First post, so hello everyone!

Got all my kit from PowerForum store and about to commence installing.... I didn't want to do it myself (still wont do it all myself, solar panels I will get someone else to do), but the wait times for reputable installers forced my hand.   Sunsynk 5kw inverter and hubble am2 battery for now, and later adding a second battery.

I just have one question:   the CT Coil,   how tight does it have to be around the live wire?    I've booked the CoCT team to allow me to open my pre-paid meter (it's in the garage next to the inverter location) and want to install the CT coil in there.   Firstly, is this location okay (it's a pain to get the CT Coil to the DB Board)?   And secondly the "hole" in the CT coil is a lot bigger than the live cable going to the DB board..... so is this okay?

 

Thanks!

You want to get the CT coil as close to the main incommer as possible. At the meter should be perfect.

The air gap is of no consequence.

Edited January 14, 20223 yr by Scubadude

8 minutes ago, Scubadude said:

The air gap is of no consequence.

Brilliant.   I was worried it had to sit tight, but it's quite a gap around the cable.

It'll be just after it comes out the meter heading to the DB board, so should be good, but also then the twisted cable only has 0,5m (maybe 1m with trunking route) to go to Inverter input which I gather is a good thing?    To get it to my main DB board (Was going to put above the main breaker) is just too far and would need the cable extended, so glad this works.

 

Now to just get the city to pop over and break the seal so I can fit it.

 

Thanks!

 

 

13 hours ago, CapeTown said:

Brilliant.   I was worried it had to sit tight, but it's quite a gap around the cable.

It'll be just after it comes out the meter heading to the DB board, so should be good, but also then the twisted cable only has 0,5m (maybe 1m with trunking route) to go to Inverter input which I gather is a good thing?    To get it to my main DB board (Was going to put above the main breaker) is just too far and would need the cable extended, so glad this works.

 

Now to just get the city to pop over and break the seal so I can fit it.

 

Thanks!

 

 

On the Solis the wire is about 5m long for the CT amp. Also and extension is available. I am using the same type of clamp for my power measurement meter and the distance is 8m to meter point. 

The current is only 50/100mA so no problem. If you think of the common clamp multimeters where the jaw opening can be 50mm they all measure correct even if the conductor being measure is a thin wire. 

I recall reading somewhere 50ft (whats that ... 15 meters) is the maximum length for CT leads. My inverter is about a 10 meter cable run from my DB.  The installer used a rather heavy solid core cable to extend the CT coil lead ... I would have used bell wire.

Edited January 15, 20223 yr by Scubadude

10 hours ago, Scorp007 said:

The current is only 50/100mA so no problem. If you think of the common clamp multimeters where the jaw opening can be 50mm they all measure correct even if the conductor being measure is a thin wire. 

 

Never thought of it from that aspect.    Good example and thanks!

 

Next question since I'm now curious.... but how / what does the CT coil actually do?    From my understanding the CT Coil would figure out the total load and then give the extra power into the non-essentials circuit, but by knowing the load would not exceed it, and thus not "export" to grid?     But how does the power from the inverter get "preference" over mains fed in power?  A light bulb or geyser just wants power?   

I would not install it in the meter. I don't think they would even allow that. Stick it in the DB around the incoming mains.

2 hours ago, CapeTown said:

But how does the power from the inverter get "preference" over mains fed in power?  A light bulb or geyser just wants power?   

The CT tries to keep the power through it at 0. So the inverter will generate enough power that there is essentially no import from the grid. You don't have to think about it in terms of "preference". Think of the inverter as a current source, and it just provides enough current to zero the current at the probe.

Thanks @P1000

My DB is far away, and I've already run the cables to and from the DB essentials part of the DB in the house.  Getting the CT there is almost impossible due to ceilings already being in on flat roof.    

Stupid Q:  any reason NOT to put in meter on DB side?

On 2022/01/15 at 3:02 PM, P1000 said:

I would not install it in the meter. I don't think they would even allow that. Stick it in the DB around the incoming mains.

The CT tries to keep the power through it at 0. So the inverter will generate enough power that there is essentially no import from the grid. You don't have to think about it in terms of "preference". Think of the inverter as a current source, and it just provides enough current to zero the current at the probe.

A good explanation but when your load exceeds the power of the panels you do in fact get say a positive reading. The CT would adjust the inverter output not to go negative which implies export. 

The way I read the question was how does the inverter power gets used as a preference. The inverter measures the grid frequency and voltage. This takes a few seconds. The inverter will then generate at about 1V higher and adjust it's own frequency in such a way that it's power get used up before drawing from the grid. This is measured all the time to ensure that no matter what the load is it's power is used before the grid. 

Even without a CT this is how the grid tied inverter works. The CT just tries to prevent export. 

Thanks @Scorp007

On 2022/01/15 at 3:02 PM, P1000 said:

I would not install it in the meter. I don't think they would even allow that. Stick it in the DB around the incoming mains.

The CT tries to keep the power through it at 0. So the inverter will generate enough power that there is essentially no import from the grid. You don't have to think about it in terms of "preference". Think of the inverter as a current source, and it just provides enough current to zero the current at the probe.

Does the Inverter only use solar power for this or will it use battery as well?

On the CT which is positive, is it white?

On 2023/03/22 at 6:30 PM, Oupa said:

Does the Inverter only use solar power for this or will it use battery as well?

Depending on how you select the settings, this applies for the solar and/or the battery.

No space in DB to fit CT

can you fit the CT before the smart meter

3 hours ago, Basio said:

No space in DB to fit CT

can you fit the CT before the smart meter

Smart meters are not all bi-directional fitting the ct coil before the meter(utility input side) the meter will go into tamper mode when your inverter supplies the non essential loads. 

Edited January 22, 20241 yr by TaliaB

On 2022/01/15 at 2:01 AM, Scorp007 said:

On the Solis the wire is about 5m long for the CT amp. Also and extension is available. I am using the same type of clamp for my power measurement meter and the distance is 8m to meter point. 

The current is only 50/100mA so no problem. If you think of the common clamp multimeters where the jaw opening can be 50mm they all measure correct even if the conductor being measure is a thin wire. 

If you are extending the wires of the CT, use the same mm2 wire and twist the pair to the same amount of coils per meter.

4 hours ago, TaliaB said:

Smart meters are not all bi-directional fitting the ct coil before the meter(utility input side) the meter will go into tamper mode when your inverter supplies the non essential loads. 

May be @p1000 and myself are missing something. The non essential should make no difference. Only the meter consumption is also measured if the CT is the wrong side of the meter. 

There might just be a problem when the grid returns and the meter draws a surge reactive current. 

Just me thinking😃

Refer to the 2nd topic on this. 

@P1000

Edited January 22, 20241 yr by Scorp007

4 hours ago, TaliaB said:

Smart meters are not all bi-directional fitting the ct coil before the meter(utility input side) the meter will go into tamper mode when your inverter supplies the non essential loads. 

On SunSynk / Deye there are two CT coils/sensors on the input/grid side.

• Internal CT sensor
• External CT sensor (can also use a RS485 CHNT meter for distance)

If you have all your load on the essential/UPS circuit and/or smart load (gen) circuits, then the external CT sensor is not required.
If you have load on the grid circuit, then you will need the external CT sensor between the load and meter.

INVERTER (with internal CT) <--"HOME" LOAD----EXT CT COIL/CHNT----Eskom METER--GRID-->
HOME LOAD are appliances that you want to power from the inverter with excess Solar



Below are my settings - I do Zero Export as I'm waiting for information from CoJ/CityPower
I don't have "Home" LOADS - all my load is on the essential/UPS circuit  - I'm zero-exporting:

Disabling Limit to Load Only will allow sending power to "Home" loads, but requires the CT Coil

Edited January 22, 20241 yr by system32