New Tesla orders - More panels / same inverter

[Sun007]

Small	4.8 kW	12	260 sq ft
Medium	9.6 kW	24	520 sq ft
Large	14.4 kW	36	780 sq ft
X-Large	19.2 kW	48	1,040 sq ft

It looks like Tesla has again changed the ratio of panels power to the inverter power
now with 400 watt panels . Go check it out

My current install is with 350 watt panels *24 = 8.16kwh

Question is why and is this really a better option, at least for some of us.

Points :
My current system - all south facing already runs at 7.2kwh in november sun.
Once i already saw it at 7.6 momentarily
I am sure it will peak out in summer month's , every day

For me at least , the new system will be bottlenecked by inverter
Also , inverters are quite cheap ......Tesla makes them in house
They also fail the first , so putting a little less continuous load , is not the worst idea

The only benefit i see is marketing only counts panel power and not inverter power , so on paper , more panels look better than less panels for that price. of people with no south may benefit, but inverter is cheap

Thoughts ?

 

[Vines]

Small	4.8 kW	12	260 sq ft
Medium	9.6 kW	24	520 sq ft
Large	14.4 kW	36	780 sq ft
X-Large	19.2 kW	48	1,040 sq ft

It looks like Tesla has again changed the ratio of panels power to the inverter power
now with 400 watt panels . Go check it out

My current install is with 350 watt panels *24 = 8.16kwh

Question is why and is this really a better option, at least for some of us.

Points :
My current system - all south facing already runs at 7.2kwh in november sun.
Once i already saw it at 7.6 momentarily
I am sure it will peak out in summer month's , every day

For me at least , the new system will be bottlenecked by inverter
Also , inverters are quite cheap ......Tesla makes them in house
They also fail the first , so putting a little less continuous load , is not the worst idea

The only benefit i see is marketing only counts panel power and not inverter power , so on paper , more panels look better than less panels for that price. of people with no south may benefit, but inverter is cheap

Thoughts ?

Your total energy harvest is going to be expressed in dollars per kWh generated. The tiny fraction you may give up over the first couple years clipping is completely the wrong thing to worry about.

First of all STC does not Equal the actual production of a module. STC is 1000 w per square meter, and at 25 degree C cell temperature. Pretty much nowhere on earth has this condition, certainly not for very long.

PTC takes into account the actual cell temperature increase of several hours in the sun, and what a 350w module actually produces is more like 325 w.

Here's a good link with more information of STC vs PTC
STC vs. PTC: Why Solar Panel Testing Matters

Basically your system, in the rooftop conditions would put out 7800W. Since your inverter is about 98% efficient that's reduced to 7644W. Between dirty panels, elevation that was not ideal, and wire losses, its amazing you are able to output 7600W ever.

 

[arnolddeleon]

Your total energy harvest is going to be expressed in dollars per kWh generated. The tiny fraction you may give up over the first couple years clipping is completely the wrong thing to worry about.

THIS ^^^!!!!!!! So many people many miss this. If you have to spend more money on an inverter (or anything) how much more energy will it return to you. In many cases the answer is more panels even though you will "spill" some. Other variants of this question should I pay more for a higher performance panel versus getting more of a lower performance one. What about optimizers? Same thing!

 

[Sun007]

ok, if inverter peaks for 3 hours every day, will that not reduce inverter life ? or is that not a concern

As i said my 8.16 system was at 7.2 kwh continuous in late Oct for 1 hours daily when sunny, when i got it installed . My roof is aligned best for summers
It once touched 7.6 max too.
I have to test in summers

If i were to get new Tesla system of 9.6 kwh , it will peak for 3 hours everyday when sunny in summer

 

[hayhayday]

1.26 ratio will have very little clipping, if not all in same direction likely no clipping at all. Mine is at 1.36 all south and I lose maybe 1-2% per year and intend to bump that up to ~1.5 eventually to help during non summer afternoons.