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Picture of A Simple Solar Charging Station
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        Hi, my name is Corwin and this instructable will be a guide for the process I used to build six solar powered charging stations as part of my Eagle Scout project for Boy Scouts. My main goal when I designed these stations was to make it easy to replicate and buy parts for. Please leave comments down below if you find better deals on parts or have a better way of doing something. I'll be glad to hear your input. So, let's begin with a parts list and cost estimate....
 
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Step 1: Parts List

Picture of Parts List
        So, obviously I tried to make this as cheap as possible since I needed to make six of them. Again, if you find better prices or have a cheaper way to make it, please share so everyone can benefit. 

Electrical Components
6   - 10 Watt Solar Panel - $40 each from Amazon -Link -
6   - 3 Amp Charging Regulator - $10.50 each from Amazon -Link -
6   - 12 Volt 7 Amp Hour Sealed Lead Acid Battery - $17.37 each from eBay -Link -
12 - Inline Fuse Holders - $1.98 each from Amazon -Link -
3   - 5 Amp Fuses - $1.98 for 5 pack from Amazon -Link -
1   - Assorted Heat Shrink Tubing -$10 from Amazon -Link -
6   - Three Way Car Lighter Socket Splitter with USB port - $1.49 each from Amazon -Link -
12 - Mini USB Car Charger Adapter - $2.39 each from Amazon -Link -
1   - Assorted Spade / Ring Connectors - (Free) Already had
1   - Assorted Wire - (Free) Already had

Electrical Components Subtotal - $484.54

Body Components - All Purchased from Browne's Lumber
2   - 1/2 inch sheets AC Plywood 8ft*4ft - $25 each
3   - 4x4 Treated Post 12ft - $15 each
3   - 1lb Box Assorted Outdoor Screws - $12 each
12 - 1/4" x 6" Hex Bolt - $.79 each
24 - 1/4" x 1 1/2" Hex Bolt - $.22 each
36 - 1/4" Locking Nut - .14 each
2   - Metal Plumbers Strap - $3 per roll
1   - Ladybug Red Flat Outdoor House Paint - $15 per quart
1   - Box Assorted Screws - (Free) Already had
6   - Quikcrete - $3 per 60lb Bag
6  - Hinge Sets - $3.50 per set of 2
6  - Black Handles - $.75 each

Body Components Subtotal - $194.30

Grand Total - $678.84 for six or $113.14 each

Please note that I live on San Juan Island in the Pacific Northwest of USA. Items bought here tend to cost more than if they were bought on the mainland, so it is entirely possible to build this cheaper.






Step 2: Building the Box

       To keep things simple I decided to go with a box to hold all of the electronics and for mounting the solar panel. To give myself a rough idea of what it would look like, I created a 3d model of it using Google Sketchup. This was not entirely accurate, but did give me a starting point for cutting wood. As well as storing the charging electronics, I added a closed off area where people could leave their devices without having to worry about them getting wet in the rain. Otherwise, the whole box could have been smaller. I changed the design as I worked on it, so I'm sure there are much better ways of building this. I also forgot that the panel would need to be angled, which could have saved me a lot of the headache involved with accurately cutting wood. However, for the sake of this instructable I will show you how to build the ones I ended up with. You can modify this design to suit your own needs. For the solar panel mounts below, you will need to do a google search to find out what the best mounting angle for you panel will be based on your location. Because I am fairly far north, mine was 45 degrees with the panel facing south. The equator would be straight up. Equivalent distance in the southern hemisphere would be 45 degrees facing north. You get the picture.... Google will answer that question for you.

You will need... (All orientations as though facing front of box)
2 for top and bottom - 10 5/8" x 10"
2 for left and right      - 9 5/8" x 1'
2 for front and back  - 10" x 1'
1 Shelf                         - 9" x 9 5/8"
2 for mounting solar panel - ?" x ?" (right angle triangle with corners cut off and modified for the angle based on global location) (Look at the pictures if you're confused)
1 six foot section of treated 4x4 (Just cut each post in half)

Building Steps (feel free to modify)

1. For the front panel, cut  a  8.5" x 9" door out out of bottom right hand corner (see picture). This will leave 3" up top for electronics and plenty of space for mounting hinges.

