The spec I have seen is 133% panel size to inverter size. So, you would be fine. I have 14.5K panels on a 11.4K inverter. Have only clipped a few times. No way we get out the rated specs from the panels, ever.
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Tesla Unveils New Tesla Brand Solar Inverter
- Thread starter willow_hiller
- Start date
The new inverter is interesting for sure. I am not an expert by any means but as I was informed about this by my project advisor a bit ago and have I have done a ton of reading in the meantime. This is not an optimized system... it is a normal string inverter. It seems would be most similar to the delta with better communication/monitoring and better interface with powerwall. With that said, even with the 4 MPPTs it can't optimize any individual panel so any panel on a string with any shade will degrade the whole string. If you have any shade, the solar edge still a better inverter. The SE is more efficient and optimized at each panel. If no shade concerns, new panel probably great. I actually just canceled my order because I was having some communication issues with my PA and I have a local company who will use a better inverter with double the warranty for only a few thousand more.
So, after reading this, I guess SE inverters use the same "string" as the new testa inverter so they could be exchanged?
SolarEdge Vs. Microinverters
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Just to be clear, you keep mentioning "running off grid" but you will not be contacting your electrical utility and telling them to "come get your meter" if you have solar and tesla powerwalls. Essentially, its a grid tied system.
Its design is such that it will allow you to use your solar when the grid is off (if there is a power outage etc), but it is not an "off the grid" type solution. Also, if you have enough solar and batteries through (any weather and sun situation) in the winter, you will likely have a huge amount of over production in the summer. This only really becomes an issue depending on how your utility handles net metering.
In any case, you are likely aware of all this, but just wanted to make sure. As a point of reference, on my own system, I have a "negative grid draw" from about March 1 to about November 15, on a MONTHLY basis, however there are definitely days in there where that is not the case, because of weather. Also, from Nov 15 to Feb 28 my solar does not cover my home usage. Yearly, I end up close to "zero" but I dont consider myself to be "off the electrical grid".
I do enjoy looking at the daily negative numbers for most of the year, minimizing my dependance on my electrical utility, but its not "off the grid"
For their new inverter, they have something called a Mid circuit interrupter... this devise will be on the string and will allow rapid shut down. So yes, they will be using the new inverter for their new panel systems.
SE doesn't use microinverters, Enphase has microinverters. SE has power optimizers on each panel and then all the DC power goes to the single inverter on the side of the house. The optimizers allow panel-level monitoring and allow for a single panel to be affected by shade but not the whole string. The optimizers allow a panel system to have the shade advantages of microinverters while still feeding to a string inverter.
I don't know if the new inverter will be compatible with panels with optimizers or not, but tesla tells me they will not be using optimizers on new panel systems with the new inverter.
I am confused with the terms. Does this article mean SE does not use microinverters since those do dc to ac at the panel.
So can a SE inverter be changed to the new tesla inverter?
SolarEdge Vs. Microinverters
That's not actually true, it depends on the fraction of panels in the string and which portion of each panel is shaded. Panels have bypass diodes to protect the PV cells from becoming reverse biased, and the bypass diodes come into play with shading. I guess a typical 72 cell panel has 3 bypass diodes, dividing it into 3 subassemblies of 24 cells each.
So if a leaf falls on one panel and shades cells in just one subassembly, you will lose 1/3 of that panel's generation, no more. If multiple leaves fall, the loss is cumulative, up until the point where the remaining insolated subassemblies no longer generate enough DC to meet the minimum input requirement of the string inverter. At that point, the entire string shuts off.
The behavior of shading effects where all panels in a string are partially shaded is more complicated.
Cheers, Wayne
Still learning. So, this implies the SE and tesla inverters cannot be exchanged. Meaning, when I hear string, this tells me if one panel goes out, the entire panel string set goes out? So confused. If true, not having compatibility is interesting?
