Hi Guys 

Just wanted to ask if anyone else has noticed something with their Sunsynk inverters that I have experienced or if it is just my one. 

Wondering if it has something to do with the new setup on the System Mode screen

My house if full of LED lights and I have a coffee grinder that is very sensitive to power, as soon the grinder detects a few missed cycles it switches off. 

Seems to usually happen around supper time when my inverter is on a battery discharge cycle, i.e. Batteries have been fully charged during the day and the inverter is now pulling power from the batteries until I reach the level that I have decided to keep in case of load shedding. 

Have noticed it more when a largish load is turned on, e.g. Air-fryer/Toaster/Kettle, I get a flicker off my lights and my grinder power switches off, this seems to happen every 2-3 minutes 

Watching my inverter when this happens, I am thinking that it has something to do with the is switching between mains power & battery power and then back again. 

My thinking is that there is perhaps a gradient between say 80% SOC @ 16:00  & 40% SOC @ 20:00, when the inverter is sitting on top side of the SOC gradient it can use the battery to power everything, but when the SOC drops too low it switches back to Mains power until such time as it catches up and it then switches back to battery power.  

Has anyone else experienced this with their Sunsynk inverter? 

Without exception every inverter will do this except double conversion "inverters" (always supply power from DC instead of directly from AC).

Switching between AC power sources requires heavier duty relays and they need time to switch.  Additionally, even if they were to make it switch faster, there are a whole bunch of situations in which it would arc between the two power sources, quite likely exploding.

As you say, some devices are really sensitive to any kind of power interruption.  Mostly because they are cheaply made.  I say this because the loss of AC power will be less than a full AC cycle, ~¼ of a cycle and a low load DC device should be able to ride through that quite easily.  AC devices typically don't have the smarts to detect such a upset and you'll notice it as a slight flicker.

Lastly even if you had a double conversion inverter, when turning on heavy loads you'd notice a flicker with lights.  The huge surge causes a voltage drop.  You don't notice it on the grid because it has, insanely low impedance.  Your inverter on the other hand has a significant impedance.  It is a side effect of components required to create a high quality AC wave.  No matter how powerful your inverter is, this impedance limits the speed at which a surge can be reacted to.  Older design inverters like Victron which use a heavy duty transformer will have significant impedance and thus very likely exhibit this even more.

Edited October 24, 20214 yr by Gnome

Sounds like your batteries are battling with a large intermittent load, and mains is required to assist with the instantaneous load.

Try the same load with mains off, and see if the inverter shuts down.  😂

15 minutes ago, TimCam said:

Sounds like your batteries are battling with a large intermittent load, and mains is required to assist with the instantaneous load.

Try the same load with mains off, and see if the inverter shuts down.  😂

Don't think it is a battery issue, runs of the batteries no problem when the SOC is above the SOC limits in the System Mode screen.

The flickering, only happens when the inverter approaches the discharge SOC limit in the system mode screen. 

I suspect the flickering is caused by the inverter switching between eskom and battery 

2 hours ago, Gnome said:

Without exception every inverter will do this except double conversion "inverters" (always supply power from DC instead of directly from AC).

Switching between AC power sources requires heavier duty relays and they need time to switch.  Additionally, even if they were to make it switch faster, there are a whole bunch of situations in which it would arc between the two power sources, quite likely exploding.

As you say, some devices are really sensitive to any kind of power interruption.  Mostly because they are cheaply made.  I say this because the loss of AC power will be less than a full AC cycle, ~¼ of a cycle and a low load DC device should be able to ride through that quite easily.  AC devices typically don't have the smarts to detect such a upset and you'll notice it as a slight flicker.

Lastly even if you had a double conversion inverter, when turning on heavy loads you'd notice a flicker with lights.  The huge surge causes a voltage drop.  You don't notice it on the grid because it has, insanely low impedance.  Your inverter on the other hand has a significant impedance.  It is a side effect of components required to create a high quality AC wave.  No matter how powerful your inverter is, this impedance limits the speed at which a surge can be reacted to.  Older design inverters like Victron which use a heavy duty transformer will have significant impedance and thus very likely exhibit this even more.

I suspect that the solution will be to make sure that the inverter is not running from batteries during the dinner rush 

That is a really strange problem , what battery do you have ?

Edited October 24, 20214 yr by Nexuss

43 minutes ago, Sc00bs said:

Don't think it is a battery issue, runs of the batteries no problem when the SOC is above the SOC limits in the System Mode screen.

The flickering, only happens when the inverter approaches the discharge SOC limit in the system mode screen. 

I suspect the flickering is caused by the inverter switching between eskom and battery 

OK, so the batteries have enough juice to supply your load, but when close to "set min" SOC, and a large intermittent load kicks in, for that instant, the "set min" SOC is passed, and the inverter switches back to mains. No hysteresis here? But then it should stay on mains until the battery reaches "set upper" SOC ?

Hi, this is a grid tie inverter and there is no switching (confirm this by checking the grid V and the load V which will be the same) except when it disconnects form the grid because the grid has failed. On mine when the minimum SOC is reached it slowly transfers the load from the battery to the grid (i.e. just reduces the inverter power).  Maybe it is a setting issue. Are you zero export to load or zero export to CT. My system regularly switches on and off a 2hp water pump and there is no "flickering" even when disconnected from the grid.  I am impressed with the performance of this inverter.  Are you sure that it is not disconnecting from the grid and re-connecting because it reaches one of the Hz or V limits in the grid settings.  Really should not do this unless you have a really weak grid connection.

Remember, the transfer time is not 0. The inverter will likely only start inverting after the next zero-crossing or the one after that. With that in mind, how the LED will respond depends on it's PSU implementation. Are these dimmable LEDs?

I would not pay much attention to it.