Everything Solar Forum

communities_1.jpg

 View Only
Expand all | Collapse all

Issues With My solar System Help

  • 1.  Issues With My solar System Help

    Posted 01-28-2023 06:35 PM
    Greetings to community and members,
    I am in search with help/similar experience with a residential system that was installed by Sunpower.
    We got our system installed last September and since then we are being charged by the utility as well.Upon carefully checking, all data by Sunpower monitor and App  for production and consumption just don't make sense and are not aligned with Edison our local energy utility company.
    Numbers just don't add up.
    We contacted Sunpower so many times about this issue and even refuse to pay for the finance company till system is working properly.Sunpower keeps sending a technician,from a third party ,who really can't resolve the issue.
    I would like to proceed at higher ways.Looking to get help and ideas via this open channel.
    Many Thanks:))

    ------------------------------
    YEHUDA GRABLI
    ------------------------------


  • 2.  RE: Issues With My solar System Help

    Silver
    Contributor
    Posted 01-28-2023 07:19 PM
    Edited by william fitch 01-29-2023 08:27 AM
    WOW!! Humm. Well, as you started with numbers being at the core of your "discomfort", to be obvious, numbers, precise numbers are most likely at the problems solution, or at least its recognition and path forward. 
    There is raw production, house load, grid load. Those three do a dance always maintaining a balance except it grid out scenarios. 

    What you need is any specific month since system operation began, retrieving precisely the total raw production for the month, the exact KWH pulled or pushed from the grid (As a total function), and as a dessert the load numbers which should be a manipulation of the first two depending on push or pull, or a CT meter energy reporting tool with directional sensitivity.

    If that is glazing your eyes over (Sorry), just tell me what you don't understand (If anything) and then we all (ASES people) can proceed....

    ------------------------------
    william fitch
    Owner
    www.WeAreSolar.com
    ------------------------------



  • 3.  RE: Issues With My solar System Help

    Silver
    Contributor
    Posted 01-29-2023 09:30 AM
    Edited by william fitch 01-29-2023 06:35 PM
    Hi: I got the email you sent me with the energy graph. You might consider posting it to this thread so others can input. It is straight forward in its appearance and numerics. The question I have to ask is where specifically is the conflict as you perceive it, between the energy report as referenced and any specific data from Edison?
    EDIT: I re-read your email response again. 
    I will try to explain this. "Edison" does not know WHAT YOU USE!! They only know WHAT YOU TAKE and what you PUSH. I want you to think about those two statements carefully. And the difference between what Edison sees as take and push is not reflective of you load because you produce as well. This can get mind bending a bit.
    The answer to the difference in your  month end being grid push by your reporting system VS them at grid take, may lie in how your "setup determines" load. Also as a side thought, do you have batteries in your system? 
    Depending on how your system is configured, the differences may lie there. In order to check their numbers, you to need a precise reading of what is pushed to and taken from the grid at meter point, which your CT's (Current transformers) may not be giving you depending on different variables. SO really what you produce is not relevant for them. Only what you take and only what you push.
    ------------------------------
    william fitch
    Owner
    www.WeAreSolar.com
    ------------------------------



  • 4.  RE: Issues With My solar System Help

    ASES Life Member
    Posted 01-30-2023 03:35 PM
    Hi Yahuda
    Your email is not clear about what 'numbers' don't add up. Solar production, net power consumption, billing charges? I have not seen the data you sent to William, but another thing to compare is what your Electric bill is saying and what the Sunpower system monitor app is saying. They should agree for net power (difference between actual load from the house which neither can measure and the PV production). Pick a sunny cloudless day and compare them, then pick a month (use same dates as in billing cycle). Are they in agreement?

    Also, remember that many utilitiies have fixed charges, with some charging PV owners additional fee as well. I dont know where you live but look carefully at your bill. Even if your solar array produced 100% of the electricity you consumed, you could still have $20-50 monthly fixed fees. 

    Steve

    ------------------------------
    Steven Hegedus
    Professor and Senior Scientist
    University of Delaware
    Newark Delaware
    ------------------------------



  • 5.  RE: Issues With My solar System Help

    Posted 01-30-2023 11:47 AM
    We also have a Sun Power system. It is a 19.8 kW panels and 26 kW battery backup. It took over a full year for the complete installation to be completed. Our EMC says they are sending more kW into the house than what Sun Powers app shows. As they just finished the battery installation of 2 13 kW units, we thought we would wait a month or two and see if anything improves. We have never seen our panels produce close to the 19.8 kW even though we are in the south and get full sun during the spring thru early fall. They say we need to send them all the information they were supposed to have done before selling the system. Angle of the sun, angle of the roof, etc. We are trying to work with them on getting our system optimized for best economy and they are helping. They are going to remove our HVAC from the batteries and see if they will last a little longer at night. As things are right now, I would not recommend a similar solar system to anyone and I have had many people ask about our experience. Over 1 full year filled with excuses and still not supplying all the power it should.

