I'm on the Octopus Intelligent Go tariff which will allocate dynamic slots for charging and only charge at the low EV rate. At night in the off-peak period I set my solar battery to charge from the grid and when the car is also charging in this period this works fine. The problem I have is when EV charging happens during peak periods in a dynamic slot, it will drain my battery very quickly when I actually want it to come from the grid. I can't set the battery to charge at these times as the are dynamically allocated.
I've found a number of articles/posts/videos online that suggest I need separate the house/solar feed from the EV feed and then the solar CT clamp can be moved on the house/solar feed and not include the EV feed and this will stop the EV charging from the solar battery.
My question is therefore, will this arrangement work with the FOX inverter and battery, or is there anything else that might be needed or considered. I don't want to pay for the re-wiring in my meter box without being confident this will resolve my issue.
Site Admin
Hi,
You have two good options.
1. Have your ev charger rewired as per the attachment, hiding the charger load from the fox system to prevent the fox system from discharging to the car charging load.
2. disable the dynamic charging, In the octopus app go to devices, then your device, settings in the top right and disable smart charging. This means your house and car get the cheap slots from 23:30 - 05:30 only with no dynamic charging slots and you can then set your car/charger and fox system to match the charging window.
You have two good options.
1. Have your ev charger rewired as per the attachment, hiding the charger load from the fox system to prevent the fox system from discharging to the car charging load.
2. disable the dynamic charging, In the octopus app go to devices, then your device, settings in the top right and disable smart charging. This means your house and car get the cheap slots from 23:30 - 05:30 only with no dynamic charging slots and you can then set your car/charger and fox system to match the charging window.
Attachments:
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Did I help you? Feel free to leave me a tip Book a zoom meeting for remote consultancy or help Switch to Octopus and earn £50 Get a heatpump from Octopus and earn £100 Subscribe to my YouTube channelFox ESS Tri Inverter Installation
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Thanks Will for the quick reply and the options. I can't seem to switch off dynamic charging in the App as it gives me an error, not sure if it's automatically tied to the Tariff. Thanks though, I'll reach out to Octopus if I decide to opt for that option.
Another new user of solar here, been installed for a week.
My setup is as per the diagram, except clamp difference on Zappi and Solar positions, with my Zappi charger CU wired off a Henley block and it’s CT clamp on the live cable that’s between the DNO fuse and the smart meter, arrow facing into the property.
The FOX CU is also wired into the Henley block as is the house CU.
The Fox CT clamp is on the live cable between the smart meter and the Henley block, arrow facing towards the grid,
I also installed another CT clamp off a Harvi, that sits between the Solar CU and the Henley block, arrow facing towards the Henley block.
On Octopus Intelligent Go
Fox battery is set to draw from the grid between 0000 and 0528, so house load in that period is grid supplied.
Everything works fine, except when Octopus set a charge schedule outside of the above battery schedule, it immediately draws all power from the house battery until it depletes to min SOC (20%).
Plugging the car in when there is excess solar above 1.4Kw min charge on Zappi, works perfectly, flips in and out dependant on excess solar and never draws from house battery, which operates as per design, ie house load, then recharge battery then once full any excess to grid, or car if plugged in.
It’s currently with Myenergi tech support to try to understand what the root cause is.
So in the mean time I’ve decoupled the charger from Octopus, and the car either charges from excess solar as above or now from the grid in the window I’ve set on the Zappi 0000-0500.
16 x 450 watt panels
1 x EP 11 10kw
6kw inverter H1/AC1
My setup is as per the diagram, except clamp difference on Zappi and Solar positions, with my Zappi charger CU wired off a Henley block and it’s CT clamp on the live cable that’s between the DNO fuse and the smart meter, arrow facing into the property.
The FOX CU is also wired into the Henley block as is the house CU.
The Fox CT clamp is on the live cable between the smart meter and the Henley block, arrow facing towards the grid,
I also installed another CT clamp off a Harvi, that sits between the Solar CU and the Henley block, arrow facing towards the Henley block.
On Octopus Intelligent Go
Fox battery is set to draw from the grid between 0000 and 0528, so house load in that period is grid supplied.
Everything works fine, except when Octopus set a charge schedule outside of the above battery schedule, it immediately draws all power from the house battery until it depletes to min SOC (20%).
