Growatt SPF5000ES and Grid ?

[Paulfrench35]

Hello, I'm French and I use google translate.

I don't have any battery on the inverter yet.

On this graph the load (blue curve) is 1500w and the solar production (yellow curve) at this moment is approximately 3000w.

Why the yellow curve is at the time heckled ?

Why will the inverter draw power from the grid ? Solar production is far greater than the load !!!



An example, in the pink circle the grid and solar supplies the inverter and in the gray circle I cut the grid.

The load is almost the same. We can clearly see in the second case that it does not need the grid, solar power is more than sufficient.

So why does he take it in?

 

[Vigo]

Are you saying that the blue and yellow lines are on different scales? 1500w vs 3000w even though they lines have the same vertical height?

Generally speaking if you do not have a battery you have nowhere to put any excess electricity from solar, so you will basically NEVER allow more solar energy into the inverter, then there is load to power with it. So those two should be on the same scale since you have nowhere to put the 'other' 1500w (no battery & no grid export).

However, solar power has a relatively slow reaction time compared to how quickly load on the inverter can change, and there are minor dips in solar production from clouds/haze that may momentarily push the solar production below what is required by the load. The inverter itself 'costs' something to run, the SPF5000ES is said to use about 60w at idle and that will scale somehow with load, but basically you would never make more solar in than the sum of Loads + Inverter's 'internal consumption' aka inefficiency.

Basically, if you have no battery, you will always have SOME grid use because the demand can change quicker than the supply so even when you have more than enough supply you will still 'miss' the moving target of your load by a little due to 'lag' and the grid source will 'fill in' to make up for that. The supply will also sometimes drop below the demand due to clouds/haze/planes/birds etc etc. Both of these effects can be so brief that they are impossible to see on a bigger time scale like we typically view things at, so they don't necessarily show up on graphs.

If you had a battery, you would probably use basically no grid at all at times when solar power was greater than load. But without battery and WITH grid, there will always be grid use to some extent due to transients.

That's how i understand it.

 

[Paulfrench35]

Are you saying that the blue and yellow lines are on different scales? 1500w vs 3000w even though they lines have the same vertical height?
No, but I know that at this time of day it is 3000w what do my solar panels produce.

An inverter produces the maximum that the solar panels can deliver, if the load does not consume all, the excess is sent to the grid. A hybrid inverter regulates the power to be at the same level as the load. So it is impossible to know the value of production at a precise moment.

Before having this Growatt, I had a classic inverter so I knew what my panels could produce depending on the weather, now with the Growatt I can no longer see it. I have 4000Wc on my roof.

Is there a solution to know the value of overall production?


Basically, if you have no battery, you will always have SOME grid use because the demand can change quicker than the supply so even when you have more than enough supply you will still 'miss' the moving target of your load by a little due to 'lag' and the grid source will 'fill in' to make up for that. The supply will also sometimes drop below the demand due to clouds/haze/planes/birds etc etc. Both of these effects can be so brief that they are impossible to see on a bigger time scale like we typically view things at, so they don't necessarily show up on graphs.

If you had a battery, you would probably use basically no grid at all at times when solar power was greater than load. But without battery and WITH grid, there will always be grid use to some extent due to transients.
You have just answered my question, your explanation is perfectly clear.


When I will have my battery, which mode is best to use? SOL, SbU or SUb ?

 

[timselectric]

SBU

 

[bt77]

Are you saying that the blue and yellow lines are on different scales? 1500w vs 3000w even though they lines have the same vertical height?
No, but I know that at this time of day it is 3000w what do my solar panels produce.

An inverter produces the maximum that the solar panels can deliver, if the load does not consume all, the excess is sent to the grid. A hybrid inverter regulates the power to be at the same level as the load. So it is impossible to know the value of production at a precise moment.

Before having this Growatt, I had a classic inverter so I knew what my panels could produce depending on the weather, now with the Growatt I can no longer see it. I have 4000Wc on my roof.

Is there a solution to know the value of overall production?


Basically, if you have no battery, you will always have SOME grid use because the demand can change quicker than the supply so even when you have more than enough supply you will still 'miss' the moving target of your load by a little due to 'lag' and the grid source will 'fill in' to make up for that. The supply will also sometimes drop below the demand due to clouds/haze/planes/birds etc etc. Both of these effects can be so brief that they are impossible to see on a bigger time scale like we typically view things at, so they don't necessarily show up on graphs.

If you had a battery, you would probably use basically no grid at all at times when solar power was greater than load. But without battery and WITH grid, there will always be grid use to some extent due to transients.
You have just answered my question, your explanation is perfectly clear.


When I will have my battery, which mode is best to use? SOL, SbU or SUb ?

Go with SBU.

And yes, Vigo's explanation is on the system inertia and it's correct. Inverter based systems don't have the sufficient inertia the "huge" power grid has. So sudden changes in load such as a washing machine starting to operate will require some inertia support from the grid. But after a few seconds the inverter will catch up and grid import will go to zero again. I have a grid tied system with a 5 kWh battery and even though my battery is never below 65% SOC, I still import 0.15 kWh from the grid every day for voltage/frequency referencing and inertia.

