I have a Solax X1 G4 inverter rated at 3.6 kW, and I've heard it can handle up to 200% oversizing. I'm planning to install about 7 kW of PV across two MPPTs. However, after chatting with a solar installer friend, I learned that many tend to recommend only oversizing by about 20% to avoid issues like peak clipping. But I wonder, isn't there a way to account for peak clipping in calculations? I'm curious if anyone here has experience with significant oversizing and whether it caused any problems. Also, if basic inverters allow for 50% oversizing and mine claims 200%, shouldn't that indicate it's safe?
3 Answers
Totally agree that oversizing is generally a good idea! Just don’t exceed the input voltage limits for your setup. I'm using a Growatt 3.6 kW unit and definitely wish I had more space for panels. But with proper planning, oversizing shouldn't be a problem.
From what I understand, oversizing is usually fine as long as the MPPT can handle the current. Basically, the MPPT draws current up to its maximum capacity, so you might as well install as many panels as your budget allows. Just make sure you're below the temperature-adjusted voltage limit for your strings, and keep your panel's Isc in mind. As long as you stay within those limits, you're likely to get more power during optimal hours, even if some is 'wasted' during peak generation.
Thanks for the reassurance! It makes me wonder why there are such strict oversizing guidelines if it’s generally safe.
Oversizing up to around 120% typically doesn't lead to noticeable clipping issues, but at 200%, you'll likely see clipping happen more often. It's really a balancing act of cost versus benefit. If you have space for 7 kW of panels, consider opting for a bigger inverter in the range of 5 kW, especially if you're going hybrid with batteries. Just keep your future load capabilities in mind when sizing your system.
If you can manage the costs, I would go for the larger inverter for better efficiency. Just keep everything within the specs and you'll be fine.
That makes sense! I'm limited to 3.6 kW for DIY certification, but it still works out for my budget compared to a pro install. It's all about weighing the options!
Exactly! The MPPT manages the current effectively, so as long as you’ve calculated correctly, you’re unlikely to burn anything out. It's all about understanding those oversizing ratings!