In a recent update, we promoted the Silfab Elite 410 W BG solar panel because it is so beautiful that we think it should become part of the building’s architecture.

How can a 410 watt solar panel work with YouSolar’s 380 watt STEP™ micro-converter?

The 410 watt Silfab Elite produces 305 watts at normal operating conditions (“NOC”). This derating in real-world operating conditions is typical for silicon solar panels. For example, the 410-Watt REC Alpha Pure-R panel states that it produces 312 Watts at NOC. Within the uncertainties of the specifications, these are the same NOC figures.

The STEP Micro-converters 380 watt rating has plenty of power for panels that are nominally 400 watt or more because, under real-world operating conditions, these panels are derated 25% from their nameplate power.

The STEP™ Micro-Converter is a panel-level DC-DC converter that steps up each solar panel’s potential to 380 volts DC. It has a maximum power of 380 watts. (NOTE: The similarity of the voltage and power rating are coincidental.)

But what if panel power increases? Will YouSolar have to build a more powerful micro-converter?

The practical physical size of solar panels and the efficiency of silicon photovoltaic cells put an upper limit on the power of residential solar panels. Let’s say that is about 500 watts. Then a 25% derate results in an actual power of 375 Watt. But even that maximum output is achieved only during a few hours of the year — no problem for the STEP.

Even if solar panel power increases to 500 watt panel, YouSolar’s 380 watt STEP™ micro-converter will require no power increase.

But it gets even better. If real panel power exceeds the STEP’s 380 watts, then the STEP micro-converter simply clips that excess power. It would not overload. We use that feature to our advantage when we optimize solar arrays for winter sun. We plan to cover this topic in a future update.