Step 4: Add the Solar Cell

There are a couple of different ways to connect the solar cell. The first is by simply shortening the connector leads and plugging the barrel plug into the barrel jack on the charging circuit.

The second method is to replace the connector with another JST connector and plug it into the third connector marked 5v on the charging circuit. I didn't have another JST connector handy so I just soldered a salvaged two pronged connector to the charging circuit where there are two open pins on the 5v line.

Using the second method certainly is a bit cleaner since you don't have the big barrel plug sticking out of the side of the tin.

UPDATE- Since the original charging circuit has been discontinued, the best way to connect the new version Sparkfun LiPo charger is to splice a mini USB cable to the solar cell wires so it can plug directly into the charger. There is a simple guide on how to do this here-

Now attach the solar cell to the top of the Altoids tin using some 2" wide Velcro. I wrapped the battery pack with a layer of clear packing tape to help protect it. Then the battery pack is simple set down on top of the two circuit boards- it's a near perfect fit.

Now set your MightyMintyBoost out in the bright sun and charge it up! You should see a little red LED on the charger board light up. Once it's fully charged connect your iPod/iPhone/USB powered device and enjoy!
Love this setup,<br><br>I plan on building a 12V system for other power hungry applications, but instead of a flimsy altoids can, i decided to beef it up a bit with a pelican project box. If anyone has any suggestions about how to cover ports a little better, that would be great. <br><br>Check it out!<br><br>Love the instructable! Great work.
<p>Love the case. I wonder if you could use sugru around the ports to make secure fittings. http://sugru.com</p>
How much did you pay for yours.
Looks awesome. Pelican cases are great- I have a large one that's over 15yrs old and it's still going strong. Maybe for port covers you could mold some silicone plugs. Try Sugru!
Thanks! They're possibly one of the best made containers of any sort. I've been using them for various things here and there over the past 7 or 8 years. I like the idea of using Sugru for port covers! I was having all sorts of failed trials with grommets, silicon and other failed devices, but sugru might just be the ticket. Thanks Honus! <br><br>
No problem- let me know how it works out!
<p>will the battery explode under heat</p>
If you apply too much heat to the battery then yes you would probably damage it. According to the manufacturer's data sheet regarding thermal shock testing- &quot;Put the battery in the oven. The temperature of the oven is to be raised at 5&plusmn;1 per minute to a temperature of 130&plusmn;2 and remains 60 minutes. No explosion or fire.&quot;
<p>Maybe I'm just slow...but in the picture, you have your own battery, charging circuit from Sparkfun, solar panel, case, et cetera...what do you need the Mintyboost for?</p>
The MintyBoost circuit boosts the 3.7V form the battery to 5V output that is suitable for USB powered devices.
<p>i love this</p>
<p>where did you get the iron</p>
<p>I purchased that soldering iron from here-</p><p>www.sra-solder.com</p>
<em><strong><a href="http://yoghfgh" rel="nofollow">yes</a></strong></em>
<p>Is this capable of handling an iPhone 6s? I would love to make this for my dad but I'm worried the iPhone 6s is is going to require more power than this would put out. Thanks in advance for the help!</p>
I don't know if it will work with a 6. It will work with all iPhone 5 versions so I'd be surprised if it didn't work with the 6 as I don't believe the charging requirements/protocol has changed. Both of the iPhone 6 versions have greater battery capacity than the 5 series so it just wouldn't charge it as much.
<p>Thanks for getting back to me. I'll give it a shot and see how it goes. Thanks very much!</p>
<p>Should the battery be the polymer version, or can it be a regular lithium-ion battery? I'm noticing a rather substantial price difference between the two.</p>
The charging circuit is suitable for either Lithium Polymer or Lithium Ion.
<p>Hey! I built this for my science fair project and I have a problem with it. Whenever I charge up the battery through USB or solar power, a few minutes later, it doesn't charge at all. It's like the battery doesn't work or something. My setup looks exactly like the one in this picture https://learn.adafruit.com/assets/1482 . Also, I don't know if this matters but what does it mean when I charge this with solar power, the power LED light flickers over and over rapidly. While when I use a USB through a wall outlet, it doesn't flicker at all. This project is due in about a week or a week and a half. I'd appreciate any help if possible.</p>
<p>I'm no genius, but I think the reason for the LED light flickering means the phone is not getting enough power or the solar panel is not producing power fast enough.</p>
So it begins charging and then stops? It sounds like the flickering LED is showing that you're not getting a consistent output from your solar panel. When it does this is it in direct sunlight?
<p>Sorry, I was thinking of something else but what I typed isn't really my problem. What's happening is if I charge the battery with solar power from the sun, the battery only seems to hold onto that energy for a few hours and then it all just disappears . I don't use it while its charging nor after I charged it. Also, when the light flickers, I am using it under direct sunlight.</p>
