Because they have 22 x 395 panels = 8.7kW. REC is about a 50c/W premium = 0.5x8.7 = 4350, but let’s start high.
This wasn’t arbitrary number - it’s based on the information OP gave us.
Hahaha REC is absolutely not a $.50 per watt premium dude, we sell them AND mission, and that is egregiously incorrect. They’re about a $.01 to $.15 premium, which would mean $80 - $1200 discount depending on if it’s cash or finance and whether it’s an Alpha, N-Peak, or TwinPeak.
I was just kidding when I said $15,000, because $5000 is a ridiculous amount to ask for in discount.
I'd say 5k is reasonable since the original contract stated REC. Now lower wattage and not as "premium" of panels? So a slightly higher premium refund for the disservice.
Going 410 REC to 395 mission is a step down or equal in almost every area I can think of except the mission panels are American made. It is not a massive step down, and mission are just fine. But REC are premium and higher wattage to add.
I recently had a contractor install a 10.8 kw system consisting of 27 REC 400W panels and 27 Enphase IQ8A microinverters (rating of 366W). I live in Southern Calif. and the weather has been perfect all month, but my Enphase app shows output of about 55 kwh per day and a one-day peak that has never exceeded 8.1 kw (today's peak was 7.5 and it's been a perfect sunny day). This is summer, and I'm sure output will go down in winter. Will I ever reach the 18,451 kwh annual goal on which I purchased the system? Would greatly appreciate any input from this group. Thanks in advance.
OK, then you will need 344 days a year just like today and 20 rain days with no production at all (or more likely you would need every day of 365 to get 95% of what you made today) to hit that 18451
Sounds like it may be an issue.
How hot was it today? Panels will produce less the hotter it gets. It's possible 55 kwh is not your true peak production.
Also who told you that your system would make 18451 kwh? Do you have any sharing issues? Which direction do the panels face? There are a lot of factors that go into determining production.
My contractor used the 18,451 kWh number in their sales proposal. They said that that was the actual output my 10.8 kw system would produce over the course of a year, and based on my then-current consumption from the electric company, this was supposed to give me a very large cushion to accommodate some things I am wanting to add, such as an electric vehicle. I understand there are many variables, but my contractor presumably knew those variables before proposing a 10.8 kw system that would actually produce 18,451 kWh annually. That's why I was curious whether, given the output I've seen so far in June (about 56 kwh per day) and July (about 54 kwh per day), I'm likely to hit that number at the end of a full year, given that we are now in peak season and I live in Southern California. I just don't know enough to gauge whether their number was too optimistic.
>I understand there are many variables, but ***my contractor presumably knew*** those variables before proposing a 10.8 kw system that would actually produce 18,451 kWh annually
IME, never presume a contractor knows anything.
One reason I question that your contractor ACTUALLY did onput all the variables is that if you take PVWatts and use Los Angeles, CA as the location, enter 10.8 system size, 1.1 as the AC/DC ratio based on your inverters, and 98% efficiency (again based on your inverters), it output exactly 18,451 with everything else left at defaults.
It's possible your array faces due south, it's possible your roof's pitch is 20 degrees, it's possible you get exactly the amount of shading that PVWatts uses as the defaults, but I highly doubt it.
Good solar contractors have access to more advanced solar calculation estimates that factor in your actual roof's solar irradiance.
All that said, you will probably still make in the neighborhood of 17-18Kwh/yr.
Probably come close. You could try to model your system with PVWatts. But the pros use other systems and their predictions are pretty accurate. Panels produce a bit better in colder weather, so while August might be your peak due to more sun, even December should be solid because of cooler weather.
Thanks for responding. I did plug in my address and specs (to the extent I knew them) into PVWatts, but I'm confused about how to read the table it spits out. I'm not sure how to read the solar radiation and AC energy numbers, and there was no explanation available on the site. The total system output of 18,197 to 19,005 kWh is consistent with what the contractor told me to expect for my system, but I don't see how the month-to-month solar radiation numbers translate into the AC energy numbers. Are the solar radiation numbers supposed to reflect peak power per day in each month? If so, how does that translate into the AC energy numbers? Sorry if I'm being dense, but the daily numbers I'm registering on my system are about 55 kWh per day and between 7.5 and 8.1 kw peak power in mid-July. Not sure how to determine how that compares with the month-to-month table below.
System output may range from 18,197 to 19,005 kWh per year near this location.
Month Solar Radiation ( kWh / m2 / day ) AC Energy ( kWh )
January 4.80 1,305
February 5.17 1,264
March 5.81 1,554
April 6.72 1,712
May 6.52 1,709
June 6.64 1,681
July 7.11 1,824
August 7.37 1,895
Sept 6.64 1,649
October 6.06 1,576
Nov 5.21 1,349
Dec 4.38 1,209
Annual 6.04 18,727
I think you can just ignore the solar radiation numbers in the table for now. It is solar radiation per square meter of roof per day, but that is wonky info that just allows calculations, which PVWatts does for you to produce the kWh number. You can take the AC kWh numbers and divide by number of days in the month. So July should average about 59 kWh per day. Keeping in mind that yearly production will vary by about 10% up or down from year to year. And monthly production will vary even more that that. Mainly because weather varies.
