Sun Synk 5kW - use for non-critical loads

[CSolar]

Hi all

 

Just had my new inverter installed and want to confirm that my understanding is correct

 

I have critical load circuits, and non-critical load circuits. The former are all connected to the inverter, the latter only consist of my oven and geyser.

 

I understand that it is possible to direct excess PV power to off-set the grid draw on non-critical load circuits (like my geyser). Is this correct? So let’s say PV generates 3000W, essential circuits are drawing 2000W and batteries are full. Geyser switches on and draws 2500W - the excess 1000W of PV is used to off-set draw from the grid and as such I only use 1500W from Eskom. This can be done without pushing back to the grid, through use of the CT clamp. Note that I am also not looking to use the Aux port for this.

Is my understanding correct? I have been told that the inverter is correctly set up, but did the following test:

Load from the house - 700W

PV generates 700W

Then I switch on the tumble dryer and load goes up to 2700W, with PV going to 2200W. OK, all good.

Switch off tumble dryer and load and PV drops back to 700W. Now I switch on my geyser, and the house load stays on 700W (as expected, as the geyser load does not go through the inverter). I would, however, expect the PV generation to go back up so that it off-sets some of the geyser draw.

Can someone please explain the flaw in my logic?

 

Edited May 13, 2021 by CSolar

[Tariq]

The geyser has to be connected after the CT clamp BUT before the inverter, now the inverter will push excess pv to the geyser, only difference is that when load shedding occurs the geyser won’t switch on

[CSolar]

6 minutes ago, Tariq said:

The geyser has to be connected after the CT clamp BUT before the inverter, now the inverter will push excess pv to the geyser, only difference is that when load shedding occurs the geyser won’t switch on

Thanks for the quick response Tariq. So still not on a critical load?

 

Is this the standard way of installing these?

Edited May 13, 2021 by CSolar

[CSolar]

1 minute ago, Brani said:

You said you are not using AUX port, so I understand you have critical loads connected to Load, and noting on aux.

Your inverter is connected directly to the mains from Eskom?

where is your geyser connected?

You said you are not using AUX port, so I understand you have critical loads connected to Load, and noting on aux.

Your inverter is connected directly to the mains from Eskom? Yes

where is your geyser connected? Directly to Eskom. So if Eskom goes down my geyser does not work

[CSolar]

2 minutes ago, Brani said:

Here is an example of how it should be connected if you want to feed non critical loads with excess solar.

Thanks Brani. Any chance of posting a link, or editing the pic so that the sides are not cut off (or perhaps it’s just me?)

[Achmat]

As @Tariqmentioned.

 

The CT sensor needs to be on the line immediately after the main incoming circuit at the meter. 

This is the standard way of installing the CT sensor. I've heard of installers putting the CT sensor right at the main feed just before the inverter, effectively not allowing the inverter to send excess to any loads before the inverter. 

[Achmat]

Pic from the installation manual. 

[CSolar]

Thanks all!

[CSolar]

On 2021/05/13 at 6:16 PM, Achmat said:

Pic from the installation manual. 

Any idea how this will have to look different when there is a three phase power supply?

[CSolar]

So I had the installed back today to try and fit the CT clamp correctly and re-did my experiment. Full sun on panels, load 400ish W and PV the same. Switch on the geyser.... Nothing happens. Fiddle in the settings and un-tick the "Limit to Load only" box on the first picture. Redo the experiment and get the following before and after pics (for grid view and flowchart view).

Does this look correct to you?

[Achmat]

1 hour ago, CSolar said:

So I had the installed back today to try and fit the CT clamp correctly and re-did my experiment. Full sun on panels, load 400ish W and PV the same. Switch on the geyser.... Nothing happens. Fiddle in the settings and un-tick the "Limit to Load only" box on the first picture. Redo the experiment and get the following before and after pics (for grid view and flowchart view).

Does this look correct to you?

That looks much better. 

Is the first pic after changing the settings? Maybe edit the post and before/after before each pic. 

[Achmat]

9 hours ago, CSolar said:

Any idea how this will have to look different when there is a three phase power supply?

No idea as I've only looked at the single phase setup. @leshencould comment on the 3 phase connections. 

[Achmat]

Would be interested to know where the installer connected the CT clamp. 

[CSolar]

20 minutes ago, Achmat said:

That looks much better. 

Is the first pic after changing the settings? Maybe edit the post and before/after before each pic. 

Cannot for the life of me find an edit button (only "share" or "report") so will do one by one. This was after the changed settings

[CSolar]

Just now, CSolar said:

Cannot for the life of me find an edit button (only "share" or "report") so will do one by one. This was the grid and flow view before switching on the geyser

 

 

[CSolar]

1 minute ago, CSolar said:

This is the view after switching on the geyser - Is it OK for the LD value to be negative?

Also, Load Power represents all the critical loads, but I am struggling to make out what "Inverter Power" represents?

 

 

[CSolar]

23 minutes ago, Achmat said:

Would be interested to know where the installer connected the CT clamp. 

The way I understand it my DB board was split into it's three phases with critical loads going on one, the oven on the second and the geyser on the third (with the latter two not working when there is load shedding). The geyser is now also on the first, but on the Eskom side of the inverter. The CT clamp is then on the Eskom side of the geyser. Or something like that...

[Leshen]

9 hours ago, CSolar said:

Any idea how this will have to look different when there is a three phase power supply?

Hi CSolar. 
 