Plugging the car in when there is excess solar above 1.4Kw min charge on Zappi, works perfectly, flips in and out dependant on excess solar and never draws from house battery, which operates as per design, ie house load, then recharge battery then once full any excess to grid, or car if plugged in.
It’s currently with Myenergi tech support to try to understand what the root cause is.
So in the mean time I’ve decoupled the charger from Octopus, and the car either charges from excess solar as above or now from the grid in the window I’ve set on the Zappi 0000-0500.
16 x 450 watt panels
1 x EP 11 10kw
6kw inverter H1/AC1
Can you take a picture of your meter cupboard showing the cables, henley block etc.. - from what you have said the inverter CT clamp is in the wrong place (with an EV charger) where the Henley block splits the power to go to the EV and the House/Inverter it should be on the House/Inverter live cable.
Thanks Dave, Myenergi have just come back with the same observation. Thats where the solar sparky placed it.
I will move and try to see what happens.
Will I lose any functionality on re fox app ?
Any issue having the 2 clamps on the same section of cable ? They can be separated by a couple of foot.
I will move and try to see what happens.
Will I lose any functionality on re fox app ?
Any issue having the 2 clamps on the same section of cable ? They can be separated by a couple of foot.
Last edited by CDubbs on Wed Sep 17, 2025 10:13 am, edited 2 times in total.
Yes that's in the wrong place it will see all load wired there.
It's not entirely clear from the image as to where all the henley block connections go, the important thing is that the Fox CT clamp must see both the house load and the inverter feed when clipped to a single cable.
If the house/inverter are being joined at that larger henley block you will need to get them to install a small henley block that connects the 2 live feeds together with a single core to connect to the other henley block and the Fox CT clipped here.
It's not entirely clear from the image as to where all the henley block connections go, the important thing is that the Fox CT clamp must see both the house load and the inverter feed when clipped to a single cable.
If the house/inverter are being joined at that larger henley block you will need to get them to install a small henley block that connects the 2 live feeds together with a single core to connect to the other henley block and the Fox CT clipped here.
Thanks Dave, I did realise it was seeing all load in that position.
The 3 CUs are all connected to that one Henley block.
So placing the clamp on the other side of the Henley to Inverter CU will only see load from inverter and no house load, so agree it needs another Henley in the position you describe.
Many thanks for the feedback and support.
The 3 CUs are all connected to that one Henley block.
So placing the clamp on the other side of the Henley to Inverter CU will only see load from inverter and no house load, so agree it needs another Henley in the position you describe.
Many thanks for the feedback and support.
Thanks for advice Dave, put this to my install company and they are happy to come back next week and install a Henley as above layout for gratis
Thanks again
Thanks again
Just an image for anyone looking for setup to separate EV charger from house load and battery, now that it’s been rewired adding new Henley blocks, with house CU & solar CU wired to new Henley’s and then live/neutral to existing Henley which EV CU is connected to.
Placement of clamps 1. EV charger CT, direction i/c to house from grid, 2. Solar CT between Henley blocks, direction towards grid, 3. Another EV CT direction towards grid, this is for an extra monitor point for Myenergi app.showing AC generation from inverter
Now Fox system cannot see the EV charger load so does not discharge when EV calls for power.
Placement of clamps 1. EV charger CT, direction i/c to house from grid, 2. Solar CT between Henley blocks, direction towards grid, 3. Another EV CT direction towards grid, this is for an extra monitor point for Myenergi app.showing AC generation from inverter
Now Fox system cannot see the EV charger load so does not discharge when EV calls for power.
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Hi Dave, thankyou for your message this is my current setup top consumer unit is house and bottom one is for solar and ev. Should I move the ev charger breaker to the house unit and then where would the clamp be positioned.
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Can you add a description for the where the solar power is connected and also the EV.
It looks like the solar consumer is at the bottom and connects to the Henley block where it splits to go to the house consumer and the smart meter - is that correct ?, I can't see where the EV feed is taken and that's the important one.
It looks like the solar consumer is at the bottom and connects to the Henley block where it splits to go to the house consumer and the smart meter - is that correct ?, I can't see where the EV feed is taken and that's the important one.
Hi Dave thankyou for the quick repost this forum is great!
