Problem Description

Your SunSynk inverter and Solar Assistant are showing power consumption values that do not make sense and do not add up when using conventional logic and even the built-in display on the inverter itself is showing grid load numbers that do not make sense at face value.

In addition, the latest version of the SunSynk mobile app that now has a detailed power flow view that splits the loads into Essential and Non-Essential loads will now sometimes show a negative value for the non-essential load, but at the same time the display on the inverter itself will show that value as 0 (ZERO).

Explanation of observed behavior and values

In order to explain this problem it is necessary to first show the most simple real world example of this actually happening on my inverter display.

When this photo was taken the Solar panel trip switches on the Solar DB were off to prevent Solar from getting involved and simplify the troubleshooting process, and the battery was at 100% and the inverter was configured to not use the battery at all.

In addition, all trip switches for all non-essential loads, on the non-essential (original) DB board were dropped, to ensure no very low latent load (e.g geyser sensors using 10 watts)  from any non-essential loads either, again to simplify troubleshooting.

A photograph of my inverter's built-in flow display was then taken:

The above photograph demonstrates the problem perfectly:  674 Watts is a fake and invalid number and 632 Watts also does not make sense

The 0 Watts indicated above the house icon (non-essential load) appears to be accurate at first glance because, as stated above, I turned off all non-essential loads completely on the old DB board, which means that there should be no draw at all from non-essential loads, and that seems to be the case in the photograph.

Unfortunately things are not as they seem because the 674 Watts shown in the second blue circle is a completely invalid number that does not correlate to any real world draw in any way.

And if you had looked at the detailed power flow diagram in the latest version of the mobile app you would have seen that it did not show 0 Watts at the same time that this photograph was taken, instead it actually showed -42 (negative 42) Watts as the non-essential load.

-42 is a very interesting number in this case because if you subtract -42 (add 42, because subtraction of a negative value is actually addition) from 632 (the actual amount of Watts the grid was allegedly supplying at the time), you get 674, which is the incorrect grid input total being reflected in the photograph above.

If you add together the amount of power that the Inverter itself was consuming at that point in time (39 watts) and the amount of power being supplied to the Essential loads at that point in time (551 Watts) you get 590 Watts, and 590 Watts is actually what the grid input total was at that point in time, not 674 watts.

Note:  590 (Actual grid input to inverter) + 42 (The hidden non-essential load value)  = 632 (The actual watts allegedly being drawn from the Grid at that time)

Note:   The 632 Watt "actual reported draw from CT" reflected in this example is also puzzling because the -42 Watt non-essential load was not actually a load, it was actually a CT calibration error, and in fact there was ZERO non-essential load at that point in time drawing 0 watts, which means that the reported current draw from the CT should have been 590 Watts, not 632 Watts. 

So what is actually going on there, how is the "Grid power supplied to the Inverter" value (674) inflated, and how can the non-essential load value be a negative number?

From some experimentation I have isolated the problem to inaccuracies on the part of the CT (The CT is not calibrated to zero accurately), and to make matters worse the inaccuracy of the CT varies dependent on how much current is being drawn from the Grid. The more current you draw from the Grid through the CT, the more accurate the CT becomes, and this is because the standard CT used with a SunSynk inverter uses a CT ratio of 2000:1 (2000 amps are reflected as 1 amp for the purposes of monitoring) and consequently a very low primary current results in an extremely low fractional secondary current that is being monitored by the inverter, to the extent that the inverter can actually under read to the point where the calculated non-essential load value reflects as a negative value when it should be zero.

You can adjust for this problem on the SunSynk inverters by modifying the CT Ratio in the advanced menu to "calibrate for zero" when you actually have zero non-essential load, but unfortunately as the Grid draw increases and the CT accuracy improves the compensation you made by adjusting the CT ratio becomes an over compensation to a small extent, and there does not appear to be any way to combat that phenomenon.

My current CT ratio is set to "2155:1" and that gives me a dead zero non-essential load reading on the built-in display AND in the mobile app detailed flow view now, if my non-essential loads are actually zero, and remains dead accurate for any very low non-essential load below around 250 watts, but any load higher than that starts to affect accuracy very slightly again.

The following photograph shows the values reflected on my inverter after adjusting CT ratio and turning non-essential loads back on (incurring 30 watts of latent non-essential power draw):

As you can see, the numbers all make perfect sense in that photo and so do the flow indicators.

The amount of power we are talking about here, as reflected in the slightly inaccurate non-essential load numbers, is very small and not really worth getting upset about BUT
SunSynk do need to update their UI to be consistent and also make sure that any graphs and reports are not incorrectly adding those negative numbers to derive inferred load values because otherwise reports over time will show totals that very inaccurate.

As a simple example, if the CT is under reading by 50 watts on average and the "Grid supply to Inverter value" is therefore inflated by 50 Watts on average, that would equate to (24 hours x 50Wh = 1200 Wh = 1.2 Kwh per day) of additional grid draw being reflected that is a complete fabrication.