2. Start by screwing the back panel onto the bottom panel from the bottom, making sure the edges are fairly flush.

3. Do the same with the side panels, but make sure they are inside the boundaries of the bottom panel. None of the pieces should be OUTSIDE the 10 5/8" x 10" limit of that bottom panel. Everything fits within it. (Just so you know :) )

4. Next, screw in the top panel.

5.Now, the front door should have been cut out of the front panel. Screw the shelf in from the front with the shelf directly in the middle and lined up flush against the top of the door cutout (Might need pics for this one).

6. Next, add hinges and knob to your door and attach it to the strip of wood you have left on the front panel, making sure things are lined up well. 

7. Then, place your completed front panel into the box and screw in from the front. You may need to sand things down if they won't go in.

8. Lastly, from a birds eye view with your new door facing you, Screw in the triangle pieces from the narrow side 1 1/2" from the front and 1' in from the side. This should leave you with two strange looking triangles sticking up and angled towards you.

Refer to the finished pictures if you get stuck....And yes, I did leave off the post for the moment as it makes adding the electronics much easier. Also, these photos are when the boxes have electronics and no triangles since I didn't take any before they were put in...




Step 3: Adding The Electronics

Picture of Adding The Electronics
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Now to the fun part....

1. With the front panel / door facing you, mount the charging regulator near the top right corner on the shelf with Philips screws.

2. Turn the battery sideways as shown in the picture with the contacts closest to the door. Make sure there is extra room on all sides and mark the edges where the battery sat with a pen. Drill a hole past where the battery should sit and close to the door. Using this hole, bolt the plumbers strap in place. Put the battery back in and bend the strap as necessary to end up on the opposite side. Find and open hole that can reach the wood and drill another hole in that location. Bolt it again. Lastly, drill a hole on the other two sides of the battery and place the bolt through with threads up. This was my cheap solution to keep the battery from moving since the bolts act like bumpers if it shifts at all.

3. Next, measure the distance from the battery contacts to the charging regulator cut a piece of wire a little bit longer than that length. Crimp a spade connector to one end, strip the other, and screw it down into the charging regulator's battery negative contact. 

4. Take your inline fuse, which should be long enough to bridge the previously mentioned gap, and do the same thing as the previous step for the positive terminal.

5. Then, take one of the three way car lighter socket splitters and cut the plug off. Open the plug up and figure out which lead is positive and mark it. (It will be the center pin on the plug). Strip both leads and add another inline fuse to the positive lead. Heat shrink this connection to make sure it is protected. On the charging regulator, there should be one symbol that is a lightbulb. These are your load connections. Same as before, positive to positive and negative to negative. The circuitry will shut off power from the battery to this splitter if the battery voltage is too low, so you don't ruin it.

6. Drill a hole in the top panel of the box ( not this shelf ) and feed about two or three feet of cable trough it. Again, you will need two leads. Mark one lead as positive on both ends. Strip the two that will be in the box and screw them down into the solar panel connections on the regulator.

7. Before you go any further, plug a fuse in to both holders and make sure things seem to be working.....A voltmeter is your friend at this point. 

8. Drill off the edge of the rear right hand corner to feed the wire from the splitter down into the main area of the box. 

9. Tighten down the wire connections one last time to make sure you don't  need to open it again. 

10. Feed the wires through as you place the front panel / door / shelf assembly back into the main box and screw it back together. Make sure you have the fuses in!!!!

11. Now, take out two of the screws on the side of the car splitter. Position yours somewhat like is shown in the pictures and drill one hole where you think there is one on the splitter. Measure the distance between the screw holes and drill another hole for that. Then, using longer screws, cinch it down against the inner wall from the out side.....Pictures will be very helpful for this step....

Now it's time for mounting the panel!!!

Step 4: Mounting The Panel

Picture of Mounting The Panel
Okay, we're almost done..... Sorry about not having pictures of this yet. I will go out and take them today....

1. Drill a hole in the middle of the triangle along the top edge. Do this to both. 

2. Cut down, strip, and crimp ring connectors to the solar panel leads coming out of the top of the case. Make sure to remember which one is positive.

