PV string sizing: Cutting it too close?

[silversaver]

I don't think you can find other inverter give you the lower value. I was wonder how their MPPT tracking on multi roofs. The MIX technology.

[HX_Guy]

To be fair, the installer actually suggested a 4 x 12 setup, which would give a high temp voltage of 276.2, well within range. That's probably the setup I have to go with, but I don't like it. Maybe I can look at some other inverters and see if they allow for lower operating voltages than 230V, though I think that's pretty standard?

[silversaver]

I am surprise your installer spot Min DC Voltage on your inverter 230V. You have to calculate the high temp operating voltage base on panel's Temp Coefcient (Pmax):0.46 %/degree C. It looks like your extreme high temp operating voltage is right at boarder line 230V. You can take the chance. I have recently hit the same problem with power loss over 35C outside temp, and my installer have no idea at all about high temp operating voltage but using VoC to calculate string sizing......

The inverter will not shut down, but you will see power loss.

[HX_Guy]

Another question here, hope you guys don't mind and can give me some constructive criticism.
Ideally I would like to setup my system in 5 strings of 10 panels, however using this PV String Sizing Tool it looks like the system would be at the Inverter's lower limit of operation and if the temperature goes above 45.6º (114º F) which is often does, would the system shut down?



The installer suggested a 4 string x 12 panel setup, but I said I would prefer the 5 x 10, which he said we could do as well.
With the 4 x 12 setup, the numbers are much more within range.



I'm pretty sure I know what the right answer is but figured I'd confirm here. Thanks for any input.