Solar install for EV charging only

[mnevar]

I've had solar on my roof since 2012. 11kW system which over produces anywhere between 1500-2000 kWhr per year. Our solar anniversary date with our utility is at the beginning of March and each year they pay out our 'bank' at a piddly rate of maybe .02/ kW. The system is a pre-paid lease from SunPower, so we can't make any changes to it unless we buy them out. Don't really want to do that.

Now that I have a M3, I won't be having this over-production situation. Got the car in November and we've just run out of 'bank'. I'm wondering if I can install another smaller array that stores directly into a battery that I can use to do DC charging to the M3. I called my installer and a few other local companies, but they don't want to deal with anything that has an existing array. I haven't been able to find anything on the interwebs. Maybe I'm not searching correctly. Anyone doing something similar?

 

[HankLloydRight]

The only DC charging you can do is Supercharging. M3 doesn't even support Chademo yet. You could do PV to a Powerwall 2 which stores up to 13.5kWh, and then charge your car with 240v AC from the powerwall, but there's inefficiency from the round trip conversions and only 13.5kWh before needing to recharge the Powerwall. So you wouldn't get much of a charge to your M3 per PW charging cycle.

But I think installing another small PV system and a PW2 just to charge your car is going to have a really really high break-even point compared to just paying for grid power.

 

[mnevar]

Thanks for the reply. I'm inclined to agree about the break-even point. It's just killing me to pay an electric bill again after 7 years without one. I'll have to see what happens over the spring/summer to see if I can still build up a bank with my energy provider

 

[jjrandorin]

Thanks for the reply. I'm inclined to agree about the break-even point. It's just killing me to pay an electric bill again after 7 years without one. I'll have to see what happens over the spring/summer to see if I can still build up a bank with my energy provider

If it helps you, calculate all that you WERE paying for your gas vehicle and know that you are not paying that anymore.

I am in a similar boat as you, with the exception that my leased solar system is a solar city / telsa one. I have had a negative balance with so cal edison for 4 years. Wont have that issue anymore.

Will likely end up owing them 300-400 on the true up this year but just got the car december of last year so need to see how it goes. Even if I owe money as I now expect to, I WAS paying about $45 every 4 days to fill my car up for my normal commute ( was a BMW 435 driven exclusively in sport mode as I wanted the throttle response).

All that is money I am now NOT spending. I keep reminding myself of that, and told my wife to remind me too, because I know next year when I true up, I am initially going to be annoyed that I now have a true up bill, even though it wont be even half of what the gas would have cost me.

Just keep telling yourself that, instead of trying to add more panels etc. Might help

 

[mnevar]

Thanks. I used an app to record all my gas purchases on my previous car, so I know exactly what I paid for the past 8 years. I guess I'll need to look at all the numbers.

 

[RalphNader]

I just bought a home in Arizona. Have NOT done the solar thing yet because I am trying to install a separate build, like a backyard patio with a solar roof. I do NOT want a solar roof YET.. so still want to know about the ability to have stored batteries as well. I have reached out to a company called exide technologies. and i am waiting to hear back from them...

 

[xcat]

Mnevar. Have you looked at other ways to reduce your home energy usage? LED bulbs, energy efficient improvements....

 

[mnevar]

Mnevar. Have you looked at other ways to reduce your home energy usage? LED bulbs, energy efficient improvements....

Yes. That's why we had such a huge bank these last few years. When the panels were installed, they electric company limited the size of our array to the average usage over the prior 2 years.