Wondering the same since I wanted to run the numbers for my system, which is 16 340w panels facing 230 with a tilt of 34°, and 8 panels facing 050 with a tilt of 34°, on a 7600w inverter.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
New install yesterday but they gave me a smaller inverter than quoted.
- Thread starter SunnyInVegas
- Start date
Wondering the same since I wanted to run the numbers for my system, which is 16 340w panels facing 230 with a tilt of 34°, and 8 panels facing 050 with a tilt of 34°, on a 7600w inverter.
nwdiver
Well-Known Member
Yes. You can merge two arrays but it's a PITA. If there's no clipping with all panels facing the same direction there won't be any if they face different directions.
You've got zero chance of clipping with that, as the DC size is only 8160W, and a third of your panels are pointed very differently from the others. So I'm confident that for any sun angle, one or both of the arrays will be illuminated sufficiently less than 100% to keep the STC DC production below 7600W.
Cheers, Wayne
nwdiver
Well-Known Member
I prefer to call it inverter 'saturation'. It's less of a negative term. I'm a big fan of saturating inverters now that panels are so cheap and mid-day energy is increasingly worthless due to over production at noon.
Even with this degree of saturation annual losses are < 5%. And not all kWh are created equal. a 4pm kWh is usually worth A LOT more than a 1pm kWh.
ChicagoSox
Member
Sorry for my lack of the obvious here... are you saying the difference between the larger inverter would be almost nothing?
nwdiver
Well-Known Member
I realize its irrational, but that graph would absolutely bother me if it was my system... even if I knew that the yearly difference was minimal. Also, im laughing at the "inverter saturation" because it sounds less negative that way (not laughing at you, just laughing in general). Kind of like the old proverbial joke of someone driving a garbage truck calling themselves a "sanitation engineer".
Just to be clear, I am not disputing your assertion that "it doesnt matter"... I just would not want my graph to look like that, and if I was in a pre install meeting and you showed me that and said thats what you were doing because it didnt matter, I would ask you what we had to do so that it didnt look like that, and how much would that cost extra.
As for the OP, it may or may not make a difference, but if the contract actually says a size, and thats not what they put in, I would want some sort of refund if I decided to keep what they put in. Personally, as long as putting in the larger inverter didnt DECREASE my yearly production, I would want it put in since that was in the contract.... but everyone has to handle these situations in the best way they see fit for themselves.
nwdiver
Well-Known Member
That's part of my motivation for discussing this issue. Array oversizing is becoming more common and that's a good thing IMHO. An oversized array is easier for the grid to manage and it makes for more predictable less erratic production.
The array I posted has an oversize ratio of 1.5. So that is on the extreme end. Most of my installs are closer to 1.2 where there's almost no saturation. In this particular install we were capped at ~15kW of inverter capacity. Adding more would have required a service upgrade at a cost of ~$5k. Not worth investing $5k for $180/yr of additional production.
What's REALLY going to skew the economics is when the depressed value of mid-day energy is passed along via TOUs. No one is going to care about inverter saturation from 11 - 3 when the value of exports is <$0.02/kWh in that period.
I signed my PTO paperwork last week and I am awaiting the PTO app approval and meter installs.
All the paperwork for the PTO lists the SE11400 inverter, just like every document I have from earlier. I asked my Tesla rep about this all and if they would replace the inverter with the specified documented SE11400 unit and her response was “I’ll have the documents rewritten to reflect the SE10000 instead”.
Her abrupt answer and attitude kind of unsettled me.
All the paperwork for the PTO lists the SE11400 inverter, just like every document I have from earlier. I asked my Tesla rep about this all and if they would replace the inverter with the specified documented SE11400 unit and her response was “I’ll have the documents rewritten to reflect the SE10000 instead”.
Her abrupt answer and attitude kind of unsettled me.
Last edited:
nwdiver
Well-Known Member
I would just ask yourself if losing ~15wh/day is worth any further thought. I mean... you could almost charge an iPhone with that much energy
Good point. I wouldn’t think it’s worth pushing the situation if it comes to it for that small of a increase.I would just ask yourself if losing ~15wh/day is worth any further thought. I mean... you could almost charge an iPhone with that much energy
However if they do offer to change it, I’ll take it for the principle idea that it was detailed originally.
CrazyRabbit
Active Member
I took the advice of others here and decided to not pursue getting the smaller 10000 unit replaced with the originally quoted 11400 unit.
My service call for my PWs came Tuesday and the tech fixed my PWs issue. I asked him if I needed to get my permits or specs updated to show the smaller inverter. He called his office manager to ask. Apparently this smaller inverter was an error on the install team. They brought the wrong part and just went with it. He said they would fix the mistake.
A service tech showed up yesterday and replaced the inverter with a SE11400 unit. Took about 1 hour to swap and register the panels.
Similar threads
