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IamIan · 01-31-21, 05:09 PM

My annual electric consumption has been around ~7Mwh .. of which about ~3Mwh is non-HVAC.

I bought 10 used Sunpower 250w solar panels for $891 delivered ~$0.356/watt .. all 10 panels seem to be working fine .. there is of course more risk buying used .. but .. as they say Reduce / Reuse / Recycle .. and it's way cheaper per watt to buy them used.

If I average 4 solar hours per day over the course of a year that ~2.5kw can potentially harvest about ~3.6Mwh per year .. Soo roughly about what my non-HVAC loads are throughout the year.

I haven't decided yet .. but I am leaning toward putting them in parallel with a DC-MPPT on each panel .. AC coupling with micro inverters is also an option , but not my 1st choice.

I like the idea for maximum space use efficiency to combine these PV panels inside my solar thermal collector .. for a combined PVT harvesting system .. the down side is that the higher temperatures will result in lower PV electric yield and faster PV degradation rates.

Spec sheet attached.

01-31-21, 05:09 PM	#7
IamIan Lurking Renovator Join Date: Oct 2012 Location: RI Posts: 20 Thanks: 4 Thanked 5 Times in 5 Posts	My annual electric consumption has been around ~7Mwh .. of which about ~3Mwh is non-HVAC. I bought 10 used Sunpower 250w solar panels for $891 delivered ~$0.356/watt .. all 10 panels seem to be working fine .. there is of course more risk buying used .. but .. as they say Reduce / Reuse / Recycle .. and it's way cheaper per watt to buy them used. If I average 4 solar hours per day over the course of a year that ~2.5kw can potentially harvest about ~3.6Mwh per year .. Soo roughly about what my non-HVAC loads are throughout the year. I haven't decided yet .. but I am leaning toward putting them in parallel with a DC-MPPT on each panel .. AC coupling with micro inverters is also an option , but not my 1st choice. I like the idea for maximum space use efficiency to combine these PV panels inside my solar thermal collector .. for a combined PVT harvesting system .. the down side is that the higher temperatures will result in lower PV electric yield and faster PV degradation rates. Spec sheet attached. Attached Images Last edited by Daox; 02-01-21 at 04:18 PM..