New Solar Panel Install - Questions

[DoyleS]

How do you know if your system is clipping?

 

[tap1936]

One other non technical question-when does tesla expect payment? It looks like two payments, when is the first one due?
thanks

 

[miimura]

How do you know if your system is clipping?

This is what the production curve looks like when the inverter is clipping.

P.S. This is not my system. I scraped the image from a FB Group.

 

[SMAlset]

One other non technical question-when does tesla expect payment? It looks like two payments, when is the first one due?
thanks

Just had this discussion yesterday with our install scheduler. We were told 1/2 due when they come out to start work, balance weeks later when PTO is issued and you get approval.

 

[wjgjr]

Just had this discussion yesterday with our install scheduler. We were told 1/2 due when they come out to start work, balance weeks later when PTO is issued and you get approval.

Just one note, which is that we (and I think some others) had 1/2 due at start but the other 1/2 was due when the inspection was complete - and before Tesla would submit PTO paperwork. Your information may be more current, or it may vary by job/jurisdiction, but just noting that distinction on the 2nd payment in at least some cases.

 

[SMAlset]

Just one note, which is that we (and I think some others) had 1/2 due at start but the other 1/2 was due when the inspection was complete - and before Tesla would submit PTO paperwork. Your information may be more current, or it may vary by job/jurisdiction, but just noting that distinction on the 2nd payment in at least some cases.

and that is what we’ve heard too so made a point of asking that submission of the balance question. In fact we asked it twice LOL. I know it has been a point of some contention with people. I guess we’ll find out in August but curious what new installs at least in our area are being told.

 

[jboy210]

I am lucky on the HOA. President of the HOA is a friend, and a supplier to Tesla. He was excited to see a Tesla SolarRoof going up in the neighborhood.

 

[dhrivnak]

This is an amazing forum, learnt a lot by reading through here but still have questions!

I have been spec'ed with a 12.24KW system with annual production of 11605 KWh

1. The inverter they have specified is a SE11400H-US. Is that enough without clipping or should I request two inverters?
2. The only document I see in my account is a customer layout. They did a site assessment before drawing this layout. They did send me some drawings to send my HOA but I have not had to sign anything and they have gone to the permitting step. Am I missing something here?
3. The tech drawing they sent for my HOA approval has a optimizer spec sheet, does that mean they will install optimizers on all my panels or only some of them? I will have shade.

I am sure I will have more questions, so thank you for your patience in answering!

RS

That is more than enough as we typically oversize inverters 20% and personally on my home I am over 30% and it is almost disappointing how little I really clip.

also 11,000 kWh out of a 12kW system seems real low. Unless you live in Seattle

 

[tap1936]

@jjrandorin - You mention that in the case of a power outage the solar production shuts down. I sort of understand that this is to protect public utility workers from unexpected electricity? Assuming this is true, can I not have some kind of automatic disengage from public power when grid power goes off and still produce electricity that I consume within my house? So I would have power during the day.

Also, maybe its just me, but I personally would never consider having another solar install without having powerwalls, having recently added powerwalls to my pre existing solar install. You dont mention them, but one thing to keep in mind is, if you have solar on your home, and have a power outage, it will not power your home during the outage without some sort of battery storage on premises.

 

[tap1936]

I live in NJ and this production is what Tesla shows. I do have trees in the back and my roof is facing East.

That is more than enough as we typically oversize inverters 20% and personally on my home I am over 30% and it is almost disappointing how little I really clip.

also 11,000 kWh out of a 12kW system seems real low. Unless you live in Seattle

 

[Akikiki]

@jjrandorin - You mention that in the case of a power outage the solar production shuts down. I sort of understand that this is to protect public utility workers from unexpected electricity? Assuming this is true, can I not have some kind of automatic disengage from public power when grid power goes off and still produce electricity that I consume within my house? So I would have power during the day.

Yes, the engineers figured out how to do that already. The PV panels are designed to fail to continue to produce electricity when there is no matching SINE wave from the grid. However with the installation of such equipment as the Tesla Powerwall supporting equipment, when the grid goes down, the "gear" senses the grid is down and switches automatically to batteries. If you have enough batteries you can operate without grid power until your PV can produce energy again to power your house - that is if you also have enough PV to recharge your batteries.

 

[jjrandorin]

@jjrandorin - You mention that in the case of a power outage the solar production shuts down. I sort of understand that this is to protect public utility workers from unexpected electricity? Assuming this is true, can I not have some kind of automatic disengage from public power when grid power goes off and still produce electricity that I consume within my house? So I would have power during the day.

TL ; DR version ..... Yes, you can, its called the gateway that gets installed when you purchase powerwalls.

Slightly longer version

In order to have your solar operational when you have a power outage, if your system is grid tied at all (meaning connected to the grid, which unless you live off the grid, it absolutely is), the only way around this is to purchase battery storage, that has the automatic load shifting you describe.

Without storage (like powerwalls) no, there is nothing you can buy that will pass any sort of permitting that gives you automatic shifting in a power outage. If you think about it for a second, you will see that, without storage, the power has to go "somewhere". It doesnt just evaporate, and you cant just "route it to ground".

If you want your solar to operate during a power outage, you must have storage, if connected to the grid at all, which, like I said, unless you live completely off the grid, you are.

 

[dhrivnak]

@jjrandorin - You mention that in the case of a power outage the solar production shuts down. I sort of understand that this is to protect public utility workers from unexpected electricity? Assuming this is true, can I not have some kind of automatic disengage from public power when grid power goes off and still produce electricity that I consume within my house? So I would have power during the day.

Then I suspect 0 clipping ever.

 

[pilotSteve]

solar newbe here... although I have a 10.4kW system with two PW's on order. My installer spec'd 32 PV modules with 32 Enphase IQ 7+ micro inverters.

question: will this system have a clipping limit, given that the IQ7s will individually enable or be shut down?

Also I understand the micro inverters are similar effect to a single large inverter with optimizers on each panel, right? Any thoughts on advantages to micro inverters that offset their increased cost?

Thanks everyone for the helpful advice and education. This set of threads in invaluable.

 

[jjrandorin]

solar newbe here... although I have a 10.4kW system with two PW's on order. My installer spec'd 32 PV modules with 32 Enphase IQ 7+ micro inverters.

question: will this system have a clipping limit, given that the IQ7s will individually enable or be shut down?

Also I understand the micro inverters are similar effect to a single large inverter with optimizers on each panel, right? Any thoughts on advantages to micro inverters that offset their increased cost?

Thanks everyone for the helpful advice and education. This set of threads in invaluable.

Im not an expert on that by any means (not even close) but from what I have read, microinverters and optimizers perform a similar function. At least one of our resident installers started a thread about whether they are even needed for most or not, but tesla installs them in certain circumstances.

Clipping isnt something to be too worried about, actually,. In summary (and others explain this better than I do but here goes anyway)....

If a system is designed so that it never, ever clips, things can be, in general, oversized for "most" production times. This means that the system is larger than it "needs to be" which means the customer spent money that they didnt need to spend, just so they wouldnt see the top of the production cut off for a small part of the day.

Said another way, the size the system might need to be to ensure it would "never" clip at all, might entail (made up numbers), an extra 3k spend, but only capture an extra $80 a year worth of electricity. In the above (completely made up) example, that would be 37 years to "break even" on the fact it never clips.

Now, whether the micro inverters / optimizers never clip based on technology, I dont know... but I do remember the basic example I laid about with the made up numbers just now. A little clipping wouldnt be bad in other words, as long as you are not losing large portions of your peak generation.

The thread started by @nwdiver on optimizers is here:

Optimizers... what are they good for?

 

[BrettS]

You can still get clipping with microinverters, but you would need to look at the inverter size as compared to the panel size. If, for example, you have a 340W panel and a 320W microinverter, then you may get a bit of clipping as the panel output could exceed the amount of power the inverter could handle.