Power infrastructure: "Alternative Power Sources for ICT aka XOs"

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Session Description

Cut and paste


  • talk on Alternative Power use with #olpc
  • in haiti, lucking if you got 2 hours of power a day
  • "western mind cannot conceive that there's no power when you need it"
  • solar panels is 3% to 17% efficiency
  • cheaper to install solar panels than extend the electrical grid
  • UN estimates 2+ million villages worldwide without electric power
  • panel efficiency drops as temperature rises
  • cells connect in series, so weakestcell will bring others down
  • charge controller needs disconnect feature to prevent loss of energy at night
  • charge controller needs to be automatically switchable between voltages
  • charge controller needs to charge battery slowly to extend battery life
  • lead acid batteries used because they're cheap and hold lots of energy. Temperature has huge effect on battries.
  • bad to store batteries (inactivity hurts them)
  • need *deep cycle* lead acid batteries, not car batteries
  • DC to AC converters loses as much as 30%
  • teachers want to charge cell phones ... do it DC-to-DC (usb in charge controller)
  • micro-hydroelectric ... power from streams and hilltops
  • micro-hydro plant for $5000
  • small wind turbines .. verticle ones $1k to $2.5k USD
  • bio-gas from big farms ... dont' dump in river, instead get 0.84 kilowatt per pig
  • charging XO ..12 to 17 watts for 1.5 hours to charge battery
  • typical laptop uses 70 watts, XO uses 7 watts
  • haiti bought 350 high-end dell servers ... uses the most amount of energy
  • green WiFi ... shut down at night to save energy ... power linksys router ... $600 traditional way ... $250 with green wifi
  • standard solar design for school with 300/200/100 XOs (+ school server)
  • MoE gets plan, to get competitive bid ... trying to get away from powering AC for principal and TV for night guard
  • building low-power data center with solar panel (in senegal)
  • good gell-cell battery (lead acid) can last 10 years
  • engaging University of Haiti students to build solar installations .. to not drop-ship
  • now starting XoDock ... students who are soon to graduate form SJSU
  • where to put the laptops, how to power them ... focused on #haiti initially .. 48 laptops for $600
  • xodock team visited 10 schools in may ... 50 in classroom to 300 in classroom
  • anything you can do to make the laptops easier to use increases the usage of them
  • xodock ... lost cost, uniterrupted power, protected storage, safe & easy mobility
  • decided to use common PVS components ... strength to weight ratio, good electrical insulation, fireproof ... "carrier stack"
  • with 8 laptops, 31 pounds, up to 48 laptops (6 racks) ... cable routing .. each rack is $35
  • uses both AC & DC (solar) ... custom built charger
  • $331 with battery for 48 laptops
  • can now charge 24 laptops in 4 hours, improvements to come ... want 24 laptops in 2 hours
  • delivery date is Dec 10th ... mechanical $210, electrical $131 = $341 ... $531 with battery