3 ms·
> For a site devoted to people who love technology this is short sighted thinking It's not short sighted thinking: Most people who use this site can do basic a
by labcomputer 6y ago
> For a site devoted to people who love technology this is short sighted thinking
It's not short sighted thinking: Most people who use this site can do basic arithmetic.
The solar radiance under AM1.5 (which approximates the surface of the earth at the latitude of Europe, the US, or China) is around 1000 kW/m^2. The very best multi-bandgap solar cells in the lab today are about 47% efficient at converting sunlight to electricity. The very best DC-DC converters have about 95% efficiency in practice.
That means upper bound on energy production is about 445 W/m^2. On a sunny day. At noon. In June. For a panel directly facing the sun. With no shade.
That means you need slightly more than 3 m^2 of sun-facing panels at noon to achieve just the charging rate of a basic 120V North American household plug (1.44 kW from a NEMA 5-15, to be precise).
That means you need well over 3 m^2 of body-conforming panel to achieve that rate at noon. And that's the best case given infinite money. And production at other times of the day will be lower (even if you assume the car is parked in the middle of a flat desert).
Since the sun moves throughout the day, leaving such a car in the sun all day will only charge it about as much as charging from household plug for about 3-5 hours. Showing that is left as an exercise to the reader.