V2L Test. 7kW output...

[deanhalllincoln]

While researching charge points I came across this. Indra are currently trialling a vehicle-to-home unit that will intelligently use your EV battery for domestic energy storage and supply. The trial runs until 2024 so it'll be a while before it's available.

Vehicle To Home (V2H) Bidirectional Chargers | INDRA

INDRA is one of the fastest-growing EV charger companies in the UK. We manufacture & install smart chargers for commercial locations & home charging points.

www.indra.co.uk

Only Chademo unfortunately.

 

[DeMille]

I do have some general concerns regarding the use of the V2L capabilities, buy then adapting it to power the home electrics.
Please don’t think for one second here, that am I criticising the time / work / skills and effort of the people that has gone into making this a workable option.
But that said, I do have a real concern here that if somebody without the necessary skill sets, attempts to make this work and gets it wrong, then the damage caused to either the car / house electrics or even themselves is very real !.
Unless you are very very experienced, then honestly, I would simply just use the V2L feature in the manor it was intended.
Having all that stored energy sitting on the drive, then makes it very tempting prospect to tap in and harness that energy to run your home.
I totally get that !.
Just to be clear, I am not knocking the use of a V2L cable, in fact I have one myself !.
I think it’s a really great feature to have.
I have been watching this thread with great interest and am fairly experienced in electrics, but really I do have genuine concerns that somebody with less experience will try to power their home(s) via the V2L cable and get it badly wrong !.
This level of electrical work should only be carried out by qualified professionals that fully understands how to achieve this type of adaption.
No two house are even going to be the same and this is where it can get a bit difficult.
This is not a DIY process here folks and if carried out incorrectly, can be fatal !.
I ask myself this question, if somebody was injured very badly or worse, as a result of a failed attempt to hack into they home electrics, could we see the V2L option be removed from EV’s ???.
I really applause the skills of the people who have made this adaption work in practice.
“If you don’t know, then don’t give it go” would be my best advice.
A little knowledge is dangerous.

The same concerns may be made for connecting a generator. Most portable generators also are floating systems suitable only to connect one double isolated device in all safety. if such generator is connected to the home electrical installation of coarse a transfer switch must be used to avoid utility and gen are coupled. One can not and may not connect the generator using a normal home socket. Then same if using V2L.

 

[Staffex]

Interesting thread and something I have been working on with my MG4. So this is what I have found so far hope it helps someone:-
a) when connecting the V2L connector (home made one) and selecting discharging in the car I get 226v between live and neutral.
b) measuring L to E voltage I get 186v
c) measuring N to E voltage I get 28v (will be an Inverter output but a behaving like a centre tapped transformer output)
d) the earth is not connected to the chassis of the car (no continuity)
e) there is no connection to ground from the earth output from the car (obviously as only 4 rubber tyres between the car and ground)
f) I can connect the earth from the car to an earth rod to give a ground connection. however this does not connect neutral to the earth/ground that is needed to operate a an RCD.
g) I have connected the live, neutral and earth from the car V2L to my consumer unit and powered my entire house from the car. tested all appliances PC, tv, oven, boiler etc… and all worked.
h) testing the connections in the house when powered from V2L provides some unacceptable results. As the earth is not connected to the neutral at the source sockets can show as reverse polarity, missing earth, RCD’s do not operate under fault conditions.
I) Connecting the earth to an earth rod at the source does not help And I get the same results.
J) the problem is that the neutral needs to be bonded to the earth at source just like a normal house TN-C-S system. This would provide the right return paths via the earth and fix the system to earth and not have a floating system.
k) I have tried connecting earth and neutral together at the output of the V2L connector to simulate a TN-C-S system and the car shuts down the discharge as it sees the connection as a fault.

So I can power my house from the V2L connector but not safely with the right level of protection I would want. The car prevents me creating a safe system as it shuts down the discharge if earth is connected to neutral.

I got this far if anyone else can come up with a safe way of doing this I’m all ears.

Dean

Hi Dean, I concur with your findings. My N to PE potential is even higher, 83V. You might be interested in my recent posts here: V2L adapters

Given the quirky, non-compliant behaviour of the car as a portable generator I think the only long-term safe solution is to introduce a 1:1 isolating transformer. The primary plugged into the V2L's trailing 13A outlet (without an earth connection to PE) and the secondary feeding an extension lead (or 6mm2 armoured cable if you prefer) entering the consumer unit via a break-before-make changeover switch.

I think this would satisfy the safety requirements of all supply arrangements whether TN-S, TN-C-S or TT. The car itself could then be connected to the domestic earth carried on the extension lead, perhaps via the 12V battery's negative terminal which is strapped to chassis. A faulty indoor appliance would trip the RCBO or RCD on the consumer unit in the usual manner. Unfortunately, hefty isolating transformers aren't cheap... Carroll & Meynell 3000VA Intermittent Isolation Transformer 230V/230V - Screwfix

 

[Mick b]

Hi Dean, I concur with your findings. My N to PE potential is even higher, 83V. You might be interested in my recent posts here: V2L adapters

Given the quirky, non-compliant behaviour of the car as a portable generator I think the only long-term safe solution is to introduce a 1:1 isolating transformer. The primary plugged into the V2L's trailing 13A outlet (without an earth connection to PE) and the secondary feeding an extension lead (or 6mm2 armoured cable if you prefer) entering the consumer unit via a break-before-make changeover switch.

I think this would satisfy the safety requirements of all supply arrangements whether TN-S, TN-C-S or TT. The car itself could then be connected to the domestic earth carried on the extension lead, perhaps via the 12V battery's negative terminal which is strapped to chassis. A faulty indoor appliance would trip the RCBO or RCD on the consumer unit in the usual manner. Unfortunately, hefty isolating transformers aren't cheap... Carroll & Meynell 3000VA Intermittent Isolation Transformer 230V/230V - Screwfix

Last winter, l had a heavy duty four way extension lead with built in trip, then ran heaters up to 2.2kwh without any problems, if I over loaded, either the extension lead trip or the car shut down

 

[deanhalllincoln]

Hi Dean, I concur with your findings. My N to PE potential is even higher, 83V. You might be interested in my recent posts here: V2L adapters

Given the quirky, non-compliant behaviour of the car as a portable generator I think the only long-term safe solution is to introduce a 1:1 isolating transformer. The primary plugged into the V2L's trailing 13A outlet (without an earth connection to PE) and the secondary feeding an extension lead (or 6mm2 armoured cable if you prefer) entering the consumer unit via a break-before-make changeover switch.

I think this would satisfy the safety requirements of all supply arrangements whether TN-S, TN-C-S or TT. The car itself could then be connected to the domestic earth carried on the extension lead, perhaps via the 12V battery's negative terminal which is strapped to chassis. A faulty indoor appliance would trip the RCBO or RCD on the consumer unit in the usual manner. Unfortunately, hefty isolating transformers aren't cheap... Carroll & Meynell 3000VA Intermittent Isolation Transformer 230V/230V - Screwfix

Hi Staffex, I laughed out loud when I read your post as its exactly the solution I have planned, even to the point of the same isolation transformer. I have not had much time recently so not got very far.

I did speak to Carroll & Meynell and they concider the concept would work. The Screwfix item is only rated at 1.5kva for constant load and 3kva for intermittent loads.

As the MG4 has the ability to output up to approx. 7kw a larger isolation transformer would be needed. Transformers of this size are not low cost at all but maybe have a payback of about a year which would be ok.

I was going to buy the Screwfix item to start to prove the concept then look to buy the larger expensive device.

I have put an oscilloscope on elthe output of the V2L as wanted to know the quality of the sign wave. Thought it maybe a poor stepped approximation to a sign wave and have an effect on a transformers efficiency but in fact its an almost perfect signwave.

Would put circuit protection before and after the transformer to protect the transformer and the car.

The internal circuits in the house would be protected in the normal way and RCD's will operate as expected.

 

[Purclewan]

I too had been looking at a similar solution i.e. an isolating transformer but realised that a big enough transformer (at least 5KW intermittent) would be prohibitively expensive for an experiment.
The transformer listed on the Screwfix site could however be a good starting point.

Perhaps @Staffex or @deanhalllincoln if you decide to go ahead and try it you could keep us posted of the results in this forum. Keep up the good work.

 

[DeMille]

Hi Dean, I concur with your findings. My N to PE potential is even higher, 83V. You might be interested in my recent posts here: V2L adapters

Given the quirky, non-compliant behaviour of the car as a portable generator I think the only long-term safe solution is to introduce a 1:1 isolating transformer. The primary plugged into the V2L's trailing 13A outlet (without an earth connection to PE) and the secondary feeding an extension lead (or 6mm2 armoured cable if you prefer) entering the consumer unit via a break-before-make changeover switch.

I think this would satisfy the safety requirements of all supply arrangements whether TN-S, TN-C-S or TT. The car itself could then be connected to the domestic earth carried on the extension lead, perhaps via the 12V battery's negative terminal which is strapped to chassis. A faulty indoor appliance would trip the RCBO or RCD on the consumer unit in the usual manner. Unfortunately, hefty isolating transformers aren't cheap... Carroll & Meynell 3000VA Intermittent Isolation Transformer 230V/230V - Screwfix

I have solar pannels and use an all in one hybrid inverter with gen port. if connecting V2L to gen port it is able to recharge the home battery or supply power the the home load. I use an AC coupled hybrid DEYE inverter with back-up but one may use an all in one in series inverter creating an Island; using V2L without transformer one must use an ATS anyway. Such a transformer/inverter has a build in ATS allowing grid power to the loads directly, without being transformed . Connected to a TT grid system the inverter must have a dry contact for switching the local N-bound on and off. It is not allowed to connect a TT grid system to a local N-bound. If V2l is used an N-bound must be available.

 

[timE]

Would it be possible to convert the AC out from the MG4 into DC and use a hybrid invertor to convert back into AC synced with the grid frequency. The hybrid invertor would have all the required functionality to disable its output if the grid fails, so would not be the solution for an emergency backup, but it would allow the MG4's battery to look just like a normal house battery system? Seems a rather convoluted process but doesn't seem to need an earth, except to the convertor.

 

[Coulomb]

Would it be possible to convert the AC out from the MG4 into DC and use a hybrid invertor to convert back into AC synced with the grid frequency.

In theory, yes, but there are issues with power factor, and the fact that solar inputs to grid tie inverters expect a high impedance string of panels, not a low impedance power supply.

I would not do it.

 

[DeMille]

Would it be possible to convert the AC out from the MG4 into DC and use a hybrid invertor to convert back into AC synced with the grid frequency. The hybrid invertor would have all the required functionality to disable its output if the grid fails, so would not be the solution for an emergency backup, but it would allow the MG4's battery to look just like a normal house battery system? Seems a rather convoluted process but doesn't seem to need an earth, except to the convertor.

if one has a hybrid solar inverter connected to batteries, most of them also have a GEN port. You just have to plug V2L output in the gen port and use it as it was an emergency generator. Using V2L one can not connect PE out to earth as this propably will stop de-charging. if only used for charging the home system batteries using the Gen port there is no safety issue. You never may or can sync it with the grid. if you connect V2L to your home system with an ATS, you may create a dangerous situation if the home system has a TT earthing system, RCD will not work. if an N to PE bound is present or is added I think the Car will stop de-charging. Of course you can use a suitable AC transformer but I think for the same price or less you will have a solar hybrid with gen port and a LFP battery set.

 

[wattmatters]

In theory, yes, but there are issues with power factor, and the fact that solar inputs to grid tie inverters expect a high impedance string of panels, not a low impedance power supply.

I would not do it.

I'd have though using a suitable hybrid inverter connected to the DC terminals of the car (a 400 V battery not unlike what many GT hybrid inverters use today) would be a more suitable manner of enabling a grid synchronised connection. Not exactly a DIY project!

Not sure about the comms with the car but DC coupled just makes more sense to me.

As I was reminded recently there are some trials in Utrecht (which I'm sure you're well aware of) using grid synchronised bi-directional AC controllers. I'm struggling to see this catch on but who knows, it might become a thing.

if one has a hybrid solar inverter connected to batteries, most of them also have a GEN port.

I have an off-grid 8 kW AIO with grid pass through (when used in that mode of operation) but it does not have a separate generator input. It runs the house.

However I do have a spare 4 kW AIO unit which I repaired recently (with some help) and so I was thinking if ever I needed to access the car's battery capacity for additional backup reserve I could use the spare AIO to charge the home batteries.

Connect the V2L outlet to the AIO's AC input and it can manage charging the home battery.

It would be a steady and controllable load for the V2L. Sure there are some losses along the way but I'm talking backup reserve capacity. It could be set to supply say 30 A (~1.5 kW) into the home battery, not stress anything but still provide quite a nice source of energy without draining the car that much.

That way I am not limited by the V2L outlet's capacity for powering the home as that can still be managed by the 8 kW inverter. And no issues/concerns with grid connection as that's already taken care of.

 

[Tig170]

.. the simplest is an AC transfer switch (link)

 

[wattmatters]

.. the simplest is an AC transfer switch (link)

Simplest for what?

 

[DeMille]

I'd have though using a suitable hybrid inverter connected to the DC terminals of the car (a 400 V battery not unlike what many GT hybrid inverters use today) would be a more suitable manner of enabling a grid synchronised connection. Not exactly a DIY project!

Not sure about the comms with the car but DC coupled just makes more sense to me.

As I was reminded recently there are some trials in Utrecht (which I'm sure you're well aware of) using grid synchronised bi-directional AC controllers. I'm struggling to see this catch on but who knows, it might become a thing.


I have an off-grid 8 kW AIO with grid pass through (when used in that mode of operation) but it does not have a separate generator input. It runs the house.

However I do have a spare 4 kW AIO unit which I repaired recently (with some help) and so I was thinking if ever I needed to access the car's battery capacity for additional backup reserve I could use the spare AIO to charge the home batteries.

Connect the V2L outlet to the AIO's AC input and it can manage charging the home battery.

It would be a steady and controllable load for the V2L. Sure there are some losses along the way but I'm talking backup reserve capacity. It could be set to supply say 30 A (~1.5 kW) into the home battery, not stress anything but still provide quite a nice source of energy without draining the car that much.

That way I am not limited by the V2L outlet's capacity for powering the home as that can still be managed by the 8 kW inverter. And no issues/concerns with grid connection as that's already taken care of.

What earthing system do you use? such off grid inverters have an internal bypass connecting the grid to the home load if batt volt is low. the AC in port can be used for grid or gen. This means it must be avoided the internal bypass to become active if connecting V2L to the AC in port to charge the batteries. Some inverters have a dry contact for managing an N-bound ( on /off ) at the AC out port but most do not have this and such inverters can not be used in TT earthing systems. Using this inverters with V2L the internal ATS(bypass) may cause safety and practical problems. One can use an ATS to switch between grid and V2L with V2L being the main source. V2l on, Grid out. it depends siff RCD are present and an N-bound is needed. Making shore only batt can be charged will solve the problem.

 

[wattmatters]

What earthing system do you use?

If I used my spare AIO as an AC charger as described above, then it would be floating as it would not be connected to the home's AC supply at all. The AIO's AC output is not used, it would only be connected to the battery. There is no pass through of AC power.

The AC input to the AIO/charger could be supplied by the car's V2L adapter or from a petrol generator. No different to using the V2L supply or a generator to power appliances if say you are out camping or at a work site.

 

[wattmatters]

What earthing system do you use?

Some inverters have a dry contact for managing an N-bound ( on /off ) at the AC out port but most do not have this and such inverters can not be used in TT earthing systems.

This is off-topic but I'll answer it. For further discussion on this specific issue it'll should be taken off-line or to another thread.

I'm not sure on the exact nomenclature so forgive me but my understanding is while Australia generally (today) uses TN-C-S (MEN) earthing system, for our property we have a TT earthing system. Supply would have been installed 50 years ago and it's rural Australia, so TT earthing makes sense in that context and aligns with our physical set up.

This is a schematic (from this site) which resembles our set up, with the exception that this is a single phase while we are 3-phase and the location of the Source earth is well away from the transformer:

Our local distribution pole (which carries LV supply, the local transformer is about 400m upstream) has three actives and a neutral, and the neutral at the local pole is earthed with a cable running down the pole to an earth rod.

From the pole the three actives and neutral feed the home and the property's main circuit board has its own earth (in our case because of the age of the system, they used a nearby water pipe, while normally today it would be a separate earth rod).

Two outbuildings are also supplied 3-phase power and their sub-boards each have their own earth rod.

In any case, I've been running our home via an AIO inverter for two years without issue. It switches daily between passing through grid power (usually daytime as we have grid-tied PV while the smaller off-grid PV charges the battery) and running from the battery/solar at night. The switching is managed by home automations, not just simple battery voltage triggers.

 

[DeMille]

This is off-topic but I'll answer it. For further discussion on this specific issue it'll should be taken off-line or to another thread.

I'm not sure on the exact nomenclature so forgive me but my understanding is while Australia generally (today) uses TN-C-S (MEN) earthing system, for our property we have a TT earthing system. Supply would have been installed 50 years ago and it's rural Australia, so TT earthing makes sense in that context and aligns with our physical set up.

This is a schematic (from this site) which resembles our set up, with the exception that this is a single phase while we are 3-phase and the location of the Source earth is well away from the transformer:

Our local distribution pole (which carries LV supply, the local transformer is about 400m upstream) has three actives and a neutral, and the neutral at the local pole is earthed with a cable running down the pole to an earth rod.

From the pole the three actives and neutral feed the home and the property's main circuit board has its own earth (in our case because of the age of the system, they used a nearby water pipe, while normally today it would be a separate earth rod).

