Inverter nominal power ratio

[Michael Lillis]

hi guys, i'm doing my MCS in the next few days, originally i was installing 12 x 250W panels. the mounting kit i've been supplied with hasn't got enough roof brackets so i can only install 9 panels. i already have the SB3000HF inverter however.

Using sunny design it tells me that the system is conditionally compatible, the only figure it flags is the Nominal power ratio of 140%

there's no way i can get the brackets in time, any advice?

would it damage the inverter to turn it on even for a short while during the assessment?

 

[BruceB]

By conditionally compatible it is telling you the inverter is underpowered by that number of panels. I have not run it through sunny design, but I would guess you could put the 9 panels in a single string and it would be fine for the assessment. Just check that the inverter can take the voltage of 9 panels - but the HF inverters have quite a wide voltage range.

 

[moggy1968]

what mouting kit are you using, maybe someone has some spare brackets?

 

[Michael Lillis]

Thanks guys, I'm using Wagner mounting kit, looks like i'll get the brackets after all. Previously been told they were completely out of stock but just received an email saying they are available.

Using SD it told me all of the voltages and other factors were ok, was only the nominal power ratio that was an issue.

thanks again for your comments

 

[redmile-energy]

the inverter is not underpowered its overpowered for the amount of panels you are using, by reducing the amount of panels its only going to make the nominal power ratio go higher. Essentially the software is telling you that the inverter will work and is suitable but that the voltage does not utilise the power of the inverter, i.e in an ideal world you might use a 2000HF and save yourself some money.

 

[mesa810]

hi, can some body tell me that how the sunny design calculate the " annual energy yield " & " performance ratio" & " typical pv voltage" ?
thank you every body,

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