What's the max generation you've seen for a 16.2kWh system at any given time?

[bkp_duke]

Interesting.

I'm curious how much temperature is going to play a factor with my system's production. My guess is I'll produce the most in May and June. Long days, but the heat isn't as bad as August and September.

If you know the panel model, you can look up the temperature coefficient and calculate it. WARNING - this is a rabbit hole I've been down and then I decided to "optimize everything" I could. LoL.

June is usually our best month, as long as the "gloom" has subsided.

 

[SoCal Dave]

If you know the panel model, you can look up the temperature coefficient and calculate it. WARNING - this is a rabbit hole I've been down and then I decided to "optimize everything" I could. LoL.

June is usually our best month, as long as the "gloom" has subsided.

Hah, I love going down rabbit holes.

As long as we are near the Tesla expected generation of 18MWh per year I'll be happy.

Also, thankfully, our roof has a lot of space left. Probably can still add another 15-20 panels. So if I add an EV or our usage goes up dramatically, I'll can just order a second system. Even if it is one of those low efficiency Tesla systems

 

[bkp_duke]

Hah, I love going down rabbit holes.

As long as we are near the Tesla expected generation of 18MWh per year I'll be happy.

Also, thankfully, our roof has a lot of space left. Probably can still add another 15-20 panels. So if I add an EV or our usage goes up dramatically, I'll can just order a second system. Even if it is one of those low efficiency Tesla systems

If I got to pick my system, Tesla would be what I would have installed. Best bang for the buck by far.

Unfortunately, the builder of our house pre-installed a SunPower system, so that was the path we had to take. It wasn't a bad decision on their part, the roof of the house is very cut up, so S+W facing roof space is at a premium. I'm actually in the process of trying to add 6-8 more panels, and it's going to be a tight fit due to vent placement, etc.

 

[SoCal Dave]

If I got to pick my system, Tesla would be what I would have installed. Best bang for the buck by far.

Unfortunately, the builder of our house pre-installed a SunPower system, so that was the path we had to take. It wasn't a bad decision on their part, the roof of the house is very cut up, so S+W facing roof space is at a premium. I'm actually in the process of trying to add 6-8 more panels, and it's going to be a tight fit due to vent placement, etc.

Are you going with Sun Power for these new panels?

If I need additional panels, I'd likely install them myself. Most of the area left is on my flat roof and now that I understand how the racking there works, it is pretty straightforward.

I'd also probably go with a hybrid inverter for that section so I can AC couple and get some generation if there was a power outage.

 

[wjgjr]

Interesting.

I'm curious how much temperature is going to play a factor with my system's production. My guess is I'll produce the most in May and June. Long days, but the heat isn't as bad as August and September.

PVWatts does take that into account, so you can use that as an idea. For example, based purely on length of day, August should outperform April, but PVWatts has a slightly higher daily average for us for April. Similarly, February sits ahead of October for us. I think in both cases, temperature is part of the reason - though cloud cover probably also plays a part.

 

[ItsNotAboutTheMoney]

PVWatts does take that into account, so you can use that as an idea. For example, based purely on length of day, August should outperform April, but PVWatts has a slightly higher daily average for us for April. Similarly, February sits ahead of October for us. I think in both cases, temperature is part of the reason - though cloud cover probably also plays a part.

If there is weather data available the PVWatts calculation uses it, so will try to take cloud cover into account.

 

[wjgjr]

If there is weather data available the PVWatts calculation uses it, so will try to take cloud cover into account.

Right - I'm just saying I don't know whether temperature or cloud cover is the main reason August underperforms April where I am, according to PVWatts. I know both are accounted for in their calculations, and I do know that August is hotter than April, but I don't know for certain whether August tends to be cloudier than April.

 

[bkp_duke]

Are you going with Sun Power for these new panels?

If I need additional panels, I'd likely install them myself. Most of the area left is on my flat roof and now that I understand how the racking there works, it is pretty straightforward.

I'd also probably go with a hybrid inverter for that section so I can AC couple and get some generation if there was a power outage.

Yes, because the system can support more (up to 12 panels per circuit - limited by total AC input of the panels - and we have 4 circuits). If I add to the system myself, I run the risk of voiding the 25 year all-inclusive warranty, and that's just not worth it for me. Also, you need a login to provision more panels, and I just don't foresee SunPower giving me one of those or doing that for me.

Our roof is not something I'm comfortable being on either, and as a kid I spent a few summers roofing houses.

 

[jjrandorin]

Late to the reporting game, but here are my numbers from yesterday:

Date =9/21
System Size = 12.06kW (see sig for details)
Highest peak generation shown =8.6kW (71.3% of full system)
Solar generated today =58.7 kWh (4.9kWh per system size kW)
Location - North SD County

We had some significant marine layer until about 9:30 AM here, so missed out on a little bit of AM production.

I feel stupid asking this, but I am going to ask anyway as I am positive it is a simple answer....

What is the calculation you guys are using to get the "system size per kW"? Above, 58.7kWh of energy was generated, and you have it listed as 4.9kWh per system size kW). I can see that is a portion of the total system size of 12.06kW but dont know the calculation you are using to determine that number.

 

[jboy210]

Ok..

Date =9/21
System Size = 8.7kW
Highest peak generation shown =5.1kW
Solar generated today =35.4 kWh
Location - North Temecula (Temecula / Murrieta Border area)

Those are some nice numbers. We only generated 21 kWh yesterday with the 12.75 kW solar roof. The highest we saw was around 5 kW. The lower sun and 60 foot Oak conspire to partially shade the roof. I guess that is why they listed annual production at 11 MW.

 

[bkp_duke]

I feel stupid asking this, but I am going to ask anyway as I am positive it is a simple answer....

What is the calculation you guys are using to get the "system size per kW"? Above, 58.7kWh of energy was generated, and you have it listed as 4.9kWh per system size kW). I can see that is a portion of the total system size of 12.06kW but dont know the calculation you are using to determine that number.

Generated power in kWh (58.7 for me for that day) divided by system size in kw (12.06 kw for my system).

 

[bkp_duke]

I'm above the marine layer this AM and ambient temps look to top out around 80F, so it will probably be a really good generation day.

EDIT - there is dust on the panels, so I don't expect things to be perfect, but better than yesterday.

 

[SoCal Dave]

I'm above the marine layer this AM and ambient temps look to top out around 80F, so it will probably be a really good generation day.

View attachment 590870

That is an awesome view.

 

[bkp_duke]

That is an awesome view.

Thanks, we are very fortunate. The view is one of the reasons to get out of bed in the mornings.

 

[SoCal Dave]

Those are some nice numbers. We only generated 21 kWh yesterday with the 12.75 kW solar roof. The highest we saw was around 5 kW. The lower sun and 60 foot Oak conspire to partially shade the roof. I guess that is why they listed annual production at 11 MW.

Ouch. Is that somewhat typical?

Personally, I'd be plotting the oak tree's death. I have those two Eucalyptus trees you can see in my profile photo. Their deaths might be in the cards soon.

 

[zƬesla]

Maybe I missed it, but when posting system specs above shouldn't you also include the inverter size(s)? That may have an impact on generation limits and/or efficiency.

 

[SoCal Dave]

Maybe I missed it, but when posting system specs above shouldn't you also include the inverter size(s)? That may have an impact on generation limits and/or efficiency.

If clipping was occurring we absolutely should, however none of the Temecula Three are hitting the clipping size of our inverters.

 

[jjrandorin]

@SoCal Dave @njhtran

Just as a FYI for us (the temecula 3, lol), our best generation months as it pertains to NEM credits are march - june. In general, because march and april have good sun, but lower temps and dont require AC usage, you will generally generate the most NEM credits march, april and may. Production itself is higher in June and July, however you will be using your AC then, so NET nem credits will be lower.

 

[TheTalkingMule]

If you know the panel model, you can look up the temperature coefficient and calculate it. WARNING - this is a rabbit hole I've been down and then I decided to "optimize everything" I could. LoL.

June is usually our best month, as long as the "gloom" has subsided.

My hell is even worse. A 6.6kW array of Panasonic panels with a +10 rating, meaning they will perform at least to rated specs and up to +10. Watts or percent.....I forget.

Anywho, I have an east/west racking system on a flat roof and my installer decided a 5kW inverter was "optimal". On certain days, production pegs to 5kW at 10am and it clearly would have approached 6.6kW at absolute peak under the right conditions.

I don't care about the minor loss from being slightly less than optimal, I just wanna know if I could exceed the rated capacity of the array! Driving me bonkers.

 

[bkp_duke]

My hell is even worse. A 6.6kW array of Panasonic panels with a +10 rating, meaning they will perform at least to rated specs and up to +10. Watts or percent.....I forget.

Anywho, I have an east/west racking system on a flat roof and my installer decided a 5kW inverter was "optimal". On certain days, production pegs to 5kW at 10am and it clearly would have approached 6.6kW at absolute peak under the right conditions.

I don't care about the minor loss from being slightly less than optimal, I just wanna know if I could exceed the rated capacity of the array! Driving me bonkers.

Post a graph of one of those days, but that sounds like inverter clipping (unless my reading comprehension is off due to lack of enough coffee).