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Monday, May 6, 2013

Here Comes The Sun...

My array generated over 56 kWh's on May 1st. That's enough electricity to power my ActiveE about 200 miles in normal driving conditions.

Now that Spring has rolled in the temperature isn't the only thing that's going up; so is my solar electric production. My 8.775kW system can produce up to 60kWh's a day under ideal conditions. That's enough to power my ActiveE over 200 miles, or enough to power it about 100 miles and supply all the power my house needs for an average day. Pretty cool stuff. Powering my car and my house for the day on pure sunlight is really awesome.

Unfortunately because of where I live in the Northeast I don't get this kind of production all year. In the winter on the shortest days of the year I'll only get about 25kWh's even on clear sunny days. Plus there are days when the whole array is buried under a foot of snow so it doesn't generate anything in those conditions. However year round it averages nearly 30kWh's every day (about 10,000kWh's annually) which would be enough for roughly 100 miles of driving in the ActiveE.

The i3 with optional solar canopy from BMW
However the ActiveE isn't the most efficient EV on the road. Since it is a converted gasoline powered 1 series BMW, it had to be retrofitted with hundreds of pounds of steel reinforcements and BMW then needed to use a big battery pack (which added even more weight) just so it could have an approximate 100 mile range. By comparison, the upcoming BMW i3 has been purpose designed from scratch as an electric vehicle. That allowed BMW to create a lightweight and efficient electric vehicle while retaining the performance expected from all BMW's. The i3 will have a battery which is 30% smaller than the ActiveE yet will offer approximately the same driving range. The official EPA efficiency specifications aren't available for the i3 yet, but many expect it will go about 5 miles for every kWh of electricity consumed. Personally I average about 3.5 miles per kWh in my ActiveE in moderate whether conditions. What that means is an average day of generation for me (30kWh's) will power an i3 about 150 miles where it will only power my ActiveE a little over 100. So when I get my i3 it will use about 30% less energy and there will be more excess electricity left over to apply to my home use. That extra energy may just eliminate my electric bill entirely and bring me close to having a "Net Zero Energy Home" like fellow ActiveE driver Peder Norby has in California.

My solar powered MINI-E
I know I've said it many times here, but EV + PV is really a fantastic combination. Driving and powering your home on sunshine is really great, and certainly empowering. I can't help but believe everybody will be doing this at some time in the future, I'm just lucky to be doing it now. I have a link on the side bar of this blog that allows anyone to view my solar array production in real time if you are interested, or you can just click HERE. I think the Beatles were onto something...


  1. Impressive electric peak production Tom!

    After having joined the rEVolution slightly under 14.5 months ago, I took your, Peder's and others advice on hooking up PVs on my roof and it's been great to see the savings grow. Especially as we head into the sunnier part of the year again (yes, we do get some weather in Southern California).

    Coupling the PV array with EV TOU Tariff in Southern California allows a PV home to generate and sell to the utility during peak and use the energy off-peak to really garner in the savings. The ability to schedule the recharge of the Active E, pool pumps, dishwashers, etc. for Super Off Peak allows one to maximize the economic savings.

    I think the Beatles wrote a song for those of you guys who get to a "Net Zero Energy Home" or more impressively, those that produce even more...

    Sun King. For that matter, with all the energy being produced cleanly, perhaps The Cult's Sun King!

    I'm just glad to save money!

  2. I can't wait to drive my solar powered BMW i3 next year! Tom do you have any information on early ordering or waiting lists?

  3. Hey Tom,
    You posted this at the right time. My 4.6 kW system is scheduled for install in 2 weeks! I can't wait!!
    Ed B

    1. Great Ed,

      I was thinking about you the other day. How's everything going?

    2. Hi Tom, it is going well. I am having fun driving the Active E. I have had it over two months now. I am glad I assumed the lease. No range anxiety at all. 80 to 100 miles a charge is plenty. It's also fun to plug the car in when I get home. Thanks for all your help.
      Ed B

  4. Tom - I've been following your EV + PV story. Its a good one. I live in NC and have a perfect south facing roof and am ready for the combo EV + PV with the i3. I've checked out your dashboard and blog entries on your PV system. Can you comment more or guide us where to read up on examples and insight on the economics and payback of a home PV system.

    Thank you.


    1. Hi Sean,

      Sorry for the late reply. The economics do change from area to area based on what you are currently paying for electricity for your utility as well as if you can sell SREC's (Green Tags) for the renewable energy you produce. I would recommend you contact a few installers in your area and let them give you their sales pitch. It won't cost you anything to listen to them and they should give you all this information so you know your payback period and any other pertinent information.

      Also, check out this website: and fellow ActiveE driver Peder Norby's blog as he talks a lot about solar payback and the PV+EV combo:

      Hope that helps and thanks for following!