Solar PV advice

[Richard77]

I think two ct clamps can be used this way (although I'venot actuallytried it myself): ideally a matched pair, but ct clamps with an identical turns ratio ought to work (not sure what that would be for your inverter but a ratio of 2000:1 is common from memory) - or a ct clamp that can take both cables which has the turns ratio to suit the inverter.

If you have two ct clamps, you connect their output wires in parallel, and then the signal from the ev charger wire ct subtracts from the signal from the meter wire ct so the inverter does not 'see' the ev charger current coming from the grid.

Thanks Marcus....

So at least it seems like it could work and not just some mad YouTube video!

Yes the ratio is 2000:1



Now to find a place that sells 2000:1 CT clamps that are compatible.

[AGT]

https://www.bmstechnologies.co.uk/produ ... 110000500/

[Richard77]

https://www.bmstechnologies.co.uk/produ ... 110000500/

Thanks AGT....will that have the two cables inside after I cut the adapter end off? Need to join it up to the others in the wago.

[John_S]

Late to looking at this thread.
Can you provide the up to date wiring diagram? Mentions of edits confuse me.
Your goal looks similar to what I ended up with.

John

[Richard77]

Late to looking at this thread.
Can you provide the up to date wiring diagram? Mentions of edits confuse me.
Your goal looks similar to what I ended up with.

John

This is what it looks like now:



Did you have the same problem with the EV getting charged from the battery instead of the grid?
Where did you end up putting your ct clamp John?

[John_S]

I fitted a single pole Henley block between the meter and the double pole Henley block and took off the EV supply from it. The CT clamp goes on the live cable from the single pole Henley block to the double pole Henley block.
It was easy to do as I have an isolation switch between the meter and the Henley blocks.

[Richard77]

I fitted a single pole Henley block between the meter and the double pole Henley block and took off the EV supply from it. The CT clamp goes on the live cable from the single pole Henley block to the double pole Henley block.
It was easy to do as I have an isolation switch between the meter and the Henley blocks.

Thanks... If going to add Henley block will get the spark to do it. I'm not confident working around that area with tails, etc.

I think I might try going the bigger CT clamp route and put the EV live cable back through the inverter CT clamp. They are close enough together to try it, to see if it works.

For now though I set the batteries to charge to 100% between 23:30 - 05:30 from the grid. Then 05:30 - 23:30 batteries to power the house.

if I plug the car in after 23:30 it takes charge from the grid only. Just need to make sure the ev gets to 100% before 05:30 otherwise it will try to take charge from the batteries after 05:30.

Can get away with that for now as never really need to charge during the day anyways.

[John_S]

If it is easier, you can put the neutral to the EV forward through the CT instead of the live backwards.
In my case the tails were too stiff and the CT clamp was too small.

I did the 2330 to 0530 as you propose for nearly a year before adding single pole Henley block. Generally worked fine except when I got extra slots from IOG when it became a pain, especially if they changed the schedule.

[Richard77]

If it is easier, you can put the neutral to the EV forward through the CT instead of the live backwards.
In my case the tails were too stiff and the CT clamp was too small.

I did the 2330 to 0530 as you propose for nearly a year before adding single pole Henley block. Generally worked fine except when I got extra slots from IOG when it became a pain, especially if they changed the schedule.

Thanks John for the info... Much appreciated.



The EV live wire going backwards is close to the CT clamp, so shouldn't be too hard if can get a bigger CT clamp. Or try the two CT clamps and connect them up.

[John_S]

This is my set up.
The big CT clamp below the earth cable is for my solar PV and the small one just above it on the live tail between the two Henley blocks is for the battery inverter/charger