residential solar pv with Micro Inverters in County Cork

Marcork

Hi there, I would like to know if there are any companies out there that offer solar panel installation combined with Micro Inverters for residential. As far as I understand the advantage of Micro Inverters are the power output per panel, individual panel monitoring and that the Inverter System is de-centralised. If a central inverter fails the entire solar is down, also a central inverter replacement is much higher in costs than a failed Micro-Inverter. We think of a 5 kw solar system.

Has anybody experience here, what company is recommendable you worked with?

Kindest Regards, M

bullit_dodger

I've got both. A full string inverter as well as 6 panels installed using micro inverters. While what you say is true, you can get panel level monitoring etc and it's decentralized, it's really not that advantageous. String inverters don't really fail that much. You have good telemetry etc.

Even though I have both, I'd recommend jsut going the normal route of a string inverter, and if you have some shading, then optimizers on the affected panels. This works very well.

Ubbquittious

I had 2 panels on microinverters but I'm in the process of getting rid of them. Not that there's anything wrong with them, they work fine

allinthehead

I have 12 panels all on 4 port microinverters. 6 on a timber frame facing SE. 2 on my shed facing SE. Another 2 on my shed facing NW and another 2 on my fence mounted vertically facing W. That is the advantage of microinverters, you can just throw up panels at any orientation or angle and the panel wattage and voltage can vary too.

They have their disadvantages too. More losses if you want to add a battery, Dc-Ac-Dc-Ac and the cost of the Ac coupled inverter.

Op why are you looking for microinverters? If I was mounting on a normally inaccessible roof then I wouldn't be fitting microinverters unless necessary. Failure on the roof will be as expensive as a string inverter failure if not more should you need to have scaffolding erected.

slave1

On a 5kW system it's probably cheaper to buy a MPPT String inverter anyhow

ELM327

https://www.boards.ie/discussion/comment/119620230#Comment_119620230

Do you have the microinverters connected to the main inverter too or do they not need to "talk"? What happens if the main inverter sees negative input from what it classes as the house?

allinthehead

https://www.boards.ie/discussion/comment/119626623#Comment_119626623

Bpe 4 port microinverters are 200 plus vat. Not much in it really.

bullit_dodger

https://www.boards.ie/discussion/comment/119626833#Comment_119626833

The main inverter never sees negative input. I've got 2x systems. Lets call them the "main roof" and "the shed" (microinverters on the shed)

So as the sun comes up the "apparent house" load drops off as the shed takes (some) of the load. For example, if I had 500watts house load at 6am, and the shed starts producing 100w at 7am, the "main roof" thinks that the house load had simply dropped by 100watts to 400watts. The only disadvantage is that since the main roof doesn't know that the shed exists, you could be exporting even though yur battery isn't full. Overall though, it works well.

graememk

https://www.boards.ie/discussion/comment/119628064#Comment_119628064

I would like to add, with the solis hybrid inverter, it can use the power from other inverters to charge the battery.

Eg array 1 producing 1 kw, array 2 generates 1kw, house load 500w.

The batteries will be charged at 1.5kw.

Edit: proof

ELM327

Graemek how have you wired that setup? I know the solis inverter can do that if it's in paralell with the other inverter. However doing so with microinverters would involve the solis seeing a negative house load. I can't imagine it's built to do that?

graememk

https://www.boards.ie/discussion/comment/119636360#Comment_119636360

They are just both (hybrid and standard inverter) wired back to the consumer unit. As soon as the hybrid sees any export it starts charging the battery accordingly. Also in backup mode, with the full changeover enabled it can charge from the second array too. But if it generates more than the batteries can charge and house load, voltage goes too high and it shuts down. So on good days when the grid is off, the second inverter needs to be shut off.

The stats are useless from the app for house load 😆 but that's the only drawback. But I have my own monitoring for that.

ELM327

Excellent stuff. I'm a meddler myself and I like to always be planning the next step. It sounds like you have a similar setup to what I'm planning, so excuse the myriad of questions! I'm planning to put a small (400-1000w) array on our pumphouse which is westnorthwest facing and will perfectly complement the 8kWp of sse panels that over produce massively up to about 3-4pm but then taper off very quickly.