How many solar panels do you need to charge an EV?

patrick0101

Active Member
Joined
Apr 4, 2016
Messages
37
Location
USA
Tesla Owner
Model X
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Country
#1
To power your EV's energy needs, it depends on what EV you drive, how far, where and how you drive it.
For energy production, it depends on where you are putting the solar panels, angle, azimuth, tilt, shading, and regional weather... There are variables, but with a few tools, you can figure it out.



If you want a rule-of-thumb, here's one:
Each 1kW of panels will get you about 4 thousand miles of EV driving.

Will this be accurate for your home and your Model 3? Nope, it's just a rule of thumb. If you want to get more precise numbers, here's a link that can give you the tools to plug in your car (after it's EPA rated) and your address to get solar energy data for your roof.
 

AEDennis

Top-Contributor
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Apr 10, 2016
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887
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Southern California, Most of the time...
Tesla Owner
Model 3
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#3
I have 28 panels on the roof. We have 2 EVs, and the panels generate 6.58 kW STC DC using Sharp panels and Enphase Inverters.

The panels are for the whole house use, so sometimes it's powering the drive, but it's also powering the rest of the household.
 
Joined
Apr 20, 2016
Messages
19
Location
chandler
#5
I just have a 4 kW GRID tied system It runs my home and 2 100% Electrics. I normally make 110% of what we use. Last month March I made 506%. My home is very efficient. I use passive and active solar, CREE USA made LED light, 3 Solar SunOvens and ride my bicycle a lot. We live in Super Sunny Chandler Arizona. I added radiant barrier in the attic, more insulation, Solar screens outside and In'Flectors inside all windows.
I have a Tesla 3 on order but will ECO drive it for 300+ miles on a charge. A lot depends on how fast and far you drive. I love 15 mph school zones, I'm the only one doing 14 mph.
 

Topher

Energy Curmudgeon
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May 11, 2016
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591
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Maine
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Reservation
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#6
Find out the number of 'sun-hours' you get (Google insolation map). Divide that into the number of miles you TYPICALLY drive in a day (ignore long trips). Adjust that by multiplying by a factor of the Watt-hr/mile of your car divided by Watt rating on the panel.

20 miles on a typical day / 5 sun-hours / day * (300 Wh/mile car / 300 W/panel ) = 4 panels

Adjust that to compensate for various efficiency losses (say 150%) = 6 panels.

Thank you kindly.