheDoItYourselfWorld]

Yes, the Dollar Tree. They come and go. You need to watch for them because they sell out fast. I just got some Christmas ones at Walmart on clearance for 60 cents each. I look around. You can also find them online at the dollar tree website. Family Dollar also carries them on holidays like the 4th and Christmas. After the holiday, I grab them all up on clearance.

[@TheDoItYourselfWorld]

You have about 7.5 amps at 2 volts (or any combination of voltage and amps) which gives you about 15 watts total. At 12 volts you probably have about 1.5 amps of charge with all your panels. It would take you 10 hours of sunlight to get 100 usable watts of energy with your panels.

[@TheDoItYourselfWorld]

It is low current so a few hours are no problem. You have to do the math. If your battery is 500 mah and your charger is 50mah, then it takes 10 hours to charge a single battery in full sunlight. My batteries are about 2000 mah so it takes a couple days.

[@TheDoItYourselfWorld]

blush. Thanks for the compliment.

[@TheDoItYourselfWorld]

I think I will get a few and tear them apart to see what makes them work. See if anything is useful in them.

[@TheDoItYourselfWorld]

Look on ebay for any solar powered toys or anything with a solar cell that costs a dollar with free shipping (if that exists in your country). Bid on a bunch of them.

[@TheDoItYourselfWorld]

I just watched a Discovery Channel documentary on a post apoc world. Was well done. Everyone will be a DIY-er very soon. I am trying to get the skills needed now so that I can survive later.

[@WhiteMustang88]

Thank you for being thorough. When other videos just sort of show & tell the project after it's finished, you actually show HOW TO DO IT! Very nice work!

[@TheDoItYourselfWorld]

I will be doing the same thing here. A small engine to power an alternator for emergencies. My batteries are 12 volts anyway.

[@anodizedblue4180]

Nice video tutorial on how-to. There is a voltage drop off with the diode attached but the diode is indeed necessary so the battery wont be discharged when there is no light. PRETTY COOL I SHOULD SAY.

[@TheDoItYourselfWorld]

For small emergency lighting, this is perfect. For lager projects, these are too weak. Visit thediyworld and you can find the book I wrote about how to make your own solar panels for $1 per watt. This is what you need for larger household needs.

[@MrIgottadrive]

To keep your solar cells working like new and charging paint them with clear nail polish they last longer great battery charger.

[@TheDoItYourselfWorld]

Ok, I will be happy to help. See you there.

[@TheDoItYourselfWorld]

You can post images on the forum, no problem. Dont worry about your writing.

[@TheDoItYourselfWorld]

I have rechargeables that I had for about 7 years now and still going strong. A few have failed along the way, but most are good. Get the good quality stuff and they last.

[@widebandrecords902]

great idea.. I still say momentum / motor / magnet energy is still the number one immutable source if you got the leg power each day..

[@bobr4987]

I saw a video once where someone took the gearing off several old 10 speed bikes and used slowly dropping weights on pulleys. As the weight drops slowly the wheel with copper coil spins fast against magnet stator. That might save the legs if you could make it work.

[@TheDoItYourselfWorld]

Yes, more panels = faster charging. If you want to charge a 12 volt battery, you need 14.5 volts to charge it.

[@TheDoItYourselfWorld]

Nice, I need to get more. I use them for a lot of projects. More ideas on the way soon.

[@TheDoItYourselfWorld]

They are designed to use 1.2 volts in and put about 3.2 volts out. Probably not much current output, but it would be interesting to find out what their limits are. I have a bunch of them laying around after hacking these solar lamps.

[@TheDoItYourselfWorld]

No problem, please join thediyworld forum and I will be happy to help you out there.

[@evolopterus]

Thanks. You think it's possible to measure the voltage (as opposed to temperature) of the batteries instead? I don't know how commercial chargers do it. But the circuit shouldn't be too expensive.

[@TheDoItYourselfWorld]

Thanks, I have been looking for one. But no, the 120 volt one doesnt strain my system much.