Application Notes/Articles

I-V Curves and Performance Verification

Field Applications of I-V Curve Tracers (SolarPro Magazine) This article provides an excellent introduction to I-V curve tracers for use in commissioning, auditing and troubleshooting PV arrays.

Interpreting I-V Curve Deviations (SolarPro Magazine) Poor PV source performance hurts the bottom line. Fortunately, performance problems show up in the measured I-V curve. This article describes the six ways that measured I-V curves can deviate from normal curve shape, and provides an Array Troubleshooting Flowchart to help you identify the most likely causes.

Commissioning for PV Performance--SunSpec Alliance Best Practice GuideThis Commissioning Guide outlines methods to use during commissioning to characterize and maximize PV system performance.

PV Analyzer Startup Training (Webinar slides)Slides from the expert training on how to effectively and safely use the PV Analyzer. Topics include PVA hardware and software, as well as PV module and system performance concepts. Voice-over version coming in June.

Building your Array Tree in Array NavigatorThe PV Analyzer user saves the I-V curve measurement of a PV string by just touching the corresponding branch of a graphical 'array tree.' This Application Note describes use of the Array Navigator, including the Symmetrical Tree Builder, that lets you quickly customize your array tree and name the layers to exactly match the engineering drawings. This improves the reliability of the measurement process in the field, and assures that the measurement results will be correctly labeled in your final report.

Measuring I-V Curves in Harnessed PV Arrays Harnessing is a strategy for reducing the number of combiner boxes and associated feeder runs, as well as the number of string home run conductors, by paralleling strings upstream of the combiner. This note describes two strategies for setting up your Project in the PVA Analyzer software for measuring and evaluating the performance of harnessed arrays.

I-V Curve Tracing of High Efficiency PV ModulesCare must be taken when selecting what I-V curve measurement architecture to use when measuring high efficiency modules and strings. This app note discusses the challenges and how the Solmetric PV Analyzer avoids the pitfalls.

Dealing with Missing PV Module Performance ParametersThe Solmetric PV Analyzer compares the measured I-V curve with the an expected I-V curve shape derived from 17 module-specific PV module performance parameters and the current irradiance and temperature. Here are the steps to take if your PV module is not one of the 60,000 modules currently in the PVA equipment database, or if one or more parameter values is missing.

Mounting SolSensor on a TripodTripod mounting is useful in situations where I-V curve tracer's point of connection is out of wireless range of the SolSensor due to distance or obstructions (i.e. bad line of sight). Here are the steps and the needed equipment.

Guide to Interpreting I-V Curves Background on DC measurement techniques for testing I-V Curves of PV modules, strings, and arrays. Includes a description of ideal performance and effects of impairments, such as shading, series resistance, loose connections, etc. Also includes description of models that predict performance and comparison to measured results.

Winning PV Contracts with I-V Curve Testing Performance testing tools and processes can be a differentiating factor for PV integrators and can communicate expectations of quality to suppliers and customers. This white paper provides language that you can use to your advantage in your proposals, including 1) a description of the business benefits of I-V curve tracing, and 2) contractual language specifying the use of I-V curve tracing.

I-V Curve Tracing Exercises for the PV Training Lab This Application Note describes a series of outdoor PV training lab exercises that use the I-V curve tracer to show how PV arrays really work and how to troubleshoot problems down to the level of the individual PV module.

Checklist for Preparing to Test PV Arrays PV arrays can be tested very efficiently if the right preparations are in place. This checklist can help you get the most out of your time in the field.

Shade Measurements and PV Design

Best Practices for SunEye210 Shade Measurements (app note) Accurate estimates for solar production require accurate shade measurements. Getting accurate and consistent shade measurements requires the right tools and the right process for data collection and reporting. This document is intended to describe best practices in the measurement of shade, and to facilitate a common approach within an organization and across multiple organizations. It includes details about using the user interface of the SunEye-210 as well as the process for how and where to make the measurements on site.

Assuring Compass Accuracy in the Solmetric SunEye (app note) This app note will help you get the most out of your SunEye-210 compass.

Residential Solar Site Measurements: New Developments (SolarPro Magazine)This article addresses recent developments and trends in residential solar site measurements, including tools and best practices for measuring roof dimensions and shade, estimating system performance, and evaluating the impact of solar leasing options and performance guarantees on site measurement approaches.

Using Solmetric SunEye results in California’s solar electric incentive programs (app note) This application note describes the details of how to extract the SunEye data and input it to either the CSI Calculator or the NSHP Calculator. The Solmetric SunEye measures both solar access and obstruction elevation angles so it provides the data necessary for either calculator.

Understanding orientation issues in solar site analysis (app note)The Solmetric SunEye provides complete solar access and shade analysis in an integrated hand-held tool that can help optimize solar panel system design and installation. This note describes how to measure and account for orientation when using the SunEye.

Understanding the Solmetric SunEye (app note)A basic introduction to solar access and shade measurements using the Solmetric SunEye. Also included are descriptions of new features for measuring on metal roofs and with an extension kit.

Solar Site Evaluation: Tools and Techniques to Quantify and Optimize Production (SolarPro Magazine)Improve system performance and energy harvest projections with a thorough site evaluation that includes shading analysis and insolation quantification.

Align with Compass / Align with Target (app note)The normal way of aligning the SunEye is to align it using the compass to point South. "Align with Target" mode provides an alternative alignment to a reference azimuth using other visual information available at the site.