As far as I can tell these new inverters are GT inverters so they will follow the grid frequency or when off grid follow the PowerWall frequency. That frequency shift is used by the PowerWall to control any AC coupled GT inverter. My hybrid inverter works the same way to control my GT inverter. Did that answer your question?
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Correct, SE does not use microinverters... they use optimizers. Both microinverters and optimizers are on each panel, but a microinverter does the dc to ac at the panel and then sends wire with ac electricity to the junction box neat your main electric panel. Optomizers condition the dc energy and allow for individual panel monitoring, then send dc electricity to a single larger inverter (likely by the main electric box). I do not know if the new tesla inverter will work with dc power coming from optimizers if you already have optimizers on each of your panels.
Yep, that is what I am asking for the technical folks. I already have optimizers on my panels with my SE inverter. I am starting to get a feeling the Tesla inverter will not work with these? But when I hear, I think, folks saying they have SE inverters on their tesla installs, ...
I would think that you would have to remove the SE optimizers from all of the panels and add the Tesla rapid shutdown device(s) to your strings in order to be able to replace a SE inverter with the Tesla one. For people with the Delta inverters it would probably be much simpler in only having to replace the Delta rapid shutdown device with the Tesla one. (Assuming that they aren't compatible.)
@HankLloydRight
that is an intriguing design. looks like you have a hip roof (sorta) with 340w panels on all 4 sides.
which is the S facing side? (I have a hip roof with 23 panels facing due east and 14 facing due south and a ginormous tree on neighbors side to the west.)
one of my panels (all with microinverters) gets some shading in early morning and you can tell since the panels are individually monitored
(17.2 megawatt hours in 2019, 17.4 megawatt hours in 2020, but i need at least a dozen more panels)
did you get System Analysis Monitor from the PVwatts site (free) to analyize output of the 4 separate arrays ?
PVWatts Calculator
(look at the tab "All NREL Solar Tools")(NREL = "National Renewable Energy Lab"
My solar water heater was on north side and in winter the solar incidence angle was horrendous (cosine of incident angle) before hurricane Irma intervened a bit
I would agree in that example that the single large inverter would likely still work. Just interesting to wonder at what point they would need to add the second inverter given that the there is no option for a smaller increment than 3.8 kW.
That was actually something I wondered about is whether they partnered with anybody, and particularly Delta, for this. The specs sound very similar to the Delta Solivia 7.6 that I have - same size, with 4 MPPT channels. Certainly one approach would be to use an existing company's technology and add the bits you mentioned to support interconnection with other Tesla hardware and their servers.
I think what he was getting at is the idea that it would be nice at some point for the powerwalls/TEG to communicate to the inverter to stop/reduce production without needing to raise the frequency. It does not sound like this inverter does that (or at least such a feature is not mentioned.) I think the frequency change would still be needed as a fail-safe/fallback option, but it potentially wouldn't be used if this hypothetical, new method worked properly.
That may be what people are quoting, expecting panels to rarely reach their potential, but on my sailboat I have 2.1kW of solar across three MPPT chargers and each one of them has seen more than quoted maximum output from the panels multiple times. I'd be losing out on some charge potential if I hadn't matched the MPPTs' capacity to the solar output capacity. Probably not much, but certainly some there.
I suppose a proprietary method could be faster. However a GT inverter still has to comply with UL1741SA.
I can imagine reflection from the sails, high clouds and the wind cooliing the panels would all contribute to that phenomena.
The thought would be that this would be an added method - hypothetically, if the frequency rise would be triggered at 95% battery capacity for a given system, then at 94% send instructions using this new protocol to the inverter to slow/stop producing so you don't get to 95%. The main advantage would really be for people who tend to have a lot of outages, in rare cases where the utility forbids export, or are planning to operate off-grid, so they don't have to deal with the side effects of a frequency change. For most people, it won't make a difference since we are grid-tied over 99% of the time and excess solar is exported to the grid.
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