9kW Solar Project - Finally complete


Hello everyone,

It's been a while since I've been around here...still riding my 650B and loving it. Since getting the bike, we've sort of embraced electric in a lot of ways, starting with changing all the lights in our home to LED, then my old 1990 2-stroke Lawn Boy mower died this spring, so I replaced it with an electric model.

I've been weighing the pros & cons of solar energy, and decided it was time. Last week, we put up 41, 225-watt solar panels. It was a big project but it turned out great. I bought the panels used, and shopped around for deals on everything from the inverters, to the rails, and found start-up firm that was looking for a reference installation that agreed to help me install everything quite affordably. I'm at $2.17 per watt which was pretty reasonable.

Anyway, if anyone has questions about solar, I'm happy answer them as best I can.

Here's a link to my monitoring site:


Here's an overhead photo during the install:



Ravi Kempaiah

Well-Known Member
Awesome !!
Good to hear from you Dave.

I would like to know more about the PV panels that you're using. I'm sure there is a reason why you picked them.

PS: Tesla Power wall + p85D = next project? :)


They are SunPower SPR-225 "E18" panels. They are five years old, and I bought them off of Craigslist. The previous owner had over 100 of these on his roof, and upgraded to the current 327 watt model. I chose them because of how they look (which was a deal breaker for my wife), but mostly because the deal was too good to pass up. I'm thrilled about how the project turned out; especially the nine panels on our west wall that fit into the architecture of the house - somewhat resembling a row of 2nd floor windows.

They were a challenge to match with a suitable inverter however. In the summer, the panels usually output around 39-45 volts but because our temperatures are extremely cold in the winter (sometimes below -30C), voltage rises as the temperature drops. We installed ABB microinverters that are able to handle up to 65 volts to comply with the permit.

Even with our very low power rates of $0.08 per kWh, The ROI will be between 10-12 years. Should rates increase, the project will pay for itself sooner than that.

Tesla P85D. Nice choice.


Active Member
Excellent ROI at Edmonton latitude. You say the panels are 5y old. Do you know if the output has decreased. I have read that the theoretical loss annually is 0.5-1%.


I'm sure output has decreased, but I have no point of reference except for spec sheets. At full sun, at 25C; my south facing panels have briefly generated over 200 watts. I'm ok with that. I'm looking forward to seeing the numbers on sunny -30C days. The panels on the west facing wall are at 90 degrees, so they should work well at catching the low horizon winter sun.