Over 30 days that equates to (30 x 1.2Kwh = 36Kwh) of non existent grid draw being reflected.

Conclusion and Suggestions

In my opinion SunSynk need to make some adjustments to their firmware and app to address this issue.

I have no problem with them ignoring negative values, hiding them from end users, and reflecting a value of zero instead, because most end users will not be able to grasp the technical reasons for those negative values and how CTs work.

But if SunSynk are going to show 0 (ZERO) when the number is negative they must also treat the value as ZERO in any calculations, they cannot substract the actual negative number and thereby add it to totals that it should not be added to.

On the mobile app they currently do show the negative number but they should probably change that to do that same thing they do on the built-in display and show Zero rather and then also make sure that the app does not subtract that negative number from any totals anywhere.

Whatever they decide, it should also be consistent between their app and the on-device display.

It also worth noting that 3rd part monitoring solutions like Solar Assistant (which I also have running) are also impacted by negative non-essential load values and the calculations made by those 3rd party systems are also affected and also produce seemingly impossible total values that make no sense because of the negative value being reported by the inverter and being used in calculations where a subtraction is expected to reduce the total and not inflate it.

If SunSynk fix this by zeroing negative non-essential load values in memory on the inverter, that would theoretically fix the 3rd party systems automatically, but if SunSynk choose to retain the negative value in memory and simply display it as zero and consider it zero in internal calculations then the 3rd party software will also need to be updated to compensate for this phenomenon.

 

 

 

 

 

 

Edited March 26, 20242 yr by SiliconKid
Value was given as Watts instead of Wh

1 hour ago, SiliconKid said:

Problem Description

Your SunSynk inverter and Solar Assistant are showing power consumption values that do not make sense and do not add up when using conventional logic and even the built-in display on the inverter itself is showing grid load numbers that do not make sense at face value.

In addition, the latest version of the SunSynk mobile app that now has a detailed power flow view that splits the loads into Essential and Non-Essential loads will now sometimes show a negative value for the non-essential load, but at the same time the display on the inverter itself will show that value as 0 (ZERO).

Explanation of observed behavior and values

In order to explain this problem it is necessary to first show the most simple real world example of this actually happening on my inverter display.

When this photo was taken the Solar panel trip switches on the Solar DB were off to prevent Solar from getting involved and simplify the troubleshooting process, and the battery was at 100% and the inverter was configured to not use the battery at all.

In addition, all trip switches for all non-essential loads, on the non-essential (original) DB board were dropped, to ensure no very low latent load (e.g geyser sensors using 10 watts)  from any non-essential loads either, again to simplify troubleshooting.

A photograph of my inverter's built-in flow display was then taken:

The above photograph demonstrates the problem perfectly:  674 Watts is a fake and invalid number and 632 Watts also does not make sense

The 0 Watts indicated above the house icon (non-essential load) appears to be accurate at first glance because, as stated above, I turned off all non-essential loads completely on the old DB board, which means that there should be no draw at all from non-essential loads, and that seems to be the case in the photograph.

Unfortunately things are not as they seem because the 674 Watts shown in the second blue circle is a completely invalid number that does not correlate to any real world draw in any way.

And if you had looked at the detailed power flow diagram in the latest version of the mobile app you would have seen that it did not show 0 Watts at the same time that this photograph was taken, instead it actually showed -42 (negative 42) Watts as the non-essential load.

-42 is a very interesting number in this case because if you subtract -42 (add 42, because subtraction of a negative value is actually addition) from 632 (the actual amount of Watts the grid was supplying at the time), you get 674, which is the incorrect grid input total being reflected in the photograph above.

If you add together the amount of power that the Inverter itself was consuming at that point in time (39 watts) and the amount of power being supplied to the Essential loads at that point in time (551 Watts) you get 590 Watts, and 590 Watts is actually what the grid input total was at that point in time, not 674 watts.

Note:  590 (Actual grid input to inverter) + 42 (The hidden non-essential load value)  = 632 (The actual watts supposedly being drawn from the Grid at that time)

Note:   The 632 Watt "actual reported draw from CT" reflected in this example is also puzzling because the -42 Watt non-essential load was not actually a load, it was actually a CT calibration error in fact there was ZERO non-essential load at that point in time drawing 0 watts, which means that the reported current draw from the CT should have been 590 Watts, not 632 Watts. 

So what is actually going on there, how is the "Grid power supplied to the Inverter" value (674) inflated, and how can the non-essential load value be a negative number?

From some experimentation I have isolated the problem to inaccuracies on the part of the CT (The CT is not calibrated to zero accurately), and to make matters worse the inaccuracy of the CT varies dependent on how much current is being drawn from the Grid. The more current you draw from the Grid through the CT, the more accurate the CT becomes, and this is because the standard CT used with a SunSynk inverter uses a CT ratio of 2000:1 (2000 amps are reflected as 1 amp for the purposes of monitoring) and consequently a very low primary current results in an extremely low fractional secondary current that is being monitored by the inverter, to the extent that the inverter can actually under read to the point where the calculated non-essential load value reflects as a negative value when it should be zero.

