Why would two Growatt SPF 6000 ES in parallel be wasting 15 Amps?

[agrogers]

I have just had two inverters installed in parallel. On a sunny day the solar panels are more than enough to fully power the load. I have set the batteries to accept no charge for testing

However, the inverters are still pulling about 7A each from the grid. This current seems to go nowhere.

On the inverter it shows that there is indeed 7A coming from the grid. However it also shows that there is only 100W of power usage from the grid. If there was really 7A coming in then I would expect the power reading to be 7A x 220v = 1540W.

The ShinePower app shows that there is no significant power coming from the grid.

The installer says that Growatts waste a lot of power... but that seems way too much waste to me. Other suggestions were to do with active and reactive power and that perhaps the power factor was very low. I dont know anything about that.

 

[AshleyL]

I have just had two inverters installed in parallel. On a sunny day the solar panels are more than enough to fully power the load. I have set the batteries to accept no charge for testing

However, the inverters are still pulling about 7A each from the grid. This current seems to go nowhere.

On the inverter it shows that there is indeed 7A coming from the grid. However it also shows that there is only 100W of power usage from the grid. If there was really 7A coming in then I would expect the power reading to be 7A x 220v = 1540W.

The ShinePower app shows that there is no significant power coming from the grid.

The installer says that Growatts waste a lot of power... but that seems way too much waste to me. Other suggestions were to do with active and reactive power and that perhaps the power factor was very low. I dont know anything about that.

Setting 11 = 0 Amp to prevent AC from charging.....if you are pure OSO type.
Use SBU mode instead. Then again, I suspect you don't even have a battery in first place.
SUB mode normally results in additional power draw from grid to maintain zero-export.

Without battery connected, the inverter will drain 2A-3A from the grid to keep the capacitors charged.
1A to keep the inverter operational, another 2A to keep the two giant capacitors charged for power buffering *in case of solar power production fluctuation.

If you have 2 inverters, 3A + 3A = 6A, roughly close to your 7A (you are probably operating in SUB mode, so plus another 1A extra grid power draw for zero export purpose, so 7A total)

With battery connected, it will use the battery+solar as buffer instead.

 

[agrogers]

Thanks for those suggestions... hadn't thought about most of those! Some extra info...

1. We have 8 x 200AH GEL batteries in 2 parallel arrays.
2. We use SUB mode and want to keep using it. I am in Myanmar where we have power cuts every 4 hours so we only ever want to use the battery when we really need to
3. I had configured Setting 2 to 0A so there was no current going to the batteries. I think that has the same affect as Setting 11 = 0A. This had no effect on the 15A total coming from the grid.
4. What is "zero export"? Might be related to my problem.
5. Your 'without battery connected' scenario feels like the problem we have (but we have a battery). My installer says that all the Growatts he has configured SUB mode always draw 3+A from the grid. Mine is drawing approx 7A for each inverter - so 15A in total.
6. We have a battery connected so it seems it should not be pulling any of this from the grid.
7. In SBU mode it did stop all grid current.
8. Could you comment on the reading on the inverter that showed 7.4A coming from the gird but only 0.02KW coming from the grid. How is that possible??

I have include some screen grabs below of what I am seeing. Mabe I am missing something.
Thanks!

 

[AshleyL]

1. Gel battery. Not good for deep cycling.
2. For your situation, understandable.......SUB mode then....
3. No, you should not set Setting 2 to 0Amp, otherwise, your solar panel or grid power will not be able to charge your battery or keep it at float voltage level. Just set setting 11 to 0Amp. Restore Setting 2 back to default C-rate of your Gel battery.
4. In SUB mode, Growatt will drain 1A from the grid if you have battery connected.
5. Total 3A only applicable if there is no battery connected.
6. Of course SBU will stop all those power draw, it basically disconnect the AC-in relay.
7. 7.4A and yet only 0.02Kw from grid. It is possible. Ever heard of active, reactive and apparent power?


If you are billed as domestic/residential consumer rates, you will only be charged with active power only and that might be exactly what your electricity meter is showing you.
However, if you are commercial/industrial consumers rates, you will be billed for apparent power (sum of reactive and active power).

From your screenshot on load amount, I guess you are running a lot of inductive load such as compressor or motor. Thus, the 7.4A probably consists of a lot reactive power in proportion to the 1A zero export drain.

Tell me, your grid meter are under which category? Residential or Commercial rate?


edit: Oh? Nice, you have latest firmware installed for both MCU and DCU. Did you do it yourself or the installer did it?

 

[agrogers]

>>>1. Gel battery. Not good for deep cycling.
I would love to get some LiPo batteries but a little expensive at the moment for us. Maybe next year.

>>>3. No, you should not set Setting 2 to 0Amp, otherwise, your solar panel or grid power will not be able to charge your battery or keep it at float voltage level. Just set setting 11 to 0Amp. Restore Setting 2 back to default C-rate of your Gel battery.
I have reset that. I was just using it for testing to eliminate current loss to the battery.

>>>4. In SUB mode, Growatt will drain 1A from the grid if you have battery connected.
1A seems reasonable to me. 7A seems excessive.

>>>5. Total 3A only applicable if there is no battery connected.
That makes sense now.

