€ for a Homemade Solar Cell Installation?

[Lord of nothing]

Hi
We have a Garage (Red) next to our Neighbour (Green) and Cyan is our Roof.


Orange mean "good" Sunligt and Red mean "much more" Sunlight.
My idea is to put Solar Cells on the Garage in some degree angle.
I am quite optimistic because its marked Orange. One small downer the Light  could only come from South and West because East is the Wall from our Neighbour. I read here some Solar Cell cost ~150€ who sound reasonable.
What does a Inverter cost? Sorry for that stupid question is possible to use at the same time both Source Mains + Solar? School was so long ago... 
Thanks

[Marco]

Not an expert, but I have looked at doing it on my own garage roof recently. So here's some points :

- Dunno what your local regulations are for electricity ... in my country everything outside of the sealed mains fuse is between you and your insurance, the insurer only demands it's up to code, but it doesn't need to be certified to be so (except for business customers). Perfectly free to mess around with your own junction box, but if you don't have a global switch to take the power off it you'll have to pay the provider to come take the main fuse out and reseal it afterwards.

- We're allowed to use a sub-junction box to put converters on an existing group if it has no connections before the sub-junction box (so for instance we could put a 300mA/20A GFCI/breaker in the main junction box to the garage and then 30mA/16A and 100mA/16A for the sockets and converter respectively in the sub-junction box in the garage). Most countries seem a lot more anal about electrical work so I'm not sure that's relevant for you.

- Most mounting systems use ballast and old flat roof structures aren't always too generous with the beams. You can also get relatively cheap anchors for bitumen/rubber roofs, but you'll have to melt or glue them to the old roof and then connect them to the mounting system. Bit of DIY required.

- You seem to have a fair bit of shade, so you might want a converter with optimizers. In my country SolarEdge is popular. For 3 kW it would be around 1000 Euro for the converter and optimizers.

[The Soulman]

When solar panels on the garage are facing south and the neighbors wall is directly against it the panels will only see halve
of the sunlight and produce halve of the energy.
 The roof of your house seems better suited.

Inverters range between 500 and 2000 euro depending on quality and capacity.
 
 -is possible to use at the same time both Source Mains + Solar?-

I assume you want a system that is tied to the mains grid,
The inverter syncs to the mains frequency and delivers power to the mains grid, your electricity meter
counts backwards.
If you're consuming power at the same time it gets subtracted from the produced power and you meter counts slower backwards or forwards depending on the amounts.

If you want to do some extensive calculations you good use the free sunnydesign web app from SMA
https://www.sunnydesignweb.com/