Peak vs. continuous power (Enphase)

[bandgap]

Can anyone help me understand the enphase spec for peak vs. continuous output? I have IQ8+ microinverters but this would apply to other enphase systems. The IQ8+ has peak output of 300w and max continuous power of 290w. But I'm seeing over 290w for pretty long periods of time. So my question is... what is the significance of the "continuous" rating? For example, is it related to the NEC definition of continuous load over 3 hours? I wonder what conditions will the power surpass 290w and for how long can it do so. If it's been at 295w for an hour will it then throttle back to 285w to make the average 290w?

 

[SeaGal]

But I'm seeing over 290w for pretty long periods of time.

Much over? How are you measuring it? I suspect it could be down to power factors and W vs. VA's

 

[DIYrich]

I'm guessing that it can "peak" at 300w, but as it heats up, it will reduce power output to avoid over heating. 290w is probably what it can invert and dissipate heat for an extended period of time at some standard temp. Probably lower temps would allow for a higher continuous output.

 

[SeaGal]

Yes, but Enphase is rated at 290VA, not 290W...

see also..

Volt-Amps and Watts

An intro to Volt-Amps vs Watts TLDR - in DC circuits VA = Watts https://www.techtarget.com/whatis/definition/volt-ampere-VA What is a volt-ampere (VA)? A volt-ampere (VA) is a measurement of power in a direct current (DC) electrical circuit. The VA specification is also used in alternating...

diysolarforum.com

 

[bandgap]

Yes, but Enphase is rated at 290VA, not 290W...

see also..

Volt-Amps and Watts

An intro to Volt-Amps vs Watts TLDR - in DC circuits VA = Watts https://www.techtarget.com/whatis/definition/volt-ampere-VA What is a volt-ampere (VA)? A volt-ampere (VA) is a measurement of power in a direct current (DC) electrical circuit. The VA specification is also used in alternating...

diysolarforum.com

Not sure what your point is, power factor cannot be greater than 1. Are you implying that enphase reports apparent power not real power? The units in my monitoring app show watts not VA.

So for example I see 291-298 watts for at least an hour in the enphase monitoring page, which is > 290 VA … cannot be explained by power factor alone

If it was a true vs apparent power issue then the reported watts should be less than 290VA

I’m not really complaining except that my installer put 290w/inverted as my AC rating for interconnection and it seems that it could theoretically surpass that for relatively long periods of time. In my system it probably won’t ever happen but it got me curious what they really mean by peak. With larger inverters/batteries peak is usually measured in seconds or possibly minutes not hours

 

[bandgap]

As a follow up I’ve seen iq8+ outputting over 290w for many hours now. Yes I’m clipping pretty hard, wish had read up more on inverter sizing before I agreed to this installation plan (probably would have paid for larger inverters). Here's an example where I get 296-298 pretty continuously for 6 hours:



(I might eventually upgrade the micros in some locations but unfortunately my best producing panels are maxed out on chain length)