André Mermoud

In the simulation, the lifetime is a mix of the "Static" lifetime and the ageing due to the number of cycles. The ageing due to the cycling is probaby much higher with your Lead-acid battery than for the Li-ion (6000 cycles at 80% DOD) But the Li-ion battery you have used is specified for a lifetime of 5 years in the database. Now it is extremely difficult to find datasheets for Li-Ion batteries, and still more difficult to find this information on these datasheets. However I finally found a value of 10 years for the static lifetime of this battery. You can modify this in your battery definition (page "Detailed Model parameters"). I will also update the database for a next version.

The Mismatch between PV modules in an array is a rather rough calculation, based on a statistical distributions of the parameters. The phenomenon is mainly related to the mix of different I/V curves, by calculating the addition of currents (in series) and then voltages (strings in parallel). This is not really sensitive on the exact I/V curve of each PV module, so that we may avoid recalculating the I/V curve from the one-diode model for each module. The shape of each I/V curve will be very similar for all the concerned modules. Therefore this tool uses the basic I/V curve of the reference module, and performs a "scaling" if the voltage and the current according to the individual Voc and Isc of each module.

The Bifacial model of PVsyst supposes that your system may be approximated by an "unlimited sheds" configuration. In your case, perhaps the altitudes of some trackers are not completely homogeneous, or the spacing between trackers is not sufficiently regular.

The web site of PVGIS has changed, so that the old versions of PVsyst cannot import them anymore. THe first version able to import the new PVgis data is V 6.86. Please update.

The *.SHD files are meant for internal use in PVsyst only. We don't provide any description nor ensure maintenance about these files, which have a very complex structure. You can import CAD files from diverse File formats (.DAE, .3DS, .PVC). See the help "Project design > Shadings > Near Shadings: Import "

You should use the "Power sharing" option for distributing the available Nominal power ont several MPPT inputs.

Please give some more information: - which Inverter model ? - How many strings on each input ? - Which PV module model and how many inseries ?

In PVsyst, the "1990" year is an indicator that the data are not real data fo9r a specified year. See the FAQ "How to obtain meteo data other than for 1990 ?" The Meteonorm data represent averages of at least 10 years of measurements. The period is mentioned in the data. For getting values corresponding to each year of your measured data, you should avail of the corresponding Meteorological data. You can take the ageing of the plant into account by using "Detailed Losses > Ageing" in the project's dialog. You have a tool for simulating the 15-25 operating years in the project's dialog "Advanced simulation > Aging tool". Here you may simulate your operating years with the same Meteo data, or specify a meteo file corresponding to each of your years. You can import your measured data. And even directly compare them to the simulation, using the "Measured Data" button on the main page.

We are indeed preparing a way of saving PAN and OND files in a format compatible with old versions. However in the mean time, for reading a file of V 7 in the versions >= 6.80, you should replace the line Version=7.0.6 by Version=6.80

Thank you for your perspicacity. We will correct this in a next version.

This was indeed a bug, that we have fixed but not yet published. Please don't use the axis orientation around 180°.

The horizon line is considered as negligible when all the points have a height less than 2°, and is not used/shown in the simulation. Now after several requests, we will put this limit in the advanced parameters.

OK, well noted. We will suppress this stupid behaviour in batch mode. And put an option for suppressing it also in other situations.

Yes, the Web service has been changed. Please see our FAQ "My Interactive map doesn't work",

On August 5th, 2020, the web access to the interactive map has been changed by the providers without notice, so that all PVsyst versions cannot use this service anymore. We had to publish a new version 7.0.7, as well as a version 6.88, for reading this service. Therefore the only way of getting the interactive map is to update your PVsyst program to these new versions. However please notice that this Interactive Map is a "comfort" tool, it is not necessary for creating a new site. You can do that by opening the first page "Geographical coordinates", and define explicitly the Site name, the country and the GPS coordinates. Then you import the meteo data in the same way as previously.

