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Cross-Mating PV Connectors
Oct10

Cross-Mating PV Connectors

DIY Solar Tip:  Cross-mating may not be the best idea. There are over thirty other connector manufacturers in the PV industry today: Amphenol, Weiland, Radox, Tyco, Bizlink, and SMK, just to name a few.   MC4, or Multi Contact connector for four square millimeter cable, is the standard locking system in the PV industry today. There are some manufacturers that will make the claim that their connectors are compatible with MC4. It is important to note that even though it is often possible to physically connect these, it does not mean it is an approved connection.  Though H4 connectors are often marketed as “fully intermateable with industry standard,” this interconnection is not approved by UL, or Underwriters Laboratories. Amphenol, the manufacturer of H4 connectors, has released reports TUV tests to confirm the compatibility between H4 with MC4.  In fact, these connectors have frequently been intermated with MC4 connectors, but it still does not have UL approval.  Even if both connectors have UL approval individually, connecting the two is not approved by UL. Cross-mating can cause additional problems, therefore GoGreenSolar.com does not recommend cross-mating connectors as a general rule of thumb.    Unless the connectors come from the same manufacturer, they often times have different chemical compositions, which can lead to oxidation and other complications. When different connectors are interconnected, potential gaps in the connection can also cause arcing and ultimately, failure. Just because they will “fit” doesn’t mean it is kosher. ...

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Pure Sine Wave Inverters vs. Modified Sine Wave Inverters
Jun19

Pure Sine Wave Inverters vs. Modified Sine Wave Inverters

True Sine Wave or Modified Sine Wave?Because the AC electricity from the electric grid is in the form of sine wave, the inverters we use aim to produce a current that is as close to sine wave as possible.  While modified sine wave inverters present an inexpensive alternative, there is no comparison to the clean, undistorted sine wave provided by pure sine wave inverters.   Pure Sine Wave Inverter    A pure sine wave inverter, also known as a true sine wave inverter, produces a clean, undistorted electrical output.  Depending on the manufacturer of the product, pure sine inverters have a perfect sine wave output that’s in phase with the AC grid of the utility company.  Because of the sinusoidal form, pure sine wave inverters are used for grid-tie solar systems and work for virtually any AC load.  Cotek SK3000-148, 3000 Watt 48V Pure Sine Wave Inverter Because they produce no harmonic distortions in the frequency, pure sine wave inverters allow any electronic device to function well without overheating or creating an irritating “buzz” sound.  Though pure sine wave inverters are undoubtedly the best and most versatile kind of inverter, they are more expensive than modified sine wave inverters.   Pure sine wave inverters are necessary for highly sensitive products such as digital clocks, audio equipment, and video-game consoles.  As a general rule of thumb, if you’re powering any electronics, you’ll probably want to stick with a pure sine wave inverter.  The image below displays the difference between a pure sine wave and a modified sine wave.   Modified Sine Wave Inverters   The cheaper alternative to a pure sine wave inverter is a modified sine wave inverter.  A modified sine inverter converts DC electricity to a nonsinusoidal AC wave that is “modified,” or distorted.   When an inverter produces modified sine wave, the voltage output (represented in the Y axis of the image) essentially jumps from zero volts to positive, where it plateaus and drops back to zero, to negative voltage, and then back to zero again. This is signified in the image by the squared edges seen in the modified sine wave, which is contrasted by the smooth oscillation of a voltage that is produced by a pure sine wave inverter.  The modified sine wave is a stepped waveform that is designed to mimic a true sine wave.  Because it is not a clean form of energy, modified sine wave does generate a certain kind of interference called harmonic distortion (though not as much as a square wave). Modified sine wave inverters can work for the majority of low-end appliances, but take caution when using them for your...

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Central Inverter vs. Microinverters: The Pros and Cons

So you’re installing a photovoltaic (PV) system.  Do you go with microinverters or stick with a central inverter? What does an inverter do? The task of an inverter is to convert the direct current (DC) electricity produced by your solar panels into alternating current (AC), which is needed for the overwhelming majority of electrical devices.  The AC power that isn’t used by your home is back-fed into the utility grid, hence the term “grid-tied.”Click here to learn about the basic components of a PV system. Microinverters Microinverters convert the DC electricity from each panel into usable, grid-quality AC electricity.   They attach behind individual solar panels in the array, allowing each module to operate independently instead of optimizing for the “weakest link.”  Turning the solar panels’ DC electricity into AC at a modular level means there is no single point of failure and you’re maximizing the potential output of your system. Because of this, microinverters are particularly advantageous for systems in locations that have shading or some potential coverage (i.e. dirt, snow, chimneys, etc). Microinverters also use a technology called Maximum Power Point Tracking (MPPT), which optimizes the electricity output by responding to the varying levels of light every couple of minutes. In addition to maximizing the yield of your system, micoinverters’ easy design, installation, and scalability have made them popular for residential applications.   Besides getting up on a roof and pulling a permitting, adding to your existing system with microinverters  like the Enphase M215 microinverter should be little trouble.   Each microinverter has its own IP address so it can be monitored remotely with web-based software.  Microinverters also allow for module level monitoring and comprehensive analytics, making it possible for you to view how much energy is being produced by each solar panel. The main disadvantage of microinverters is the price tag- they still cost more per Watt than central inverters.  Critics of microinverters have also made note that these sensitive electronics can exposed to elevated temperatures on the roof and there is lack of field data to go along with their 25-year warranty. Enphase Energy currently dominates the microinverter market and has been increasingly popular for residential applications, particularly in California.   Enphase offers a twenty-five year limited warranty on their microinverters. Microinverters are recommended for residential and DIY solar applications, especially if there are shading concerns or there’s a chance of expanding the system in the future. Pros: • Easy design, installation, & scalability • Maximum Power Point Tracking (MPPT) • Optimized for shading • Remote monitoring capability Cons: • Less of field data • More expensive • Relatively new technology Central Inverter Traditionally, central inverters have...

