Micro inverter for injecting straight to wall connection at home (Hoymiles)

Hi,

Since it is now allowed in Belgium i see “balcony packages” get marketed.

Basically 1 or 2 solar panels and a micro inverter that you can directly plug in to your house (max 800W).

My eyes felt on the micro inverters from Hoymiles.

Hoymiles 800W

as an example.

I really like this idea, you can plugin the solar panels and get a traight 800W ac output AND also feed it into your house. The only thing i’m missing here is a battery connection.

What Victron product can i use that does all this?

  • mppt
  • battery charging
  • inverter with possibility to feed directly to the house

Some technical questions:

  • Why do they limit to 800W in Belgium?

  • They say you can only use the generated power in the same circuit as the solar power is connected. Doesn’t the solar power feed the whole house?

  • How do you know for sure that the electricity you use, comes from the solar panel and not from the grid? Because electricity takes the way of least resistance?

  • When you don’t use all the power of the solar panel, it wil be injected onto the grid?

Thanks for answering.

Hi,

Yes, balcony packages are a nice thing. They are limited to 800W, because… the approach has some flaws which may result in a cable overload under certain circumstances that doesn’t trip the breaker.

So, the 800W limit is basically to ensure an “acceptable” overload if all these circumstances come together.

Understanding, if and when this will happen is difficult, so there is simply an official 800W limit to make sure it won’t cause issues, if it happens.

  • the power can only be used on the phase it’s feeding in.
  • if you have a saldaring grid meter, it can be “virtually” used in your whole home.
  • yes, excess not beeing used will be feed into the grid.

But you should do some overall research and reading. Just having 2x 400 Watt Solarpanels doesn’t make you have 800 Watt available always. To really achieve 800W availability throughout sunny days, these microinverters can usually be commected to 4 panels. (But doing that requires a good understanding and knownledge of all parameters or you could easily damage the inverter)

Because electricity takes the way of least resistance?

Yes, basically. The microinverter is feeding in at a slightly higher voltage than the grid, so current has no other option than flowing “away” from it towards the grid (or consumers therefore)

Can you eleborate on “the approach has some flaws which may result in a cable overload under certain circumstances that doesn’t trip the breaker.”

Can you give a example?

  • the power can only be used on the phase it’s feeding in.
  • So my house runs only on 1 phase, so the entire house can benefit, right?

What do you mean with this “Just having 2x 400 Watt Solarpanels doesn’t make you have 800 Watt available always”

I know it depends on the orientation from the panels, the time of year and weather conditions.

Am i missing something else?

With 4 panels you mean like directing them from east to west to have “constant” 800W?

Thnaks again :folded_hands:

Sure. It is a “theoretical possible Use-Case” that goes like follows:

Assuming, there are 2 outlets connected behind a 16A breaker.
On one, you connect the balcony inverter. Now, while that is feeding in at maximum power, you connect something to the second outlet, so the energy from the inverter can directly flow to that consumer without passing the breaker. That consumer could now draw a current of 16A (through the breaker) + Whatever the inverter is actually producing.

So, by limiting that to 800W (~ 3.3A) the load on the second outlet (or it’s wiring) can be limited to 19.3A which is “acceptable” for a short time. If the inverter would be able to produce upto 3600 W (15A) that second outlets cable could be hit with upto 31A without dripping the 16A breaker which is … not so good :wink:

Example drawing:

Since most (private) owners would not be able to identify and prevent such a situation - it is simly avoided by limiting the power allowed for “outlet-based-inverters”.

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