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  • J.P.M.
    replied
    Originally posted by Sando
    That's correct and again thank you all for your input.
    You're welcome.
    Good luck.

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  • Sando
    replied
    That's correct and again thank you all for your input.

    Leave a comment:


  • J.P.M.
    replied
    Originally posted by Sando
    Thank you all for your help. I feel better about my production now at this time of year and kind of know more now about what to look at. I'm not going to be changing anything at this point anyway. If the production continues to be low in the summer months I'll look at everything again and talk to NM Solar. One of those trees is actually my neighbors and we talked about him possibly trimming mine when he does his, so that might happen down the line. This is a very helpful forum, I'm glad I found it.
    So, I'd take that to mean that you're no longer looking for input about any analysis of your output, correct ?

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  • Sando
    replied
    Thank you all for your help. I feel better about my production now at this time of year and kind of know more now about what to look at. I'm not going to be changing anything at this point anyway. If the production continues to be low in the summer months I'll look at everything again and talk to NM Solar. One of those trees is actually my neighbors and we talked about him possibly trimming mine when he does his, so that might happen down the line. This is a very helpful forum, I'm glad I found it.

    Leave a comment:


  • SunEagle
    replied
    Originally posted by SolTex
    You set the "azimuth" in the PVWatts to 180 degrees, when your panels actually face 99 and 279 degrees. Your results will be lower with the actual panel azimuth entered.
    Along with getting the wrong azimuth in the calculations I would also say that those trees will provide some shade on the East panels and the chimney could cause shade on a couple of the panels. If they are all on one string then IMO any shade will result in a lower output.

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  • oregon_phil
    replied
    Originally posted by Sando
    I read through all the comments and found some more info regarding my system. Also used the PVWatts calculator, although I did not break it up like previous poster into 2 calculations for east (5 panels) and 6 on the west side. I have monthly estimates by NM Solar (they should say 2023, not 2022), the project overview with array details and what I got from PVWatts. Jan. and Feb. are closer to installers estimates, March looks like it is going to be a lot less. Also read the article from AC Electric, not sure I understand it completely.
    Here's a stab at your location using 6 East and 5 west panels with your roof pitch and orientation. Your actual roof pitch is not 18 degrees, it's closer to 45 degrees from what I can gather from google maps.

    Those deciduous trees in your front yard look like they are maybe 100 feet tall. You might be getting some low angle shading in the winter. Sometimes it is difficult to see shading on the panels caused by branches. Morning shading in the summer might should be watched too; especially with 45 degree angle roof pitch.

    It would be helpful to know which SolarEdge optimisers were selected for your project. Also, it would be helpful to get per panel power and voltage if the SolarEdge app allows it. Maybe some SE people could help walk her through how to do this.

    For what it's worth, use a full width black marker next time when blocking out sensitive information on your paperwork for public consumption.

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  • SolTex
    replied
    You set the "azimuth" in the PVWatts to 180 degrees, when your panels actually face 99 and 279 degrees. Your results will be lower with the actual panel azimuth entered.
    Last edited by SolTex; 03-25-2023, 02:42 PM.

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  • Sando
    replied
    Sorry, here's the attachments:
    Attached Files

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  • Sando
    replied
    I read through all the comments and found some more info regarding my system. Also used the PVWatts calculator, although I did not break it up like previous poster into 2 calculations for east (5 panels) and 6 on the west side. I have monthly estimates by NM Solar (they should say 2023, not 2022), the project overview with array details and what I got from PVWatts. Jan. and Feb. are closer to installers estimates, March looks like it is going to be a lot less. Also read the article from AC Electric, not sure I understand it completely.

    Leave a comment:


  • SolTex
    replied
    Our system in Midland, TX will generate (on a good clear sunny day) between 2.25 and 2.50 kWh per panel per day. We have 380W (STC rating) panels with IQ7+ micro inverters. Our output is limited (clipped) by the max AC output of our inverters. The OP's numbers in the first post indicate she is getting (so far in March) a little over 1.0 kWh per panel per day. ("March so far" = 305kWh divided by 24 days = 12.71kWh per day divided by 11 panels = 1.16kWh per panel) That seems kinda low to me.
    Last edited by SolTex; 03-25-2023, 06:29 PM.

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  • J.P.M.
    replied
    Originally posted by SunEagle

    I think the OP has a lower production rate due to the E / W panel orientation and possibly due to the inverter rating
    We'll have to see if the OP comes back with an array tilt. If it's greater than say 45 degrees or so, the E-W orientation and a high tilt will hurt production, more than a DC/AC ratio of 1.16, which doesn't seem too bad to me, especially if tilts are higher than, say, 30 degrees or so.

