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The Best Solar Inverters of 2015: A Comprehensive Guide

Solar photovoltaic (PV) technology has advanced by leaps and bounds over the past decade. Solar panels are more efficient and affordable than ever before, allowing more and more homeowners to slash their electricity bills by generating their own clean, green power. However, solar panels are only one part of the equation. To actually make use of the electricity your panels produce, you need a critical component called a solar inverter.

As a computer and solar energy enthusiast, I‘ve watched solar inverter technology evolve rapidly in recent years. Leading manufacturers are constantly innovating to make their products more efficient, reliable, and feature-rich. If you‘re in the market for a solar PV system in 2015, you‘ll be amazed by the cutting-edge inverter options available to you. But with so many choices, picking the best solar inverter for your needs can seem overwhelming.

Don‘t worry – I‘m here to help break it all down for you. In this comprehensive guide, I‘ll highlight the top solar inverters of 2015 and explain the key factors you should consider when making your selection. Whether you‘re a solar novice or a seasoned pro, by the end of this article you‘ll be equipped with the knowledge to choose the optimal inverter for your PV system. Let‘s get started!

Solar Inverter Basics: What Are They and How Do They Work?

First things first – what exactly is a solar inverter and what does it do? In simple terms, a solar inverter is an electronic device that converts the direct current (DC) electricity generated by your solar panels into the alternating current (AC) electricity used by the appliances and devices in your home or business.

You see, solar panels produce DC power, but most electronics and appliances are designed to use AC power. That‘s where the inverter comes in. It acts as the gateway between your solar panels and everything that consumes electricity in your home or building. The inverter not only converts the current, but also regulates the voltage and frequency to match the grid supply.

Without an inverter, the energy collected by your solar panels would be unusable. So while the panels may be the most visible part of your PV system, it‘s really the inverter that functions as the brains of the operation. The inverter is what enables you to power your lights, charge your phone, watch TV, and keep your fridge running, all with the free energy from the sun.

Key Factors to Consider When Choosing a Solar Inverter

Okay, so we‘ve established that inverters are important – now how do you go about choosing one? While it may be tempting to just go with the cheapest model, there are several factors you should weigh to ensure you get an inverter that will perform optimally with your panels and meet your long-term energy needs.

Here are the top things to look at:
Power Output – Inverters come in a range of power ratings, from a few hundred watts up to tens of thousands of watts for commercial-scale systems. You need to select an inverter that can handle the maximum power output of your solar array. Don‘t undersize it or you‘ll limit your system‘s production.

Efficiency – Not all of the DC electricity flowing into your inverter makes it out the other side as AC power. Some of it gets lost as heat during the conversion process. The less energy lost, the more efficient the inverter. Always look for an inverter with a high efficiency rating – preferably 96% or greater.

Reliability – Your inverter will be working hard day in and day out throughout the 25+ year life of your solar panels. Insects, dust, moisture, and heat are all enemies of sensitive electronics. Make sure you choose a brand with a track record for manufacturing high quality, long lasting inverters.

Warranty – A solar inverter is a significant investment, so you want to be certain the manufacturer will stand behind their product. The best solar inverters of 2015 come with warranties of up to 10 years or more. Beware of brands offering short warranties.

Monitoring – Many of today‘s leading inverters come equipped with wifi or ethernet capabilities that allow you to keep tabs on your system‘s performance via a smartphone app or web portal. This kind of 24/7 monitoring helps you identify issues and optimize your energy production and usage.

Scalability – Think ahead to the future when sizing your inverter. Will you want to expand your solar array down the road? Make sure you choose an inverter with enough capacity to accommodate add-on panels, or consider an easily expandable microinverter system.

The Best Solar Inverter Brands and Models of 2015

Now that we‘ve covered the key characteristics of top-notch solar inverters, let‘s take a look at some of the best options on the market in 2015. Be aware that solar inverter technology is evolving quickly, with new and improved models being released all the time. But as of this writing, here are some of the leading inverters for residential and small commercial applications:

SMA Sunny Boy 240-US – This reliable workhorse from one of the most trusted names in solar is a top performer. The 240-US is a transformerless string inverter with a maximum efficiency of 96.5%. Plug-and-play installation and an integrated DC disconnect make it easy to deploy.

Enphase M250 Microinverter – Enphase pioneered the microinverter and continues to lead the pack in 2015. With a microinverter system, each solar panel gets its own miniaturized inverter. This setup optimizes performance and allows for panel-level monitoring. The Enphase M250 boasts an impressive 96.5% CEC efficiency.

SolarEdge 3000 HD-Wave – SolarEdge made a splash in 2015 with the introduction of its HD-Wave technology inverter. This novel design does away with electrolytic capacitors, making the inverter smaller, lighter, cooler, and more durable. It sports a weighted CEC efficiency of 99%.

ABB PVI-3.0-OUTD-S – This inverter from leading power electronics firm ABB packs smart grid capabilities into a sleek design. With dual MPPT trackers and a CEC efficiency of 96%, it‘s an attractive option for residential systems. It also has built-in ZigBee communication hardware.