    ------------------------------
    Barry Rosenberg
    British Car Service
    ------------------------------



  • 6.  RE: Issues With My solar System Help

    Silver
    Contributor
    Posted 01-30-2023 12:02 PM
    Yes, ongoing issues. As a connected thought, I would absolutely say that EVERY PV SYSTEM should have a 100,000 KWH mechanical meter connected at the main string inverter output. If you have micro inverters, then it should be placed where the small feeds come together (Maybe combiner box), BUT BEFORE any wires "split off"  to satisfy loads or battery interfaces. And I don't care what smartphones, wi-fi, CT's etc., etc. you have. This meter will provide you with an unarguable production output even if the inverter(S) are down or any other system part. Call me old fashioned if you like. I don't care. it should be present.
    Sunpower, at least pre the split off, made the best or at least among the very best solar panels in the world! I have them! They are engineering superior and fantastic. However, the panels are one part of an engineered system. And for the owner, all parts must function and information should be available and readable in a way that they can have confidence in.

    ------------------------------
    william fitch
    Owner
    www.WeAreSolar.com
    ------------------------------



  • 7.  RE: Issues With My solar System Help

    ASES Award Winner
    Posted 01-31-2023 12:18 PM
    William is correct. All systems have different designs.

    I have Sunpower, and may sensors at the panel level shows what is being produced.
    If you have combiner boxes, charge controllers, and different inverters draw down the 
       power before the end-point. Even the differences in connectors degrade power.

    Good article by Fluke about trouble-shooting systems
    https://www.fluke.com/en-us/learn/blog/hvac/troubleshooting-photovoltaic-systems-three-typical-problems

    Good article on fuses and combiner boxes
    https://www.solarpowerworldonline.com/2022/04/the-solar-pv-system-troubleshooting-checklist/

    Great under-performing PV panel article
    https://www.ecowatch.com/solving-solar-panel-output-issues-2655223014.html

    Regards, Scott 

    _____________________
     
    Scott Sklar, President, The Stella Group, Ltd., VA
    Phone:  703-522-3049 direct) E-mail:   solarsklar@aol.com
     
    Adjunct Professor & Sustainable Energy Director
    Environment & Energy Management Institute (EEMI)
    The George Washington University (GWU)
     
    _______________________





  • 8.  RE: Issues With My solar System Help

    Posted 01-31-2023 03:08 PM
    The "Utility Grade" (VERY Accurate...) was a requirement 9 to 14 years ago when "SRECS" (Solar Renewable Energy Credits) were a nice way to help pay off the system.  For every 1 MWh generated you got ONE "SREC".  Back in the day when I set up my first (personal) system, I was able to get Almost $300 per SREC!!!!!!  Over the years as solar became more popular, the law of supply and demand took over. Last time I checked, an Ohio SREC was only worth 5 bucks - NOT worth the time to register, keep track, and sell them on the open market via a trading platform....  But, like the man said, if you want an ABSOLUTE measure of how much solar power you're generating, the meter is the way to go. Just install it IN LINE between the inverter and your backfeed point.

    ------------------------------
    Joe Utasi
    PV Solar Consultant
    Cinci Home Solar, Keowee Home Solar, DIY Solar Helper
    ------------------------------



  • 9.  RE: Issues With My solar System Help

    Silver
    Contributor
    Posted 01-31-2023 03:15 PM
    Hey Joe! If you are going to talk about Ohio, you are suppose to be over on the California thread....

    ------------------------------
    william fitch
    Owner
    www.WeAreSolar.com
    ------------------------------



  • 10.  RE: Issues With My solar System Help

    Posted 01-31-2023 10:31 AM
    The ONLY time that your panels MIGHT produce 100% of their rating is on 2 days of the year at solar noon. Depending on the SLOPE (tilt) of your panels, 99% of solar owners see on average about 80 to 90% of the rated power. In order to produce RATED POWER, the sun must be hitting the panels STRAIGHT ON.  (this is called "mutually orthogonal". For fixed panels, a good AVERAGE ANGLE is 30 to 40 degrees, depending on location. It's not the BEST for either winter OR summer, but it is a good compromize.   IN the winter when the sun is LOW on the horizon, unless you can CHANGE THE TILT, a 30 to 40 degree installation will make 70 to 80% at best during the winter.

