http://www.west.net/~jay/images/voltsolar.jpg

Wow!

I didn't expect that much interest.

Gory details...

The car:

Chevrolet Volt, 2011 model. Made in Detroit, USA. Lithium-ion battery, 16 kWh capacity, of which it uses about 10. The reason they don't use it all is to prolong battery life and to keep enough juice to spin up the gasoline engine as the battery is depleted.

About 35-45 miles electric range, depends on how heavy your foot is and the climate. Best range in stop-and-go city driving. Worst on the freeway when it's very cold. If I baby it I can go from Goleta to Carpinteria and back all-electric. 100 MPH top speed. No, Loren, I haven't verified this - yet.

When the battery is depleted, there's a gasoline engine that primarily acts as a generator to power the electric motor. Wheels are driven by electricity under almost all circumstances. When the battery is depleted and speeds are over 70 MPH the gas engine is coupled to the wheels as well as the electric motor. At higher speeds with no battery left this is more efficient. If you never exceed electric range before recharging you theoretically never will need to buy gas. However the engine is programmed to run briefly every couple of months to circulate the oil and burn off stale fuel. On the other hand if you want to go cross-country you can do so and just fill it up like a regular car.

Charging is via J-1772 SAE standard connector. "Charger" equipment is essentially a smart extension cord that delivers 120 VAC or 240 VAC to the car along with a PWM pilot signal to tell the car the maximum charge rate to pull without tripping the breaker. GFCI and handshake keeps the output pins dead until car is connected, communicating, and requesting to charge. A "proximity" pin disables the drive electronics while the connector is plugged in to prevent you from driving off and dragging he charger behind you. There are a few free public charging stations around town but most of them are the old style inductive coupling paddle. The Nissan dealer has the new ones, and Costco is supposedly going to upgrade theirs. Rabobank in Goleta has one too.

Charging time is four hours from 240 volts, ten hours on 120 volts if the battery is fully depleted. The car is smart enough to charge based on departure time for off-peak rates. In other words, if I plug it in at 6 pm and have programmed it that my morning drive never starts before 6 am, it will start charging at 2:00 am if the battery is fully drained, later if not. One minor annoyance... You have to set the clock! What's up with that? This car has TWO extremely accurate sources of time built in; a GPS receiver and a CDMA cellular phone (OnStar). The GPS can even update the time zone on the fly based on your location. Yet they make an inaccurate human set the clock!

Really fun to drive, standard equipment includes all the bells and whistles. Totally blows the doors off of a new Prius when the light turns green. Don't ask me how I know this, but the guy really gave me "the look"...

There's a waiting list unless you want to pay way over sticker. (I didn't). Graham Chevrolet just didn't have their act together in three separate visits and numerous phone calls starting in July 2010. This may have changed. Sunset in Lompoc was awesome to deal with. I had a GM order number in hand within 20 minutes of walking in the door, no markup over sticker, no dealer tricks.

Chevy and GM are really in touch with anyone buying this car. They have a "Volt Advisor" team that assists with questions, order tracking, charging equipment, etc.

I took delivery on January 5. Tank holds 9.3 gallons, dealer filled it up and charged the battery before delivery. I bought gas for the first time last Friday, February 25. It took six gallons, 1356 miles on the odometer. Not bad.

The solar:

18 modules, each rated 230 watts peak output. Maximum net measured from the array so far is about 3600 watts after inverter losses, etc. I use Enphase inverters, made in USA. This system is kind of different from the typical grid-tied arrangement. Typically, the panels are connected in a string for about 600 VDC which goes into a big inverter that converts it to AC where it connects to the electrical panel.

Enphase uses one inverter per solar module (panel). This means no HV DC to deal with, no extra DC safety disconnect, and also means that bird droppings on one panel don't pull down a whole string. It also makes things much more scalable as you can add a single panel to an array. The inverters are totally weatherproof potted assemblies that mount under each panel.

Another advantage is that each inverter and thus each panel can be individually monitored to show performance and alert to any problems. For example...

http://enlighten.enphaseenergy.com/public/systems/zyRu12037

If you view the animation you can see that there's low output from the lower right panel until about 10:00 in the morning. That's due to the shadow of a Ku-band FTA satellite dish. Not a big deal and I'll move it eventually. I'm kind of curious to see if it's an issue in the summer when the track of the sun moves farther north. Overcast days and clouds passing overhead are very clear on the graphs and take a big hit on power produced.

The panels are REC Solar, made in Norway. I was going to go US made here as well, SolarWorld in Chatsworth makes nice panels but they're on backorder.

Edison will pay you for your excess electricity as well as a large chunk of the cost of the system including installation. I just got the smart meter about a month ago. This month I've sold Edison 505 kWh and bought 493 kWh. The cool thing is that you can go on a time-of-use metering plan. This means that you're selling electricity in the afternoon at high rates when the sun is shining. Then you buy it back (to charge your car) at super off-peak rates between midnight and 6 am.

This system has no batteries and will automatically shut down in a power failure, so don't depend on this type of arrangement as a backup. A small generator makes more sense from a cost perspective for backup power. You would need enough battery to power your house (and optionally car) in the event of three or four cloudy days if you really want to go off-grid. Not practical.

The inverters shut down if utility power fails as a safety mechanism. You don't want to risk back-feeding the utility lines and endangering Edison workers who would think that the load side of a fault is dead. Utility power has to be present within voltage and frequency limits for five minutes before the inverters will turn on.

With tax and Edison rebates the net cost is about 40% of the quoted price to just buy it outright. I saved additional money by doing the electrical wiring and some of the physical labor but wanted to use a licensed contractor for the roof penetrations (scary for me) and to deal with the permit process. Payback should be about four years.

[Feel free to borrow any or all of this for Key-Klix if you like.]

-- Jay Hennigan - CCIE #7880 - Network Engineering - jay@impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV