Since 1984


IEE (Institution of Electrical Engineers), SAE (Society of Automotive Engineers), SME (Society of Manufacturing Engineers) Members – Custom Solar Cell/Photovoltaic/ Solar Panel Test Equipment Integrators

May We Help You?


*Required Fields

First Name*

Last Name*





Attach a File:

Enter Code*



Cognex, Keysight Technologies, and Vector CANTech Partners - Test Equipment Integrators



Solar Cell Test Equipment— PV Testing Equipment — Solar Panel Test Systems

Photovoltaic Testing for Research and Development, DV, and Manufacturing

Freese Enterprises (FEI) can create custom solar/photovoltaic test equipment using the various types of PV test and measurement instrumentation from our industry leading partners such as Agilent Technologies. The goal of achieving ever increasing solar cell efficiency and reduced cost demands accurate, repeatable, fast, and reliable test results. The research, design, and development work necessary to achieve superior performing, highly manufacturable solar cells, modules, and arrays requires this high performance test equipment.

FEI can decide what instruments fit where and what common PV test configurations to use with a focus on high power PV test. We can integrate an entire test system together for your application after analysis and optimization of parameters including: temperature considerations, fixturing, lighting, and the delicate balance of cost, speed, accuracy, and reliability. FEI recognizes the potential impact of the PV market and will continue to invest in our expertise, test and measurement solutions for continued collaboration with the solar/PV market.

  • PV test and measurement solutions
  • High power PV test solutions
  • Photovoltaic test system integration
Solar Panel Testing Equipment
Solar Cell Test Fixtures
Automated Solar Test Equipment Solar Cell with Heat Sink

Photovoltaic Test Areas of Focus

Solar Cell, Solar Module & Solar Array Testing - Components and Specific Devices

Common Measurement Needs for Photovoltaics

  • Open-circuit voltage (Voc)
  • Short-circuit current (Isc)
  • Maximum power output of the cell (Pmax)
  • Voltage at Pmax (Vmax)
  • Current at Pmax (Imax)
  • Conversion efficiency of the device (η)
  • Fill factor (FF)
  • Cell diode properties
  • Cell series resistance
  • Cell shunt resistance

Solar Cell DC Circuit Equivalent

  Solar Cell I-V Curves

Common Solutions for Photovoltaic Test Equipment Customers

Testing a PV Device:
  • Illuminated requires quad 4, sink current
  • Dark requires quad 3, source reverse current
  Four possible quadrants
for power instrument
Instrument Illuminated Dark Power Range Cost Per Watt Accuracy Notes
Four-quadrant DC source Yes Yes Low High High There are some higher 4-quad but accuracy limited
Two-quadrant DC source Yes No Medium Medium Medium Requires polarity reversal switching for dark meas.
DC Electronic Load Yes No High Low Medium Can handle high power so good for panels and CPV
DSinglequadrant DC source No Yes High Low Medium Can handle high power so good for panels and CPV

Choices for High Power PV Test (>5A)

Solar modules, panels, large area cells, and concentrated PV

Three power product instrumentation choices:
  • Two quadrant supplies
  • Four quadrant supplies
  • DC electronic loads
  Solar/PV Test Instrumentation
Solar/PV Test Instrumentation

Using Two-Quadrant Power Supplies

For High Power PV Test

Three power product instrumentation choices:
  • Two-quadrant supply can source and sink current
  • Fairly low cost and widely available
  • Voltage step and measurement speed can be too slow for manufacturing
    • Add external analog programming and measurement
  • Illuminated and dark I-V curve measurements with added hardware (discussed next)
  • If you just need illuminated I-V measurements, use DC electronic load

Using Two-Quadrant Power Supplies

Illuminated and Dark I-V Measurements with 2-Quad Power Supplies

Configuration 1: Supply with switching
  • Discontinuity at 0V
  • Requires switching
  • Supplies like the 6631B are available
    with polarity reversal relays

  Configuration 2: two supplies in anti-series
  • No discontinuity at 0V
  • Requires two supplies

Using Four-Quadrant Power Supplies

For High Power PV Test

Three power product instrumentation choices:
  • Provides illuminated and dark I-V measurement capability with no discontinuities
  • If you just need illuminated I-V measurements use DC electronic load
  • Access to all 4 power quadrants giving you ability to perform less common tests
  • At these current levels 4-quad supplies are typically slow and have poor measurement accuracy
    • Need external instrumentation for control and I-V measurements (discussed next)

Using Four-Quadrant Power Supplies

For High Power PV Test

At these current levels 4-quad supplies are typically slow and have poor measurement accuracy
  • Need external instrumentation for control and I-V measurements

Using DC Electronic Loads

For High Power PV Test

  • Electronic loads are a great solution for high power PV testing because they can sink a lot of current for a low cost
  • Electronic loads (eload) typically have three modes of operation: Constant Voltage (CV), Constant Current (CC), and Constant Resistance (CR)
  • CV mode for capturing the I-V curve: step through voltages incrementally and measure the current

Using DC Electronic Loads

For High Power PV Test

  • Eload specifications begin to de-rate at constant voltage levels typically < 5 V
  • At 0 V, no current can flow into the eload
  • Add a simple power supply in series with the eload to maintain optimum performance

The need for a boost supply adds expense and complexity to the configuration,
but as you will see next it also expands our test capabilities…….

Using DC Electronic Loads

For High Power PV Test

  • In the figure, we removed the eload from the circuit and replaced it with a short
  • We are left with a power supply connected in reverse bias with the PV cell
  • If we make the power supply variable, add voltage and current measurement capabilities we have a reverse bias I-V curve measurement setup

Making illuminated and Reverse Bias I-V Curve Measurements with an Eload and Boost Supply

3 ways to do it with an eload and boost supply

  • Configuration 1: Shorting the eload out of the circuit
  • Configuration 2: Sweeping both the eload and boost supply
  • Configuration 3: Using a fixed boost supply and sweeping the eload

National Renewable Energy Laboratory PV Test System

Outdoor Test System for Prototype CPV and Solar Panel Testing

Outdoor Solar Test System for Prototype CPV and Solar Panel Testing

Typical Integrated Photovoltaic Test System

Typical Integrated Solar/PV/Photovoltaic Test System
Switch and measurement or redundant DMMs/DAQ
  • I-V curve measurement
  • Temperature measurements
  • Calibrated reference cell measurements to measure irradiance

  • A switch and measurement unit avoids the need for costly redundant measurement equipment
  • Light sources have low frequency noise so using multiple DMMs/Daq units with common trigger ensures each measurement is made at a common irradiance level

Basic System Configuration Questions

  • Type of system (Laboratory, Design/Product Validation, Environmental or Production)
  • Number and type of measurements to be made
  • Measurement speed and accuracy
  • Environmental considerations (chamber or real world)
  • Test cycle time
  • Calculation requirements

Identify specific test system issues that may require specialized system integration approaches

  • Thermal stresses on part and fixture and test equipment (material selection, thermal expansion considerations, stand alone remote data collection)
  • Effects of noise on system design (galvanic issues, synchronous detection requirements for irradiance measurements)
  • Sensor connection requirements (strain, 4 wire, thermal couple)
Connection Issues
  • Test system design and influence on test results
Sensor Issues

Important questions to consider when selecting a solar test equipment integrator

  • Is specialized test fixture expertise required?
  • Are there specific or unusual test interface or reliability requirements?
  • Are there specialized thermal testing requirements?
  • Are there consequences to inadequate or false "failure" detection?
  • Are there MTBF (Mean Time Between Failures) or MTTR requirements (Mean Time to Repair)?

About Us | Solar Cell Test Equipment | Systems Integration — Software/Hardware | Test Fixtures | Partners | Custom Test and Measurement Equipment | Automated Test Equipment | Contact Us

Some of the types of test equipment and test system projects that Freese Enterprises can assist you with:

Keysight Technologies test instruments, assembly and test equipment, auto test equipment, automated test design, automated test equipment, automated test systems, automated testing equipment, automatic test systems, automotive test equipment, battery test equipment, circuit test equipment, custom test equipment, electrical testing devices, electrical testing equipment, electronic component testers, electronic test benches, electronic test equipment, electronic test fixtures, electronic test systems, electronics test equipment, Vector CANtech instruments, functional test fixtures, high voltage test equipment, high voltage test fixtures, inspection fixtures, instrument test equipment, laboratory testing equipment, manufacturing test equipment, material testing machines, material testing system, measurement equipment, measurement test equipment, mechanical test equipment, mechanical test fixtures, medical test equipment, pcb test fixtures, pneumatic fixture, rf test equipment, rf test fixtures, solar module, solar array testing equipment, solar cell test and measurement equipment, photovoltaic test and measurement instruments, test electrical equipment, test electronic equipment, solar test fixtures, industrial testing equipment, PV/photovoltaic cell testing systems, solar panel test equipment, data acquisition systems, production testing equipment, mobile test equipment, custom instrumentation control units, durability testing equipment, automated vision systems, automatic inspection machines, automatic machine vision system, automatic machine vision systems, industrial machine vision, machine vision systems, machine vision system integrators, vision test machines, vision testing equipment, vision testing machines, Cognex vision system components, production testers