What's the latest on the Vehicle to Grid (V2G) software fix to allow people with Solar Panels to limit the total export amount?

  • 12 February 2020
  • 19 replies

Hello all


Is there any news yet on the software fix to allow people with Solar Panels to limit the total export amount? We were told by OVO that our DNO was not happy us having a 3.3kw solar array and the V2G as there is a risk of exporting too much energy. 


Awaiting a fix from Kaluza which will get round this




Best answer by Transparent 14 February 2020, 21:49

Hi @powerbee and @Brie 

This subject is being discussed over here on another Topic.

I will be posting possible solutions there for us to mull over. I’m just putting a diagram together at the moment!

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19 replies

Looking for an answer to this too. My home charger has broken and don’t want to fork out for another if G100 is nearly sorted. 

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Hi @powerbee and @Brie 

This subject is being discussed over here on another Topic.

I will be posting possible solutions there for us to mull over. I’m just putting a diagram together at the moment!

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That diagram can now be viewed here. Please add your comments on that Topic.

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Hi @powerbee and @Brie 


Apologies we have not updated you sooner in regards to G100. 

Unfortunately due to a number of dependencies, the G100 dynamic export limitation will not be implemented into the V2G this quarter as we had planned. Our current estimate is that the feature should be ready for release toward the end of April 2020, though this is dependent on the successful release of Firmware 8.x. This updated firmware will fully support the G100 functionality at the device level.


We appreciate your interest in the V2G trial and hope that the successful release of the G100 functionality will unblock your onboarding process and allow you to become active members of our V2G community.

@Bobby_OVO thanks for the update. It’s so frustrating as I’m only 0.6kW over. Considering I now need a new home charger anyway I’m wondering whether it’s worth getting 3 of my panels uncoupled temporarily. 

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Where are you based @Brie ?

Is your Distributed Network Operator (DNO) one of those that is strictly applying the rule about micro-generation needing to be less than 16A/phase?

I don’t understand how you can be “only” 600W over. But if you are, then I have a solution to propose(!)

As I see it, the V2G charger exports at 16A or zero. Unlike a PV panel, it isn’t delivering varying current to the grid. I’ve picked that up by looking at this graph from the January webinar.


As this is a screenshot, the resolution isn’t good enough to show the export with sufficient granularity, but those look like digital (on/off) peaks to me.

@Bobby_OVO@Ash_OVO? - are you able to confirm this?


And Moderators (@Eva_OVO@Nancy_OVO?) can we please merge this Topic with the other one here asap?!

@Transparent It’s Western power and they will allow 6.68kW on single phase. Unfortunately with the V2G at 3.6 and solar at 3.68 it takes me to 0.6kW over. I’m going to find out how much it will be to get my inverter limited to 3kW. 

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@Brie- WPD are well known to me.

I’ve been working with them for over a year now on the Community-stage of substation monitoring (Ofgem funded). They’re probably the most adventurous of the DNOs, and they’ve been proactive in working with Kaluza on storage technology.

I’d be interested to see why they’re allowing you 6.68kW export.

Would you be happy to Direct Message me with your postcode to I can look up the distribution network that feeds you?

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OK, so I’ve had a look at the Distribution Network around you @Brie - many thanks for sending me your post-code.

It appears you’re in an excellent position. The 440v (3-phase) supply to your road is a branch off a larger underground cable which interconnects between two sub-stations. I’m unsure whether it only gets supplied from one transformer at a time, or whether it shares the load across both simultaneously. That strategy is called Meshing. It helps to even out the load in an area.

Whichever is the case, your export is more valuable.

If houses had 3-phase supplies, then I’m certain that WPD would take even more stored energy from you. But alas, everything you feed to the grid also imbalances the current on the sub-station transformers, and that increases losses.

Did you have any official notification from Kaluza or WPD that they would accept a maximum 6.68kW (29A) from you?


You have also brought up another concern regarding V2G export and storage.

If some customer’s houses are in a location where their stored-charge is of more value to the Distribution Network, should they expect to receive greater financial benefit as a result of their participation?

@Transparent thanks that’s really interesting. Yes they offered 6.68kW now and 9.68kW if I upgraded to a 3 Phase system at a cost of £1900, but of course I can’t be in the trial with a 3 phase system. The offer will expire next week though, which is why I’m trying one last push to bring my solar down to 3kW in the interim. I’ve contacted my solar provider and WPD. My inverter can be limited to 3kW, but I’ve no idea how easy it is to do or what it would cost. I don’t suppose you have any contacts in my area who could advise do you? You obviously know what you’re talking about!

