SolarEdge SE3800 from SE3000 - Any Downside to Oversize?

[rick.m650]

Planning a 12-panel SW280 system which would call for SolarEdge 3000 Inverter w/ P300's. But to provide the potential of adding 3 add'l panels in the future, I could spend an extra $100 +/- now and get the 3800 model. Would I experience any performance issues with the extra but unused inverter capacity? Seems like a decent trade off to preserve an upgrade path, however unlikely. Thanks.

[inetdog]

Planning a 12-panel SW280 system which would call for SolarEdge 3000 Inverter w/ P300's. But to provide the potential of adding 3 add'l panels in the future, I could spend an extra $100 +/- now and get the 3800 model. Would I experience any performance issues with the extra but unused inverter capacity? Seems like a decent trade off to preserve an upgrade path, however unlikely. Thanks.

The efficiency of the larger GTI might be a little lower when working at less than its design output. Or it might be higher. No way to tell for sure.
But other than the up front cost I would not expect it to have any effect on your system performance.
Double check by comparing the specifications and performance graphs for the two though. YMMV.
As for later expansion, keep in mind that your area might want a modified POCO interconnect agreement and/or a new permit and inspection, making the minor upgrade a larger hassle and expense.

[sensij]

As for later expansion, keep in mind that your area might want a modified POCO interconnect agreement and/or a new permit and inspection, making the minor upgrade a larger hassle and expense.

If your Poco is PG&E, the current situation is only a 10% increase in system size can occur before the agreement needs to be made. If you upgrade more than 10% after July 1, 2017 (or possibly sooner, if the NEM cap is hit), you will lose grandfathering of your existing net metering agreement, which would otherwise be good for 20 years. The replacement for net metering is still in planning stages, and it is too early to tell how much better or worse it will be compared to the existing terms.

[Amy@altE]

I just ran the SolarEdge Site Designer, and both the 3000 and 3800 had an estimated annual output of 5.48Mwh (with a lot of assumptions on my part, not knowing your details). So according to their tool, there is no loss oversizing it.