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Discussion Starter · #1 ·
Just wanted to post that our off grid system is putting PV electrons into my PHEV bank. Kinda neat.

Only problem is I can't leave it charging all night...just strains my inverters, batteries too much. But...when the sun is shining, make hay!


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Cool. Would love to see pictures and specs on your PV setup. I've been researching adding some panels on the back of the garage to charge our 2016 Volt since a large hackberry tree came down last summer.
 

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I am still waiting for a Hydro off grid Volt owner to post a picture.
 

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Discussion Starter · #7 ·
I am still waiting for a Hydro off grid Volt owner to post a picture.
We are fully off (the electric) grid. Here is a collage picture. I have two charge controllers pushing power from two PV strings into a 48 V battery bank.

The first string is producing power that is used by the house, and is supplying all loads, including the car.

The second charge controller is showing "bat full", meaning the PV system was now actually redundant. 81V but no amp useage. (As a result I beefed up the car charge amps to 12, forcing the system to move to "float" mode).

The other two pics are proof of charging :)


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Nice solar progress!
Whether the rooftop solar panels actually charge the car depends on the time of the day:

  • Between 9am and 5pm on a sunny day there is a good chance that the Volt will be charged using clean, home-generated electrons. See here for the average solar production today and yesterday in California.
  • At other (dark) times the energy comes from the grid, and uses the same energy mix as all others. Here in California, only ~8% of the energy is renewable during the off times.

So to minimize CO2 impact and emissions, we should charge during the day. I don't have rooftop solar, but if I charge during a sunny day ~35% of the electrons that charge my Volt are renewable.
The silly thing is that the pricing of the PG&E Time-of-Use plan forces me to charge the car during the night when renewable production is smallest.
 

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I would not shell out for solar just to charge the car...

What I did is charge the car with an already sunk cost...
Me too. Before buying the Volt, my solar system was producing about 1,000 kWh more per year than we used. Con-Ed bought that from me at wholesale rates of around $.05/kWh. After I bought the Volt, we produce no excess - but about 1,000 kWh of the Volt's yearly energy draw comes from power that effectively costs me 5 cents per kWh. That's about a quarter of the retail cost of electricity around here.

Based on charging the car with roughly 9-10 kWh/day*, I estimate that about a quarter to a third of its annual cost of charging is from energy priced at 5 cents per kWh. Now, if I'd already had an electric car when I had the solar system installed, I might have been tempted to get a few more panels - but I certainly wouldn't install a solar system just to charge a car.

(* Based on the fact that I rarely use an entire charge in a typical weekday's driving. I come close in winter, but use only 60-70% of the battery's charge in summer, and on weekends it's typically much less.)
 

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Just wanted to post that our off grid system is putting PV electrons into my PHEV bank. Kinda neat.

Only problem is I can't leave it charging all night...just strains my inverters, batteries too much. But...when the sun is shining, make hay!


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Do they offer net metering in Ottawa? Very cool; I would like to add a system to my house in a few years.
 

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I would love to go solar. Though it'd have to power more than just my Volt to make it worth it.

I probably won't get a solar system until I build a new home. I'd rather have the optimum roof configuration for solar so I would make no compromises with an existing roof. I'll also of course have two 240v circuits in the garage for two EV's!
 

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Discussion Starter · #18 ·
I'll also of course have two 240v circuits in the garage for two EV's!
Just to manage expectations....

I paid for our off grid system in 2007. Back then, we essentially could afford a system that amounted to a 2,204 Ah battery bank wired at 24V. That was about 38K, including generator.

A 240 V EV charger, I believe (stand to be corrected by forum members), is a 30A charge...that is 7.2kW, per hour, assuming full capacity...times two if you have two EVs...running the math, that is a big system...

My only point being, you need alot pf panels!! But - the big bonus though, PV is plummeting in price, and, if you live in Cali, you may get massive incentives! Good luck!



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Just to manage expectations....

I paid for our off grid system in 2007. Back then, we essentially could afford a system that amounted to a 2,204 Ah battery bank wired at 24V. That was about 38K, including generator.

A 240 V EV charger, I believe (stand to be corrected by forum members), is a 30A charge...that is 7.2kW, per hour, assuming full capacity...times two if you have two EVs...running the math, that is a big system...

My only point being, you need alot pf panels!! But - the big bonus though, PV is plummeting in price, and, if you live in Cali, you may get massive incentives! Good luck!
Many other states have strong incentives, too. And the federal 30% tax credit is still in effect. Finally, one doesn't need a battery if the system is grid-connected, as most people's are, so that brings the price down. It's not unusual for the payback time for a solar system to be about 8-10 years, and after that the electricity is free (or, more precisely, it is the cost of maintaining the system - as it ages, components will begin to fail, and even if the component is under warranty the labor to replace it is not covered).

If you have a large piece of property on which you can install a solar farm of 50+ panels, you could probably pretty easily produce the energy needed for a house and one or two electric cars. For everyone else with just a roof, you will most likely cover just a fraction of the energy you use.
 

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5KW solar system, plus 100% renewable (mostly wind) from the utility provider. Net metering, I pay them $0.116/KWHr, they pay me $0.116/KWHr. Installed July 2016. Hoping for solar to cover ~60% of my annual consumption.

I find the solar consume vs. sell ratio fascinating, since it is so dynamic.

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