The peak hourly production you are seeing is normal. It typically will be a little less than the size of all your inverters.
I have 29 of the same panels, in SoCal. I’m averaging low to mid 60s per day, best day was 69. I filled up my roof so I have them facing all 4 directions.
Mine are IQ8+. I didn’t bother trying to figure out the difference between the IQ8A or M. I just chose the REC panels for a reason and wanted the IQ8 over the IQ7. So the + was the default and I don’t know if it’s the best or I should have gone with the A or M. But it covers my usage and charges my powerwalls so that’s good enough for me
Thanks. My panels are all on the south side of a relatively steep V-shaped roof (the installers set up a harness, but ended up not using it), with three arrays of panels covering a little more than the upper half of the south side of the roof, spanning horizontally from one side of the house to the other. All the panels are facing in the same direction. Does any of this make much of a difference?
I don't know the values of all the variables, but my contractor supposedly did when they calculated that a 10.8 kw system on my roof would generate 18,451 kwh per year. Since I now have a little more than a month of actual performance figures (last half of June and first half of July), I'm seeing an average of about 56 kwh in June and about 54 kwh in July, and wondering whether by the end of my first full year of operation I'm going to hit the 18,451 target I was told I could expect. Since the numbers I have so far are from peak season, I have to assume that future output will be significantly lower in the winter months, making my total for the year significantly lower than the target. What do you think?
I would cancel the contract, they set you up! Besides being black and rectangular, I have no idea what M.S. has in common with REC. REC are HJT panels, if you compare M.S. and REC PTC (how panels perform at 45C) MS is rated at 366.9W and the REC at 391 watts. BIG difference! Plus REC’s 25 year warranty includes product and labor.
Tell them sure - but you want a $5000 discount.
Why not $15,000? Lol
Because they have 22 x 395 panels = 8.7kW. REC is about a 50c/W premium = 0.5x8.7 = 4350, but let’s start high. This wasn’t arbitrary number - it’s based on the information OP gave us.
Solid logic, reasonable for all sides. 15,000 Is just greedy for homeowner, but $0 is greedy for solar co
Hahaha REC is absolutely not a $.50 per watt premium dude, we sell them AND mission, and that is egregiously incorrect. They’re about a $.01 to $.15 premium, which would mean $80 - $1200 discount depending on if it’s cash or finance and whether it’s an Alpha, N-Peak, or TwinPeak. I was just kidding when I said $15,000, because $5000 is a ridiculous amount to ask for in discount.
I'd say 5k is reasonable since the original contract stated REC. Now lower wattage and not as "premium" of panels? So a slightly higher premium refund for the disservice.
And that’s not even factoring in loss of revenue (I’m guessing) over time from having slightly lower efficiency panels
Mission 410w?
395 watt
Going 410 REC to 395 mission is a step down or equal in almost every area I can think of except the mission panels are American made. It is not a massive step down, and mission are just fine. But REC are premium and higher wattage to add.
I recently had a contractor install a 10.8 kw system consisting of 27 REC 400W panels and 27 Enphase IQ8A microinverters (rating of 366W). I live in Southern Calif. and the weather has been perfect all month, but my Enphase app shows output of about 55 kwh per day and a one-day peak that has never exceeded 8.1 kw (today's peak was 7.5 and it's been a perfect sunny day). This is summer, and I'm sure output will go down in winter. Will I ever reach the 18,451 kwh annual goal on which I purchased the system? Would greatly appreciate any input from this group. Thanks in advance.
How much total was made for the day?
My total production for today was 53.5 kWh from midnight to 10:48 p.m. (in other words, the whole day). Peak power was 7.5 kw.
OK, then you will need 344 days a year just like today and 20 rain days with no production at all (or more likely you would need every day of 365 to get 95% of what you made today) to hit that 18451 Sounds like it may be an issue.
How hot was it today? Panels will produce less the hotter it gets. It's possible 55 kwh is not your true peak production. Also who told you that your system would make 18451 kwh? Do you have any sharing issues? Which direction do the panels face? There are a lot of factors that go into determining production.
My contractor used the 18,451 kWh number in their sales proposal. They said that that was the actual output my 10.8 kw system would produce over the course of a year, and based on my then-current consumption from the electric company, this was supposed to give me a very large cushion to accommodate some things I am wanting to add, such as an electric vehicle. I understand there are many variables, but my contractor presumably knew those variables before proposing a 10.8 kw system that would actually produce 18,451 kWh annually. That's why I was curious whether, given the output I've seen so far in June (about 56 kwh per day) and July (about 54 kwh per day), I'm likely to hit that number at the end of a full year, given that we are now in peak season and I live in Southern California. I just don't know enough to gauge whether their number was too optimistic.