In a single phase home, that has a single phase supply, you have one live, one neutral and one earth cable that is fed into your main DB from your outside supply. 
 

The inverter will use this single phase as its AC supply as well as feed power back into the grid or into what’s called the Non essential load. This is marked “Grid” on the inverter and is a bi directional port. Note that the non essential load needs to be “tapped off” between the inverter and the CT. This is crucial. 
 

Regarding 3 phase, you have 3 live wires, red, yellow and blue, one common neutral and one earth from your outside supply that’s fed into your main DB. For you to power all 3 phases with a Sunsynk, you will need 3 separate inverters all wired in the same way as above using the 3 lives with a common neutral. The big concern here is to figure out the correct phase rotation or else a 3 phase setup won’t work and you get all sorts of weird faults. 
 

In a 3 phase home, you can also just have 1 Sunsynk powering just 1 phase, all you will need to do is to use the 1 live and the common neutral to supply the inverter. 

[CSolar]

4 minutes ago, leshen said:

Hi CSolar. 
 

In a single phase home, that has a single phase supply, you have one live, one neutral and one earth cable that is fed into your main DB from your outside supply. 
 

The inverter will use this single phase as its AC supply as well as feed power back into the grid or into what’s called the Non essential load. This is marked “Grid” on the inverter and is a bi directional port. Note that the non essential load needs to be “tapped off” between the inverter and the CT. This is crucial. 
 

Regarding 3 phase, you have 3 live wires, red, yellow and blue, one common neutral and one earth from your outside supply that’s fed into your main DB. For you to power all 3 phases with a Sunsynk, you will need 3 separate inverters all wired in the same way as above using the 3 lives with a common neutral. The big concern here is to figure out the correct phase rotation or else a 3 phase setup won’t work and you get all sorts of weird faults. 
 

In a 3 phase home, you can also just have 1 Sunsynk powering just 1 phase, all you will need to do is to use the 1 live and the common neutral to supply the inverter. 

Thanks for the info Leshen - in my case we have done the latter (i.e. use only one of the three phases)

[Leshen]

1 minute ago, CSolar said:

Thanks for the info Leshen - in my case we have done the latter (i.e. use only one of the three phases)

Seems to be working fine from your pics. If you don’t have a smart meter, reduce the 50w on the System Mode page to 0. Just a waste to keep drawing a constant 50w unless you have a sensitive meter that trips then leave it at 50. 

[YellowTapemeasure]

1 hour ago, leshen said:

Seems to be working fine from your pics. If you don’t have a smart meter, reduce the 50w on the System Mode page to 0. Just a waste to keep drawing a constant 50w unless you have a sensitive meter that trips then leave it at 50. 

+1

I have a Landis Gyr meter, and initially I set it to draw 20W as per Sunsunk support, and it idid not trip. Then set the Sunsynk to draw 10W. Did not trip for many months. Now set it to draw 0W, the same result.

Sometimes it needs a little experimentation, but some meters just do not trip.

I haven't tried grid feed yet, because I am led to believe that the meter will count up instead of down. Anyone with a Landis Gyr that can attest to this?

[Convict]

Hi .With regards to the non essential load aka the grid input . What is the max wattage that can be returned.  I have a 5 kva unit and if oven comes on and the mic it tops out over 5kva .I do know the load side must be under the 5 kva  but is there a limit on wattage for the return . As the little house icon can go up to 7500w and is a bit worrying . Not sure if the it's just measuring the total house draw then . Thanks   

Craig 

[Gerrie]

On 2021/05/17 at 9:11 PM, YellowTapemeasure said:

I have a Landis Gyr meter, and initially I set it to draw 20W as per Sunsunk support, and it idid not trip.

Hi YellowTapemeasure I also have the Landis Gyr pre-paid meter with Sunsynk set to draw the 20W, it has not yet tripped but I did notice on the inverter screen today that while the washing machine drum ramps up and down (non essential load) there is a slight back feed to grid of +-10 to 40Watt. This happens for about 3seconds and than changes to draw again the 20Watt. Happens about 5 times a minute but I could not see any effect on meter or credits changing.

Do you know what is meant by pre-paid meters tripping? does it actually stop working or what state does it go to, and how does it come right again. I also want to set the draw to zero but don’t know what to expect.

[YellowTapemeasure]

15 hours ago, Gerrie said:

Hi YellowTapemeasure I also have the Landis Gyr pre-paid meter with Sunsynk set to draw the 20W, it has not yet tripped but I did notice on the inverter screen today that while the washing machine drum ramps up and down (non essential load) there is a slight back feed to grid of +-10 to 40Watt. This happens for about 3seconds and than changes to draw again the 20Watt. Happens about 5 times a minute but I could not see any effect on meter or credits changing.

Do you know what is meant by pre-paid meters tripping? does it actually stop working or what state does it go to, and how does it come right again. I also want to set the draw to zero but don’t know what to expect.

From what I understand, some prepaid meters are sensitive to current flowing in the "wrong" direction as it is seen as potential tampering, so they will trip (at the actual meter in the street), necessitating it to be reset.

[Laurene]

Hi. Forgive me if this is not 100% on topic. I have a Sunsynk 8kw. Regarding non essential load side: if I have excess PV power and it feeds the non essential side but the non essential load is more than the excess PV will it use battery to “top up” or pull from grid. Ie. Non essential is 3kw, excess PV is 2kw, will the 1kw shortage come from batteries or grid?