Solar Industry News

Guide to Solar Panels and Solar Inverter Equipment Selection

With so many solar panels on the market, what's the best choice for your home? The experts at ReVision Energy aim to make the decision easy for you.

We've been installing solar electric (also, photovoltaic, or PV) arrays in Maine, New Hampshire, and Massachusetts since the early 2000s, when solar panel sizes were very modest and systems were only suited for remote locations where grid connections were not possible. Now since solar panels have gotten much more efficient - and dropped in price by over 75%! - you can power your entire home with solar panels.

While solar technology continues to improve by iterations, the core components have not changed much, and, while the finer points are quite detailed, the basic concept is simple. Grid-tied solar arrays need solar panels and one or more inverters .

Solar Panels

Vassalboro Maine Solar WeidNearly all solar electric modules sold in the United States are crystalline silicon modules (cSi), a form of modules that consist of rigid silicon wafers (which may be 'poly' or 'mono' crystalline - referring to the process by which they are manufactured and grade of silicon from which they are cut) housed in a weatherproof enclosure (tempered glass and aluminum).

All electronics are soldered to a backing board and positive and negative electrical outputs allow the module to be connected to others in a string. This is the same basic design of solar collector that has been used since the 1970s.

We frequently hear about upcoming future generations of PV (everything from thin film to building integrated PV) however we strongly feel that cSi modules remain the right choice for the New England market. Solar modules need to endure decades of abuse from wind, snow, and hail, and we know that cSi modules can do that. With over 100,000 modules in the field, we can say that roof leaks and module failures are nearly unheard of.

There are a variety of choices in solar modules today. Nearly all reputable manufacturers will offer a 25-year power production warranty (guaranteeing output of 80% over 25 years, though people have found collectors from the 1970s that still produce 100% of their rated power today). The better manufacturers will also offer at least a 10-year aesthetic warranty, which covers defects in the look of the collector that do not affect performance. Both REC and Q CELL, the companies we partner with for our panel offerings, bring to market high-quality, high-efficiency solar panels that will serve our customers for years to come.

Our team that procures modules have over 50 years combined experience in the solar energy industry and scrutinizes manufacturers and their products over a wide range of factors including: performance, build quality of the product, aesthetics, capitalization of the manufacturer (i.e. will they be around 20 years from now to honor a warranty should it be required), product availability, and price. We make large product acquisitions with our partners in the Amicus Solar Cooperative when possible such that we can pass through volume savings onto you.

Know that any proposal received from ReVision Energy includes modules that any member of our company would be proud to install on their own roof.

Solar Inverters

Dunne Pika Energy Island Harbor WebPictured above: Solar Champions standing in front of their Pika inverter system.

Other than modules, the other major component of a solar electric installation is the solar inverter(s), a piece of electrical equipment that generates grid-compliant alternating current (AC) electricity from the direct current (DC) electricity produced by the solar panels. It is responsible for allowing the electricity from the solar modules to flow and ensuring that power is clean (from an electrical perspective) and able to interact with the grid.

Ground Mount InvertersModern grid-integrated inverters feature a suite of performance-enhancing, safety, and reliability features. For example, the modern range of SMA inverters features dual multi-point power tracking (MPPT), a transformer-less design, and optimizations that make them much more shade-tolerant than predecessors (obviating the need for micro-inverters in a number of situations).

New fire codes are requiring increasing module-level controls, and in those situations our preferred solution is generally is the SolarEdge inverter system with DC Optimizers on each inverter. This system claims nominally better solar harvest (because of the optimization on the module level) though for simplicity's sake and reliability we tend to prefer single string inverter installations when feasible. Micro-inverters and other module-level electronics have become very trendy, but we have experienced much higher failure rates with this new equipment (which also costs more) than the rugged, reliable string inverters from manufacturers like SMA.

Data Monitoring

SMA Webbox Data Monitoring DashboardPictured above: dashboard for a live PV installation (at our office in Portland, ME)

Solar PV is an extremely reliable technology, but truth is, it's also really fun to see what's happening during a sunny day and to track a system's progress against its modeled performance. While all inverters feature some sort of read-out on a their display, most systems offer web-based data monitoring either for free out of the box or for a nominal add-on fee. An internet router at your home with ability to add a wired connection is required.

The data monitoring package looks a bit different for each manufacturer, but general features include daily and historical tracking of array performance, cumulative stats, a website and often also a mobile application.