Power Your Car For $125/Year, Every Year, For 25 Years With DIY Solar


The emergence of the EV market and its battery technology are certainly exciting.  As the number of EVs increases, so does the awareness of energy independence. For many enthusiasts DIY solar is on the rise.  What if you could pay $4000 for the life energy of your new EV and all your EVs to follow for the next 25 years? Would you? So what is involved? What size system do you need? What will it cost? If you are looking for a system to power your new or future EV, a 2 KWh system is a good start for the 15,000 mile per year driver.  So where do you start? The first step is the paperwork.


A Typical 2 kW Solar Install

You will need to

  • Get an electrical permit;
  • File an application with your electrical utility;
  • File with your state utility commission;
  • Apply to be a power generator with your state generator provider;
  • Know your state tax credit;
  • Contact your home owner’s insurance provider.

Each state has its own tax credit and options for becoming an alternative energy generator. You may be inclined to build a photovoltaic system large enough to power all of your electrical needs, when in fact the best sized system may be limited by your “in state” generator contracts. A common sized system is 5kWh.

A good place to start is with your utility company.  They will provide you with the necessary applications to meter your system as well as directing you to the organizations responsible for providing credits for the power you sell. That’s right, in many areas, you will be able to sell your excess electricity for equal to or even double your purchase rate.  The most popular system is referred to as a “grid-tied” system. This system functions without expensive batteries and is plugged directly into a double pole breaker in your main supply.  The grid-tied system uses or sells electricity by day and buys electricity by night.  What are the components and their costs?

You will need:

  • Adequate sized solar panels;
  • String or micro inverters;
  • Monitoring system (optional);
  • Mounting racks , clamps and possible posts if ground mounted;
  • Grounding rods and connecting wire;
  • Disconnect switch at your meter and your array if ground mounted.

A common size for each solar panel is around 250-270 watts.  The price of a quality panel in 2013 is around $200-$300 per panel. Hence, if we are building the 2kWh system for your EV, you will be looking at eight panels for around $1600-$2400.

For the DIY system I chose the Enpahse M215 micro inverter for my system.  You will need one micro inverter for each panel. The panels are configured with either a Tyco or MC4 connector. You must specify the same connector when ordering.  Such an inverter will cost about $180 per inverter or $1440 for your 2kWh EV system. With this brand, you will also need a special cable to chain the inverters into one branch circuit for around $100.

There are many cool monitoring systems that let you view your daily energy production.  The Enphase Envoy Management system is optional and around $475

Mark’s DIY Solar Array

You must decide whether your will have a roof or ground mount system.  The roof mount is the easiest and most economical. Your 2kWh roof mount can be purchased for around $400. I chose a ground mount system for a better southern angle. The ideal angle is from southeast to due south.  Theoretically, true south will yield the best production, but the lack of morning heat in some areas will make a southeast orientation an equally good angle.  Ironically I recycled my ground brackets from retired utility electrical towers.  For this example, we will assume the roof mount.

The remaining electrical hardware will be around $500 plus the cost of your electrician.  The more DIY labor you supply, such as mounting your racks, the better your cost savings.  For our example, I will budget $500 for our electrician.

So, adding $500 for shipping and miscellaneous,  you have built your DIY EV fueling station for  $5040 before tax credits.  You have a 30 percent tax credit from the federal government through 2015. Most states range from 10-40 percent additional tax credit. So wrap your head around this statement:   You have paid forward the cost of driving your new EV, and your next EV, and probably your next EV for between $3000-4000.

The New Nuclear Family

What are the weaknesses of the system? The four areas of concern are hail, wind, lightning, and theft.  All reputable panels come with a 25-year warranty on golf ball sized hail and 100 mph wind. Beyond the manufacture’s warranty, all reputable home owner policies cover all four.  If your provider does not, there are many reputable providers more than willing to write your policy at no additional cost.

Two other considerations are panel efficiency loss and geographic solar insulation.  The photovoltaic panels lose up to 20% efficiency over the 25 years of their warranty.  A 2kWh system will start out producing slightly more than the 15,000-mile driver uses.  Depending on your usage, you may add another panel and inverter over the life of the system.  This example is also geared toward all areas other than Alaska and portions of the North East and Pacific North West.