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Personally @Brie if you have to act within one week, then I favour your suggestion of removing 3x 200W PV panels from your current array.

But whilst that’s being done, I’d re-couple those three in parallel and bring that pair of wires into the house.

We can then start a new Forum Topic where we can discuss all manner of useful things you can do with an off-grid battery supply!

I run LED lights and my WiFi Router off-grid for a start :relaxed:

Your main expense is getting to the PV panels in the first place. An hour’s hire of a cherry-picker would cost a lot less than scaffolding.

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I’ve been mulling this over in my mind, @Brie and I have another solution to put forward.

I’m also tagging @Ash_OVO because it would require actions to be taken by Kaluza but there are benefits to them from doing so.

What about Kaluza preventing export from your V2G charger until the sun is low enough that the output cannot be greater than 3kW?

There are charts and online calculators that actually enable this to be evaluated with considerable accuracy, such as the EU Science Hub.

But even without using these formulae, a reasonable estimate is that peak output will have decreased to 80% (below 3kW) about 2 hours before sunset (if your panels point due south).

So if Kaluza simply inserted a block on your V2G export until that time, the conditions requested by WPD could be achieved whilst leaving your PV array intact.

The Kaluza Platform already has weather inputs, so later refinements could be made whereby that block is only applied on days when your location has full sunshine.


The benefits of this approach for Kaluza are twofold:

  • This workaround might be acceptable for locations where there are already difficulties with obtaining permission to connect from the DNO, such as experienced by @Dambrogio .
  • This allows Kaluza to investigate a further parameter as an input to their software. Since it increases the proportion of renewables available, it would be looked on favourably by their financial partners.

I’m not as familiar with the SMETS1 meters used for those on the V2G Trial as I am with the current SMETS2 versions. However it’s possible that OVO already obtain a total for “export” when they send the “Data read” command each night.

If that’s so, then Kaluza are in a position to confirm to a DNO that they are indeed successfully limiting total export to an agreed figure. That should increase confidence in the system.

@Transparent intriguing idea and I’ll be interested to see Kaluza’s response. My meter shows export as I tried to switch to Octopus outgoing tariff. I cancelled my application when it still hadn’t started after 5 months and because I was accepted onto V2G so I don’t see any readings, but the total is still there and with it, presumably, half hourly readings.  It does seem uncoupling the panels or limiting the inverter would be the easiest approach in the short term. 

I’m in a very similar boat, WPD , 2Kw existing solar and a maximum export of 5.3Kw as I’m on a long bit of cable from the substation, so less than 400W over.

removing panels was a non starter, its still a 2Kw solar inverter irrespective of how many panels, and thats what the DNO use.

What I have agreed is to swap the inverter for a 1.5Kw unit, but also to add more solar but with export limiting, so if the V2G fires up, the export limited solar shuts down- it looks easy to set up, you put a current clamp round your meter tails and set a max power on the inverter.

@Brie - some inverters can just be turned down on the front panel, the issue you have is locking that off in a way that the DNO is happy with - otherwise what stops you turning it up again? - can you not ask your solar provider to quote for doing that?

If you need a current clamp, for export limiting that has to go on the meter tails, so it depends how far the inverter is from the meter and how difficult that cable route is.

@Transparent , Whilst your ‘dont export till sunset’ idea is great in principle I’m going to play devils advocate and say - “prove it fails safe”, cos I think thats what the DNO’s will say :)

The export limit application forms I have looked at for WPD need you to prove that the system is robust, and if there were any comms failures the V2G would not export.

@adz Thanks. I’ve asked my provider about turning it down as it can be limited to 3kW, but they weren’t keen. Not sure why. I’ll try some other companies as my system is out of warranty now anyway. 

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Good points @adz 

So which do you think is easier to prove:-

a: that a customer really has retained the approved export current limiter and therefore cannot be exporting more than the agreed amount?

b: that Kaluza has the graphs of your export to demonstrate compliance?

@Transparent absolutely the graphs, it looks trivially easy to circumvent or derate a clamp based limiter.

Would they be granular enough for the DNO? eg if its a half hourly total you can achieve 3KWh average by exporting 6Kw for half the time then nothing. 

I think there are a number of ‘smart’ ways you could limit export, I think your main battle could be against the mindset of DNO’s who seem to like simple hardwired electrical solutions to this sort of issue ( obviously historical as that used to be the only way you could do it ) as opposed to new fangled cloud based solutions.

I wish you well in your endeavors.

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@adzif you listen to the V2G webinar, you’ll hear it stated that the Kaluza Platform uses 1-minute granularity to control the export. That was a very important announcement. :slight_smile: