Having one charger compatible with many electronic devices eliminates the need for additional cords and equipment when traveling.

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Since I have an external charger I never really have one off a charger long enough for even this to matter.

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We were lucky we had a charger in one of our cars.

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Now consider the fact that all it would take to wipe out these emissions would be the introduction of a small photovoltaic device to replace each charger - one which is flexible, durable, cheap to produce and, crucially, works in ambient (indoor) light.

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And in yet another unexpected use for coffee, we bring you the Epiphany onE Puck, a phone charger that siphons energy from your mug and uses it to power your gadgets.

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One prime example there is laptop charger bricks, which Transphorm says could be reduced or even completely eliminated by building the necessary components right into the laptop itself.

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You'll want a cellphone charger that works without electricity, such as one used in a car.

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You have to charge it, slowly, by plugging it into a computer, or, more rapidly, by using one of a list of approved chargers from other devices, such as an iPhone charger.

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In addition, over a dozen specific changes are being made to the design of the battery and its charger, such as adding more insulation to prevent the spread of overheating from one cell to another.

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If you happen to forget one, you are probably screwed because there is little standardization and the odds of you finding a random charger that fits your proprietary connection are slim to none.

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But, if you're not lucky enough to have access to one of those, the Model S will be quite happy to pull juice from a standard Level 2 charger -- and, should you opt for a second, the car can top up again in half the time.

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This means that switching the phone charger off for a whole day saves the same energy as is used in driving an average car for one second.

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