    Your installation should NOT have taken a whole year. But with Europe and CHINA behind on production and delivery, LiFePo4 (Lithium Iron Phosphate) batteries are way behind on delivery. It's getting better, but there are still delays...

    If you system has CURRENT TRANSFORMERS (donut or square shaped parts) that connect around the two leads coming from your power meter, then it SHOULD be reporting accurately how much power you USE and how much you SEND TO THE UTILITY. If these transformers are not installed in the right locations, this could possibly be your "reporting" issue.

    Hope these bullet points help you better understand how your panels work...

    ------------------------------
    Joe Utasi
    PV Solar Consultant
    Cinci Home Solar, Keowee Home Solar, DIY Solar Helper
    ------------------------------



  • 11.  RE: Issues With My solar System Help

    Posted 02-01-2023 05:46 AM
    Run PVWatts from the National Renewable Energy Labs as I have found it to be the most accurate predicter of what a system will make.  It is fairly easy to use and appears to work around the world. PVWatts
    Nrel remove preview
    PVWatts
    Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations
    View this on Nrel >


    ------------------------------
    David Hrivnak
    Sales/Engineering
    EcoLogical (part time)
    ------------------------------



  • 12.  RE: Issues With My solar System Help

    Posted 01-30-2023 04:24 PM
    If you can provide more details on that data you are seeing in the monitoring app for production and consumption versus the consumption from your utility maybe we can help. Also, please provide details on your PV system, such as the total PV array size in kW DC, what size inverter you have in kW AC, and general location (City and state would be fine) and the array orientation, such as "mounted on 28 degree roof, facing 20 degrees east of due south" or something like that. Also, if the array is shaded by nearby trees at all, and if so, approximately what time of day the shading occurs, such as "before 10am" or "after 5pm", etc.
    For any conversation about performance, I always like to make sure the proper terminology and units are used, so that there is no misunderstanding. So here are basics.
    1. Power is an instantaneous measurement, with units Watt (W) or kiloWatt (kW).  1000W = 1kW.
    2. Energy is Power used over time, with units kiloWatt-Hour (kWh).  1 kWh = 1000W used for one hour.  Energy is what your utility charges you for.  Typically 1kWh cost between $0.11 to $0.22 depending on where you live.
    3. Production, consumption, import, and export can refer to either power or energy, depending on the context, so it is important to describe in the discussion.
    4. Production (Energy) is the number of kWh your inverter produces in a certain period, whether hourly, daily, monthly,  etc.  Production (Power) is the number of kW your inverter is producing at a certain point in time.
    5. Consumption (Energy) is the number of kWh used in your home over a certain period (hr, day, month). It can also refer to the instantaneous power being consumed in the home kW at a certain point in time.
    6. Import (Energy) is the number of kWh brought in from the utility grid to serve loads in your home over a certain period.  It can also refer to the instantaneous power flowing from grid to your home at a point in time.
    7. Export (Energy) is the number of kWh sent out to the grid from your home, which is possible because your have a solar generation system installed which is am energy source.  You can also refer to export of instantaneous power at a point in time.
    8. The numbers for the above can be known by measurements and by calculations. Production is directly measured and reported to the monitoring system by the inverter.  In order to measure import and export, sensors (usually current transformers) are located at the service conductors that connect your main service panel or main service disconnect to the utility meter, and the sensors are connected to a meter installed with the solar that use the measured current (Amps) and the measured voltage (seen by the inverter) to calculate power and energy. If the service conductors are not instrumented, then your monitoring system can not know how much energy or power is being imported from or exported to the grid.  Consumption can be calculated by adding the import number to the production number, and subtracting the export number.  For example, if in a day you imported 10kWh, and the solar produced 20kWh, and you exported 5kWh, then the energy consumed in the home for the day was 10+20-5 = 25kWh.

    I know many people know the above and I apologize for the long boring and basic explanation.  But any time there is an effort to look at monitoring data and utility bill data and use it to determine if something is not operating properly, it is important to make sure the data is complete and understood.  There are a few things that are fairly common to mess things up.  First, sometimes the CT's that do the import export measurement are installed backwards (one or both). Second, sometimes the CT values or the meter itself are misconfigured in the inverter.  

    If all the data is good, the import data should match what the utility shows for usage, as long as you are looking at the same time frame.  There should also be a second counter on the utility bill that usually is labeled "kWh out" or "export".  This counter should match the export value in the monitoring system.  The utility should charge you the difference of Import - Export, or the net usage, if you have a net metering agreement with them.

    ------------------------------
    Ken Nadsady
    AviSun Renewable Energy
    Hudson OH
    ------------------------------



  • 13.  RE: Issues With My solar System Help