So the bottom board is the ev board as pictured. The bottom board is fed fin the Henry block you can see the 2 grey cables running down the side i think!
The solar and the ev are both in the same bottom consumer unit.
So the bottom board is the ev board as pictured. The bottom board is fed fin the Henry block you can see the 2 grey cables running down the side i think!
The solar and the ev are both in the same bottom consumer unit.
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Ahh that's a problem, there's nothing you can do about the CT clamps to solve the problem with the EV charger being taken off at that point - the only option you would have for now is to disable smart charging on IOG and set your home battery and EV to charge at the same time.
To fix this correctly so that you can use IOG to start and stop randomly as it does you would need to remove the EV feed from there, split the feed from the smart meter via another Henley block and wire the EV via a breaker to that (as per this post download/file.php?id=2025&mode=view) - it's a pain but your EV installer should have known that.
Do you have home assistant ?, my home is wired like yours which would flatten the home battery when the EV charges, but with home assistant I have an automation that looks at the state of the Octopus tariff and when it goes low it sets my minsoc to 100% which stops the discharge (and slow charges the battery).
To fix this correctly so that you can use IOG to start and stop randomly as it does you would need to remove the EV feed from there, split the feed from the smart meter via another Henley block and wire the EV via a breaker to that (as per this post download/file.php?id=2025&mode=view) - it's a pain but your EV installer should have known that.
Do you have home assistant ?, my home is wired like yours which would flatten the home battery when the EV charges, but with home assistant I have an automation that looks at the state of the Octopus tariff and when it goes low it sets my minsoc to 100% which stops the discharge (and slow charges the battery).
Hi Dave,
The home assist and all that raspberry pi is to complicated for me at this stage.
In the immediate do you suggest to move the breaker from the ev board into the main board if that what you mean by splitting as per the diagram it shows it separate so I don't want to get another unit if I can move it to the main board apologies am not a sparky so the terminology is tricky
The home assist and all that raspberry pi is to complicated for me at this stage.
In the immediate do you suggest to move the breaker from the ev board into the main board if that what you mean by splitting as per the diagram it shows it separate so I don't want to get another unit if I can move it to the main board apologies am not a sparky so the terminology is tricky
No don’t move the EV breaker to the main consumer as that would still be seen by the inverter as house load.
In effect what you need an electrician to do is to install a small distribution box with the single breaker to the EV charger which is connected to another Henley block which needs to be added to split the feed between the smart meter to the existing henley block.
For now as long as you set a charge period whenever your EV is plugged in, your home battery will be protected.
In effect what you need an electrician to do is to install a small distribution box with the single breaker to the EV charger which is connected to another Henley block which needs to be added to split the feed between the smart meter to the existing henley block.
For now as long as you set a charge period whenever your EV is plugged in, your home battery will be protected.
Hi dave,
Appreciate the help, i have spoken to the sparky, he can do the above, but he did say adding a second henley will be doing the same thing as the 1st one, as in why can you not connect directly into the spares on the 1st block and then into a new DB board
Otherwise once this is done, will IOG charge directly from the grid at all times and not take batter.
And my current stored battery settings which are 2 hrs 3am to 5am will not be disturbed.
Finally if and most likely when the car wants to charge through a slot in the early hours simultaneously to the force charge of the battery would it just evenly distribute charge
thanks
Appreciate the help, i have spoken to the sparky, he can do the above, but he did say adding a second henley will be doing the same thing as the 1st one, as in why can you not connect directly into the spares on the 1st block and then into a new DB board
Otherwise once this is done, will IOG charge directly from the grid at all times and not take batter.
And my current stored battery settings which are 2 hrs 3am to 5am will not be disturbed.
Finally if and most likely when the car wants to charge through a slot in the early hours simultaneously to the force charge of the battery would it just evenly distribute charge
thanks
Not quite, it's actually about where the inverters CT connection is as it needs to be able to see all of the load of the existing 2 consumer units but not the EV load - the only way to do that is to use the existing Henley block to make a single connection that the inverters CT can be clipped to before it gets to the new Henley block where the EV is connected; that way the EV load will be on the grid side of the inverter CT clamp and it cannot be seen.nadlad1984 wrote: ↑Sun Oct 19, 2025 2:52 pm Hi dave,
Appreciate the help, i have spoken to the sparky, he can do the above, but he did say adding a second henley will be doing the same thing as the 1st one, as in why can you not connect directly into the spares on the 1st block and then into a new DB board
Note the EV CT clamp needs to be moved as shown once it is re-wired but leave the inverters CT clamp where it is.