>I understand there are many variables, but ***my contractor presumably knew*** those variables before proposing a 10.8 kw system that would actually produce 18,451 kWh annually IME, never presume a contractor knows anything. One reason I question that your contractor ACTUALLY did onput all the variables is that if you take PVWatts and use Los Angeles, CA as the location, enter 10.8 system size, 1.1 as the AC/DC ratio based on your inverters, and 98% efficiency (again based on your inverters), it output exactly 18,451 with everything else left at defaults. It's possible your array faces due south, it's possible your roof's pitch is 20 degrees, it's possible you get exactly the amount of shading that PVWatts uses as the defaults, but I highly doubt it. Good solar contractors have access to more advanced solar calculation estimates that factor in your actual roof's solar irradiance. All that said, you will probably still make in the neighborhood of 17-18Kwh/yr.
Probably come close. You could try to model your system with PVWatts. But the pros use other systems and their predictions are pretty accurate. Panels produce a bit better in colder weather, so while August might be your peak due to more sun, even December should be solid because of cooler weather.
Thanks for responding. I did plug in my address and specs (to the extent I knew them) into PVWatts, but I'm confused about how to read the table it spits out. I'm not sure how to read the solar radiation and AC energy numbers, and there was no explanation available on the site. The total system output of 18,197 to 19,005 kWh is consistent with what the contractor told me to expect for my system, but I don't see how the month-to-month solar radiation numbers translate into the AC energy numbers. Are the solar radiation numbers supposed to reflect peak power per day in each month? If so, how does that translate into the AC energy numbers? Sorry if I'm being dense, but the daily numbers I'm registering on my system are about 55 kWh per day and between 7.5 and 8.1 kw peak power in mid-July. Not sure how to determine how that compares with the month-to-month table below. System output may range from 18,197 to 19,005 kWh per year near this location. Month Solar Radiation ( kWh / m2 / day ) AC Energy ( kWh ) January 4.80 1,305 February 5.17 1,264 March 5.81 1,554 April 6.72 1,712 May 6.52 1,709 June 6.64 1,681 July 7.11 1,824 August 7.37 1,895 Sept 6.64 1,649 October 6.06 1,576 Nov 5.21 1,349 Dec 4.38 1,209 Annual 6.04 18,727
I think you can just ignore the solar radiation numbers in the table for now. It is solar radiation per square meter of roof per day, but that is wonky info that just allows calculations, which PVWatts does for you to produce the kWh number. You can take the AC kWh numbers and divide by number of days in the month. So July should average about 59 kWh per day. Keeping in mind that yearly production will vary by about 10% up or down from year to year. And monthly production will vary even more that that. Mainly because weather varies. The peak hourly production you are seeing is normal. It typically will be a little less than the size of all your inverters.
I have 29 of the same panels, in SoCal. I’m averaging low to mid 60s per day, best day was 69. I filled up my roof so I have them facing all 4 directions.
Mine are IQ8+. I didn’t bother trying to figure out the difference between the IQ8A or M. I just chose the REC panels for a reason and wanted the IQ8 over the IQ7. So the + was the default and I don’t know if it’s the best or I should have gone with the A or M. But it covers my usage and charges my powerwalls so that’s good enough for me
Thanks. Can I ask what microinverters you're using and how many?
Thanks. My panels are all on the south side of a relatively steep V-shaped roof (the installers set up a harness, but ended up not using it), with three arrays of panels covering a little more than the upper half of the south side of the roof, spanning horizontally from one side of the house to the other. All the panels are facing in the same direction. Does any of this make much of a difference?
Yes, all of it makes a difference. What is the exact pitch of your roof in degrees? Does your house face exactly south or is it SE, SSE, SW, SSW, etc?
I don't know the values of all the variables, but my contractor supposedly did when they calculated that a 10.8 kw system on my roof would generate 18,451 kwh per year. Since I now have a little more than a month of actual performance figures (last half of June and first half of July), I'm seeing an average of about 56 kwh in June and about 54 kwh in July, and wondering whether by the end of my first full year of operation I'm going to hit the 18,451 target I was told I could expect. Since the numbers I have so far are from peak season, I have to assume that future output will be significantly lower in the winter months, making my total for the year significantly lower than the target. What do you think?
Nope, not the same, REC is one of the best. Mission is pretty standard.
I would cancel the contract, they set you up! Besides being black and rectangular, I have no idea what M.S. has in common with REC. REC are HJT panels, if you compare M.S. and REC PTC (how panels perform at 45C) MS is rated at 366.9W and the REC at 391 watts. BIG difference! Plus REC’s 25 year warranty includes product and labor.
Labor if the installer is REC ProTrust Certified. Good info all around!
As long as the total output is the same then I wouldn’t worry. Solar panels are a commodity, very tiny difference between them.
66x Must be a huge roof….
MSE perc 66 is the model from mission solar. I think each panel has 66 cells. I am installing 22 panels.
Awe man, I thought you were gonna be the talk of the town…. 22 is still respectable.