Hi Folks,

I have 2 12kva 3 phase inverters, 2 x 10Kw batteries and 20 panels. 
My entire DB is connected to the system to run the entire house. 
It’s been running for 8 months now. 
I however noticed, that despite batteries being full, enough solar production, there is a still a continuous draw from the grid. To give perspective, according the SUNSYNK app, I should have used approx 300 units from the grid, but i have purchased 900 for the month. 
Soc set to below 40%. Any ideas?

49 minutes ago, Kingsway said:

Hi Folks,

I have 2 12kva 3 phase inverters, 2 x 10Kw batteries and 20 panels. 
My entire DB is connected to the system to run the entire house. 
It’s been running for 8 months now. 
I however noticed, that despite batteries being full, enough solar production, there is a still a continuous draw from the grid. To give perspective, according the SUNSYNK app, I should have used approx 300 units from the grid, but i have purchased 900 for the month. 
Soc set to below 40%. Any ideas?

Perhaps easier if one can see your graph with use and generation stats. 

The entire DB is connected to the essentials side of your inverters or does some get fed from the non-essentials?

 

Most obvious issue based on what you have said is that the electrician did not wire it up correctly?

The entire db is connected to the inverters. 

5 hours ago, PsyCLown said:

The entire DB is connected to the essentials side of your inverters or does some get fed from the non-essentials?

 

Most obvious issue based on what you have said is that the electrician did not wire it up correctly?

I concur with @Kingsway the only way other way would be to look at the wiring on the DB. I once had my neighbour who's wiring wasn't done properly at the DB and when she wanted to by-pass the inverter, the wiring wasn't done correctly so she couldn't. Had to rewire the DB. Such errors also mean that some loads may appear to be phantomic as they are not fully captured by the app as they my have 'jumpered" lines on the DB. One way to check would be to switch off inverter and batteries and see if there's anything being powered up when you have the grid.

7 hours ago, Moffat said:

I concur with @Kingsway the only way other way would be to look at the wiring on the DB. I once had my neighbour who's wiring wasn't done properly at the DB and when she wanted to by-pass the inverter, the wiring wasn't done correctly so she couldn't. Had to rewire the DB. Such errors also mean that some loads may appear to be phantomic as they are not fully captured by the app as they my have 'jumpered" lines on the DB. One way to check would be to switch off inverter and batteries and see if there's anything being powered up when you have the grid.

This is a good idea - turn off inverter & batteries and then walk through the house testing everything connected to power and see what might still work.

Gate motors, pumps, plugs, geyser, lights etc.

Thanks. I’ll give it a go and see what happens. 
 

17 hours ago, Kingsway said:

Thanks for the extra information. Based on the period on the graph you got about 5 times more power from PV than what you used from grid. 

If you bought 900 units last month of prepaid and all 900 were used up and not available and the inverter shows only 300 used from grid then one would need to look at much shorter periods. 

Compare say on a daily basis what the inverter indicates vs how many units you have used from the grid. 

At any given time during the day the readings from the inverter will have to be compared to an actual measurement of what the grid is providing. Readings taken at the same point in time as the screen shot. 

Here the screen shot from the inverter during a sunshine day will also help but only if this actual reading is available. 

Are you setup to export to the grid with the proper bidirectional meter?

3 hours ago, madness_za said:

Are you setup to export to the grid with the proper bidirectional meter?

I had a look at the stats for export being the problem but that only accounts for 31 kWh over 4 months so that is thus excluded. Too little money to have the major affect of 600 units difference last month. 

I did make a mistake as the 6 items for the legend seems to be for the last month and not a total for the 4 months. 

That's how I see it. 

Edited December 2, 20232 yr by Scorp007

@madness_za no its not setup to export to grid. I dont have a bi directional meter. 

 

@Scorp007 the 31 export is for the month on Nov. even though its setup as no export. 

It still doesn’t account for the large difference though.Even on a daily basis, the consumption on the app reading is lower than actual units on the prepaid meter. The meter is using 15 units on a sunny day when the app says i should have used 2kwh. 

Ill get installer back to check CT coils installation

Thanks. I’ll give it a go and see what happens. 
 

3 hours ago, Kingsway said:

Thanks. I’ll give it a go and see what happens. 
 

There is a total disconnect between the grid power value of 33W and the amps on all 3 phases. At the point of the screen shot the inverter was basically powering your load and over 50% of PV is used to charge the battery due to the negative reading. 

I would say the CTs need to be checked as the grid current makes no sense. 

May be @GreenFields can comment based on the values provided. 

You are paying for your neighbours power - stuff up in the meter box?

27 minutes ago, Paulcupine said:

You are paying for your neighbours power - stuff up in the meter box?