This is done in the "Module layout" part. You can put your modules in portrait or landscape, and attribute each string to inverters with a great variety of strategies.

In fact in this tool, we don't need the full one-diode model as the addition of I/V curves is only done at STC values. Therefore PVsyst simply performs a scaling of the I/V curve in voltage and current, with respect to the original model. This is an approximation, however probably largely sufficient for such an "uncertain" random calculation.

I don't understand well. If your customer has sent a project in a Zipped file, you have to import it by using the main menu option "File > Import projects". This option cannot return a message "This Zip file does not contain a PVsyst Workspace"

This option of mixing different orientations in a same string is indeed only possible with optimizers. However this is not yet implemented in PVsyst.

The measurement of modules temperature in a field is a delicate operation. To my mind, just gluing the sensor on the backside of the module is not quite correct. The layout of the measurement is very important. Remember that a temperature sensor always measures its own temperature ! See our FAQ "How is evaluated the Module temperature during the simulation ? ". At the end of this post you have a paragraph with our advices: "PV array temperature measurement" Now PVsyst doesn't use the Sandia or NREL thermal model. It proposes a model in which you can adjust the "Thermal Loss factor" (U-value) in order to match you measurements at best. Please read the help "Project design > Array and system losses > Array Thermal losses". NB: expressing temperature differences in terms of percentages doesn't make sense. Percentage with respect to what ? If it is 0°C, this doesn't have a physical meaning. The reference could be anything else (25°C, -273°C, etc) The only way is to express the temperature differences in terms of °C.

it is strongly discouraged to put modules of different orientations in a same string. And especially in 2 opposite orientations. This leads to very high mismatch losses (the current in the string is the current of the worst irradiated module in the string, therefore almost nothing in the morning and the evening). PVsyst doesn't allow to do that. The only way would be to use optimizers, which overcome this problem of currents mismatch. However this is not implemented in PVsyst yet.

If your original data are measured in the horizontal plane, for calculating the GlobInc, you have to use a transposition model. You can use PVsyst for that. - Import your Irradiances data file using "Databases > Import Meteo Data > Custom file". When you are here press F1 for the procedure. NB: PVsyst only works in hourly values. During the import process, it will accumulate your minutes data into hourly values. - In "Databases", open "Meteo Tables and Graphs". Here you can see a table of all your data in hourly, daily or monthly values. You can get the values "Global tilted plane", which is indeed GlobInc or POA.

The position Portrait vs Landscape only affects the electrical losses. Any other discrepancy has probaly another cause. The electrical losses may be calculated: - either using the shading mode option "According to module strings". In this case for sheds or trackers arrangement you should use "Fraction for electrical effect" = 100%. In you "landscape" case, when you have 2 strings on 2 rows, you should define 2 sub-ectangles in the tables. - or using the ModuleLayout option. In your case the rigorous comparison is not possible as the sheds width is about 4 m in 2L, and 1.6 m in 1P configuration. You should keep the GCR constant (adjust the pitch). However the IAM and transposition should be identical. You have probably something different in your layouts. By the way you should only compare the electrical losses.

For the calculation of the weather corrected PR, you need indeed the array temperature, but in hourly values. The expression proposed by the NREL supposes an accumulation/calculation with hourly values. NB: This calculation is done in PVsyst. You can get it under the variable named "Weather corrected PR", i.e. PRTemp. You can show it on the report, by using in the Report's dialog menu: "Settings > General Options > Monthly values table". Here you can choose "Weather corrected PR".

The use of Y-connectors is not involved in PVsyst in any way. With some inverter, the number of input connectors is specified. But this is not used by PVsyst. The only relevant information is the number of strings effectively connected to the input of each MPPT input. PVsyst doesn't check if this matches the number of connectors. For the use of the option "Use multi-MPPT feature", please read the Help "Project design > Grid-connected system definition > Multi-MPPT inverters: power sharing"