One year of driving off my solar panels!
 

I just got my year end statement from my electric company, and despite driving 4,500 miles in my electric car I still banked 405 Kwh of electricity. I was worried that with my car now using electricity I wouldn't be able to draw all of my power from the sun. I must admit, I was particularly careful this year about electricity use. I have a 7 KW solar panel system and am lucky enough to live in Colorado. I'm thrilled that I could "drive for free". Not really considering the cost of the car, but it's cool anyway.

What's your calculated payback time?

I'm not sure if you mean my paypack time for my solar panels or my electric car. For my panels it will be about 12 or 13 years. For my car, it probably won't happen. I would need to drive closer to 10,000 miles every year to pay back in 5 years. The midget I was driving before got 30 mpg, so the savings on gas for 5,000 miles per year isn't that much. The cost of batteries is still too high to justify this on economics along. Even with the generous rebates given in Colorado for converting the car to electric, the payback is still many years out. I had a lot of enjoyment researching, engineering , and building the car, so I count it as entertainment along with not having to pay for gas. I wish I could say it was saving me money, but it's not quite reality yet.

You know, pay back, like you figure the pay back on a new TV, washing machine or what's the pay back on your lawn mower?
The solar panels give you a higher interest rate then most other investments, around 7% and are much more stable.

I've never figured out how to quantify the enjoyment of driving a car that is quite and smooth, refueling at home has it's own qualities and enjoyments as well that are difficult to quantify.

You put 450 KWH on the grid last year or you only used 450KWH from the grid? Either way ... that's pretty impressive!

So enough spare electricity that you could have driven another 1,600 miles on electricity, refined 18 gallons of gasoline or powered my house for over a month.

The midget gets close, if not equal to 5 miles for every Kwh put into it. So it took 900 Kwh to drive my 4500 miles. I still had 504 Kwh left after charging my car and running my house. So I could have driven another 2500 miles this year. I was used to having an extra 750 Kwh left in a year before I had my car. This summer I changed my air conditioning to kick on at 80 deg F instead of 78 degress, and we cut down on Christmas lights. (We had a lot of Christmas lights in the past.) I wanted to be net zero on electricity use this year, and I got it. My family is not thrilled since I try to reduce electricity use as much as possible. This does show how good a choice it is to convert a MG Midget to electric. I have thought over the last 10 years, that as tiny a car it is, it should be perfect for conversion. Obviously I'm very happy how it turned out.

Given that your solar setup is oversized for your home's needs, an electric car is a beautiful way to leverage that excess capacity. On that same note, how do you heat your home? Adding some incandescent bulbs during heating season would nibble away at your surplus production while cutting down a bit on whatever heating fuel you buy (assuming you don't already heat with electric).

In the winter I'm not so worried about leaving lights on, or running the computer a little longer because I know all the excess electricity use ends up heating my house. I don't monitor my electricity use close enough to realize that I need to burn up some in the form of heat. I'll be changing my plan over to one where the energy company rolls over my electricity. Sine the payments are so small, I'd rather have the cushion if I need it. The sad part is that the electric company is allowed to cancel the surplus if I sell my house to someone else. Must be nice to write your own rules.

I got 6 in tota and 2 grid tie inverters. I started with 1 of each and was surprised at how much they help. In the summer I save 50 bucks a month, in winter its all over the place. I neet to better understand the mppt technology and see if I can parallel my cells vs serial to the inverters. :eek: