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Solar charging of Tesla

Solar charging of Tesla

I was really hoping there was a way to charge my Model 3 (when I get it) by solar power at my home. Is anyone already doing that? I am hoping to put a few panels on a shed in my backyard and use it only for my Tesla. Is that possible?

ken | 02. November 2017

A few panels is probably not going to cut it, even on the sunniest day. I am having an 8KW array installed (27 panels). But to your question, juice is juice as long as your inverter can get it to a proper AC level and socket, the charger should take it. You would probably need around six 250W panels and a sunny day just to match the rate you would get plugging the car into a 120V outlet. Putting maybe 2-3 miles per hour back into your car at peak daylight.
I am not an electrical engineer. This is just rough math based on my system.

abasile | 03. November 2017

In the future, I hope that Tesla chooses to produce a "solar aware" charging station (aka. "wall connector") capable of automatically soaking up whatever "excess" solar generation might be available, rather than needing to draw from the grid. This would be nice for customers who generate at least as much energy as they use, or for whom the utility doesn't offer decent net metering.

At peak, our 6.48 kW (DC) system (18 panels) generates about 5.7 kW AC. Our Model S is capable of charging at rates up to 10 kW while our Nissan LEAF charges at about 3.7 kW. If we plug in our LEAF while the panels are getting plenty of sun, then it does charge exclusively from solar provided our home use isn't too high. With a Tesla vehicle, you do have the ability to manually lower the charge rate. That said, because of trees that shade our solar panels for a number of hours per day, and because we own two EVs, we still consume more electricity than we generate. With net metering and TOU (time of use) rates, it makes the most sense for us to charge our EVs at night on the lowest rates.

sashton | 03. November 2017

There is a charger that will do exactly what you want - Myenergi Zappi (silly name but don't let it put you off).It works in a similar way to the PW II AC, sensing export then charging the car in E++ mode. Indeed it is even a bit smarter than that as, if configured with a second clamp, it can work in conjunction with your PW II. It was only released a month ago. Mine is due to be installed next week. Only downside is that it may only be destined for UK markets presently.
Good luck with balancing your self-consumption with your need to have the car charged at the time its needed. I have who expects me to "just make sure its charged!", 2 EVs, 16kWp - I did well in the summer but as the nights draw in I'm thinking I need to put up another 8kWp string (and another PW - but it looks like Tesla are no longer supplying the UK so it may have to be LG).

sashton | 03. November 2017

oops - "I have a wife who expects..."