Expansion of a 3kWp system in Denmark

The Fronius Primo 3.01 is single-phase and delivers 4.5 kWp. I have installed panels of 6x 305 watts (JAM60S01-305/PR). So there is still potential for more, I assume I can easily install 6 kWp.

The first step would be to accurately measure the available roof area and then plan what fits on it.
Self-installation on a flat roof can be done by anyone who can assemble Ikea cabinets. So that is definitely your way to go. The electrical connection should of course be done by an electrician. By the way, I would look for one BEFORE installation, so that he doesn't end up not wanting to take jobs just like the solar installers.

I would always mount with a 15° tilt on a flat roof. Usually east-west. But that depends on the space. North-south is also possible. Without tilting, you have to clean annually, as you can see well from the pictures of the existing modules. The grime easily costs 20% performance, so get rid of it!

Modules nowadays are almost all good. I don't know why you want to stick with 320 watts. 380 watts should hardly be more expensive. At least here in Germany.

Whether a battery pays off always depends on the price of the battery and electricity prices. In Germany, batteries still don't pay off. How much do you pay for electricity? Without feed-in remuneration, the electricity price would have to be around 50 cents for a battery to pay off for you. But that depends on so many factors that you can only plan this at the end when you know electricity consumption, photovoltaic size, etc.

The first step would be to accurately measure the available roof area and then plan what fits on it. Anyone who can assemble IKEA cabinets can do self-installation on a flat roof. So that is definitely your way. The electrical connection should of course be done by an electrician. By the way, I would look for one BEFORE installation, so that the electrician is not just as uninterested in jobs as the solar installers.

I would always angle flat roofs at 15°. Normally East-West. But that depends on the space. North-South is also possible. Without angling, you have to clean annually, as can be clearly seen from the pictures of the existing modules. Dirt easily causes a 20% loss in performance, so get rid of it!

Modules nowadays are almost all good. I don’t know why you want to stick with 320 watt. 380 watt should hardly be more expensive. At least here in Germany.

Whether a storage system pays off always depends on the storage price and electricity price. In Germany, storage systems still don’t pay off. How much do you pay for electricity? Without feed-in tariff, the electricity price would have to be around 50 cents for a storage system to be worthwhile for you. But that depends on so many factors that you can only plan it at the end, once you know electricity consumption, photovoltaic size, etc.

1,000 THANKS for your time!!!

So I would probably find/have an electrician; I’m relatively optimistic about that. I’ll measure tomorrow by the way and fly the drone up. But I really have quite a lot of space, estimated around 200 sqm. I would rather not replace the inverter right now. Therefore, the best thing would probably be to fully load the inverter. I understand that with a 4.5 kWp inverter I can easily install 5-5.5 kWp, especially in Denmark. Correct?

I’m only dealing with the 320 watt modules because I learned that I can’t mix, especially if my inverter only has one phase (= 1 string??). Of course, I could also remove and replace the existing modules, but apparently it is really difficult to find a supplier able to deliver in such small quantities (e.g. 10-15 modules).

Ideally, I would leave the old modules in place and then add another 9 or 12 next to them. Under what conditions can I connect them all to the same string?

In a second step, when the market has calmed down again, I can then fully utilize the entire area, buy a bigger inverter, and then consider a storage system. For now, I just want to start and increase from 1.8 kWp to 5 kWp.

this is what it looks like. Quite a lot of space.

With an east-west orientation, you can connect significantly more than 5.5 kWp to a 4.5 kW inverter. However, this must be carefully planned and installed. Can a regular electrician do this?