Solar PV

 

My garage has 24 solar panels arranged in a grid of 8 wide by 3 tall.

Each solar panel is a Helios 260 watt poly-crystaline PV module. Behind each is an Enphase M215 micro-inverter. Each inverter individually converts direct current from the panel to alternating current. Wiring combines the output of each micro-inverter where it travels through wiring inside conduit down the side of the building to a Midnite Solar Combiner/Disconnect box.

That feeds to a 30A circuit breaker used as a load-side connection in the garage main power panel. From there, the electricity powers loads in the garage such as lights or charging my electric car. Any excess power simply runs back to the house to power that building. If there is still excess power, it runs back OUT through my main power meter to the grid where I get credited for it by my power company.

The system was designed to provide the average amount of electricity we use throughout the year. In the summer, we produce more power than we use (and get credited for it) and in the winter we produce less than we use. The goal was to produce what we use on average over a year, sometimes called “Annual Net-Zero”.

Total faceplate power capacity of the solar panels is 6,240 watts (at laboratory test conditions) but real-world power production is really 5,400 watts maximum.

On a clear, sunny summer day, I can charge my electric car, power my garage and house, and STILL have extra power I’m selling to the electric company!

My out of pocket expense to install the solar was $10,500, but the total was reduced to $6,500 after a number of tax and other incentives. The solar array produces about $1,000 worth of electricity per year, so it pays for itself in 6.5 years. After that, I’m getting PAID $1,000 per year!

Most solar panels generally have a 20-25 year warranty. I know people who installed solar panels 40 years ago, and those panels are still functioning just fine.

You can see the output of the solar anytime at SOLAR PRODUCTION LINK.

I have a whole series of videos about designing and installing the solar on YouTube. To see how much I save on my electric bill each month, please view https://www.youtube.com/playlist?list=PLmHss3DBZUimMu2T5B198sNn6A4cp2zvG

{ 5 comments… read them below or add one }

1 Aaron April 27, 2019 at 11:10 pm

What is your yearly production and your yearly consumption?

2 admin April 28, 2019 at 8:53 am

About yearly production and use. The system is new enough that I only have one complete calendar year of production data. Based on that and partial year data, I can also say that production varies a bit year to year (due to weather – an especially cloudy fall, hot summer, etc.)

In our first full year of production, we made 7,408 kWh of energy. My original goal was averaging 600 kWh per month, and that annual production averages out to 617 kWh per month.
However, we also did USE quite a bit more energy as well. Going through and adding up all my utility bills, it looks like we used 1,653 kWh more than we created, (9061.) I was also experimenting at the time with electric heat for some special events. (Hosting meetings in my garage in the winter, etc.) I logged that energy usage with an old-fashioned mechanical power meter, and it showed 1018 for electric heat use for the year.
If I deduct that from my total use (as I was never using electric for heat before the solar) I end up with an annual usage of 635 kWh more from the power company than I used. About a month’s electric use. (The U.S. National Average is right around 900 kWh/mo.)

Another way to look at it is that the solar covers all of our power use 11 months out of the year. I’d love to have it hit 12, but we have also increased the use of our electric car (which has also DECREASED use and cost of gasoline!) and have a school age child at home, which has changed electric use patterns.

Another way to look at this is that we went from 100% of our power coming from a utility down to about 8.5% coming from the utility!

3 Aaron April 29, 2019 at 8:49 pm

We are currently looking at 23 LG 330 panels. Is estimated that it will produce 13,231 Kwh a year. We’ve had our house about 9 months so we estimate we’ll have used 11,000 Kwh so we should do okay. I want to eventually have an electric car, but we’d have to update our breaker box to get a level 2 charger installed. Unless you know of another way to do it.

4 admin April 30, 2019 at 7:16 am

If you are installing solar anyways, you’ll have an electrician there. That’s a good time to upgrade your breaker panel. You can even install just the wiring to where you would plan to install an EVSE or have the electrician mount a NEMA 14-50 outlet, which is a great all-purpose high power outlet appropriate for electric car use.

5 Aaron April 30, 2019 at 3:53 pm

Unfortunately, I don’t have the cash right now and it week be a while before I can get an electric vehicle.

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