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Is 7.6 kW Tesla enough for 10.4kw pv array solar panel system?
- Thread starter abp5070
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- solar array Tesla Energy
It’s common to undersize the inverter.
It’s not that common you’ll hit that peak and if you do it won’t be that often.
Are all panels facing the same direction. Are all panels clear at the same time during peak of day at peak season?
I have a 7.8kw with 6kw inverter. It clips sometimes. But it would probably only add 1-2% to yearly total if I used a larger inverter.
Mentally it drives you nuts. But it is practical. Wiring, panel capacity all have to go up when inverter goes up too.
It’s not that common you’ll hit that peak and if you do it won’t be that often.
Are all panels facing the same direction. Are all panels clear at the same time during peak of day at peak season?
I have a 7.8kw with 6kw inverter. It clips sometimes. But it would probably only add 1-2% to yearly total if I used a larger inverter.
Mentally it drives you nuts. But it is practical. Wiring, panel capacity all have to go up when inverter goes up too.
Yes, All panels facing south (best generation). No trees or any shadows. I am in Pennsylvania
dhrivnak
Active Member
We almost always oversize the DC array as this allows the inverter to start earlier, run later and stay in its efficiency band more of the time. And the reality, at least in NE TN one produces peak power just a few hours a year when the angles and weather are perfect.
Tesla clearly said, they won't let me have 2 inverters. I will have one big inverter 7.6 kw
Just to be clear, this is entirely a marketing issue, and I'm not sure any PV installer/seller does a good job explaining.
First "turbo" or "overdrive" doesn't mean that your PV inverter can produce over 7.6 kW at any time. When the sun is well aligned and the temperature is cool and your PV panels could produce more than 7.6 kW DC, your inverter will clip and limit you to 7.6 kW AC. What the 1.7 ratio means is that the inverter will handle that clipping gracefully without overloading any of the components, up to a 1.7 nominal DC/AC ratio.
The thing that is not immediately obvious is that if you want to design a system with an optimal lifetime kWh/$ (i.e. you can't improve limeftime production by spending a little less (or more) on inverters, and using that savings (or cost) to add more (or fewer) PV panels), then you will end up with a system with a DC/AC ratio bigger than 1.0. That's because inverters are not free, and the number of hours per year that PV panels will produce their actual nameplate rating (or close to it) is fairly low. So given the cost of the inverters, it makes sense to spend some more on extra PV panels so that you have less "idle" inverter capacity, even at the expense of having some "idle" PV capacity.
Once your realize that you should generally only sell and install PV systems with a DC/AC ratio bigger 1.0 if you want to be more economically optimal (assuming no other constraints like limited roof area, etc), then the question is what figure do you use to market the "size" of the system? The vendors like to use the DC size because it's a bigger number and sounds more impressive.
That's fine as long as everyone realizes that when they are getting a "10 kW" PV system, that means a system with 10 kW of PV panels, and a smaller inverter size, and that given their location it should work out on average to so many MWh of energy per year over 20 years. It doesn't mean a system that will produce as much energy as possible as any system with 10 kW of PV panels could produce at that location. Because it doesn't make sense, e.g., for Tesla to raise their prices by 5% so that they can give you 2% more energy.
Cheers, Wayne
First "turbo" or "overdrive" doesn't mean that your PV inverter can produce over 7.6 kW at any time. When the sun is well aligned and the temperature is cool and your PV panels could produce more than 7.6 kW DC, your inverter will clip and limit you to 7.6 kW AC. What the 1.7 ratio means is that the inverter will handle that clipping gracefully without overloading any of the components, up to a 1.7 nominal DC/AC ratio.
The thing that is not immediately obvious is that if you want to design a system with an optimal lifetime kWh/$ (i.e. you can't improve limeftime production by spending a little less (or more) on inverters, and using that savings (or cost) to add more (or fewer) PV panels), then you will end up with a system with a DC/AC ratio bigger than 1.0. That's because inverters are not free, and the number of hours per year that PV panels will produce their actual nameplate rating (or close to it) is fairly low. So given the cost of the inverters, it makes sense to spend some more on extra PV panels so that you have less "idle" inverter capacity, even at the expense of having some "idle" PV capacity.
Once your realize that you should generally only sell and install PV systems with a DC/AC ratio bigger 1.0 if you want to be more economically optimal (assuming no other constraints like limited roof area, etc), then the question is what figure do you use to market the "size" of the system? The vendors like to use the DC size because it's a bigger number and sounds more impressive.
That's fine as long as everyone realizes that when they are getting a "10 kW" PV system, that means a system with 10 kW of PV panels, and a smaller inverter size, and that given their location it should work out on average to so many MWh of energy per year over 20 years. It doesn't mean a system that will produce as much energy as possible as any system with 10 kW of PV panels could produce at that location. Because it doesn't make sense, e.g., for Tesla to raise their prices by 5% so that they can give you 2% more energy.
Cheers, Wayne
Earlier this month Tesla installed my 10.4KW system - Installation included two SolarEdge Invertors (7.6KW Invertor - Connected to 18 panels and 3.8KW Invertor - Connected 8 panels) and 26 SolarEdge Optimizers. I am waiting for Tesla to submit final papers to PPL (utility company); township inspection and Tesla Quality inspection is completed
No, but Enphase recommends oversizing the DC rating of an individual panel vs the AC rating of the microinverter it is connected to. For example, my 10 year old system has nominal 240W panels on nominal 215W microinverters.
So same issue, just on a distributed scale.
Cheers, Wayne
Which direction are your panels facing? What i heard is tesla doesn't install 3rd party inverters anymore. I have PPL (utility) as well. I am in Souderton, PA. My installation is scheduled next tuesday and all panels are south facing.
Your installation will NOT be Tesla Inverters for 100% sure. You can check your design document. There are few electric companies (like PPL) where they have approved list Invertors and PPL list does NOT include Tesla Invertors. So Tesla has to install 3rd party inverters for PPL customers - It will be either Delta or SolarEdge.
charlesj
Active Member
If I would have known back then. I only have a 235W panels.
Only once I saw 226W production on my 215 inverter, early on, May 2012.
Yes, I confirmed with Tesla and also checked my planset where it shows they will be installing 7.6 Kw tesla inverter. I know tesla inverter is not in PPL list of approved inverters, but Tesla just have to prove them it meets PPL requirements. See my attached planset screenshot.Your installation will NOT be Tesla Inverters for 100% sure. You can check your design document. There are few electric companies (like PPL) where they have approved list Invertors and PPL list does NOT include Tesla Invertors. So Tesla has to install 3rd party inverters for PPL customers - It will be either Delta or SolarEdge.
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nwdiver
Well-Known Member
It's even a tiny bit worse with micro inverters. With a string inverter you can mitigate inverter saturation slightly with arrays that face different directions so not all panels hit their peak at the same time. It's a lot harder to face a single panel in different directions.
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