Schedule

Schedule

Wednesday, October 1

1412177400 FLOSS Weekly
1412182800 Tech News Today
1412186400 Windows Weekly
1412193600 This Week in Google
1412204400 Tech News 2Night
1412211600 Ham Nation

Thursday, October 2

1412269200 Tech News Today
1412272800 Know How...
1412276400 Marketing Mavericks
1412281800 Coding 101
1412285400 Home Theater Geeks
1412290800 Tech News 2Night
1412292600 The Giz Wiz

Friday, October 3

1412355600 Tech News Today
1412359200 This Week in Law
1412366400 Android App Arena
1412377200 Tech News 2Night

Saturday, October 4

1412445600 The Tech Guy

Sunday, October 5

1412532000 The Tech Guy
1412546400 This Week in Tech

Monday, October 6

1412614800 Tech News Today
1412618400 Triangulation
1412623800 iPad Today
1412636400 Tech News 2Night

Tuesday, October 7

1412701200 Tech News Today
1412704800 MacBreak Weekly
1412712000 Security Now
1412719200 Before You Buy
1412722800 Tech News 2Night
1412726400 All About Android
1412735400 Padre's Corner

Wednesday, October 8

1412782200 FLOSS Weekly
1412787600 Tech News Today
1412791200 Windows Weekly
1412798400 This Week in Google
1412809200 Tech News 2Night
1412816400 Ham Nation

Thursday, October 9

1412874000 Tech News Today
1412877600 Know How...
1412881200 Marketing Mavericks
1412886600 Coding 101
1412890200 Home Theater Geeks
1412895600 Tech News 2Night
1412897400 The Giz Wiz

Friday, October 10

1412960400 Tech News Today
1412964000 This Week in Law
1412971200 Android App Arena
1412982000 Tech News 2Night

Most Recent Episodes

All About Android

The week was filled with new initiatives by Google that directly affect independent developers.

Before You Buy

Jason Howell reviews the HTC Desire 510.

MacBreak Weekly
Episode #422: Designed by Aggle September 30th, 2014

iOS 8.0.1 issues, bending iPhone 6 Plus.

Windows Weekly

Microsoft announces Windows 10, with a focus on enterprise.

Tech News Today

eBay and PayPal will become two separate companies.

This Week in Enterprise Tech
Episode #109: The IxCharriot September 29th, 2014

Troubleshooting your network with IxChariot

iPad Today

MyScript, Fleksy, hidden iOS albums

Tech News 2Night

The app powering the Hong Kong protests.

Triangulation

How to use Facebook better.

Tech News Today

China's iPhone 6 black market falls apart.

Know How... 91

F1 Turbo, Solar Powered Rasp Pi, and Goat Sim Tips

May 1 2014

Mercedes is wining F1 with a new twist on an old technology, power your Raspberry Pi with the sun, and Goat Simulator Tips.

Solar 101: Solar-Powered Pi

Materials:
Solar Panels
Charge Controller
Battery
12v to 5v (USB Charger)

Tools:
Wire Snips
Wire Strippers
Screwdrivers
Multimeter

Steps:
1. Determine the Draw of your Device(s)
2. Size your Battery
3. Calculate your Solar Panel Needs
4. Choose your Controller
5. Wire it!

The Draw of your Devices:
* If you're building for a house, you can look at your electricity bill for the past 12 months. That gives you a good indication of your total usage as well as your high and low usage months.
* For medium-applications, a Kill-O-Watt works well, but it has a large margin for error, especially when dealing with smaller devices
* If you're building for a small device, check the specs of the device(s) you want to power.
- A spec sheet is a good place to start
- Remember that you must also account for the inefficiency of any charging unit

A Raspberry Pie pulls 700 mA of current at 5 volts at maximum power. (It pulls 300mA at idle)

Watts = Volts * Amps
- W=VA
- West Virginia

That means the RasPi draws 700mA at 5volts, or 3.5 Watt/Hours at maximum load.
** We need to supply the RasPi with 84 Watt/Hours of power per day.

Size your Battery
You need a battery that will support your application.
* Your typically want a battery that can support your device(s) for an acceptable amount of time, assuming that there will be days when your solar panels are completely ineffective.
* For an application like the Raspberry Pi, since it doesn't draw that much, I wanted to design a system that could go 2 days without ANY solar power input.
- Since the daily draw of a RasPi is a maximum of 84 Watt/Hours a day, I need at least 168 Watt/Hours of storage.
* Most small-application solar charge regulators work at 12 or 24 volts. I chose 2 x 12v 8Ah battery that will give me 192 Watt/Hours of storage

Make SURE to get a deep-cycle battery. If you don't you'll quickly find that your batteries don't provide their rated power because of the memory effect. (Most batteries are NOT designed to run all the way down.

Calculate your Solar Panel Needs:
You need to know (1. Draw of your devices) and (2. PEAK Hours in your Location)

Peak Sun Hours is the equivalent number of hours per day when solar irradiance averages 1,000watts per square meter.
- You want to know the amount of sun energy you'll receive per day on the WORST MONTHS of the year.
- Included is a "worst case scenario" solar map based on data from the past 30 years.

* You can use this information to determine how much panel you need.
* In our example. We know that our draw will be 84 Watt/Hours a day
- We need a panel that can generate 84 Watt/Hours a day with MY Peak Hour value
- We also need to keep in mind the charging of the battery. The more power OVER than number, the faster I'll charge a depleted battery.
- I also like to give myself a margin of safety to account for inefficiencies. (I use 20%)

In my location in San Francisco, the worst-case Peak Sun value is 3.6
- That means I can expect MAXIMUM solar exposure for a minimum of 3.6 hours a day
- I have two 90Wh batteries to fill and 84Wh of draw, but only 12.6 Watt/hours of that draw (3.6 hours x 3.5 Watts/hour) will come from the solar panel, the rest will come from the battery.
- I also want to account for the inefficiencies of the system. (I'll add in another 40W/h)
- That means I want a Solar Array that can give me ~240W/H in those 3.6 hours of Peak Sun.

I actually have a 240W/H solar panel… which means I am WAY over supplying the Pi!

Choose your Solar Charger
- You need a unit that will support the total wattage of your Solar Panels AND the total draw of your electronic devices.

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