Category: Enphase

The Effect of Shade on Solar Panels

The Effect of Shade on Solar Panels

Just a little shade can affect a solar panel ‘s power output dramatically. Diffuse shade from a “soft” source, like a distant tree branch or cloud can significantly reduce the amount of light reaching a solar panel’s cells. “Hard” sources stop light from reaching solar cells, such as debri or bird dropping sitting on top of the panel. If even one full cell is hard shaded, the voltage of a solar panel drops to half in order to protect itself. If enough cells are hard shaded, the module will not convert any energy and will, in fact, become a significant drain of energy on the entire system over time.

Partial Shading of Cells on a Solar Panel
Partial cell shading that reduce solar panel power by half.

Partial shading of even one cell on a 36-cell solar panel will reduce its power output. Because all cells are connected in a series string, the weakest cell will bring the others down to its reduced power level. Therefore, whether half of one cell is shaded, or half a row of cells is shaded, the power decrease will be the same and proportional to the percentage of area shaded, in this case 50 percent.

When a full cell is shaded, it can use energy produced by the remainder of the cells, and trigger the solar panel to protect itself. The solar panel will route the power around that series string. If even one full cell in a series string is shaded, as seen on the right, it will most likely cause the module to reduce its power level to half of its full available value. If a row of cells at the bottom of a solar panel is fully shaded, the power output may drop to zero. The best way to avoid a drop in output power is to avoid shading whenever possible.

A solar panel affects an array in much the same way a single cell affects a solar panel. In a centralized inverter system, where panels are strung in series, if only one of the solar panels is shaded in an array, the rest of the solar panels’ output diminishes.

When choosing a grid tie solar power system for their home or business, folks often prefer the tried and true technology of a centralized inverter systems. And the price tag on these is pretty good. When you consider the effects of shading, however, it’s easy to understand how microinverter and SolarEdge systems have become so popular.

While using different technologies, both SolarEdge and Microinverter systems allow each solar panel in an array to maximize power output independently, thereby maximizing a system’s power generation. If one solar panel is shaded in either of these systems, the rest of the array’s panels can still operate at full capacity. (SolarEdge provides DC to DC power optimization for each solar panel, while microinverters provide DC to AC optimization at the module level.) Both of these systems allow solar panels to be facing different orientations giving you more design flexibility if part of your installation site is in the shade. A centralized inverter system requires panels to facing the same direction.

Read more about SolarEdge, Enphase Microinverter and Centralized Inverter Systems.


SolarEdge, the New Kit on the Block

SolarEdge, the New Kit on the Block

Wholesale Solar is now offering solar power systems using the SolarEdge Systema new approach to gridtie systems. In these new systems, SolarEdge PowerBox optimizers are paired up with Astronergy solar panels and strung to an ETL listed SolarEdge inverter.

The Solar Edge Gridtie System
In a SolarEdge System, SolarEdge Power Boxes are paired with solar panels to provide DC to DC Power optimization. Click For a Larger View.

SolarEdge Systems share some similarities to Enphase Microinverter Systems, and offer many of the same benefits. Like SolarEdge PowerBox optimizers, microinverters control the output of each solar panel with Maximum Power Tracking. While microinverters optimize DC power and convert it to AC power, PowerBoxes offer DC to DC power optimization. Compared to a traditional gridtie system, both SolarEdge and Microinverter systems offer much more flexibility when it comes to system sizing and design:

  • There is no more need for string sizing.
  • Temperature is not a factor because fixed string voltage ensures the inverter always operates at its peak efficiency voltage and prevents under-voltage power losses even on hot days.
  • Panels don’t all have to be facing the same way
  • Different string lengths can now be accommodated.
  • Solar power ratings and technologies can vary.
A Traditional Gridtie System
In a traditional gridtie system, a centralized inverter is responsible for the DC to AC conversion.

A traditional gridtie system is similar to a SolarEdge system in that it has one or more inverters responsible for DC to AC conversion for all of the solar panels in an array. Some prefer traditional gridtie systems,because the inverters are more accessible than microinverters. Others prefer to rely on a system with proven technology that has been around awhile.

Read more about SolarEdge…

Solar Panel’s Cooling Effect

Solar Panel’s Cooling Effect

San Diego, CA-  The benefits of installing  solar panels on your home go far beyond the electricity produced. According to new research by the University of California at San Diego, the shade provided by a solar panel array will actually insulate your home from heat to the point of lowering cooling costs. It is estimated that these savings will result in a 5% discount on the price of the system over its lifetime.

The Jacobs school of engineering’s research team used thermal imaging cameras to analyze the difference in heat signatures coming from roofs with and without a solar array. On average, a building’s ceiling structure with a solar array turned out to be 5 degrees Fahrenheit cooler than buildings in the direct Sunlight. One would expect the shaded roof-tops to be cooler, yet the surprise came from how much cooler they turned out to be. In one study, a building was found to experience a 38% reduction in the amount of solar heat directly hitting the roof, indicating that savings can exceed the 5% estimate in the long run.

Your solar panels essentially act as roof shades, taking the brunt of the Sun’s heat.  Air between the panel and the roof helps dissipate this heat as most solar arrays are set up on a tilt. It was found that at night, solar panels also assist in preserving heat stored in the building, being an effective insulator in the winter.

Solar panels can be fastened to most rooftops with minimal perforation or structural interference. There is a wide range of racking and mounting hardware options available, and most of them can be installed by the homeowner or a general contractor.

Enphase Starter Kit is the perfect gift.

Enphase Starter Kit is the perfect gift. you know someone who wants to get started with solar, consider giving them the Enphase 235-watt Micro-inverter Starter Kit. It costs just $594 after applying the Federal tax credits. It comes with a 235-watt Trina solar panel and an Enphase Microinverter. They’ll be able to expand their system with one solar panel and one micro-inverter at a time–whenever they’re ready. It’s the perfect gift.