If you’re looking at your monitoring app and wondering why your system isn’t generating as much as you expected, we can help put your mind at ease. The answer boils down to having different DC and AC sizes. If you’re still a little confused—don’t worry—we’ll explain what exactly that means and why the difference isn’t something to be concerned about.
What Is the Difference between DC/AC and how does it affect my system?
The main concept we need to understand is the difference between direct current (DC) and alternate current (AC). Your panels absorb the sun’s energy to produce DC. However, since DC can’t be used to power your house directly, inverters are necessary to convert DC into usable AC electricity for your home.
The numbers on your monitoring app and proposals might look a little different because your monitoring app shows you AC size from your inverters as opposed to DC size from your solar panels and proposal. The difference comes from the fact that your panels and inverter have different sizes.
Why Is My AC Size Lower Than DC Size?
DC/AC ratio is your installed DC capacity (wattage of your panels) compared to your inverter’s maximum AC capacity (power rating). Finding the perfect ratio is how we optimize your production and savings.
It’s standard to design systems with a higher or oversized DC/AC ratio to avoid under-utilizing your inverter. Whether it’s due to the time of day or weather conditions, your panels usually do not perform at their maximum capacity. Since your inverters can only convert the amount of energy received from your panels, an oversized DC/AC ratio ensures that you’re able to use your inverter’s maximum power output for a longer amount of time throughout the day.
As seen from the graph below, your panel’s peak production only occurs for a short amount of time during the day. It would not be productive to have a smaller DC/AC ratio because it would mean less overall AC output.
Reference from: Solar Power World
Why Is My AC Output Curve Flat At The Top?
If you notice your graph flattening at the top, you could be experiencing solar clipping. Solar clipping occurs when your panel’s production—the power being sent to your inverter—surpasses your inverter’s maximum power rating, causing the top to be “clipped”. This is completely normal for systems with higher DC to AC ratios and isn’t harmful to your panels or inverters.
Although it might look like you’re losing some energy at the top, a high DC/AC ratio can actually help your system work more efficiently throughout the rest of the day during low and mid-levels of production. You’ll have more energy during the early mornings and late evenings since a larger DC size means a wider overall curve, as demonstrated from the graph above.