# Re: [EVDL] Solar trailer

```You're getting power and energy mixed up.
```
Your Leaf has a POWER rating of 30 kW, which means that (at full power) it consumes 30 kW-hours of energy per hour. It does not get 4.5 miles per kW because a kilowatt is a unit of power, not energy - maybe 4.5 miles per kWh which is roughly consonant with its power rating and speed. To support that speed without dipping into batteries, you need a solar array that constantly produces 30 kW, which at 20% efficiency, receiving 100 watts per square meter, will require 300/.20 square meters of solar photovoltaic panels, or 1500 square meters. Not easy to tote around.

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It is safe to say that you cannot generate enough juice to recharge while driving.
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On the other hand, having a much smaller array can still allow your car to recharge while it is parked in the open, and that might be worthwhile, depending on your application. This would work if you have a short commute, followed by the car being idle for nine hours or so in broad daylight in a sunny climate.
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Marc de Piolenc

On 12/28/2017 11:52 PM, ev-requ...@lists.evdl.org wrote:
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```My math is good enough to figure out I get about my 30kw Leaf gets 4.5 miles
per kw at 55mph more or less depending on wind.? What I'd like to know is what
size solar panel would be needed to support that speed.? Now don't tell me it
can't be done.? I just want to know the formula for figuring it out.? My puny
brain exploded when I thought of all the variables.? I do know that a 3000 watt
system would charge my car in 10 hours.? I would just like to know the numbers
of what would be needed for continuous power at speed.? I guesstimated it would
be about 10000 watts.? I'd just like the exact number.? Thanks,? Lawrence
Rhodes...the point is to build a teardrop solar range extender/RV that could
charge while driving.
```
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