Inverter Selection

by Anders Alexander


Why Does Bloom Solar Energy prefer to use SMA and SolarEdge inverters out of all the great options out there?

First off, let’s review how the inverter is the brain of the solar system. Solar panels produce DC electricity and the inverter turns it into AC so our homes can use that electricity. The inverter also handles system safety and rapid shutdown, gives monitoring info that can be viewed online, manages the battery if it's added to the system, and depending on the inverter it limits the effect of shade on the panels. The panels produce the electricity, but the inverter does everything else.

Here are resources for you to do your own research:

SolarEdge warranty

SolarEdge spec sheet

SMA warranty

SMA spec sheet

At Bloom Solar, we want to be installing the best equipment, and we want to have each design be appropriate for the site and customer. We accomplish this by having a consultative sales approach where we talk customers through their options. So, let’s review why Bloom Solar prefers to use SMA and SolarEdge inverters.

In solar, there are a ton of numbers. Those numbers don’t lie and you can find the numbers you need on an “inverter spec sheet.” For example, the efficiency of the inverter matters. Any inefficiency means that the panels are sending electricity to the inverter and some small amount is not getting through. SolarEdge HD wave inverter is 99%, for Enphase microinverters it's 96.5%, and for SMA it’s more like 96%. You can see quickly here in the numbers that SolarEdge has the edge on squeezing the most juice of the system, but for SMA there are other strengths that make it a desirable unit to purchase.

Reliability and warranties are very important in solar. For SMA their product has only one reliable box that has a low failure rate, and it comes with a 10-year warranty that can be extended for another 5 or 10 years. Having the inverter reduced down to one reliable box has a lot of advantages, like the ease of troubleshooting issues and ease of installing new parts. 

SolarEdge has a central box too, and it also has a component called an “optimizer” attached to each panel. Having more parts, and putting those parts on the roof, naturally creates a higher fail rate for the system as a whole. The SolarEdge warranty starts out at 12 years to give you longer coverage, and it can be purchased up to 20 or 25 years. Keep in mind that even if SolarEdge provides a new part in year 15, you will still have to pay a little bit to get that new part installed.

Shade is a big issue in Washington, and while the site has to be chosen appropriately there still might be some shade, and the inverter can help. SMA is a simple inverter system where we group panels together and when shade covers one panel in the group it reduces the production of all the panels in the group. This shading effect for SMA is reducing over time with better panels and better strategies within the SMA product to deal with the effect of shade. SolarEdge, on the other hand, has an “optimizer” unit attached to each panel and is able to isolate the effect of shade down to only the panel that has the shade on it. With SolarEdge the optimizers can increase the annual performance of a system. Depending on the amount of shade your site gets you might need SolarEdge to get sufficient production, or you might be able to get away with the more simple SMA system. 

Extra features are new to inverters, they used to just convert electricity from DC to AC. One new feature that SMA provides is the ability to get power from the system when the grid is down and without using batteries. SMA created the Secure Power Supply to pass on a little power when the sun is up and the grid is down, check out their explainer video here. SolarEdge is coming out with some new features soon as well including direct to vehicle charging so the power can go directly from the panels to an electric vehicle.

A ground-mounted solar project has a lot of benefits and SMA is a really good inverter to use. When placing a ground mount it is typically located where there is no shade so the more simple SMA is appropriate. Then, on a roof mounted system there is a requirement called Rapid Shut Down, for SMA it takes an extra product to comply, but with a ground mounted system that extra part is not needed and SMA is the lower cost inverter option.

Monitoring is important and both SMA and SolarEdge come with internet-based monitoring so you can view the system on your computer or smartphone. SolarEdge does have the edge here again though because they have panel level monitoring, and SMA just reports on groups of panels or the system as a whole. Both monitoring systems will allow you to manage your system, and while SolarEdge might give you more detailed info to view you will be able to manage your system well with both monitoring types.

Batteries are the future for solar, they are still expensive but their price has come down enough and the products have developed enough that adding batteries to solar is possible. SMA and SolarEdge both have inverters that can manage a battery, SMA has the Sunny Island, SolarEdge has the StorEdge. There are some main differences that might influence which battery-based inverter system to use. The SMA Sunny Island has an extra input for a generator so you can charge up the batteries, but you’ll now have 2 inverters to run the system and that comes with a good cost. For SolarEdge they just add the StorEdge system onto their existing inverter and that makes it less expensive to add batteries. There are a lot more details to go over here and you can see that adding batteries to a system opens up the conversation quite a bit to become more complex.

The goal of the sales process at Bloom Solar is to inform you, the customer, so you can make an informed purchase of a solar system that matches your particular home and set of preferences. By signing up for a free quote today through our website Bloom Solar will talk you through your options to create a custom system for you and your home.