3. Take off the screws from the junction box on the solar panel and screw through the spade connections while observing polarity.

4. Once finished, take one of your 6" bolts and thread it first through the outside hole on the solar panel and then through the hole you drilled in the wood. Follow suit on the other side and lightly place a nut on each. At this point I would suggest making / using spacers to give the bolts something to cinch down against so it doesn't move around. When you have that done, really cinch those bolts down.

5.  Now measure the gap between the upright triangles from the back and cut a piece of wood to fit it. Screw it in from both sides to give the entire setup some extra strength.

Step 5: Final Testing / Mounting / Finshed!!!!

Picture of Final Testing / Mounting / Finshed!!!!
Plug something into one of the usb ports and make sure it's working. If so, leave something plugged in until the device shuts itself off from low voltage (make sure to cover the solar panel with something for this step). Then, place it in the sun for a while, come back, and make sure it turned back on and is working properly. If everything checks out, you are ready to put on the post.

Remove the bottom panel from the box and drill a hole in the center. Take your post and drill another hole in the center. Screw the two together, but not all the way tight. Once you have everything squared up properly, drill another hole through both the bottom panel and post. and add another screw. This should keep it from moving. You can now add a couple of extra if you want to be extra sure it doesn't fall off.

That's it, you're done!!!!! You can add paint if you want to, but otherwise, dig a hole in the ground and either cement the post in or pack dirt around it. Make sure you face the panel in the proper direction for your global location and watch your devices get charged by the sun. 

Thanks for taking the time to view my project. I'm sure there are many things I could have done better, but I learned a lot while making these and hope to improve the design on my mark two model. Let me know what you think and what ideas you have for mark two!
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rbinford22 months ago

Chief Seattle council troop 282 alumni here, nice eagle project bud! Wish i would've had the resources to do something like this when i was in scouts. but i'm old now, we did trail projects and built bridges in those days ,none of this fancy solar stuff hah just teasing. Great to see some washington state scouts doing cool projects like this. keep it up, and help out the youngers!

I would suggest these two projects are radically different. First this one is all DC and focused on USB outputs. Second the box etc is cheap.

A couple suggestions.

Mount the top at a degree measure equal to the latitude of the location, then point that south. That will optimize a non moveable solar array output.

Second, you should be able to drop the lighter sockets but wiring only the USB.

Finally, I would suggest using rechargeable NiCad batteries vs lead acid. As long as they are well maintained you can string them together and likely come up with a cheaper solution.

Also if you begin with aharbor fright solar system, you can likely cut out some components via scavenging.

Good idea to share power around.
Lead acid batteries are better suited to solar applications as they are much easier to keep charged as they no not mind being float charged, they actually prefer it. Ni-Cd's can exhibit a "memory effect" and can become damaged when improperly charged.

Wikipedia says "The primary trade-off with NiCd batteries is their higher cost and the use of cadmium. This heavy metal is an environmental hazard, and is highly toxic to all higher forms of life. NiCd batteries are also more costly than lead-acid batteries because nickel and cadmium are more costly materials."

Lead acid batteries are recyclable and are usually made from reclaimed lead.

Phil
Toxicity isn't a key issue since lead is also toxic to most life forms.

But, my real point for considering NiCd rechargeables is that you can scale the size of storage easily and simply and generally for less. I can buy a 12 pack (1.5v and 1100 mAmphr each or 18V 13 amp hr combined) of cheap rechargeable NiCd for $6-10 where he was spending $18 for a single 12v 7amp hr lead acid, if I remember the facts correctly.

Additionally, a creative charge controller can push lower voltages into a serial connector and charge 1.5v batteries better than pushing to charge a 12v system.

Finally on the consumption side, since USB is pushing out at 5v, you could tune the system to use fewer NiCd and a lower voltage, likely cutting out components and wasted energy. Design might be impacted because it isn't the simpler 12v components but there are lots that work for 5v as well.

Just trying to offer and alternative vision. Yes lead take trickle charge better. Full discharge kills lead but not sure that is a risk. Nicad are likely going to get a memory over time, but that can be fixed with replacement.

