question

Hi @Dom,

Thank you for enabling those features, and I can now see some changes that need adjustment.

The charge current limit for each inverter is set to 150A, where it should be adjusted to the maximum 200A.

It is possible for these setting to be changed on each of the 3 Quattros remotely via the Remote VEConfigure setting and the VEConfigurator tool, Training for how to use this tools is available on Victron Professional E-Learning.

I am able to change this now myself, but would prefer of course if you were able to do it yourself.

Then I would like to see how the system responds to this adjustment. I expect that more power will be allowed to flow from the AC PV inverters.

There may be another issue (eg balancing), which is also preventing the existing limit of 150A x 3 from being achieved, and one of the inverters might be doing more work than the others and reaching the 150A individual limit to trigger the frequency shift. That may require someone on site with a clamp meter to diagnose.

We will not know if this is an issue worth investigating until after the adjustment to 200A per unit is made. That may allow enough to resolve it.

I also noticed that the AC PV Inverter assistant has only been loaded into the first Quattro, this assistant requires that it be loaded onto all Multi's (Quattros) in a system.

I have also seen that the location of the AC PV inverters is listed as on the AC input, but I don't believe this is correct? Can you please confirm the location of the AC PV inverters in the system.

The system is currently AC input limited at the Quattro level to 10A, and 6A respectively. I presume that this is for a (relatively) small generator. If the AC PV is actually connected to AC input, then this would also be a constraint.

This is also marked as NOT allowed to be overruled by the remote (CCGX).

These are two different values, and describe two different things.

The CCGX value relates to the AC input current limit, in this case limited by the AC transfer switch of the Quattros. 120A x 3 is extremely large ( 240VAC x 120A x 3 Quattros = 86.4 kW ).

However the CCGX AC input current limit is secondary in priority to the individual AC1 input limit that is set inside VEConfigure, and in this case, the AC input limit for AC1 is only 10A ( 240VAC x 10A x 30 Quattros = 7.2 kW ).

The value that you have just changed is the maximum DC Current that will be converted from AC to charge the batteries. (~50VDC x 200A x 3 Quattros = ~30 kW). That 30 kW is the maximum amount of power that these Quattros can convert from the AC PV to DC battery charging power.

It is more likely that this figure will be less, due to heat temperature derating,

I believe this is the most likely limitation that we are seeing that is causing the frequency to rise. Time will now tell if increasing the value from 150A DC to 200A DC makes the difference to this site.

Given there is 45 kW of AC PV, to a maximum possible 30 kW of battery charging power, there will always be some constraint of the PV, unless you also have 15 kW of AC loads to make the difference.

Other Changes before Firmware Update

I see that you added the PV inverter assistant to one of the other Quattros, but still not all three?

Also you made an adjustment to another of the AC input current limits in VEConfigure to 40A, but again did not do this for all 3 units. Some are still set at 10A.

Also the Overruled by remote box is still not ticked, so the CCGX value will not be applied. Perhaps you have a reason for this, but I would suggest enabling it for the 3 units if you do not.

Firmware update

We will not know if this is necessary or beneficial until all the other suggested changes are made, and there is time for more solar data to collect in VRM.

Hello @Dom,

There is another issue I raised earlier, that you did not yet respond too.

The Fronius AC PV inverters are configured as connected to AC Input. I believe they are actually connected to the AC output.

This looks like it is causing issues in VRM - as it sees the Consumption = Production Please confirm the configuration setting matches the installation, and make the correction if it is required:

Photos would be very useful!

If it is possible to wait a few days to collect a bit more data before making more changes to settings and firmware etc.

What did you set the Aircon temp too? Is there any way of keeping track of the air temperature inside the equipment structure?

I only have 2 data points, the temperature of the batteries, and the over temperature alarm of the inverters.

Yesterday the inverters still over temp warning. At least one of them. My theory is there is some issue with the wiring, or connection, and one inverter is working harder than the others, and limiting the whole system. But I have no proof, just an idea.

So the way to know for sure is to run a test. When the system is limited, Using a clamp meter over the DC positive wire leading into the bottom of each of the Quattros, take a measurement of the current. To get maximum performance, each should be equal.

I suspect one will be different to the others. If it is, then you should try to find out why by inspecting all the wiring and making sure that it is equal to the others, without any parts that are loose.

A thermal camera would be an EXTREMELY useful tool, only a few 100 Euros. That will show you visually if one inverter is hotter than the others, and also show you if there are any hot spots in the wiring/circuits to any of them that is leading to increase resistance, the imbalance (and less than maximum).

Also I note that this system recharged yesterday from 33% state of charge to fully charged 100%. A massive recharge, with batteries full at 3:45pm with another 2 hours of Sunshine still to go.

I don't know how much you changed the aircon temp down by, but the battery temperature only reduced by 1 degree. So either change it down further, or that aircon/building insulation is insufficient to handle the heat load that is created by those high powered electronics.

Cooling required for heating load

Seeing some photos of the structure and design would be very useful.

Who did the thermal design?

On the back of my envelope; If they are all in the same room (AC PV, Quattros, & Batteries), and the room is reasonably well insulated.

45 kW AC PV @ 95% efficiency = 2.25 kW

33 kW Quattro charging @ 85% efficiency = 4.9 kW

33 kW Lithium Batteries at 90% efficiency = 3.3 kW

40 sq M of building heat gain ~ 5kW (A vague guess here)

So to get peak performance from this system, you are looking at an aircon of at least 15 kW, or usually 2 x 8kW. That is cooling energy/rating, not electrical energy as aircon gets some energy advantage from the atmosphere.

If you can, reduce the night time temp on the aircon down to 16 degrees, at the moment it only gets to 20 degrees. That will hopefully keep the daytime temperature down to 25 degrees, as it still gets to 30 degrees. Those measurements are at the batteries, so the inverter temperatures will be much higher.