Mac OS X Issue - String Voltage (DC V) Not Calculating in Report

  • schmidly
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11 Feb 2015 04:32 #3064 by schmidly
Paul, I thought I would bring this to you attention as you make a list of things to fix in the new Mac OS X version of SAM. When I run the report, the string voltages under the 'Array' category on the first page calculates/shows a '0.0'. Is this an issue when you run it, too? Please advise on your thoughts.

Also, Paul I notice that the voltage/string calculations are not getting calculated correctly with you specify the desired array size. You have to manually update them based on number of inputs by inverter on the 'specify modules and inverters' section to get a correct calculation. Can you see if I'm the only one seeing/having this issue? Here's an image of what I'm talking about.

Thanks, Brian S.

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  • Paul Gilman
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16 Feb 2015 21:31 #3065 by Paul Gilman
Hi Brian,
The first issue is a bug in the report template for SAM 2015.1.30 that affects both the Windows and OS X versions. The template uses an invalid variable name for the maximum power string voltage. To fix the problem, you can replace the pv.samreport file in your SAM installation with this one ( SAMREPORT 12 KB ):

  1. Download the pv.samreport file from the link above.

  2. If SAM is running, close it.

  3. Replace the pv.samreport in the runtime/reports folder of your SAM installation: 

    In Windows, by default, the folder is in C:\SAM\2015.1.30.

    In OS X, in the Finder, control-click the SAM app, and click Show Package Contents and then navigate to Contents > Runtime > Reports. 
Be sure to replace the existing file with the one you downloaded.
For the second issue, I think SAM is working correctly, although I can't tell for sure without knowing which module and inverter you used. From the screenshot you provided: For the 10 kWdc desired array size with a 1.1 DC-to-AC ratio you specified, SAM chose 1 inverter, because its capacity is 10 kWac. Because the inverter you chose (on the Inveter page) does not have data for the operating voltage limits (maximum DC voltage, minimum MPPT voltage, and maximum MPPT voltage -- note that all of those variables' values are zero), it has insufficient information to determine how many modules per string to use, so it designs a system with 1 module per string, and enough strings in parallel to achieve the desired array capacity.
Best regards,

Paul.

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