Fronius symo gen24 plus oversizing with battery

[Seneca_]

Hi, I'm looking to expand my current installation with a 10kw Fronius hybrid inverter. And when I look at the technical specifications, we have four inputs, one for the battery and three string inputs divided into 2 MPPT's. MPPT 1 is 25A and MPPT 2 is 12.5A.

Fronius officially supports oversizing by about 150% (but recommend 130%), provided that you stay within open circuit and max short circuit limits. And that is what I'm aiming for, but my question is relating to clipping behaviour when you also have a battery connected.
If you have 150% oversizing and are in fact receiving peak solar irradiation on the panels, 50% will be "clipped" from the AC production and produce a flat top production graph. If you have a hybrid inverter, will this DC overcapacity be utilized for battery charging since that is a DC-to-DC load (hence power can be drawn to the battery since there's surplus production on MPPT1&2)? Meaning this particular inverter would produce 10kw AC and 5kw DC (the oversized capacity) and would be charging the battery? A total of 15kw combined production.

Does anyone have any experience regarding this scenario with Fronius or other brands of inverters?

Cheers

 

[bobthegreat]

My understanding after listening to a lot of fronius videos on youtube is that if you have a battery it will send the over inverter capacity part of dc to the battery. I have a 5k gen24 plus but I did not get a battery because it is very expensive here in Turkey. I have 6.3kw of panels and its maxing out at 5.2kw production which is the max of the 5k inverter.

 

[wattmatters]

Does anyone have any experience regarding this scenario with Fronius or other brands of inverters?

I think you'll need to ask Fronius directly if this is not covered in their user/installation manuals. Other hybrid inverters can do what you are suggesting but whether that specific Fronius unit does, I'm not sure. When I look at the installation manual it says max processable PV power is 10.3 kW, which suggests that's the limit no matter what the loads are. But it is a bit vague on this point.

 

[blobbs]

I also have this question.
I have a Fronius gen24 6kW grid tie inverter ( no battery ) with ~8kW of panels.
I would like to get a battery if I could use whatever the excess available is over and above the max AC output of the inverter. At this time of year ( Oct) there is surplus energy available in the middle of the day ( on a good day of course ).
Fronius uses this term Max. PV generator output but doesn't seem to define it anywhere. This is 9kW for my inverter
They specify Max. DC input/output power as 6200 watts, which I take to mean the max power available to and from the battery.
So perhaps in my case , you could say have a 4kW AC output with a 4kW charge being directed to the battery at peak generation times?

BTW has anyone else experienced high impedance connections limiting the amount of export ( feed in ) in NZ?
A.

 

[wattmatters]

Fronius uses this term Max. PV generator output but doesn't seem to define it anywhere. This is 9kW for my inverter

That's the maximum size of PV array(s) you can connect to the inverter.

They specify Max. DC input/output power as 6200 watts, which I take to mean the max power available to and from the battery.

That's the AC power output capacity of the inverter.

I would like to get a battery

You'll need one compatible with the inverter, which AFAIK is limited to some specific types of higher voltage BYD batteries.

 

[blobbs]

That's the maximum size of PV array(s) you can connect to the inverter.

Yeah that's my assumption, that the balance could be used ( e.g anything other than the inverter is drawing ) to charge a dc coupled battery. But its not clear from what I've read that this is correct.

That's the AC power output capacity of the inverter.

I don't believe this is quite correct. The max AC output power of the inverter is 6000VA. This could be 6000 watts but only in the case of a purely resistive load , which for me doesn't happen often.
I think this may refer to the max DC current either supplied to the inverter for AC generation , or sourced from the inverter in the case of charging the DC battery from the AC source.

You'll need one compatible with the inverter, which AFAIK is limited to some specific types of higher voltage BYD batteries.

Yeah BYD is in there, so is LG chem. Not sure I would want a NMC battery though.
Thanks for your reply.
A.

 

[wattmatters]

Yeah BYD is in there, so is LG chem.

I'd be leaving LG well enough alone with all their home battery failures and recalls.

 

[wattmatters]

I don't believe this is quite correct.

I probably misread your post. Yes I think you are correct. The spec sheet does say this:

Fronius Symo GEN24 6.0 Plus

www.fronius.com

MULTI FLOW TECHNOLOGY​

Using Multi Flow Technology, different DC and AC energy flows are possible in parallel. On the one hand, this allows energy from the modules and from the battery to be made available for domestic use at the same time. However, it is also possible for the energy from the modules to be simultaneously fed into the battery and the in-house network. Furthermore, not only can the battery be charged from the DC side, but also from the AC side (for example from existing PV systems or other energy sources, such as a wind turbine). This means the inverter is also suitable for AC-coupled retrofitting. The inverter manages these energy flows in such a way that the highest possible degree of self-sufficiency is achieved.

 

[blobbs]

Ah yes, good spotting. Thanks for your reply ( again ) .
A.