In most areas, this system will pay for itself within 8-10 years. It is difficult to know all future obstacles. Some will be good and others bad.  There certainly might come a time when your utility company no longer pays for the surplus electricity you generate and feed back to the grid. You may find in 8-10 years a need for an expensive battery backup—you know, like the old battery in your EV that is now down to 80 percent.  In time, it will make the perfect battery backup for your charging station! The glass is definitely half full.

And a closing thought  about energy independence.  You have fixed a large portion of the cost of your auto fuel for 25 years and I have to tell you, that is a great feeling every day.

Category: Charging


14 responses to "Power Your Car For $125/Year, Every Year, For 25 Years With DIY Solar"
  1. RRM says:

    Great article ! Would like to see an installation guide to your system if you get a chance.
    Keep up the good work !

  2. ClarksonCote says:

    Nice article. In it, the statement was made that, in many areas, you can sell power back onto the grid at up to double the price that you would typically pay for that same kWh. Are there any references to back this up?

    I have net metering, but would love to find out more about selling at a premium.


    1. Jay Cole says:

      You want me to bristle your arm hairs Clarkson?

      The zenith of selling power back to the grid is in Ontario, Canada. The ‘off peak’ price for power is 6 cents per kW to purchase (although you get dinged about 4 cents in fees as well), but if you are selling power back to the grid, the government buys the excess power back at 80.2 cents.

      And that isn’t a limited time variable either, they lock down your rate for 20 years.


      1. ClarksonCote says:

        Wow, that’s sweet. And free healthcare too? Looks like I need to move North. 🙂

    2. Mark H says:

      I tried to keep it generic to bring a broad audience in. Attached will help one find there state tax credit. For the generator credits, I for one get double from NC Green. Their current contracts are 75 percent. As Jay mentioned, there are areas that pay higher, but I did not want someone in an area paying less to stop thinking solar and EVs because the justification in the article is now. How much a generator pays has a lot to do with how many systems both commercial and residential are in place in that state. I can look for a state by state generator map if you think it would be helpful.

      1. ClarksonCote says:

        Thanks Mark!

  3. Shawn Marshall says:

    Good common sense article = thank you. Agree also with your projection for the use of old EV batteries and no fancy studies required.

    Seems like folks could make good money from solar in Ontario? Statik talked about this some years ago at that other website. Seems a little too good to be true-amazing.

    1. Jay Cole says:

      Good memory Shawn. And you can say GM-Volt.com, we are all friends, hehe. All part of the same movement.

      In fact, you can pretty much say whatever you like, unless you disparage black EVs…which, as we all know, are not only faster than their colored counterparts, but achieve much greater range. Do that, and it is perma-ban time.

      1. Frank says:

        LOL! – My Volt is silver, but still very funny Jay.

    2. Mark H says:

      Thanks. People need an ROI number to hold onto so I tried to pick one in the middle. My long term hope for small generators is that they will be able to sell for at least the same price that they buy. With the EV battery scenario that you picked up on, at least it gives us an out and a good one at that. Exciting times…..

  4. Christine A says:

    Love my Leaf, but in Maui, Hawaii, we have more solar in certain areas than the utility would like (due to market share, not grid issues). I cannot afford to install PV because our utility requires a $30-40,000 interconnection study. 🙁 The emerging vehicle to home/vehicle to grid (V2H/V2G) technologies will, hopefully, help those of us no longer permitted to install grid-tied PV to overcome utility roadblocks. If nothing else, they may allow us to capture more off-peak juice for our cars.

    1. Mark H says:

      Wow! Probably should include Hawaii along with my other omitted areas. As I mentioned, the credits will go away for any area that has exceeded the federal green credits. This is why a small 2KWh system would be a good starting point for most in that there would be very little selling of power. It would make the perfect platform to add your EV battery later and allow for expansion to overcome this issue. I was unaware of the penalty Maui was imposing toward interconnection though. Can you supply a link to your utility company?

  5. Jonathan B says:

    Great article Mark. Once the mystery is taken out of many eco-friendly ideas, it makes it tough to not follow the good example of pioneers like you. Education is the key!

    1. Mark H says:

      You are spot on Jonathan. Education + economics will pave the road to success for the emerging EV market.