<p>What solar panel are you using and have you checked its output? If <br>you're using the Adafruit solar charger circuit they recommend a solar <br>panel that puts out at least 6V. As far as the battery charge <br>dissipating that has me stumped- there has to be some load somewhere <br>that is draining the battery. Maybe there is a short somewhere? Check <br>the battery voltage before and after charging and let me know what it <br>is. The battery voltage shouldn't ever drop below 2.8V and at full <br>charge it should be around 4.2V.</p>
<p>Hmm, maybe the solar panel is the problem? I bought the same one put at the top of the website. It has 0.45W and it's rated for a 4.5 open voltage. Here is where I got mine from. <a href="https://www.sparkfun.com/products/7845" rel="nofollow">https://www.sparkfun.com/products/7845</a></p><p>As for the battery, I just tested what I had now since it is dark out, the multimeter showed me 4.17V in the battery. </p>
<p>That could definitely be part of the problem as that panel was what I used for the original charging circuit- Adafruit specifies a higher output panel for their charging circuit. </p><p>It appears that your battery has a full charge. I'd check the battery voltage again in a few hours to see if there is a drain on it.</p>
<p>Okay, so I'll try to buy a different panel. I plan on rechecking the battery voltage in the morning once I leave for school and tell you the results asap. Also, since i noticed that the battery has a charge, I went ahead and tried to charge my phone with it, but it didn't work. But for some odd reason when I plug in my USB power meter, ( I bought it from Amazon. Here's the link : <a href="http://www.amazon.com/DROK-Dual-USB-Voltmeter-Multimeter-Alignment/dp/B00J3JSEG6/ref=pd_cp_pc_1" rel="nofollow">http://www.amazon.com/DROK-Dual-USB-Voltmeter-Multimeter-Alignment/dp/B00J3JSEG6/ref=pd_cp_pc_1</a> ) it showed me 3.9V and 0 amps. Any idea's as to why I can't charge my phone but the USB power meter still shows that there's energy?</p>
<p>What kind of phone do you have?</p>
<p>I have an iPhone 5s that was bought about a year and a half ago.</p>
<p>OK so you have good battery voltage but the Mintyboost circuit output is at 3.9V and the 5s is a supported device according to the Mintyboost specs. I would double check all of your soldered joints on the Mintyboost circuit and make sure all of the parts are installed correctly. If your battery voltage is good you should be seeing a regulated 5V output out of the Mintyboost USB output- it won't charge your phone if the output is less than 5V. I think that's the problem and it would definitely explain why the phone isn't charging.</p>
<p>I plan on building a 12V system for other power hungry applications, but instead of a flimsy altoids can, i decided to beef it up a bit with a pelican project box. If anyone has any suggestions about how to cover ports a little better, that would be great.</p>
<p>what size battery and solar panel (and anything else) would I need to mount on the back of an 08 MacBook pro to charge it?</p>
I have no idea. You would have to look up the specs for the battery and figure it out from there.
<p>Wonderful project. Thanks for the clear instructable</p>
<p>Love this Intractable</p>
<p>Hi- love the idea. How would you modify it to make it into an ipad 4 charger?</p>
You would just need to figure the pinout for the thunderbolt connector. It would take it an awfully long time to charge an iPad though since the batteries in those are much larger.
Would I be able to add a higher wattage solar panel to get more energy quicker, and what would I have to do to do this? Also, would I need to add more batteries to the pack to increase capacity?
<p>You can certainly do that. Have a look at the FAQ section- there is a charger listed there than can handle up to 1 Amp. You absolutely can add a larger capacity battery and you don't need to change the circuit at all.</p>
<p>good project. well done!</p>
<p>interesting, and the solar parts looks small and nice.</p>
<p>i have a 7.2v Ni-Mh rechargable battery would this be effective with a 6v 1Watt solar cell?</p>
No it wouldn't work. The charging circuit is designed to work only with single cell LiPo batteries.
Hhmm...'ok thanks.<br>
<p>I made one out of an old Shrek DVD case because I have a bad sense of humor. I also made an adjustable stand with Velcro that allows me to adjust the angle of the solar panel. Works very well, but do be conscious of the casing you pick out. Because this case is black, it can heat up rather quickly, which reduces performance and risks damaging the circuitry and battery inside. I always make sure to hide the case from the sun, which can be a bit inconvenient since the panel is on a short leash.</p>
<p>No- LiPo cells are very particular regarding charging rates so you must use a proper charging circuit.</p>
<p>No- LiPo cells are very particular regarding charging rates so you must use a proper charging circuit.</p>
<p>Is it possible to charge the Lipo battery directly off the solar panel, instead of using a charging circiut - which adds cost to the project?</p>
No- LiPo cells are very particular regarding charging rates so you must use a proper charging circuit.

About This Instructable




Bio: I'm a former bicycle industry designer turned professional jeweler. I like working with my hands and am happiest when I'm in the shop ... More »
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