User:Ccarrick/Power Generation: Difference between revisions

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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:
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?
How much power does the XO consume?
:: Depends on state of XO
: Depends on state of XO
:: Charging
: Charging
::: Max draw of 17 W
:: Max draw of 17 W
Not Charging
: Not Charging
:: 1 W idle
:: 1 W idle
:: 4-7 W Average
:: 4-7 W Average
:: 9 W peak, when using camera
:: 9 W peak, when using camera
Charging
Charging
:Laptop off
:Laptop off
:: 1 hr 47 min at best
:: 1 hr 47 min at best
:Laptop on
:Laptop on
:: 2 hrs 30 min
:: 2 hrs 30 min
Battery good for 2000 cycles
Battery good for 2000 cycles
Off Grid Charging Options
Off Grid Charging Options
:Solar Panel
:Solar Panel
:: Durable amorphous silicon panels that can be rolled, though not the most efficient
:: Durable amorphous silicon panels that can be rolled, though not the most efficient
:: 5 W Panel
:: 5 W Panel
::: Charges with laptop off in 5 hrs 15 min
::: Charges with laptop off in 5 hrs 15 min
::: Not intended as a primary shipping device
::: Not intended as a primary shipping device
:: 7 W Panel
:: 7 W Panel
::: Charges with laptop off in 3 hrs 45 min
::: Charges with laptop off in 3 hrs 45 min
:: 10 W Panel
:: 10 W Panel
::: Charges with laptop off in 2 hrs 40 min
::: 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
::: 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
:: 60 W Solar blanket
::: Charging times highly dependent on weather
::: Charging times highly dependent on weather
::: Charging times not linear- Doubling wattage doesn’t halve charge time since battery can only charge so quickly
::: Charging times not linear- Doubling wattage doesn’t halve charge time since battery can only charge so quickly
:Weza
:Weza
:: Foot pedal
:: Foot pedal
:: 30 W output
:: 30 W output
:: Charges 2 batteries in 2 hrs using a 7ah lead acid battery
:: Charges 2 batteries in 2 hrs using a 7ah lead acid battery
:: Costs $160- $200+
:: Costs $160- $200+
:Crank
:Crank
:: 22 W, requires 2 hrs of constant cranking
:: 22 W, requires 2 hrs of constant cranking
:: Not viable until Gen 2
:: Not viable until Gen 2
:Grassroots efforts
:Grassroots efforts
:: Cow power- Arjun in charge of this
:: Cow power- Arjun in charge of this
:: Wind, water, pedal, treadle
:: Wind, water, pedal, treadle
:: Freeplay currently working on water generator
:: Freeplay currently working on water generator
Human Power Generation
Human Power Generation
:Requires at least 1 hr and 47 min to charge a laptop
: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
:Can transfer power to a separate battery to recharge more than one laptop battery at a time
Multi-Battery Charger
Multi-Battery Charger
: Prototype available, hoping to get price below $300
: Prototype available, hoping to get price below $300
: 300 W AC
: 300 W AC
:: Charges 15 batteries in 2 hrs
:: Charges 15 batteries in 2 hrs
: 120 W DC
: 120 W DC
:: Requires 10-28 V input
:: Requires 10-28 V input
:: Charges 8 batteries in 2 hrs
:: Charges 8 batteries in 2 hrs
:: Can direct connect two 60 W solar blankets to charge batteries
:: Can direct connect two 60 W solar blankets to charge batteries
Battery life
Battery life
: 4 hrs during normal use
: 4 hrs during normal use
: 14-16 hrs in sleep mode
: 14-16 hrs in sleep mode
Helpful information for implementing power generation at a location
Helpful information for implementing power generation at a location
: Climate & geography of area
: Climate & geography of area
: Natural resources available
: Natural resources available
: How many schools/kids/kids per class
: How many schools/kids/kids per class
: Reliability of grid
: Reliability of grid
: Expected laptop usage
: 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
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