You can adjust for this problem on the SunSynk inverters by modifying the CT Ratio in the advanced menu to "calibrate for zero" when you actually have zero non-essential load, but unfortunately as the Grid draw increases and the CT accuracy improves the compensation you made by adjusting the CT ratio becomes an over compensation to a small extent, and there does not appear to be any way to combat that phenomenon.

My current CT ratio is set to "2155:1" and that gives me a dead zero non-essential load reading on the built-in display AND in the mobile app detailed flow view now, if my non-essential loads are actually zero, and remains dead accurate for any very low non-essential load below around 250 watts, but any load higher than that starts to affect accuracy very slightly again.

The following photograph shows the values reflected on my inverter after adjusting CT ratio and turning non-essential loads back on (incurring 30 watts of latent non-essential power draw):

As you can see, the numbers all make perfect sense in that photo and so do the flow indicators.

The amount of power we are talking about here, as reflected in the slightly inaccurate non-essential load numbers, is very small and not really worth getting upset about BUT
SunSynk do need to update their UI to be consistent and also make sure that any graphs and reports are not incorrectly adding those negative numbers to derive inferred load values because otherwise reports over time will show totals that very inaccurate.

As a simple example, if the CT is under reading by 50 watts on average and the "Grid supply to Inverter value" is therefore inflated by 50 Watts on average, that would equate to (24 hours x 50Wh = 1200 Watts = 1.2 Kwh per day) of additional grid draw being reflected that is a complete fabrication.

Over 30 days that equates to (30 x 1.2Kwh = 36Kwh) of non existent grid draw being reflected.

Conclusion and Suggestions

In my opinion SunSynk need to make some adjustments to their firmware and app to address this issue.

I have no problem with them ignoring negative values, hiding them from end users, and reflecting a value of zero instead, because most end users will not be able to grasp the technical reasons for those negative values and how CTs work.

But if SunSynk are going to show 0 (ZERO) when the number is negative they must also treat the value as ZERO in any calculations, they cannot substract the actual negative number and thereby add it to totals that it should not be added to.

On the mobile app they currently do show the negative number but they should probably change that to do that same thing they do on the built-in display and show Zero rather and then also make sure that the app does not subtract that negative number from any totals anywhere.

Whatever they decide, it should also be consistent between their app and the on-device display.

It also worth noting that 3rd part monitoring solutions like Solar Assistant (which I also have running) are also impacted by negative non-essential load values and the calculations made by those 3rd party systems are also affected and also produce seemingly impossible total values that make no sense because of the negative value being reported by the inverter and being used in calculations where a subtraction is expected to reduce the total and not inflate it.

If SunSynk fix this by zeroing negative non-essential load values in memory on the inverter, that would theoretically fix the 3rd party systems automatically, but if SunSynk choose to retain the negative value in memory and simply display it as zero and consider it zero in internal calculations then the 3rd party software will also need to be updated to compensate for this phenomenon.

 

 

 

 

 

 

Thanks for so much detail information. I have always wondered if the CT ratio can be adjusted to about within 0.005 to 1.

Can you please indicate under which menu item to find it. 

15 hours ago, Scorp007 said:

Thanks for so much detail information. I have always wondered if the CT ratio can be adjusted to about within 0.005 to 1.

Can you please indicate under which menu item to find it. 

On the inverter itself go into the Advance menu and then go to the Others tab and you will find CT_Ratio there as an integer number you can edit.

You can also change it via the inverter settings from the Equipment page in the mobile app, under the Advanced options.

5 hours ago, SiliconKid said:

On the inverter itself go into the Advance menu and then go to the Others tab and you will find CT_Ratio there as an integer number you can edit.

You can also change it via the inverter settings from the Equipment page in the mobile app, under the Advanced options.

Thanks. I am sure some members will find it useful to try out to get more accurate readings. I have not seen this point covered in manuals or videos. 

Hi SiliconKid

I also wanted to start a thread related to this problem. It's very annoying and Sunsynk needs to fix this problem. The picture below shows my inverter stats which have inaccuracies. This inverter is not exporting anything to non-essential yet here it shows -24watts. What is this -24watts?

 

 

 

1 hour ago, Scorp007 said:

Thanks. I am sure some members will find it useful to try out to get more accurate readings. I have not seen this point covered in manuals or videos. 

The CT ratio change will not entirely remove the problem.. the moment the inverter is loaded the numbers will be off again.

Edited March 24, 20242 yr by Jakac

8 hours ago, Jakac said:

 

The CT ratio change will not entirely remove the problem.. the moment the inverter is loaded the numbers will be off again.

Correct, as stated in my original post above:

"but unfortunately as the Grid draw increases and the CT accuracy improves the compensation you made by adjusting the CT ratio becomes an over compensation to a small extent, and there does not appear to be any way to combat that phenomenon."

We actually need SunSynk to make some changes, treat the negative load values as zero, and stop using the negative values in their internal calcs.