I started talking about these numbers with my roommate today. I mentioned that the MBP battery lasts a good 5 to 6 hours on casual use. This means that with a 34W panel, you could successfully USE AND CHARGE (simultaneously) a MacBookPro with that solar panel. If you dropped the panel in size to a 17Watt, you would be looking at a 5hour time for full charge. – But that means that you could use the laptop while charging, and essentially counteract the battery’s ‘uncharging’!

A 17W panel could be made small. Maybe as small as my MacBook Pro’s lid. Exciting…

This is a collection of theoretical data and calculations for the charge times and feasibility of using a custom 40W solar panel to charge Apple products.

To make the most efficient charger, I want to use specific solar cells in my panel. Each device has a different charging voltage, and for efficiency sake I want to get as close to that voltage as possible with my solar cells. This is because, when I regulate my panel to the voltage I need for charging, the excess voltage is being given off as heat. If I’m regulating down a lot, I have to be concerned about heat sinks, and my panel is even bigger than I need it to be. Stupid, right?

For example, my MacBook Pro’s AC Adapter puts out 16.5Volts at 3.65Amps. If I make a 40Watt solar cell array that puts out 20Volts @ 2Amps, and then I regulate it down to 16.5Volts, I’ll be loosing (assuming my DC regulator works at 90% efficiency) – (90% * 2Amps = 1.8Amps) .2 amps for every volt that I’m outputting. This means that instead of having a 40Watt panel, I’ll actually have a 1.8*16.5 = 29.7Watt panel when everything is said and done. And that’s just from the efficiency of the regulator!

When you factor in the 3.5Volts that are being regulated away, you have (3.5*1.8 = 6.3) 6.3Watts that are being given off as heat. That’s hot and unnecessary.

So, lets say that I get my panel to put out 17Volts at 2Amps. That would be a 34W panel. I would only be loosing (.5*1.8) .9Watts to heat, and I’ll have a smaller panel in the long run. After using a 90% efficient regulator, you pull 10% off that 34W (3.4W) and you have a panel that puts out 30.6W in full sunlight. Then, shave off the .9Watts that is lost to heat and you have 29.7W again. That would take (73/29.7 = 2.46) a bit less than 2.5 hours to fully charge my MacBook Pro from a completely dead state. Not too shabby.

You can see that the best way to increase efficiency is by finding the closest voltage possible and then bringing up the amperage. That’s why it’s important that you choose the best wiring circuit for your panel! (Series or Parallel)

Here are some stats for the batteries in the newest Apple products. You can see how this hypothetical 34W panel would run them.

For the iPad and iPhone, the input voltages are completely different.

I think you can safely charge an iPhone with 5Volts at a 1Amp maximum. 5V is the USB standard, and our computers put out .5Amps at that 5V. Not wanting to go too much higher than that for the iPhone, you could make a 4.5W panel at 6V and .75Amps – regulated down to 5V @ .75A that would charge the phone fully in 72 minutes.

As for the iPad, we’ll have to see what the input voltage is when it comes out!

After being on Fiverr for a few days, I’ve made connections with very cool business/website owners, and have gotten to advertise their websites on my arm.

It sparks up interesting conversation wherever I go, and as I mentioned before, has lead to quite a few new business ideas.

Here are some of the people I’ve advertised for so far:

• WorldOfSolitaire
• SingleAlert
• SpidVid

WorldOfSolitaire is a web-based Solitaire game that has loads of options. All of the gameplay is in the browser, and you can even use custom backgrounds! I got a chance to talk to the site owner and was happy to advertise for him.

SpidVid is a new social platform for ‘Video Production Individuals’. If you like to do any type of video work, you can join the site and collaborate with other professionals.

Very neat stuff.

Fiverr is a new marketplace for Any and All services that people are willing to do for $5. You can browse the things that people are already doing, or make an account and offer up a service of your own.

I made a profile and offered to write a company name on my arm (and leave it there for 24 hours) for $5. So far I’ve gotten one order, and the idea sparked a handful of new thoughts on marketing and advertisement in a college setting.

Here's the shed for the FreeStore!

Yesterday my friend Trenton showed me a blog about a new FreeStore that just opened a few months ago right next to our college campus.

A FreeStore is a place where you can bring things that you don’t need, and take things that you do. It’s a community-run trade market that is open to everything.

We headed over to this FreeStore – The Hammer Time Tool CoOp and met the owner Garrett. A few months ago, Garrett opened the FreeStore in a small shed attached to his garage. It’s open 24/7 for anyone to go in and make a quick exchange, find something they need, or drop off something they don’t. – What a killer idea, right!?

Yesterday, Garrett held the final opening of the actual Tool Co-Op. The HT Tool Co-Op is a center (The actual garage) where anyone can come and work on their own projects with all of the available tools. What another superb idea.. The Tool Garage is open on Mondays and Thursdays, from 4:00PM to 9:00PM.

-The Tool Garage is also heated! A woodstove made out of a Beer Keg with a bike crankshaft as the lock and handle. – SUPERB.

At first I was a bit skeptical, but now I love the idea of the FreeStore and the Tool Co-Op. It will be a lot of fun using the store and tool area, and helping build and promote the central idea of a community-run FreeStore.

Head over to HammerTimeToolCoOp to check out the new developments!

The Brain Project is a website that I started working on for my  ’Intro to the Grand Challenges of Engineering’ Class. The project requirements were pretty broad:

Do a project on the Human Brain. Show that you’ve done your research and that you learned something new in the process.

Over the past month, our class has been looking at the Human Brain from a reverse engineering perspective. We’ve discussed ways in which humans have studied the brain, and how technology is advancing that research.

I decided to build a website that would label each region of the Human Brain, show (neatly) what we know about it, and give links to recent research/development articles about that region.

I’m quite excited about how the site looks so far. I’m still adding the content – take a look and let me know what you think!

My iPhone Solar Charger has been featured on the front page of the popular DIY site Instructables.com!

Instructables is a fantastic site. It’s filled with DIY projects from all categories. I was considering building an iPhone app for the site at one point, but the project didn’t end up following through. None the less, this is awesome!

I have many plans for design-revisions, so hopefully further versions will do even better.

Check out the tutorial at Instructables!

**DISCLAIMER**

I am not responsible for any damage that you may cause to your iPhone or any device that you use with this charger. I can not stress the importance of checking your circuits with a multimeter enough, and I can assure you that I’ve done so at every step in this build process. Your phone is a very expensive device. Treat it like one!

Intro and Design:

Over the past month or so, I’ve been working on designs for a stationary solar iPhone charger. By stationary I mean a charger that will be kept in a fairly permanent place. I bring mine with me if I’m going to be camping or staying somewhere for a while, but it’s really not meant to be portable.

This isn’t only a solar iPhone charger. You can use it with any device that will charge via USB. I just happen to use it to charge my iPhone. Also, this design doesn’t include a battery in the circuit – which means that you’ll have to charge your iPhone when the sun is out and shining. I know it’s a serious inconvenience, but adding a battery makes the circuit much more complex – and is a bit more costly. I’ll be following up this design with an update on how to add a battery conveniently into this circuit.

The idea behind this panel is that it’s simple (and cheap!). You don’t have to have any prior circuit knowledge,or familiarity with electronics. I’m really just stepping out of the novice stage as far as soldering is concerned, so this is a great beginner project for just about anyone!

How It Works:

The design for this charger is quite simple. We’re essentially taking energy from the sun, and regulating it down to the same amount that comes out of your computer’s USB port. Plug your phone or device into the regulated output and Viola.

With that said, let’s get started on the project.

Parts list:

As I say in the title, I built this charger for just a bit less than $50. That doesn’t include the cost for tools and a few of the materials that were salvaged, but if you spend enough time on eBay you should be able to build yours for the same amount, if not less.

Let’s take a look at what was used to build the panel.

