Inverter sizing and unequal strings

[J.P.M.]

New member. San Diego County, CA. Signed for 15 panel Sunpower 327's w/Sunpower SPR5000m inverter (at $4.50/N.P.Watt BTW). 2 month signup to startup baring gross permitting delays or vendor picks up elec. bill after 60 days until startup
Roof azimuth 15.8 deg. west of due south. Roof el. 18.8 deg. No shade any day between 0800 and 1600 hrs. solar time. 16 panels possible but tight and somewhat funky looking pretty much regardless of how I do it. If I had more room It wouldn't be Sunpower.
A few questions about the choice of inverter and stringing if I might:

1.) Is the inverter oversized ?
2.) Is the inverter transformerless ?
3.) Is it possible/adviseable using this inverter to have 2 strings of unequal size, 7 on one string and 8 on the next ? OR,

4.)Have 3 strings of 5 panels/string ?

Regards,

J.P.M.

[Mike90250]

Inverter might be a little oversize, but it only hurts the pocketbook. Maybe the next size down is too small.

If it's heavy, it has a transformer - or read the fine print.

Strings MUST be equal panels, 3 strings of 5 might work, but 7 & 8 will not be good.

You must look for 2 specs in the inverter, it's MPPT range (not the same as operating range) and the Max input voltage. Then you see if 5 series panels approaches the Max voltage, and if it is nicely inside the MPPT range.

[J.P.M.]

Inverter might be a little oversize, but it only hurts the pocketbook. Maybe the next size down is too small.

If it's heavy, it has a transformer - or read the fine print.

Strings MUST be equal panels, 3 strings of 5 might work, but 7 & 8 will not be good.

You must look for 2 specs in the inverter, it's MPPT range (not the same as operating range) and the Max input voltage. Then you see if 5 series panels approaches the Max voltage, and if it is nicely inside the MPPT range.

Funky or not, I went to 16 327's, 25 strings of 8. I think this will fit inverter parameters.

Thanks for the help.

J.P.M.

[J.P.M.]

Funky or not, I went to 16 327's, 25 strings of 8. I think this will fit inverter parameters.

Thanks for the help.

J.P.M.

Correction: 2 strings of 8

J.P.M.