Bursu Posted May 9, 2023 Share Posted May 9, 2023 (edited) Hello beautiful people. I have 13 panels installed on each of the two MPPT, in my garden over grass, at 30⁰. So 26 panels in total split into two equal strings. The installer said is ok to have 13 panels per each string since I don't go over the maximum VOC. However my worry is that my total wattage is over the maximum recommended by the inverter. So far Solar Assistant says I never went over 650v on any string. The panels are Risen RSM132-8-660BMDG, and are bifacial ones. STC ratings at extra 10% back side gain are: Rated Power in Watts-Pmax(Wp) 726W VOC 46v Short Circuit Current-Isc(A) 20A Maximum Power Current-Impp(A) 19A Maximum Power Voltage-Vmpp(V) 38.23 Temperature Coefficient of Voc -0.25%/⁰C My inverter is Deye 12kw SUN-12K-SG04LP3-EU. AC-DC rate 1.3 Max. DC input power 15600w. PV input voltage 200v-800v, MPPT range 200v-650v. PV input current 26A+13A. Am I safe like this, 2x13 panels? If not, how many panels should I have on each strings? I appreciate any recommendations, thank you. EDIT: I now have three strings of 7 panels. I haven't decided if i would sell the rest of the panels or put another inverter for more energy over the winter. Thank you all for your advices. Edited May 11, 2023 by Bursu I made modifications to my PV System system32 1 Quote Link to comment Share on other sites More sharing options...
WannabeSolarSparky Posted May 9, 2023 Share Posted May 9, 2023 Just means you will have plenty/good power in winter months. In summer you will have some clipping, but that's ok. If it's already installed and working as expected, then you should be ok Quote Link to comment Share on other sites More sharing options...
McGuywer Posted May 9, 2023 Share Posted May 9, 2023 Please post some pictures of your solar panels? Not related to the questions, I am just curious how they look. Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted May 9, 2023 Share Posted May 9, 2023 (edited) This is one for the clever members. Seems you decided on these panels even if they will with the 10% bi-focal yield exceed the Isc and Imp indicated in the specs of the inverter? Also the 18kW of panels when the specs indicate 15.6kW is something I would not do. Are you using 2 strings in parallel into MPPT1? May be I'm just Bangjan Edited May 9, 2023 by Scorp007 Quote Link to comment Share on other sites More sharing options...
GreenFields Posted May 9, 2023 Share Posted May 9, 2023 Personal 2c, for discussion with your installer, at your own risk. MPPT1 should be fine, but you should be careful of the PV input current on MPPT2. I'm just referencing Kilowatt Power below, but maybe double-check the specifications against the manual. Specifically the statement that the maximum Isc (A) is rated as 34A+17A, basically 34A on MPPT1, and 17A on MPPT2. So if you put a 19A panel on that 13A MPPT2, you may be overloading it, even exceeding its ability to clip the current down. So basically, even beyond the fact that you are limited to only ever see under 70% of peak output on that MPPT, if you ever get higher current output at the height of summer, you might be at risk of damaging your inverter. Personal take, you could consider putting 16 of those panels on MPPT1, and then maybe consider selling the rest and getting around 6 x 450W 13A panels for MPPT2, and rather use ordinary non-bifacial panels. Quote Link to comment Share on other sites More sharing options...
WannabeSolarSparky Posted May 9, 2023 Share Posted May 9, 2023 2 hours ago, Bursu said: Hello beautiful people. I have 2 strings of 13 panels installed in my garden over grass, at 30⁰, 26 panels in total. The installer said is ok to have 13 panels per each string since I don't go over the maximum VOC. However my worry is that my total wattage is over the maximum recommended by the inverter. So far Solar Assistant says I never went over 650v on any string. The panels are Risen RSM132-8-660BMDG, and are bifacial ones. STC ratings at extra 10% back side gain are: Rated Power in Watts-Pmax(Wp) 726W VOC 46v Short Circuit Current-Isc(A) 20A Maximum Power Current-Impp(A) 19A Maximum Power Voltage-Vmpp(V) 38.23 Temperature Coefficient of Voc -0.25%/⁰C My inverter is Deye 12kw SUN-12K-SG04LP3-EU. AC-DC rate 1.3 Max. DC input power 15600w. PV input voltage 200v-800v, MPPT range 200v-650v. PV input current 26A+13A. Am I safe like this, 2x13 panels? If not, how many panels should I have on each strings? I appreciate any recommendations, thank you. That IS BY FAR the coolest looking ground mount structures I have seen. Need that for the Cape South Easter Raiden2912 1 Quote Link to comment Share on other sites More sharing options...
Kilowatt Power Posted May 10, 2023 Share Posted May 10, 2023 22 hours ago, GreenFields said: Personal take, you could consider putting 16 of those panels on MPPT1, and then maybe consider selling the rest and getting around 6 x 450W 13A panels for MPPT2, and rather use ordinary non-bifacial panels. I concur with @GreenFields 16s1p on MPPT1 will safely provide 11,616 Wp (11.69% above 10,400W) at 734.24 Voc, 611.68 Vmp, 19.00 Imp and 20.11 Isc At 0 deg C, Voc will rise to 780.13 Vdc which is still below the 800 Vdc max DC voltage of the Deye 12K 3PH hybrid inverter. Bursu 1 Quote Link to comment Share on other sites More sharing options...
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