 

[timselectric]

In SUB mode, the 5000ES will constantly draw up to 500w from the grid. This is to avoid exporting power to the grid. Because in SUB mode the inverter output is placed in parallel with the grid.
The 500w is a cushion, to give the unit time to adjust to the changes in load demand.

 

[Paulfrench35]

The 5000ES is unable to export power to the grid.
I am advised to use SBU and not SUB.

What does "by pass" mean that we see at the top of the image?

At the moment I'm like this:

 

[Vigo]

There is a fancy relay inside the unit that can connect the AC input directly to the AC output, bypassing the inverter function. That is what AC Bypass refers to. This relay is also what you would call an automatic transfer switch or ATS. If the AC input drops it will automatically transfer the output back to being hooked to the inverter. Or if the inverter had insufficient solar or battery power (depending on settings) it would automatically hook the AC outputs back to the AC input. You'll head a pretty loud click when it does this.

Things to note about AC bypass:

1. AC bypass will use power equal to your ac loads PLUS your battery charge current, if any. So if the unit is powering 3kw of loads but it is also set to do 100a of battery charging (roughly 5kw) then your AC input would have to supply 8kw. This is an issue to be aware of if you are using a small generator as your ac input, but doesn't really matter if your ac input is the grid. You currently have no batteries but if you add them you may have to tailor your max battery charge current setting to limit the total draw of the inverter to whatever your source can handle. If your grid input is over 10kw (40a+ breaker and wiring on the circuit you are feeding the growatt with) then you can leave it at default max settings and it will be fine.

2. Solar power still gets used when in AC bypass. So if you have 5kw of loads and make 2kw of solar, only 3kw comes from the AC input.

3. Battery does NOT get used in AC bypass. This inverter cannot mix power from battery & grid to power loads, only grid + solar, or battery + solar. Never grid + battery. Some other inverters can do this.

 

[timselectric]

The 5000ES is unable to export power to the grid.
I am advised to use SBU and not SUB.

What does "by pass" mean that we see at the top of the image?

At the moment I'm like this:

View attachment 166219

That is SUB mode.
AC input is connected to AC output (bypassing straight through the Growatt).
The second row of dotted lines show that AC input is connected to through the Growatt to the output, along with the inverter output.
This unit can not export. But that's only because the firmware won't let it. However, the physical connection does exist.

 

[Paulfrench35]

When I go to plug in my battery, I wish the network could never charge the battery. Only solar, is this possible?
Another example, the solar produces 4000w and the house consumes 3000w, the remaining 1000w will go to charge the battery? Will the inverter send the excess solar to the battery?

 

[timselectric]

When I go to plug in my battery, I wish the network could never charge the battery. Only solar, is this possible?

Yes, setting #14 (OSO)

Another example, the solar produces 4000w and the house consumes 3000w, the remaining 1000w will go to charge the battery?

Yes

 

[bt77]

There is a fancy relay inside the unit that can connect the AC input directly to the AC output, bypassing the inverter function. That is what AC Bypass refers to. This relay is also what you would call an automatic transfer switch or ATS. If the AC input drops it will automatically transfer the output back to being hooked to the inverter. Or if the inverter had insufficient solar or battery power (depending on settings) it would automatically hook the AC outputs back to the AC input. You'll head a pretty loud click when it does this.

Things to note about AC bypass:

1. AC bypass will use power equal to your ac loads PLUS your battery charge current, if any. So if the unit is powering 3kw of loads but it is also set to do 100a of battery charging (roughly 5kw) then your AC input would have to supply 8kw. This is an issue to be aware of if you are using a small generator as your ac input, but doesn't really matter if your ac input is the grid. You currently have no batteries but if you add them you may have to tailor your max battery charge current setting to limit the total draw of the inverter to whatever your source can handle. If your grid input is over 10kw (40a+ breaker and wiring on the circuit you are feeding the growatt with) then you can leave it at default max settings and it will be fine.

2. Solar power still gets used when in AC bypass. So if you have 5kw of loads and make 2kw of solar, only 3kw comes from the AC input.

3. Battery does NOT get used in AC bypass. This inverter cannot mix power from battery & grid to power loads, only grid + solar, or battery + solar. Never grid + battery. Some other inverters can do this.

Point 2 is not correct as far as I know (I have experience with SPF 6000 ES PLUS which is very similar to this one). Once bypass is active, solar is not used either. You can use the inverter as you described (solar+grid) but it should be in "normal" grid mode not bypass. In that case, the top bypass line on the display won't be there, just the second line from the top, grid going into inverter.
The reason it's in bypass has something to do with battery not being present but voltage settings not adjusted accordingly. Check Programs 12, 13, and 21.
What's really stupid with this series is that you don't have a mode in Program 5 called "no battery" (you have to select a battery), like simply using the inverter without one and SOC set points in Programs 12, 13, 21 get deactivated. Also you keep running with Warning 19 as you can see in the display.

 

[Vigo]

It's getting to be a pretty long time since ive used my growatts with anything going into the AC input so i may have misremembered that!

I DO use the dry contacts to switch things based on the ac to battery and battery to ac setpoints so those function even with no actual ac input.

 

[Paulfrench35]

The goal is not to run it without a battery. It's just time for me to finish building it.

 

[timselectric]

Once bypass is active, solar is not used either.

It is in SUB mode, for the 5000ES.