Solar Panel limits in Summer

Just to say I believe it's normal to just export any surplus power rather than a percentage. I don't have solar so I can't go any further with that.

Peter

I can see no reason why all surplus power should not be exported!

If not, surely it cannot be generated, as it would have to go somewhere?

I have the SolaxCloud app, but only for my batteries (my PV has another inverter) but I cannot see anywhere that a percentage export can be set, or turned off.  Though there are many variations of models etc.

Thanks all. My understanding of the Solax Self Use or Self Consumption was that PV powers the house then PV powers the Battery then after Battery is full PV sends surplus to Grid. So “Mavison” you’d be right I think, why not get paid for all the surplus. The 50% I don’t export they get for free I suppose?

If you generate electricity it has to be used or exported. I do not think it can just be "lost".

Strictly speaking it can go nowhere. If you don't take power from the panels the power is still generated but it gets sunk into the panels themselves. If you want me to explain I will but it involves a describing how the panels work in the first place which is physics/electronics.

Peter

I was really referring to the power that is generated out of the inverter - ie about 240v 50hz AC. I have never looked at the panel side of the inverter.

You're right. It's got to go somewhere so if it's not used in the house then its exported. If you have a SEG agreement then you get paid. If not then one of two things would happen. If you have a smart meter then it goes to the grid but you don't get paid. Smart meters won't run in reverse and it may also set off an alarm for the situation to be investigated. If you have one of the old meters then you can get those to run in reverse and you effectively get paid at your tariff rate which is better than any SEG.

Peter 

Some setups are available with a false load applied when there is surplus but the local grid connection does not allow export (not usual for UK).

Generally, you would set your export level to what you are prepared to ‘sell’ to your registered supplier (for export). This is generally 100% but can be set differently for specific situations.

But if you set the export level for surplus power to, say, 60%, what happens to the other 40% ?

That is a good question. I didn't know you could set an export level because it doesn't really make any sense but I've just had a look and this is what I've seen that does make sense 

Your DSO (formerly known as the DNO) will set an export limit for your system. Let's say your panels could generate 5kW and the DSO sets a 3kW limit and you are using 1kW you could say where is the last 1kW going. The answer is what I said earlier, it goes nowhere. At least nowhere outside of the panels (before the inverter). It gets sunk in the panels themselves by an internal mechanism that is inherently part of the process of generating power in the first place.

As for the percentage figure in this case it would be the DSO limit / System peak power (assuming a 5kWp system) or 60% in this case. But I'm not sure that figure should be alterable by you unless the grid tie inverter is only rated at 3kW. In thus case you can set an percentage value but above 60% the inverter will limit at 3kW.

So all of the above is guesswork because I don't know the details of your system but it makes slightly more sense to me.

Peter