Shockin Posted April 4 Share Posted April 4 Hi, I am looking at installing a solis s6 8kw pro inverter with longi 555w panels. I can fit 8 panels facing north (1 mmpt?) Can fit 5 panels facing north east and 5 panels facing east, these two areas are next to each other. How do I do this without destroying everything? Specs are as follows Quote Link to comment Share on other sites More sharing options...
Shockin Posted April 4 Author Share Posted April 4 I tried doing calculations and worked out that I can do 10 panels in series on string 1 (mppt1)and 8 panels in series on string 2 (mppt2). does this look right? Steve87 1 Quote Link to comment Share on other sites More sharing options...
Sidewinder Posted April 4 Share Posted April 4 (edited) @Shockin, Just off the cuff, you maybe a bit marginal with 10 PV's in a string. Voc = +-500V already, and then one needs to allow for the Temp Co-efficient factor (you will find that in the full Longi specs, not on the label). Randburg can get minus Temps easily in Winter. With Vmax mppt being 520V, I'd say your are too close for my (never mind your own) comfort. So I would go for a 2 strings of 9 PV config. If you don't have space for 9 in any one direction, then a shorter string will do. Edited April 4 by Sidewinder Quote Link to comment Share on other sites More sharing options...
abd7 Posted April 4 Share Posted April 4 (edited) 20 minutes ago, Sidewinder said: @Shockin, Just off the cuff, you maybe a bit marginal with 10 PV's in a string. Voc = +-500V already, and then one needs to allow for the Temp Co-efficient factor (you will find that in the full Longi specs, not on the label). Randburg can get minus Temps easily in Winter. With Vmax mppt being 520V, I'd say your are too close for my (never mind your own) comfort. So I would go for a 2 strings of 9 PV config. If you don't have space for 9 in any one direction, then a shorter string will do. Vmax is 600v according to the specs Edited April 4 by abd7 Quote Link to comment Share on other sites More sharing options...
abd7 Posted April 4 Share Posted April 4 (edited) 1 hour ago, Shockin said: I tried doing calculations and worked out that I can do 10 panels in series on string 1 (mppt1)and 8 panels in series on string 2 (mppt2). does this look right? Each string should ideally face the same direction. So you could put the 8 north facing on the one string, on one mppt. With the 5 x 2 panels north east and east, you could do 2 strings of 5 in parallel, onto the 2nd mppt. Edited April 4 by abd7 Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 4 Share Posted April 4 (edited) 56 minutes ago, Sidewinder said: @Shockin, Just off the cuff, you maybe a bit marginal with 10 PV's in a string. Voc = +-500V already, and then one needs to allow for the Temp Co-efficient factor (you will find that in the full Longi specs, not on the label). With 10 panels one is still 100V away from the maximum. The Solis has a higher Voc than most other brands. 10 seems fine to me. Edited April 4 by Scorp007 Steve87 1 Quote Link to comment Share on other sites More sharing options...
Steve87 Posted April 4 Share Posted April 4 +1 the Solis has an updated MPPT that is higher spec than the others. 500V is the usual limit but here we have 520V MPPT upper range & 600V Maximum before things get hairy. Id stick 10 panels in series without hesitation. The winter temps might flash possiblly over 520V but by no means will we reach 600V DC. So id make that call easily. I especially like the higher rated Amperage of the Solis it seems a good specification on their MPPTs. Scorp007 1 Quote Link to comment Share on other sites More sharing options...
abd7 Posted April 4 Share Posted April 4 @Steve87 He has space for 5 north east panels and 5 east panels , you rate its better to put them all together in one string of 10 in series? Or 5S2P? Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 5 Share Posted April 5 7 hours ago, abd7 said: @Steve87 He has space for 5 north east panels and 5 east panels , you rate its better to put them all together in one string of 10 in series? Or 5S2P? Never great to put string in different direction in series. 5S2P into 1XMPPT and leave the north string as mentioned into the other MPPT. Quote Link to comment Share on other sites More sharing options...
Steve87 Posted April 5 Share Posted April 5 I would not mix these directions at all. I would only parallel east & west. The north 5 will be strong because they facing a good orientation. The NE direction of 5 will make the other 5 behave poorly. Will be like connecting 10 NE. Given a choice I wouldn't connect these together. If no.choice then yes. abd7 1 Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 6 Share Posted April 6 On 2024/04/05 at 6:46 AM, Steve87 said: I would not mix these directions at all. I would only parallel east & west. The north 5 will be strong because they facing a good orientation. The NE direction of 5 will make the other 5 behave poorly. Will be like connecting 10 NE. Given a choice I wouldn't connect these together. If no.choice then yes. It will be interesting to see the actual calculated results say for a full sunshine day from another calculator. My calculator gives NE in parallel with E a daily yield for current weather a rough estimated figure of 7.45kwh per 1kW PV. For E and W in parallel it indicates 6.7kWh per 1kW PV. Per day maximum values. From this it seems like the string 45 degrees closer to north makes the difference. The calculator used is know to be optimistic but for this the delta is what we want to find out. Steve87 1 Quote Link to comment Share on other sites More sharing options...
Steve87 Posted April 6 Share Posted April 6 What's even more interesting with orientation: east and west Vs north, is the lower peak of east & west combined, but the array starts up earlier & ends off later. So on average the results looks the same in terms of kWh production. So many ppl have theories based that you can't parallel E & W on the same MPPT. To each his own, but having installed & seen so much E & W can be actually a very interesting installation. No high peaks but when you have energy production at 6am all the way to 6pm in the Summer it's just magic. PV is a science all on its own & needs to be considered very well to see all the possibilities... Derek3 1 Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 6 Share Posted April 6 16 minutes ago, Steve87 said: What's even more interesting with orientation: east and west Vs north, is the lower peak of east & west combined, but the array starts up earlier & ends off later. So on average the results looks the same in terms of kWh production. So many ppl have theories based that you can't parallel E & W on the same MPPT. To each his own, but having installed & seen so much E & W can be actually a very interesting installation. No high peaks but when you have energy production at 6am all the way to 6pm in the Summer it's just magic. PV is a science all on its own & needs to be considered very well to see all the possibilities... Thanks for your expert input. Yes if one needs the long production period then E in parallel with W is what we recommend provided the MPPT maximum is not exceeded. With the higher current panels this is something that is sometimes overlooked. I just took the maximum provided. This is where the science part comes in in knowing or measuring a client's load profile. If they can export and receive a reasonable income then one can say kWh is the in thing. Quote Link to comment Share on other sites More sharing options...
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