Old SMA Inverter Stand Bys: The Sunny Boy and Windy Boy Inverters
When shopping for an SMA inverter these are the specifications that will guide you. As you may have guessed efficiency is the overriding factor when it comes to picking an inverter. Of course all inverter manufacturers want you to buy their product and tend to tout peak efficiency which is misleading. Peak efficiency only occurs when the inverter is fully loaded (getting its max input from your solar panels. What you really want to see is a SMA inverter that has high efficiency over a variety of factors such as the temperature that effect it, the inverter’s output load and its input power. You also want one with modular circuitry. This will allow you (or your serviceman) to easily troubleshoot or cheaply replace parts right inside your home.
Here are some important specs you need to be mindful when choosing an SMA inverter.
CEC Rated Power output: this is the maximum wattage the inverter outputs and is affected by temperature change.
Maximum recommended PV input power: Tells you the acceptable high power limit your inverter can accept from your solar panels. If you exceed this rating your inverter efficiency degrades. This spec will tell you how to match your solar panels output to your inverter.
PV Start Voltage: This is the starting voltage at which the inverter starts to produce electricity. A real factor when the sun first rises and is setting. You want to squeeze as much time out of your inverter as possible. This important spec basically tells you the overall efficiency of your system.
SMA of Germany make the Sunny Boy and Windy Boy solar panel inverter lines, and has been doing do since the mid-90s, so like Fronius, they are very good at what they do. SMA revamped nearly their entire Sunny Boy America models in 2007 to ramp up performance, releasing higher and lower end units for a total offering of 700, 1,800, 3,000, 4,000, 5,000, 6,000, and 7,000 watt options.
The 3,000 through 7,000 watt models feature an auto DC disconnect proportional cooling fans and a 4-circuit string combiner that provides better energy efficiency at these higher power load levels. 5,000 through 7,000 watt units also come with a built-in AC disconnect as well. That saves you having to install multiple electrical boxes and makes for fast, user-friendly, simple installation that has made the Sunny Boy solar power inverters an American favorite.
Regardless of size, every Sunny Boy is covered with a powder-coated, stainless steel enclosure that can be used outdoors or in, but prefers being outside. Their bright red color scheme was not very environmentally-friendly, so they have tanked that in exchange for a universally acceptable beige look. The display board is mounted on the inverter, and shows cumulative watts produced daily, since installation, and any error codes or other information it deems important.
As with the above companies, SMA offers web and remote monitoring for up to the minute information, and every Sunny Boy solar power inverter is FCC compliant as well for radio noise levels. 10 year warranties are standard, and cost runs from a miserly $.60 to $1.00 per watt. To get those super low $.60 per watt prices, you have to buy one of the larger units, but all Sunny Boys are priced inexpensively in regard to production. With a CEC efficiency rating of 95 to 96%, they lead the industry.
Appropriately named Windy Boy, SMA has developed a solar inverter for wind turbine use. These are the only UL1741-certified inverters made for wind turbines, and any of the 3,000 to 7,000 watt Sunny Boys can be software configured to work as a Windy Boy. However, software must be precisely matched to the turbine it powers, so you will only see Windy Boy software sold with the turbine it has been created for. Also, extra “control hardware” is needed for periods when the wind is not blowing to keep everything working properly. SMA has also released a cool battery-based solar power inverter that can work in concert with emergency and off-the-grid direct-intertie units.
Typically the price per watt is about a $1.00 or less so no matter which SMA inverter you pick, be sure to get one with a 10 year warranty. It should be at least 93% efficient. If you stick to these pre-requisites your intertie solar home system will be controlled by the best solar power inverter money can buy.