Serial or parallel micro inverter connection

[darwenn]

Hi there. I ordered the EVT720 micro inverter from Invertech.

I have 6 solar panels of 150W each in 12V, i.e. 22V in open circuit and 8A each, currently connected in parallel to a small 12V inverter. Total theoretical power therefore 900W.

The new Invertech micro-inverter has an operating range of between 16V and 60V, but if I leave my panels there in parallel, the 22V voltage they will send to it will probably be too tight to make it work properly. performance, especially since they would send him more than 40A when he can only collect 12 on each input. So I plan to connect them in series. Except that the micro inverter only has two panel inputs.

My problem is that: if I make two series of three panels, they will each send 66V to the inverter (3x22 volts) on 8A, knowing that it only supports 60V maximum. I therefore plan to connect two series of two panels to it (44 volts each at 8A) and the last series of the last two panels connected in parallel to one of the other two. But that seems a bit barbaric to me. According to you? Especially since it would be 44V but at 16A.

In the end, I think I can only settle for two sets of 2 panels. 2X22 volts in series on 8A per inverter input. But first, I still prefer to ask your opinion, my knowledge being limited. The last two panels will serve me for something else independent.

Here are some photos. First the inverter.

Image4.png (87.76 KiB) Viewed 5587 times

The technical aspect:

Image7.png (80 KiB) Viewed 5587 times

And finally, the assembly that I envisage.

[sicetaitsimple]

Hello Darween,
I will not venture into this field because I have no personal experience, but I note that in your proposal the second circuit could deliver up to 16A while the "maximum input" of each input is 12A according to the technical sheet.
Are you sure that your panels deliver "in real life" 22V? With a little less, a solution with 2 times three panels in series would perhaps be possible? This is only a lead, certainly not a recommendation, others than me may be able to tell you.

[izentrop]

Hello,
I also think that the maximum values ​​will depend on the place where you are and the orientation.
If we choose to orient them for maximum efficiency in mid-season, they will not deliver their maximum power, nor their maximum open-load voltage at the height of summer.
Moreover, by adding bypass diodes, the MPPT power point changes https://energieplus-lesite.be/theories/ ... oltaiques/

Are you sure about 22v? did you measure it? https://allo.solar/panneau-solaire-150w ... iteck.html

[darwenn]

Hello,
I also think that the maximum values ​​will depend on the place where you are and the orientation.
If we choose to orient them for maximum efficiency in mid-season, they will not deliver their maximum power, nor their maximum open-load voltage at the height of summer.
Moreover, by adding bypass diodes, the MPPT power point changes https://energieplus-lesite.be/theories/ ... oltaiques/

Are you sure about 22v? did you measure it? https://allo.solar/panneau-solaire-150w ... iteck.html

*

Yes, I have already measured no load, it is between 21 and 22 V, and often even 22V. The panels are already equipped with diodes to avoid swinging their potatoes between them. So, it would be better to avoid being too fair for the inverter, because my panels are due south with a tilt angle of 39/40° so they are, in a way, optimized at best.

I therefore think to start with 2 series of 2 panels in series, to make 44 volts in 8A, it will be ok for each input of the inverter with enough safety margin not to burn or to heat the inverter at the limit of its capacities. And I can then buy another micro inverter for the last 2 panels. That's all I can see.

My panels are Enjoy Solar brand monocrystalline, ECO LINE ES150M36 models, their open circuit voltage is given as 22,8V for 8,12A