Fronius Primo 6.0-1 – Austrian manufacturer Fronius is making a strong push into the US market and the transformerless Primo line shows why. The Primo 6.0-1 can be used with a wide range of solar panels, offers a CEC efficiency of 96.5%, and features wifi and Ethernet monitoring.

While these are some of the standout solar inverters of 2015, there are many other great options out there from manufacturers like Schneider Electric, Power-One (acquired by ABB), Kaco, Chilicon Power, and Darfon. The key is doing your homework and selecting an inverter that has the right combination of performance, features, and reliability for your specific PV system and needs.

Microinverters vs String Inverters: Which Is Right for You?

We can‘t talk about the best solar inverters of 2015 without touching on one of the biggest debates in the industry: microinverters vs string (aka central) inverters. With a conventional string inverter system, multiple solar panels are wired together in a series string, and then connected to a single central inverter that converts the aggregated DC power to AC. With a microinverter system, each solar panel gets its own miniaturized inverter mounted on the back. So which way to go?

Each approach has its pros and cons that you‘ll need to weigh. String inverters have been the default choice for many years because they tend to have a lower equipment cost. But microinverters are rapidly gaining popularity because of their module-level optimization and monitoring capabilities. If one panel in a microinverter system is shaded or malfunctions, it doesn‘t drag down the performance of the whole system the way it can with a string inverter.

Microinverters tend to cost more upfront but generally offer greater energy harvest over the life of the system. They also provide more flexibility in terms of system design and future expansion. And if one microinverter fails, the rest of the system keeps humming along.

Before you make a decision, I‘d advise talking to a few solar installers to get their take on which approach makes the most sense for your property and budget. The experts at Enphase, the top microinverter manufacturer, and Tigo, which makes optimizers that can be used with string inverters to provide some microinverter-like features, are also great resources to consult.

Tips for Sizing and Installing Your Solar Inverter

We‘ve covered a lot of ground on the different types of solar inverters and their key features. But how do you go about actually sizing and installing one for your PV system? Here are a few tips to keep in mind:

Inverter Sizing
As I mentioned before, you want to select an inverter that can handle the maximum power output of your solar panels. But you don‘t want to dramatically oversize it either, as that would be a waste of money. To determine the right size, you‘ll need to know the power rating of each of your panels (in watts) and the number of panels in your array. Multiply those two numbers together to get your array‘s maximum output.

For example, if you have 20 panels rated at 300 watts each, your array‘s max output will be 6000 watts (20 x 300 = 6000). So you‘d want an inverter with a rated continuous output power of at least 6000 watts. Most solar installers will also include a DC to AC "derate factor" of around 0.8 when speccing out your inverter to account for losses from things like wiring voltage drops, module nameplate rating tolerance, and module mismatch.

Professional Installation
Unless you are a skilled electrician, I would not advise trying to install a solar inverter yourself. Inverters contain high-voltage components and connect to your home‘s electrical system, so for safety reasons it‘s best to let a professional handle the actual installation. Your installer will ensure the inverter is mounted in a cool, dry location (usually near your main AC panel) and properly connected and grounded to meet the National Electrical Code and utility company requirements.

Monitoring and Maintenance
After your inverter is installed, be sure to take advantage of any monitoring features it offers. Download the smartphone app or check the online portal regularly to keep an eye on your system‘s performance. If you notice a sudden drop in output, it could be a sign that something‘s amiss with your panels or inverter that warrants a service call. With microinverter systems, you can zero in on the exact panel that‘s having an issue.

Also don‘t forget that solar inverters have a shorter lifespan than panels – usually around 15-25 years. Whereas solar panels rarely need any maintenance, your inverter may need to be replaced at some point to keep your system running optimally. Having a professional inspect your inverter every few years is a good idea to nip any potential problems in the bud.

The Bright Future of Solar Inverter Technology

In summary, a solar inverter is the unsung hero of your solar PV system, quietly and efficiently converting the current behind the scenes to power your home. The good news is that inverter technology is advancing as rapidly as solar panel technology, opening up exciting new possibilities.

In 2015 we saw the introduction of groundbreaking technologies like SolarEdge‘s HD-Wave inverter and "smart" inverters with advanced features like built-in energy storage management, EV charging support, and grid stabilization functions. I expect we‘ll continue to see major efficiency gains and further integration of smart home energy management features in the coming years.

At the end of the day, the "best" solar inverter is the one that meets your specific budget and system requirements and comes from a manufacturer with a solid reputation for quality and customer support. Whether you opt for an innovative module-level power electronics (MLPE) system or a tried-and-true string inverter, you can feel good knowing you are making an important investment in clean energy technology.

As you explore your solar inverter options, don‘t hesitate to consult multiple resources, talk to several installers, and even visit manufacturer websites for specs and support. The more educated and informed you are, the better chance you‘ll have of getting an inverter that will keep your solar investment paying dividends for decades to come. Here‘s to positive (DC to AC) energy flowing your way!