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I have commando socket (32A) where i plug my ohme go charger to use intelligent octopus tariff. However, when i plug it in and it get's extra off peak slots it starts draining my house batteries first. I suspect it is something due to badly connected cables or just CT clamp being in the wrong place.
How should it be connected to avoid draining batteries? I was thinking if moving CT clamp before ohme would help but then the CT clamp won't see if the load goes over the limt.

Unfortunately the extra slots won't be in your normal cheapslot time window which will be programmed into your inverter. For me to use any extra cheapslots I have to re-programme my inverter every time so I typically don't use the extra slots.

Your inverter will see the PV charger in the same way it sees any other house load.

I just use it as if it was a Go tariff with a 6 hour window.

I've just realised I don't think you have any solar, just batteries ?, and you just want the charger to ALWAYS charge from the grid ?

If so the EV charger circuit would have to be henley blocked (T'd off) off from the meter tails or similar between the grid and the incoming live cable to your other circuits where you could put the CT clamp. So the CT clamp ONLY sees the house load and not the EV charger load.

It really depends on how your commando socket circuit is currently wired with regards your consumer unit. I.e, is it in your consumer unit or is it in a separate mini consumer unit.

If I assumed correctly in my last post to what you want, there is also another, maybe easier way and that is to run the live wire which is going to the Commando socket and loop it back through through the CT clamp in the opposite direction so it cancels itself out and the EV charger load is not picked up by the CT clamp.

nowty wrote: ↑Thu Jan 19, 2023 5:25 pm Unfortunately the extra slots won't be in your normal cheapslot time window which will be programmed into your inverter. For me to use any extra cheapslots I have to re-programme my inverter every time so I typically don't use the extra slots.

I'm not bothered with sofar not picking up extra slots, more about EV draining my batteries.

nowty wrote: ↑Thu Jan 19, 2023 5:43 pm I've just realised I don't think you have any solar, just batteries ?, and you just want the charger to ALWAYS charge from the grid ?

If so the EV charger circuit would have to be henley blocked (T'd off) off from the meter tails or similar between the grid and the incoming live cable to your other circuits where you could put the CT clamp. So the CT clamp ONLY sees the house load and not the EV charger load.

It really depends on how your commando socket circuit is currently wired with regards your consumer unit. I.e, is it in your consumer unit or is it in a separate mini consumer unit.

Yes, that's the case. At the moment inverter, lights, garage 13A and commando sockets are in a mini CU. Everything else is in the main CU.
I was wondering whether commando needs to go from henley blocks. However, how can I prevent inverter + EV + big appliances in house going over 100A fuse if CT doesn't see EV?

At the moment the henley block goes into 2 places: mini CU and main CU. Mini CU is where inverter, lights and commando is. Does it mean that if I connect CT to the 2nd cable (main CU) it will not discharge batteries while using commando socket?

ducabi wrote: ↑Thu Jan 19, 2023 7:04 pm Yes, that's the case. At the moment inverter, lights, garage 13A and commando sockets are in a mini CU. Everything else is in the main CU.
I was wondering whether commando needs to go from henley blocks. However, how can I prevent inverter + EV + big appliances in house going over 100A fuse if CT doesn't see EV?

You seem to be asking two completely different questions now.

1) How can I stop my EV charger draining my battery ?
I've answered that, there are three ways, see my previous posts.

2) How can I prevent inverter + EV + big appliances in house going over 100A fuse if CT doesn't see EV ?
Its irrelevant whether the CT sees or doesn't see the EV, if you turn on enough loads you may bust the 100A fuse. That's why I got up at before 5am this morning and turned stuff on manually and monitored so I did not go over 90A during the saving session in day adjustment window. Unless you have a very fancy setup its hard to automatically avoid an overload, you need to add up what everything takes and take appropriate action.

And you need appropriate monitoring.

I have,

A) My smart meter local IHD monitor for external grid import.



B) I have my Octopus Mini APP live monitor of my smart meter.



C) I have my SMA Sunny portal grid point monitor via APP and website.



D) I have a live voltage and current grid hardware monitor display.

ducabi wrote: ↑Thu Jan 19, 2023 11:12 pm At the moment the henley block goes into 2 places: mini CU and main CU. Mini CU is where inverter, lights and commando is. Does it mean that if I connect CT to the 2nd cable (main CU) it will not discharge batteries while using commando socket?

Sorry, I did not see this post before my previous reply.

If you said ONLY the Commando socket was connected to the mini CU, I would say yes.

But I've had too much red wine.

I still think its yes as long as you can also live with the lights powered off the grid, I'm just not 100% cos your inverter is there too.

nowty wrote: ↑Fri Jan 20, 2023 1:05 am Sorry, I did not see this post before my previous reply.

If you said ONLY the Commando socket was connected to the mini CU, I would say yes.

But I've had too much red wine.

I still think its yes as long as you can also live with the lights powered off the grid, I'm just not 100% cos your inverter is there too.

I had g&t .
I'll do a test and will share my findings.

Thanks, nowty!
It seems working when battery are in use and I force charge my car, i.e. it goes from grid not from batteries. I've made a note of what export i have (with no PV) on my inverter (0.6kwh from this week so not much) and will check in couple days time how much it costs me to have it like this.