Hi all,
I need some advice on whether the output of my systems seems to be performing up to par. It would seem to me that it is not, but I have very little experience in this area and am looking for guidance / help. I recently took the plunge into a Tesla Solar Glass roof (v3) and 2 Powerwalls. In general, I love it. Beautiful roof and keeping me mostly off grid. We maxed out the roof and I was told that the system would rate at 12.98kW. This equates to 222 PV roof tiles. Here are the specs for the tiles:
At 25 degrees C:
Voc (v): 13.34
Vmp (v): 10.99
Isc (A): 5.65
Imp (A): 5.32
Pmax (W): 58.47
Temp coefficient:
Voltage at open circuit: -0.299
Max power: -0.395
Short circuit current: 0.047
Using the Tesla app I observe the following. I live in S. Calif. and summer is kicking in. My roof is not shaded. Tiles are installed on both North and South facing roof angles. At mid-day, and to a couple hours on either side, the sun hits both N and S surfaces and is unobstructed. On hot days (outside temperature of 90+F) I have observed the system producing a maximum instantaneous output of 8.0kW. Hotter days I have seen less. This is at 12:30PM. Total production of about 61kWh per day in hot conditions.
On cool days with clouds that part momentarily to let through the sun, I have observed up to 12kW instantaneous output. But in general on cool days I observe somewhere in the 9.8 to 10.5 kW sustained instantaneous output.
This seems to be a really huge swing. It seems that the temperature coefficient should account for only about a 20% drop. Factor in some general loss in the system itself, and I would think that it should be producing about 9.75kW sustained on a really hot day, at a minimum. But I may be looking at this wrong. That is where I am looking for advice for you.
I understand that certain factors are not optimal, such as the North-facing tiles, but still do not think this accounts for the drop. Also, I have been told that as the tiles are mounted with a relatively small air gap, this impacts productions a lot compared to traditional panels. Tesla quoted 16,444 kWh production per year.
I cannot be 100% certain if they actually put up 222 PV tiles as the roof seems to be too slippery for me to go up and count them
. Any pointers on how to walk on this roof without slipping off?
WHat are others with a Solarglass roof experiencing? Any thoughts, advice, direction would be hugely appreciated!!
John
I need some advice on whether the output of my systems seems to be performing up to par. It would seem to me that it is not, but I have very little experience in this area and am looking for guidance / help. I recently took the plunge into a Tesla Solar Glass roof (v3) and 2 Powerwalls. In general, I love it. Beautiful roof and keeping me mostly off grid. We maxed out the roof and I was told that the system would rate at 12.98kW. This equates to 222 PV roof tiles. Here are the specs for the tiles:
At 25 degrees C:
Voc (v): 13.34
Vmp (v): 10.99
Isc (A): 5.65
Imp (A): 5.32
Pmax (W): 58.47
Temp coefficient:
Voltage at open circuit: -0.299
Max power: -0.395
Short circuit current: 0.047
Using the Tesla app I observe the following. I live in S. Calif. and summer is kicking in. My roof is not shaded. Tiles are installed on both North and South facing roof angles. At mid-day, and to a couple hours on either side, the sun hits both N and S surfaces and is unobstructed. On hot days (outside temperature of 90+F) I have observed the system producing a maximum instantaneous output of 8.0kW. Hotter days I have seen less. This is at 12:30PM. Total production of about 61kWh per day in hot conditions.
On cool days with clouds that part momentarily to let through the sun, I have observed up to 12kW instantaneous output. But in general on cool days I observe somewhere in the 9.8 to 10.5 kW sustained instantaneous output.
This seems to be a really huge swing. It seems that the temperature coefficient should account for only about a 20% drop. Factor in some general loss in the system itself, and I would think that it should be producing about 9.75kW sustained on a really hot day, at a minimum. But I may be looking at this wrong. That is where I am looking for advice for you.
I understand that certain factors are not optimal, such as the North-facing tiles, but still do not think this accounts for the drop. Also, I have been told that as the tiles are mounted with a relatively small air gap, this impacts productions a lot compared to traditional panels. Tesla quoted 16,444 kWh production per year.
I cannot be 100% certain if they actually put up 222 PV tiles as the roof seems to be too slippery for me to go up and count them
WHat are others with a Solarglass roof experiencing? Any thoughts, advice, direction would be hugely appreciated!!
John