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XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
XO Laptop Power (Richard Smith)
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XO Laptop Power (Richard Smith)

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OLPC country workshop, May 22, 2008 …

OLPC country workshop, May 22, 2008
http://wiki.laptop.org/go/Presentations/May_2008_Country_Workshop

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  • 1. One Laptop per Child Laptop Power May 20, 2008 One Laptop per Child
  • 2. Challenges
    • Supplying power is one of the largest and most difficult challenges in a deployment. Even in areas with a power grid
    • Lack of an established power grid increases the difficulty significantly
    • Each site is unique
  • 3. How Much Power?
    • 2 Primary modes
      • Charging battery
      • Not charging
    • Charging battery
      • Max draw of 17 Watts
    • Not charging
      • Less than 1 watt in sleep
      • Avg 4 – 7 watts while running w/ peaks up to 9
  • 4. Charging. How Long?
    • Fastest. Laptop off
      • All power used to charge battery
      • 1 hour 47 Minutes
    • Laptop on
      • Excess power used to charge power
      • About 2 and half hours
  • 5. Various solar panels at MAX output
    • Laptop off
      • 5W 5 hours 15 minutes
      • 7W 3 hours 45 minutes
      • 10W 2 hours 40 minutes
  • 6. Alternative Power Sources
    • Solar
      • 5/7/10 Watt solutions
    • Weza
      • Approx 30 Watt output
      • 2 Batteries in 2 hours
      • 7Ah LA battery. Will charge 2 batteries
        • Weza battery needs recharging after
  • 7. Alternative Power Sources
    • Crank
      • Still needs 2 hours of cranking.
      • Not really viable until Gen 2.
    • Grass Roots
      • Cow power
      • Water, Wind, Pedal,Treadle
  • 8. Multi-Battery Charger
    • Charges 15 batteries in 2 hours
      • 300 Watt AC
      • 120 Watt DC option (10 – 28 Volt input)‏
        • 8 Batteries in 2 hours
        • Direct connection to 60W solar blanket(s)‏
  • 9. Power Management
    • Available today:
      • Hardware ready for suspend/resume
      • Update.1 has support for sleep on lid close or button
      • About 4 hours of battery life during normal use
      • 14-16 hours of battery life in sleep mode
    • Future:
      • OHM management for suspend/resume
      • Aggressive CPU suspend
        • Suspend measurements are in the 2 watt range.
  • 10. Helping OLPC
    • Deployment Location Information
    • Information we need
      • Whats the climate and geography of deployment areas?
        • Names of closest large city.
      • What natural resources are available?
      • How many schools, how many kids, and how many kids per class?
      • How many of those schools don't have a power grid or have unreliable power?
      • Expected laptop usage. How often will you need to recharge the batteries?

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