Yes once this is done, your EV will charge without disturbing your inverter at whatever times IOG starts instructs it to and you can leave your inverter charge time settings to be whatever you want to suit your low tariff.nadlad1984 wrote: ↑Sun Oct 19, 2025 2:52 pm
Otherwise once this is done, will IOG charge directly from the grid at all times and not take batter.
And my current stored battery settings which are 2 hrs 3am to 5am will not be disturbed.
Finally if and most likely when the car wants to charge through a slot in the early hours simultaneously to the force charge of the battery would it just evenly distribute charge
thanks
OK I'll get on to it so basically they will work independently then .... so what's the point of doing the raspberry thing then.. if this works.
Thanks for all your help and support great forum. Cheers
Thanks for all your help and support great forum. Cheers
Hi Dave, got it all sorted, I tested it by doing a max charge and it didn't draw from the battery so all good...
Here a pic of the install...
Thanks to you and everyone for sorting...
Here a pic of the install...
Thanks to you and everyone for sorting...
Attachments:
Just a note to add
Wired as above
I’ve got a Zappi charger and if the car is plugged in and showing ‘waiting for surplus’ if you then do a forced discharge back to the grid, it will drain straight into the car, as at that point the charger sees excess power available
That’s a pain if you have a favourable tariff for import/export
Wired as above
I’ve got a Zappi charger and if the car is plugged in and showing ‘waiting for surplus’ if you then do a forced discharge back to the grid, it will drain straight into the car, as at that point the charger sees excess power available
That’s a pain if you have a favourable tariff for import/export
I have another question....
On the Octopus IOG it seems like there are no more off peak slots so all the charging is between 11.30pm and 6am.
1) if my battery discharges coinciding with a scheduled car charge will it still battery dump.
2) Will my battery still Force Charge if the car is charging/
With the latter my battery usually pulls from the grid at approx. 4.8kw so will this impact the speed of the car charge or is it throttled or can i pull 7.5kw for the car and 5kw for the battery at the same time?
Just wondered if its better to dump the battery at say 10pm so it finishes by 11.30pm and then have the window open for charging car baring in mind i need 2hrs of off peak to charge my 10kw solar storage battery.
cheers
On the Octopus IOG it seems like there are no more off peak slots so all the charging is between 11.30pm and 6am.
1) if my battery discharges coinciding with a scheduled car charge will it still battery dump.
2) Will my battery still Force Charge if the car is charging/
With the latter my battery usually pulls from the grid at approx. 4.8kw so will this impact the speed of the car charge or is it throttled or can i pull 7.5kw for the car and 5kw for the battery at the same time?
Just wondered if its better to dump the battery at say 10pm so it finishes by 11.30pm and then have the window open for charging car baring in mind i need 2hrs of off peak to charge my 10kw solar storage battery.
cheers
No 1 Nonadlad1984 wrote: ↑Tue Oct 21, 2025 6:48 pm I have another question....
On the Octopus IOG it seems like there are no more off peak slots so all the charging is between 11.30pm and 6am.
1) if my battery discharges coinciding with a scheduled car charge will it still battery dump.
2) Will my battery still Force Charge if the car is charging/
With the latter my battery usually pulls from the grid at approx. 4.8kw so will this impact the speed of the car charge or is it throttled or can i pull 7.5kw for the car and 5kw for the battery at the same time?
Just wondered if its better to dump the battery at say 10pm so it finishes by 11.30pm and then have the window open for charging car baring in mind i need 2hrs of off peak to charge my 10kw solar storage battery.
cheers
No 2 Yes
For the next question. Your car will charge at 7kw, and your battery will charge at whatever rate you’ve set your force charge for
IOG rates are 2330 to 0530
As long as your car charge is scheduled by Octopus, with your current wiring setup it will not charge from your battery, if you have excess solar during the day that is destined for the grid, depending on your charger and its features it may divert to the car first before you exporting