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Monocrystalline or Polycrystalline?
Jun01

Monocrystalline or Polycrystalline?

Most solar modules used today are either polycrystalline or monocrystalline, otherwise known as mono and poly. So what is the difference between poly and mono? For the sake of brevity, the difference between the two is that monocrystalline is composed of a single crystal of silicon, while polycrystalline is composed of many crystals.  Generally speaking, mono solar panels are more efficient but poly solar panels are a better use of your money. Monocrystalline Monocrystalline, which is also called mono or single crystalline, is the older of the two technologies and has been around since 1955.  Monocrystalline is still used to manufacture photovoltaic cells today and is arguably the most efficient material available. A monocrystalline solar cell is composed of a single crystal of silicon, a purity that can be identified by a dark, even coloring.  Extensive filtration is required to purify the silicon so it can be used for monocrystalline solar cells.   A single monocrystalline silicon seed crystal is slowly pulled from the high-heat molten silicon.  As it’s drawn upwards, the silicon cools and solidifies as a single ingot.  This cylindrical ingot is then sliced into thin pieces that are then cut into the cell shapes you see on a monocrystalline solar panel. Monocrystalline solar panel panels will typically have higher efficiency rates (15-20%), converting energy particularly well in low-light and lab conditions.  Mono panels will generally have higher nameplate ratings than poly.  Because monocrystalline solar cells usually have higher efficiency, these solar panels will make good use of limited roof space. The biggest draw-back is cost.  Mono solar panels come at a premium so unless you’re particularly limited on roof space, they’re not the best use of your money. Pros: • High efficiency • Good for limited space • Performs well in low-light conditions Cons: • High Cost • Sensitive to soiling and shade • More silicon is wasted in the manufacturing process Polycrystalline Polycrystalline, which is also called poly or multicrystalline, has been used since 1981.  Until recently, polycrystalline solar panels were easily identified by their solar cells that have a textured look resembling a granite countertop or shattered glass.  Most poly solar panels just have a dark blue color now. Polycrystalline cells are composed of multiple silicon crystals, which is a cheaper way to manufacture solar modules.  Polycrystalline cells are commonly made with a cast of molten silicon.  When these cells are being created, they cool faster, creating smaller crystals.  Just remember that poly means many because it has many crystals.  Because poly solar panels are easier to produce, they’re less expensive – making them the ideal choice for most people.   Though monocrystalline is still...

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Enphase M215, meet the 3rd generation of solar micro inverters

The solar micro inverter from Enphase Energy has come along way since their first generation M175 micro inverter released back in 2008. The Enphase M175 was considered the first commercially successful micro inverter followed by a successor, the Enphase M190 which was introduced in 2009. Since Enphase Energy began selling the M175 to date they have shipped more than 500,000 micro inverters making their product one of the most highly sought after solar inverter by customers. Say hello to the third generation of the solar micro inverter by Enphase Energy, pictured above the Enphase M215 will be released in early June 2011 and will be a game changer in solar inverter market by not only delivering better performance and simplified installation but is now backed by a 25 year limited warranty! One of the key improvements with the new Enphase M215 micro inverter is its innovative cabling system, which offers the benefits of a 12AWG trunk cable which bumps up the number of micro inverters that can be on a single branch circuit up to 17. The Enphase M190 can only support 15 micro inverters per branch circuit. The Enphase M215 is rated at 215 AC Watts which will allow the new inverter to be compatible with high power output 60 cell solar panels such as 250 watt and 260 watt rated solar panels. Mechanically, the Enphase M215 offers faster mounting through its single-bolt design, unlike its predecessors the Enphase M190 and M175 required two bolts to fasten each micro inverter to the rail. check out the video below, what do you think about the new Enphase M215 micro inverter by Enphase Energy? Will micro inverters phase out central string inverters and be the new standard in the solar industry? what do you...

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installing solar panels on a spanish s-tile roof

Installing solar panels on Spanish S-Tile or Curved Tile can be one of the most difficult roof tops to install solar panels onto. See solar racking components for an s-tile roof ? These types of tiles are very popular in California and the west coast in general and have a tendency to be very delicate. Many professionals compare getting around on a Spanish S-Tile roof to walking on egg shells because many curved roof tiles will break when you walk on them incorrectly. After you get around the challenges of properly walking on a curved tile roof to minimize tile damage, it’s imperative to have a roof flashing system designed specifically for this typf of roof style. We recommend the Quick Mount PV Curved Tile Flashing with Mounts Check out the video below of how the Quick Mount PV Curved Tile Flashing System in 8 easy steps will help you install solar panels minimizing the risk of developing a leaky roof in the future. What do you think about Quick Mount PV Curved Tile Flashing with...

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