Tools:

• Soldering Iron w/ Solder and Flux
• Needle Nose Pliers
• Wire Cutters/Stripper
• MultiMeter (IMPORTANT)

Materials and Prices:

The Panel:

This Solar Panel is a 10W panel made by LaVie Solar. You can check out their website, but your cheapest bet is to use eBay. Their eBay user ID is lavie-inc. I snagged a pretty great deal at $41.45. The panel has a really sturdy build quality. It has an aluminum frame, and seems to be entirely weatherized. I wouldn’t have too much of a problem leaving it in the rain. Also, All of the wiring has been done for us which saves a LOT of time. They even put a blocking diode into the connection on the back, so we don’t have to worry about that in our circuit.

The panel has an output rating of 21.6 Volts (Open Circuit) and .62Amps (Short Circuit). These are optimal ratings, but when I tested my panel in direct sunlight, that’s almost exactly what I got.

As far as efficiency goes, this is not the ideal panel to be using as a direct USB charger. We’ll be loosing a lot of energy as heat when we regulate the 20V output down to 5V to match USB standard. – However, using a larger panel means that there will be more current flowing even when there’s not a lot of sun. I’ve even seen my iPhone charging when the solar panel is in the shade!

The Build Process:

After gathering all of the materials, I sat down and got to work.

I cut 2 pieces of Black wire and 2 pieces of Red Wire. The lengths were around 5-6 inches. Then, I cut a little bit less than an inch off both ends of each wire.

With my black and red wires ready, I cut my USB extension cable in half and stripped the cut half of the female end to expose all of the individual wires. There are 4 wires in all USB cables- Green, White, Red, and Black. The Green and White wires are for data, so those are not needed. I snipped the Green and White wires, along with all of shielding and fiber – leaving only the Red and Black wires coming out about an inch and a half from the USB cable. I stripped a little bit less than an inch off the Red and Black wires on my USB extension.

Since the 5V regulator only has one Ground pin, I used the two black wires that I cut initially- to make the soldering a little bit easier. I took both of my black wires, along with the black wire coming from my USB extension, and twisted them all together carefully and securely. I put some solder on that connection to make sure that all of the wires stayed together. Then, to keep things safe, I covered the 3-way connection with electrical tape.

Once all of the wiring was prepped, it was time to put the 5V regulator into the equation. Soldering wires onto the tiny pins from the 5V regulator can be a task. I used a small Zip Tie to hold my wires to the 5V regulator to make things much easier. It really helped – I was able to do pretty clean solder jobs on each of the pins. Since neither of the red wires were connected to anything, it didn’t matter which ones I soldered to which pins. – Just make sure you know that if your 5V regulator is laying flat, the input pin is on the bottom, and the output pin is on the top!. – I also bent the pins in opposite directions to keep everything separate.

The fantastic part about this charger is that we’re already done with our circuit. Once I was done soldering to my 5V regulator, I connected the Red wire from the Output pin on the regulator – to the Red wire coming from my USB extension cable. – Now, I only had 2 wire ends left. A Red wire connecting to the input pin on my 5V regulator, and a Black wire connecting to the regulator’s Ground Pin and my USB extension cable.

Since the LaVie Solar Panel has a pretty simple connection panel, pinching the Black and Red wires to the right screws on the panel was easy! Now comes the testing!

I used my MultiMeter to measure my Input voltage that was going into my 5.00V regulator. – about 20V @ 0.50A – Good!. Then, I measured the output voltage coming from my Regulator. The reading was 5.00V @ 0.50A – Perfect!. Those readings meant that everything was working correctly. Watch out, that 5V regulator gets hot when electrons are flowing through it!

Fully convinced that everything was working as it should be, I covered all of my open wires with electrical tape, took a deep breath, and plugged my iPhone in.

IT’S CHARGING!

Final Results and Conclusion:

In future designs, I’ll definitely be adding a battery so that you can charge  your devices at a more convenient time. I’d also like to make a more portable version of this charger. With all of the new solar technology, flexible panels are bound to cheapen up sometime!

If you have any questions, please leave them in a comment.

Thanks!

Brennan