I am having solar panels installed on my house. My contractor told me that they are installing 20 Canadian Solar CS3k-325-MS panels. I just got a copy of the plants they sent to the city for their permit though, and those plans say they are installing Q.Cell Q.PEAK Duo G5 325s. Comparing the two, it looks like the Q.PEAKs have a little better specs, better reviews, and are also a fair bit more expensive.

I was fine with using the Canadian Solar panels, but I'm wondering why they made the change. They emailed me asking about the Canadian Solar panels after the plans with the Q.Cell panels had already been approved by the city, but before I got a copy. When I asked my contractor about it, he just said "We will correct it before inspection."

Is this okay? It smells a little funny to me to change to a cheaper panel type from what was approved in the permit, and I'm wondering if I'm going to have problems clearing inspection after they're done. I'm in the US.

Datasheet on the Canadian Solar panels: https://www.canadiansolar.com/upload/bc48dbe8c5c41fed/ab28643aabcece82.pdf

And on the Q.Cell panels: https://www.q-cells.com/dam/jcr:4fcbaac5-18ed-4e46-aa6c-fb53b5dbe957/Hanwha_Q_CELLS_Data_sheet_QPEAK_DUO-G5_315-330_2018-03_Rev03_NA.pdf

To my eye, the specs look pretty similar. The Q.Cells have a slightly better linear dropoff warranty and a few other pretty minor differences. The Canadian Solar panels are monocrystaline while the Q.Cells are two crystals. To my eye, in terms of what's on the datasheet, there isn't a lot of difference, but I am not expert enough to know if I'm missing anything major. The Q.Cells seem to have generally better reviews and are markedly more expensive, but I'm not sure why.

  • You may want to check with the city to see if the brand of panel matters.
    – jwh20
    Commented Sep 7, 2019 at 19:50
  • Can you post specsheets for both panel types? Commented Sep 7, 2019 at 20:40
  • 3
    If the panels are listed it would not matter in my jurisdiction as long as the specs are similar. I have not had an inspector look at brand, just sizes and listing information.
    – Ed Beal
    Commented Sep 7, 2019 at 22:01
  • @ThreePhaseEel, added to my original question. Commented Sep 8, 2019 at 22:19
  • @jwh20 I have called the city and the person I talked to didn't think it would be an issue. They mainly care about the total kilowatts, and that's going to be exactly the same. Commented Sep 9, 2019 at 19:32

1 Answer 1


If you're using microinverters there are some circuit calculations you're supposed to do using the panel specs and local temperatures to let you know the maximum number of those panels that can be chained together.

If you got different panels then you paid for, I hope you got refunded appropriately! Besides initial specs, I believe mono panels age better than poly in terms of output degradation over time.

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