4 or 4.5 kw system?

Martyn1981

Kernel_Sanders wrote: »

In June and July, the 4kW inverter on my 3.92kWp sytem shows that it is quite capable of producing in excess of 4000W continuously (as opposed to continually). I've always assumed (until now ) that this display is after inverter losses and not before.

Hiya, I'd have thought your display is after losses too, as I assume you're referring to the AC wattage display. But I'm shocked at the outputs your getting. Are you saying that your 3.92kWp system can hold 4kW continuously?

I've seen all my systems hit spikes above their kWp ratings briefly when the sun pops from behind a cloud, especially in April and October when the sun angle is good, but air temps are low. But never seen these figures held for more than a few mins, before dropping to about 90%.

In June and July, with warmer air, and therefore less panel cooling, I'm lucky to see sustained generation above 80% of panel rating.

Panel ratings are usually stated at 25C. All panels will be a little different, but on average they seem to have an efficiency drop off of about 0.4% per degC, or about 1% per 2.5degC. So will very quickly lose 10% or 20% efficiency in direct sunlight.

If your system isn't dropping off, then I doff my hat to you, and turn a little green with envy.

Does anyone else's system resist drop off?

Mart.

InVestor_2

Martyn1981 wrote: »

Hiya, I'd have thought your display is after losses too, as I assume you're referring to the AC wattage display. But I'm shocked at the outputs your getting. Are you saying that your 3.92kWp system can hold 4kW continuously?

I've seen all my systems hit spikes above their kWp ratings briefly when the sun pops from behind a cloud, especially in April and October when the sun angle is good, but air temps are low. But never seen these figures held for more than a few mins, before dropping to about 90%.

In June and July, with warmer air, and therefore less panel cooling, I'm lucky to see sustained generation above 80% of panel rating.

Panel ratings are usually stated at 25C. All panels will be a little different, but on average they seem to have an efficiency drop off of about 0.4% per degC, or about 1% per 2.5degC. So will very quickly lose 10% or 20% efficiency in direct sunlight.

If your system isn't dropping off, then I doff my hat to you, and turn a little green with envy.

Does anyone else's system resist drop off?

Mart.

I was generating a sustained 95-97% yesterday late morning. Although I don't think that is the norm for my system. Usually more like 90%ish on a sunny day.

Kernel_Sanders

Martyn1981 wrote: »

...never seen these figures held for more than a few mins, before dropping to about 90%

Sorry Mart, I presumed you considered several minutes to be continuous generation, as opposed to the few seconds of boost caused by emergence from a lengthy period behind cloud i.e. before the heating effect kicks in.