Schedule

Schedule

Thursday, October 23

1414083600 Tech News Today
1414087200 Know How...
1414090800 Marketing Mavericks
1414096200 Coding 101
1414099800 Home Theater Geeks
1414105200 Tech News 2Night
1414107000 The Giz Wiz

Friday, October 24

1414170000 Tech News Today
1414173600 This Week in Law
1414180800 Android App Arena
1414191600 Tech News 2Night

Saturday, October 25

1414260000 The Tech Guy

Sunday, October 26

1414346400 The Tech Guy
1414360800 This Week in Tech

Monday, October 27

1414429200 Tech News Today
1414432800 Triangulation
1414438200 iPad Today
1414450800 Tech News 2Night

Tuesday, October 28

1414515600 Tech News Today
1414519200 MacBreak Weekly
1414526400 Security Now
1414533600 Before You Buy
1414537200 Tech News 2Night
1414540800 All About Android
1414549800 Padre's Corner

Wednesday, October 29

1414596600 FLOSS Weekly
1414602000 Tech News Today
1414605600 Windows Weekly
1414612800 This Week in Google
1414623600 Tech News 2Night
1414630800 Ham Nation

Thursday, October 30

1414688400 Tech News Today
1414692000 Know How...
1414695600 Marketing Mavericks
1414701000 Coding 101
1414704600 Home Theater Geeks
1414710000 Tech News 2Night
1414711800 The Giz Wiz

Friday, October 31

1414774800 Tech News Today
1414778400 This Week in Law
1414785600 Android App Arena
1414796400 Tech News 2Night

Saturday, November 1

1414864800 The Tech Guy

Most Recent Episodes

Ham Nation

Gordon West explains why use a dipole.

This Week in Google
Episode #272: Check Your Inbox October 22nd, 2014

Google looks to reinvent email with Inbox.

iFive for the iPhone

Vine updates, landscape mode app folder tricks

Tech News 2Night

Homeboy security cam, Microsoft's app Garage

Windows Weekly
Episode #385: President Spacey October 22nd, 2014

Updates for the Xbox One and Windows Technical Preview.

FLOSS Weekly
Episode #313: FenixEDU October 22nd, 2014

FenixEDU is a platform to manage data for education.

Tech News Today

Tim Cook visits with Chinese official after claims that China is harvesting iCloud logins.

Padre's Corner
Episode #11: Pandora's Promise October 21st, 2014

Documentary filmmaker Robert Stone, Nuclear Power, and

All About Android

A deep dive into all of Google's latest announcements around Lollipop and the new Nexus family.

Before You Buy

Leo Laporte reviews the Galaxy Note 4.

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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