My 8 x 450W panels are generating enough power to keep me going through the night - my14,3 kWh battery doesn't get down to the threshold I've set (40% SoC) where it needs to top up from the grid.  However, every day, the Sunsynk 8 kW inverter draws about 0,8 kWh from the grid, always the same every day.  If I switch the mains switch off, everything keeps working just fine, but I'd prefer to keep the grid connected.   Any ideas as to why the Sunsynk uses that 0,8 kWh every day ?

Check if the unit has a minimum load threshold for battery use, some inverters will disconnect from batteries/solar sources while the load is under 300W or something arb like that. I would recommend looking into whether your SunSynk does this as well...

Otherwise, it be related to your settings/priorities... perhaps take a moment to post your inverter settings, there is a chance there is something in there causing your minor grid usage. 

Lastly, it could just be a Sunsynk thing... not super familiar with the units but hopefully someone with a little more experience with these will pick up if we're missing something silly xD

43 minutes ago, Pramod said:

However, every day, the Sunsynk 8 kW inverter draws about 0,8 kWh from the grid, always the same every day.  Any ideas as to why the Sunsynk uses that 0,8 kWh every day ?

The Sunsynk constantly draws a minimal amount of grid to be able to synchronize with the grid.

In your inverter menu under System Mode on the 2nd page is a setting 'Grid Trickle Feed' where you can adjust how much that constant draw must be. Some prepaid meters are more sensitive than others, so you must play around with it. Mine is set to 10W.

53 minutes ago, Pramod said:

If I switch the mains switch off, everything keeps working just fine, but I'd prefer to keep the grid connected.

I have connected a 63A smart relay before my inverter grid feed - so that I can easily disconnect/reconnect my inverter to the grid. In summer, I basically run completely offgrid. But if I see that I might need grid support, I can easily reconnect with a button-press on my phone. Advantages are that I save the small grid draw and that my house does not get exposed to the grid voltage fluctuations 

48 minutes ago, Psy said:

Lastly, it could just be a Sunsynk thing... not super familiar with the units but hopefully someone with a little more experience with these will pick up if we're missing something silly xD

Yup - it's a Sunsynk thing 😉 Even though I would expect other grid-tied inverters to do something similar (but have no real idea as I don't have any experience with any other inverters that can blend grid/PV)

I've been seeing the same with my Goodwe inverter. It turns out there are (in my case) two things going on

1) The system has to sample the grid all the time so that it can match the grid voltage & frequency. But this shouldn't take a lot
2) As @Psy has said, some inverters have a threshold below which they will not draw from battery when PV is unavailable. I presume this is to do with the overhead of running the circuitry that converts 12vDC to 230vAC. Anyway, it was recently pointed out to me that the Goodwe manual says this that this will occur if load drops below 150W. I think they're out by 30W or so, but anyway, this is definitely happening all night long except when there's load shedding (at which point the inverter has no choice but to rely on battery) or when load is over the threshold. Mostly the load alternates between a bit above the threshold and a bit below, and you can see the draw from grid turning off and on as load rises and falls.

 

Edited December 7, 20223 yr by Bobster.
fix mistake

1 hour ago, Pramod said:

My 8 x 450W panels are generating enough power to keep me going through the night - my14,3 kWh battery doesn't get down to the threshold I've set (40% SoC) where it needs to top up from the grid.  However, every day, the Sunsynk 8 kW inverter draws about 0,8 kWh from the grid, always the same every day.  If I switch the mains switch off, everything keeps working just fine, but I'd prefer to keep the grid connected.   Any ideas as to why the Sunsynk uses that 0,8 kWh every day ?

What is the SunSynk "Grid Trickle Feed" set to?

This is to prevent some pre-paid meters from tripping.
0.8kWh/24h ~ 33W
I reduced mine from 50W to 20W - YMMV before issues.

On 2022/12/07 at 9:16 AM, Pramod said:

My 8 x 450W panels are generating enough power to keep me going through the night - my14,3 kWh battery doesn't get down to the threshold I've set (40% SoC) where it needs to top up from the grid.  However, every day, the Sunsynk 8 kW inverter draws about 0,8 kWh from the grid, always the same every day.  If I switch the mains switch off, everything keeps working just fine, but I'd prefer to keep the grid connected.   Any ideas as to why the Sunsynk uses that 0,8 kWh every day ?

I have a new installation with 8kW Sunsynk inverter.
Like @Pramod, we also have 0.8kWh constantly drawn form the grid.
Already set to Zero Export with Limit to Load Only and Grid Trickle feed set to 20W.

If I switch the grid feed to inverter off, everything is working fine, but I prefer to keep the grid connected to top-up batteries before load shedding if required.

Any input on what else can I set / check to remove the 0.8kWh constantly drawn?

8 minutes ago, DeonBez said:

I have a new installation with 8kW Sunsynk inverter.
Like @Pramod, we also have 0.8kWh constantly drawn form the grid.
Already set to Zero Export with Limit to Load Only and Grid Trickle feed set to 20W.

If I switch the grid feed to inverter off, everything is working fine, but I prefer to keep the grid connected to top-up batteries before load shedding if required.

Any input on what else can I set / check to remove the 0.8kWh constantly drawn?

You can set it to 0w and see if that helps... as long as this wont trip your meter

17 hours ago, mzezman said:

You can set it to 0w and see if that helps

Thanks, I set it to 0W. Difficult so see the exact difference as I am using an Efergy energy meter to meausre it, might be slightly lower but still around 0.8kW drawn.
As soon as I switch the grid feed to inverter off, the stray grid power usage disappears.
 
What is interesting, is that the inverter does not show this as part of the Grid usage.

Extra info and explanation:
This morning I captured the prepaid meter reading and waited around 2 hours.
During this time the Efergy meter showed around 0.8kW.
After two hours the prepaid meter reading did not change.
This means that the power seen by the Efergy is not "real" power (but rather reactive power). 
This hooks on to and is confirmed by discussions in the thread below: 

Edited December 13, 20223 yr by DeonBez
Updated info

Thanks for your replies, folks. I spoke to the installer and he said that it was OK to set the grid trickle feed to zero, which I have now done. It was previously set to 10W.

I will monitor for a few days and then report back. I have also noticed what @DeonBezsaid, that the grid usage on the Sunsynk Connect app shows as zero.

When I did the installation, the City of Cape Town came by to change the prepaid meter, because they said that if any power was fed back onto the grid from the inverter, it would have locked up the meter that was installed previously. Next step is to wait for them to lift the restriction that forces us to be net consumers, to justify the R12,000 that they want to charge to install a smart meter. They currently pay about R1 a kilowatt hour that is fed back into the grid.

 

Reducing the grid trickle feed amount to zero reduced the daily grid consumption to about 0,4 to 0,5 kWh.