There are always design trade offs, he had asked for other ideas. Since weight wasn't an issue, I didn't bring it up, but a traveling version of this would be significantly better.
You have a good point. transforming 12DC to 5vDC has significant energy losses as the load increases. Hwvever 6v Pb Batteries exist, 6v solar panels exist and 6v solar charge controllers exist.

The solar Panel and Charge controller chosen here is 12v. For the project to use a 6v Ni-Cd battery pack, then an appropriate 6v Solar panel and 6v Charge controller capable of charging Ni-Cd's must be used. I would be interested if someone can give a link but I'm pretty sure standard solar charge controllers are only capable of charging Pb. So a modified battery charger of custom charger would have to be configured.

StuNutt sammons4 years ago
You can still buy NiCad batteries in USA?

NiCads have been banned for a while in Europe because of their toxicity - It's illegal to make them here or to import them. Everybody who used to use NiCads now uses NiMh or Li-Ion.

To avoid deep-discharging your lead batteries, I'd suggest a voltage sensing circuit to shut off the output when the battery starts running low.
tcambrón StuNutt6 months ago

replying to an old old post haha. Yes we can still buy NiCad batteries in USA. NiCad batteries are mostly used for the toy R/C Cars from Toys R Us and Target and RadioShack. I believe NiCad are also used in the solar powered garden lights sold at Home Depot, which explains why need to replace the batteries each year. I bought a battery hair clipper kit and I have no idea why they put NiCad in it but I want to convert it to Lion.

Actually you would only have 14.4 volts and 1100 mAH with 12 NiCd batteries.
Each cell is 1.2 volts and if you place them in series you only add voltage not amps. For 18V and 13AH you would need 180 NiCds and that puts you in the $90.00-$150.00 range making an $18 SLA battery quite the bargain.
caperren (author)  leifjohnston4 years ago
I'm planning on building a portable version at some point.... I might even decide to do that for mark two rather than my third revision...
caperren (author)  leifjohnston4 years ago
I live at the 49th parallel and just made mine 45 degrees to make it simple. However, I did make sure to face them all south. I would have done usb only, but due to time constraints and the fact that I wanted at least on car light socket for those who had their own chargers, I decided against it.
tcambrón6 months ago

Cool thanks. I want to download this pdf for later. I was wondering which parts I should get for setting up my old Galaxy S as a ip camera powered by solar.

US 7110 months ago

You can sometimes find deals on solar panels at Harbor Freight stores.

mzahead1 year ago
hi, i was thinking of charging only a phone using this project, but can i reduced to quantity of the panels battery and regulator to 2?
mzahead1 year ago
hi, if let says i want to charge a Normal phone, can i change the quantity of the panel, battery and charge regulator to 2?
GeekTinker4 years ago
Are you worried about people damaging the boxes or stealing the parts?

I like your Instructable, however to avoid vandals and thieves who will take advantage of a target of opportunity, I would suggest mounting the solar panel and battery on a much higher post, far above the height of a human being. It would get more sunlight and less susceptible to being damaged or taken by the unscrupulous.