We still need to see the system screen where the CT is shown as well as the other data. The graphic and not the text version. 

Edited December 6, 20232 yr by Scorp007

51 minutes ago, Paulcupine said:

You are paying for your neighbours power - stuff up in the meter box?

This can be a thing.

Some years ago I declared war on my municipal bill. First round was to switch all lighting to CFL (LED not being an option back then). Then I put in solar water heating. 

The electricity section of the bill kept on going up.

Long story short. After a series of queries to City Power, they sent out a lady who had a tool for tracing cables. She found out that the whole street was cross wired. Sub contractors had done work for them and had wired any old house to any old meter. The City had, according to their rules and the way the meter box in the street was labelled, matched each meter to the property it SHOULD have been feeding.

One consequence of this was that my neighbours were getting all the savings that should have been mine.

So eventually they traced all the cables. Remapped the meters to the accounts. Now they had to reconcile the accounts back to the date of the installation of the meter box. This resulted in some folks (EG me) getting a series of credits on their account, and others (eg my neighbour) suddenly having to break open the piggy bank. 

This is less likely to happen where I live now, because there are no meter boxes in the street. Every house has it's own meter, inside a box with the main breaker. 

@Kingsway,

I picked up an error like this on a family member's fresh 3ph 12kW Deye installation, and had taken screenshots of the pre-paid meter every morning after the installation, and he was using many units. I realised that the Inverter was "trying" to export, simular to yours. which it shouldn't do, as the prepaid meter will trip. But those fedback units does make your pre-paid meter run faster - in the wrong direction - hence your elevated top-up. After many phone calls, got the installer to swop one of the CT coils (just swopped the wires around) and that sorted it out. 

For those with non-essencials connected, you may as well check if those take power from solar when the grid is available, else the position (as appossed to the orientation) of the CT coil/s are also incorrect. A common mistake if the DB for the incoming grid feed is not near your inverter DB.

 

1 hour ago, Sidewinder said:

@Kingsway,

I picked up an error like this on a family member's fresh 3ph 12kW Deye installation, and had taken screenshots of the pre-paid meter every morning after the installation, and he was using many units. I realised that the Inverter was "trying" to export, simular to yours. which it shouldn't do, as the prepaid meter will trip. But those fedback units does make your pre-paid meter run faster - in the wrong direction - hence your elevated top-up. After many phone calls, got the installer to swop one of the CT coils (just swopped the wires around) and that sorted it out. 

For those with non-essencials connected, you may as well check if those take power from solar when the grid is available, else the position (as appossed to the orientation) of the CT coil/s are also incorrect. A common mistake if the DB for the incoming grid feed is not near your inverter DB.

 

Good reply. That's the reason why I mentioned the screen showing the CT as one will then see the direction of the flow to see if it is exporting indicating a wrong polarity. We see it with so many members and that while the instructiins/manual is very clear on the direction. 

The one funny in this case is the PV generated matches the power to load as well as battery that is charging. 

Edited December 6, 20232 yr by Scorp007

@Kingsway,

This is the screen you need to look at. If any of the CT values are red, it indicated, as in this case, 2 of the CT coils were in the wrong direction.

One wonders how so-called professional installers get accredited when they make such rooky mistakes. (and get paid for it)

Quote

I however noticed, that despite batteries being full, enough solar production, there is a still a continuous draw from the grid.

Set Zero Export + Limit to Load Only this will prevent export and only supply output to the "Backup Load" UPS circuit.

Or:

1. Check that all 3 CT coils are installed in the correct direction.
2. Check that there is no loads between the CT coils and the metro meter.
3. Reduce the inverter trickle feed - mine is set to 20W on CoJ pre-paid with no issues.

 

eg
100W * 24h * 30days = 72kWh per month - not sure if 72kWh per phase

 

 

 

Edited December 6, 20232 yr by system32

can induction on cables change the app readings - eg cable magnetic feed that cancels grid use kw on app or inverter but grid is used?

43 minutes ago, craig shaw said:

can induction on cables change the app readings - eg cable magnetic feed that cancels grid use kw on app or inverter but grid is used?

I guess it can if running parallel to other cables but dc in other cables I think will have less of an affect? The CT wires are at high frequency and might be affected but no experience of high frequency stuff. 

12 hours ago, Scorp007 said:

I guess it can if running parallel to other cables but dc in other cables I think will have less of an affect? The CT wires are at high frequency and might be affected but no experience of high frequency stuff. 

Also by now it would be known, and there would be shielding in the cables or instructions to run them on separate conduits. 

ISTM The most common problem we find here with Deye/Sunsynk is CT coils the wrong way around. Which I don't think is a Sunsynk thing, it's just because that is such a common inverter here.