User:Ccarrick/Power Generation: Difference between revisions
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How much power does the XO consume? |
How much power does the XO consume? |
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: Depends on state of XO |
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: Charging |
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:: Max draw of 17 W |
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: Not Charging |
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:: 1 W idle |
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:: 4-7 W Average |
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:: 9 W peak, when using camera |
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Charging |
Charging |
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:Laptop off |
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:: 1 hr 47 min at best |
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:Laptop on |
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:: 2 hrs 30 min |
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Battery good for 2000 cycles |
Battery good for 2000 cycles |
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Off Grid Charging Options |
Off Grid Charging Options |
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:Solar Panel |
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:: Durable amorphous silicon panels that can be rolled, though not the most efficient |
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:: 5 W Panel |
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::: Charges with laptop off in 5 hrs 15 min |
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::: Not intended as a primary shipping device |
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:: 7 W Panel |
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::: Charges with laptop off in 3 hrs 45 min |
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:: 10 W Panel |
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::: Charges with laptop off in 2 hrs 40 min |
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::: Can be made into a solar blanket which folds into a compact shape as well, though this option is more expensive |
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:: 60 W Solar blanket |
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::: Charging times highly dependent on weather |
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::: Charging times not linear- Doubling wattage doesn’t halve charge time since battery can only charge so quickly |
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:Weza |
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:: Foot pedal |
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:: 30 W output |
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:: Charges 2 batteries in 2 hrs using a 7ah lead acid battery |
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:: Costs $160- $200+ |
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:Crank |
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:: 22 W, requires 2 hrs of constant cranking |
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:: Not viable until Gen 2 |
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:Grassroots efforts |
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:: Cow power- Arjun in charge of this |
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:: Wind, water, pedal, treadle |
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:: Freeplay currently working on water generator |
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Human Power Generation |
Human Power Generation |
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:Requires at least 1 hr and 47 min to charge a laptop |
:Requires at least 1 hr and 47 min to charge a laptop |
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:Can transfer power to a separate battery to recharge more than one laptop battery at a time |
:Can transfer power to a separate battery to recharge more than one laptop battery at a time |
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Multi-Battery Charger |
Multi-Battery Charger |
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: Prototype available, hoping to get price below $300 |
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: 300 W AC |
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:: Charges 15 batteries in 2 hrs |
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: 120 W DC |
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:: Requires 10-28 V input |
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:: Charges 8 batteries in 2 hrs |
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:: Can direct connect two 60 W solar blankets to charge batteries |
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Battery life |
Battery life |
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: 4 hrs during normal use |
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: 14-16 hrs in sleep mode |
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Helpful information for implementing power generation at a location |
Helpful information for implementing power generation at a location |
||
: Climate & geography of area |
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: Natural resources available |
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: How many schools/kids/kids per class |
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: Reliability of grid |
|||
: Expected laptop usage |
|||
Latest revision as of 17:16, 23 May 2008
The power generation talk during one of the Wednesday sessions of the Global Country Conference was helpful in gaining a sense of the current challenges for generating power for the XO. Take home messages are 1) human power generation is viable only if it can be sustained for 2 hrs or more, 2) grassroots options provide a lot of flexibility but are very location specific and 3) multi-battery chargers are incredibly helpful for charging XOs. Notes taken from the talk are below:
How much power does the XO consume?
- Depends on state of XO
- Charging
- Max draw of 17 W
- Not Charging
- 1 W idle
- 4-7 W Average
- 9 W peak, when using camera
Charging
- Laptop off
- 1 hr 47 min at best
- Laptop on
- 2 hrs 30 min
Battery good for 2000 cycles Off Grid Charging Options
- Solar Panel
- Durable amorphous silicon panels that can be rolled, though not the most efficient
- 5 W Panel
- Charges with laptop off in 5 hrs 15 min
- Not intended as a primary shipping device
- 7 W Panel
- Charges with laptop off in 3 hrs 45 min
- 10 W Panel
- Charges with laptop off in 2 hrs 40 min
- Can be made into a solar blanket which folds into a compact shape as well, though this option is more expensive
- 60 W Solar blanket
- Charging times highly dependent on weather
- Charging times not linear- Doubling wattage doesn’t halve charge time since battery can only charge so quickly
- Weza
- Foot pedal
- 30 W output
- Charges 2 batteries in 2 hrs using a 7ah lead acid battery
- Costs $160- $200+
- Crank
- 22 W, requires 2 hrs of constant cranking
- Not viable until Gen 2
- Grassroots efforts
- Cow power- Arjun in charge of this
- Wind, water, pedal, treadle
- Freeplay currently working on water generator
Human Power Generation
- Requires at least 1 hr and 47 min to charge a laptop
- Can transfer power to a separate battery to recharge more than one laptop battery at a time
Multi-Battery Charger
- Prototype available, hoping to get price below $300
- 300 W AC
- Charges 15 batteries in 2 hrs
- 120 W DC
- Requires 10-28 V input
- Charges 8 batteries in 2 hrs
- Can direct connect two 60 W solar blankets to charge batteries
Battery life
- 4 hrs during normal use
- 14-16 hrs in sleep mode
Helpful information for implementing power generation at a location
- Climate & geography of area
- Natural resources available
- How many schools/kids/kids per class
- Reliability of grid
- Expected laptop usage