Exactly, who would leave an expensive toy on a charger for hours, while hiking? When you returned to the charger, only to find your costly toys gone!! NOT ME! NO WAY!
caperren (author)  GeekTinker4 years ago
Yes, this was a minor concern, but I didn't have enough time to add that into my design since the entire project had to be finished by today. To help deter people, I epoxy'd over everything that I felt would be worth getting at once I made sure the station worked.
triumphman3 years ago
All those parts (6 of each)! Must have cost a bundle from all the different sources for the shipping! Wow!
caperren (author)  triumphman3 years ago
To be fair, it did cost more than it could have were there appropriate stores to purchase parts for this project at in my hometown. However, since I live on an island with very few stores on it, most parts were only available to me through online sources.
triumphman3 years ago
This whole thing is sold at Tractor (China) Supply store! It has been around for a long time! It charges electric fences! We have them on horse, cow, pig and chicken farms. So why did it win? Oh, right, the headquarters for this site is in San Fran.! They don't have farms there. Oh well, sorry! FYI
If you leave your stuff charging and go hiking you can kiss your expensive toys goodbye! Too many dishonest people out there! It takes hours to charge stuff. You can bet my stuff won't be there! FYI
caperren (author)  triumphman3 years ago
There aren't hiking trails at the park where these were placed, so that wasn't much of a worry. I figured most people would keep an eye on the box from their campsites since they're visible from almost every one. Before I put the charging boxes there, people would leave their phones and devices in the public bathroom and leave wires trailing in the sinks. I figure this was a better alternative and a fun project to put together. And if you're worried about theft, then there's no one telling you you have to use the station. It just there for convenience.
caperren (author)  triumphman3 years ago
Yes, I am aware that there are similar items for sale that may be cheaper, but this was a project that interested me, and since I like building things myself the extra cost to make it diy was worth it. Also, considering it was an eagle scout project, it would have been dishonest for me to simply buy pre-made stations. That's wouldn't really leave me with much of a project.
triumphman3 years ago
Tractor(china) Supply store sells these for a lot less! They have been around for a long time! They charge electric fences with solar low voltage setups for horses, cows, pigs and chickens too! You can adapt them to charge USB devices (phones, ipods & ipads, and more!) FYI
caperren (author)  triumphman3 years ago
This is essentially a repost and I already covered my views on this topic above....
kill-a-watt4 years ago
What are you charging? Cellphones? Battery powered scooters?

It looks like you are using the solar cells to charge a gel cell and providing cigarette lighter sockets or something.

A circuit diagram would sure be helpful.
caperren (author)  kill-a-watt4 years ago
These went up at some local county parks for people to charge cellphones, ipods, global positioning devices, etc....The solar panel is charging a sealed lead acid battery, which is then providing 12 volts to the lighter socket splitter. Two of the three slots have car lighter to usb adapters epoxy'd into them. I was planning on making a circuit diagram, but I made this later last night, and decided I would add it later once I redownload TinyCad.
Who would leave their expensive toys on a charger, out in the park? Then go hiking! Then only to find the expensive toys were stolen! NOT ME! NO WAY!
jsilvers13 years ago
to me the only thing that would make it better is if u added the means to put a small wind generator attachment so when the sun is not out u could still get some power but other then this is the greatest one i have seen
caperren (author)  jsilvers13 years ago
Yes, that would be a rather nice addition. If I ever have some extra money, I'm going to build one for myself and include some features that this one doesn't have, and maybe I'll have to look into that when I do. I'm also glad that you like it otherwise.
Tampaguy4 years ago
Noticed that your parts list showed:
"2 - 1/2 inch sheets AC Plywood 8ft*12ft - $25 each"

The only ply I've ever seen is 4' x 8' - I think either you have a very special supplier, or perhaps you just mis-stated the item.

Just curious
sguzzi Tampaguy3 years ago
He put up " Body Components - All Purchased from Browne's Lumber
2 - 1/2 inch sheets AC Plywood 8ft*4ft - $25 each " Not 8ft*12ft. just saying
caperren (author)  sguzzi3 years ago
No, he was right. I changed it to 8x4 when I he mentioned it, so that's why it says it now.
caperren (author)  Tampaguy4 years ago
Nope, you were right....I have changed it to be 4' x 8'. I just happened to skip over that error when I was writing this late at night.
Sheet goods can be acquired in 4'x 12'.
4'x 8' is more common because it's easier to handle and more convenient for
"home use"
sushixxxx3 years ago
Is it water proof?
caperren (author)  sushixxxx3 years ago
It should be. All of the joins in the wood were done so that water would fall off and not pool and seep inside. the only place that might let a little bit of water in would be the hole where the wire for the solar panel is, though because the solar panel is directly above it, water should be directed away from it. Otherwise, a little hot glue to fill in the hole would fix that potential problem.
gkern3 years ago
Thanks nice simple design used it with a larger 12v battery, and a 15 watt solar cell. Thanks for the overall design made nice and simple which I put in a plastic tool box for portability.
gbearpdm4 years ago
Could you run an inverter on this to run C-Paps all night? Would be nice to make a portable version for my scout camp for the adults who need electricity to run these machines at night. I love the idea and will be doing some for our camp either way.
You would need to charge deep cycle or dry cell 12 volt 100 amp or better batteries to power your C-PAP machines. That is my experience with mine.
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