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  • J.P.M.
    replied
    Originally posted by Sando
    I'm the original poster (70 yr. old female) and am going to try to answer some of the questions. By the way, I really appreciate everyone's input. My inverter is a solaredge SE3800H, and there is a number saying Max output Wac 3800 W. (I'm looking at the contract I signed). For the system it says 4.4 kW DC. Zip is 87740, Raton, NM right up by the Colorado border. We have not had a lot of rain or snow this winter, but lots of cloudy days. I have 2 big trees on the East side of the house and some smaller trees on the West side. Two story house with the panels at an angle. I'm not sure if I got a monthly output estimate from the vendor, will look for that. (They are in Albu. and not very helpful. But I haven't pushed very hard, I'm going to wait and see what happens production-wise) I'm not sure I'll be able to run an estimate on PV watts, but will look into that also.
    Thank you.

    What is the vendor's name in Albuquerque ?
    I've been through the Raton pass and in/around Raton several times. I remember BBQ at the Ice House.

    Do the trees shade the panels during daylight hours ? If so approximately how much of the time ?

    For many reasons I'd encourage you to check out PVWatts on the net. It's a user friendly model that takes about 20 minutes to read through the help screens. After that, the input and familiarization may take another 20. After that it'll become old hat. What you learn will be well worth the investment of your time.

    If you provide a tilt off horizontal for your arrays and given your zip and azimuth, any number of folks here will most likely be willing and able to answer any questions you may have to get you going. Just provide an estimate of the arrays' tilt (horizontal = zero degrees tilt, vertical = 90 degrees).

    As a rough 1st approximation, I'd expect about twice the output from your arrays in the summer months vs. the winter months.

    Good luck.
    Last edited by J.P.M.; 03-25-2023, 12:21 AM.

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  • oregon_phil
    replied
    I ran a hypothetical PVWatts E/W array of 5 East/6 West x 400 watt panels on a 34 deg pitch roof at Zip Code 87740. See attachment NM estimate. We can do a better estimate if the OP can give us the actual number of panels East and West, the actual house orientation and the actual roof pitch. But maybe it's a starting place.

    Since the system is a Solar Edge system, minimum and maximum strings lengths are specified: 8 panels minimum, 25 panels maximum. This implies that the installer used one string for all panels since there are 11 total panels. See SE String Length attachment.

    I remember reading an article from MC Electric regarding issues with SolarEdge production issues due to voltage blocking. See attachment SE Blocking. The part that concerns me in the article is where it says "However, if we have a string with 6 or fewer panels in the sun, the system will suffer voltage blocking at best, or it will just shut down at worst. This is even when the electrician installs to SolarEdge guidelines." You can read the full article googling MC Electric and SolarEdge. If this was a flat roof, then no issues. The steeper the roof and/or the more shading on the panels, my guess is that voltage blocking would have a greater chance of impacting inverter output.

    I am not an installer nor do I own SolarEdge equipment so I am not an expert. I'm just a retired mechanical engineer with an interest in Solar. Please take anything I have said with a grain of salt. A solar professional designer should review any and all data.

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  • SunEagle
    replied
    Originally posted by Sando
    I'm the original poster (70 yr. old female) and am going to try to answer some of the questions. By the way, I really appreciate everyone's input. My inverter is a solaredge SE3800H, and there is a number saying Max output Wac 3800 W. (I'm looking at the contract I signed). For the system it says 4.4 kW DC. Zip is 87740, Raton, NM right up by the Colorado border. We have not had a lot of rain or snow this winter, but lots of cloudy days. I have 2 big trees on the East side of the house and some smaller trees on the West side. Two story house with the panels at an angle. I'm not sure if I got a monthly output estimate from the vendor, will look for that. (They are in Albu. and not very helpful. But I haven't pushed very hard, I'm going to wait and see what happens production-wise) I'm not sure I'll be able to run an estimate on PV watts, but will look into that also.
    Thanks for the update. IMO the problem of low production could be shade from the trees or clouds above the panels based on the time of day. Without more details on the system and what is actually expected this time of year it could be a system not working up to par or just crappy weather causing a reduction of output. Too bad you can't run the PV watts estimate to see what history says the system should produce.

    Leave a comment:


  • Sando
    replied
    I'm the original poster (70 yr. old female) and am going to try to answer some of the questions. By the way, I really appreciate everyone's input. My inverter is a solaredge SE3800H, and there is a number saying Max output Wac 3800 W. (I'm looking at the contract I signed). For the system it says 4.4 kW DC. Zip is 87740, Raton, NM right up by the Colorado border. We have not had a lot of rain or snow this winter, but lots of cloudy days. I have 2 big trees on the East side of the house and some smaller trees on the West side. Two story house with the panels at an angle. I'm not sure if I got a monthly output estimate from the vendor, will look for that. (They are in Albu. and not very helpful. But I haven't pushed very hard, I'm going to wait and see what happens production-wise) I'm not sure I'll be able to run an estimate on PV watts, but will look into that also.

    Leave a comment:

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