>>>7. 7.4A and yet only 0.02Kw from grid. It is possible. Ever heard of active, reactive and apparent power?
I have - the installer mentioned it. I like your diagram.

Only problem is that I don't think we have any inductive load. We just have 40 computers, lots of lights, 10 TVs and a septic pump very occasionally. All ACs etc are on another circuit. But even if we did have pumps etc, I would expect the current to fluctuate. Our Grid amp reading just sits constantly on 15A. I assume this is possible because the PV is providing everything to the load and charging the batteries and the 15A is just being wasted by some constant drain (ie the two Growatt inverters).

Re our meter, I dont know how to answer that. We have our own 160KVA transformer and the meter is in there somewhere. But I am not concerend about electricity costs. What I am trying to avoid is diesel costs which are much higher. Ideally, when the sun is shining, my PV arrays can fully provide the power for our load - about 7KW - to computers and network and lights etc. They are doing that nicely... but now I also have an extra constant 15A coming from the Grid/Generator and going nowhere.

>>> Firmware... that's good to know. I thought I might have had an old version that was creating problems. It came with this version. Interestingly, the installer says that on the old firmware he has only ever seen a consumption of about 3A per inverter. He is surprised by our 7+ amps.

 

[AshleyL]

>>>>Only problem is that I don't think we have any inductive load. We just have 40 computers, lots of lights, 10 TVs and a septic pump very occasionally. All ACs etc are on another circuit. But even if we did have pumps etc, I would expect the current to fluctuate. Our Grid amp reading just sits constantly on 15A. I assume this is possible because the PV is providing everything to the load and charging the batteries and the 15A is just being wasted by some constant drain (ie the two Growatt inverters).

>>>>Re our meter, I dont know how to answer that. We have our own 160KVA transformer and the meter is in there somewhere. But I am not concerend about electricity costs. What I am trying to avoid is diesel costs which are much higher. Ideally, when the sun is shining, my PV arrays can fully provide the power for our load - about 7KW - to computers and network and lights etc. They are doing that nicely... but now I also have an extra constant 15A coming from the Grid/Generator and going nowhere.

>>> Firmware... that's good to know. I thought I might have had an old version that was creating problems. It came with this version. Interestingly, the installer says that on the old firmware he has only ever seen a consumption of about 3A per inverter. He is surprised by our 7+ amps.

Light? LED or fluorescent lamp? You will be surprised with how much reactive power the fluorescent lamp have. Even computers also some minor reactive power and with 40 units, it quickly adds up. Of course every motor stuff gonna have reactive power, so there is that.

You better hope your electricity meter are not under commercial rate/tariff. That amount of reactive power is not going to be cheap. In SUB mode, that reactive power going through the grid.

So, your installer updated the firmware for you? Good to hear that....meanwhile I had to do it on my own.......

 

[jmerrikhi]

>>>1. Gel battery. Not good for deep cycling.
I would love to get some LiPo batteries but a little expensive at the moment for us. Maybe next year.

>>>3. No, you should not set Setting 2 to 0Amp, otherwise, your solar panel or grid power will not be able to charge your battery or keep it at float voltage level. Just set setting 11 to 0Amp. Restore Setting 2 back to default C-rate of your Gel battery.
I have reset that. I was just using it for testing to eliminate current loss to the battery.

>>>4. In SUB mode, Growatt will drain 1A from the grid if you have battery connected.
1A seems reasonable to me. 7A seems excessive.

>>>5. Total 3A only applicable if there is no battery connected.
That makes sense now.

>>>7. 7.4A and yet only 0.02Kw from grid. It is possible. Ever heard of active, reactive and apparent power?
I have - the installer mentioned it. I like your diagram.

Only problem is that I don't think we have any inductive load. We just have 40 computers, lots of lights, 10 TVs and a septic pump very occasionally. All ACs etc are on another circuit. But even if we did have pumps etc, I would expect the current to fluctuate. Our Grid amp reading just sits constantly on 15A. I assume this is possible because the PV is providing everything to the load and charging the batteries and the 15A is just being wasted by some constant drain (ie the two Growatt inverters).

Re our meter, I dont know how to answer that. We have our own 160KVA transformer and the meter is in there somewhere. But I am not concerend about electricity costs. What I am trying to avoid is diesel costs which are much higher. Ideally, when the sun is shining, my PV arrays can fully provide the power for our load - about 7KW - to computers and network and lights etc. They are doing that nicely... but now I also have an extra constant 15A coming from the Grid/Generator and going nowhere.

>>> Firmware... that's good to know. I thought I might have had an old version that was creating problems. It came with this version. Interestingly, the installer says that on the old firmware he has only ever seen a consumption of about 3A per inverter. He is surprised by our 7+ amps.

I hope you're doing well. I came across your post regarding the issue with the Growatt SPF6000 ES Plus inverter drawing power from the grid, even when solar power is sufficient. I’m experiencing the same issue where the inverter pulls around 6A from the grid, even when the solar panels are producing enough power.

I’ve been trying to figure out the cause of this, but I’m still not entirely clear on why it happens. Based on your experience, do you have any insights into what might be causing this behavior? Any advice or explanations would be greatly appreciated, as I’m still working to understand why this occurs.

Looking forward to hearing from you and thanks in advance for your help