Two outbuildings are also supplied 3-phase power and their sub-boards each have their own earth rod.

In any case, I've been running our home via an AIO inverter for two years without issue. It switches daily between passing through grid power (usually daytime as we have grid-tied PV while the smaller off-grid PV charges the battery) and running from the battery/solar at night. The switching is managed by home automations, not just simple battery voltage triggers.

An AIO is an external ATS, automatic transfer switch? (I looked it up and it seems to be an All In One, normally having an internal bypass ( ATS); with or without usable dry contacts?) This info is also for connecting solar panels and it is important to warn for the possible problems if AIO are used to power TT home systems and if they are used to connect VtoL AC power.
In Belgium the TT earthing system is the only standard for residential use. it is not allowed to connect a private N to PE bound to the grid . All residential installations must be protected with a main RCD 300 mA and 30 mA RCD for different sections. Hybrid solar inverters coupled with the grid also may have a Gen port and a back up port (off grid) and normally have a dry contact for the N-bound needed for the RCD to stay functional. The dry contact is powered in function of the position of the internal bypass, connecting grid with the back-up port. The private N-bound is removed just before the back-up load is connected to the grid. Uing AC coupled solar hybrid inverters in general the GEN port can be used to charge the batteries.
Using an Off grid solar hybrid inverter( AIO) these inverters in general have one GRID/GEN AC IN and one A/C OUT port to connect the loads and usaualy have an internal bypass ( ATS) to connect grid/ gen to the AC output port. A lot of such inverters on the market do NOT have a dry contact to switch the N-bound in function of the position of the internal bypass; As a private N-bound is needed if the bypass is open for the installed RCD to work these inverters can not be used if connected to the grid. If connected and the bypass closes the main RCD will cut off all power. it is not allowed to conect consumers not protected by the main RCD or and connect a privat N-bound to the grid. The internal bypass may not be usable wich means the inverter only can be used if the grid port is NOT connected. So, an external ATS must be used to bypass the inverter and N-bound to connect a TT grid system to the loads.
V2L as power source only may be used using double isolated consumers. Not allowed for normal residential use. V2L can be connected using the AC IN port of AIO, hybrid solar inverters, to charge the batteries connected. The AC OUT must provide an N-PE bound for RCD in the residential installation to stay functional. What happens if for some reason the automatic internal bypass is closed?!
Solutions are to use a good solar inverter with dry contact or a separate gen port making it possible only charge the batt with V2L.
Use an other battery charger for only charge the home batt with V2L.

In residential TT home distribution systems, needing working RCD to be approved, connecting V2L to the home system using an ATS to swtich between grid and VtoL, the ATS V2L IN should have an N-PE bound . I think in practice this is not possible because I suspect EV decharging will be stopped immediataly.
Of cource there are solutions turning the home system into an IT earthing system and it can work for years without problems. But in my country IT systems are not allowed to be used in residential home systems and will never be aproved, althoug connecting a private IT system to a TT grid turns the system into a normal TT earthing system
Only if the home installation is made an island and can not be powered by grid power, an IT setup can be used. if RCD are present, they must be operational.

 

[wattmatters]

Use an other battery charger for only charge the home batt with V2L.

Which is exactly what I said I would do.

My spare AIO would use the V2L on its AC input and be connected to the battery only for charging. It would have zero connection on the AC output.

Same as if you used a regular 240 V AC charger for a 48 V battery system, something like the Chargeverter.

As to all the rest - my licensed electrician has sorted out all the relevant safety switching and isolation for how my off-grid system interfaces with our home's supply. And I have used my generator as the AC input instead of the grid plenty of times before - it works perfectly fine. It's quite a common arrangement here.

 

[timE]

In theory, yes, but there are issues with power factor, and the fact that solar inputs to grid tie inverters expect a high impedance string of panels, not a low impedance power supply.

I would not do it.

So would there be a real opportunity for a hybrid invertor company to develop a version that would take a low impedance input - demand that surely will be on the increase given the number of EV's that provide V2L to various degrees, whilst none make DC available to output.

 

[DeMille]

So would there be a real opportunity for a hybrid invertor company to develop a version that would take a low impedance input - demand that surely will be on the increase given the number of EV's that provide V2L to various degrees, whilst none make DC available to output.

Most car batteries are +- 350 - 400V DC.

Hybrid solar transformers supporting high volt batteries are available. In that case the dc port of the EV can be used and the transformer to limit the current. I think making the EV dc port bi-directional should not be a big technical issue. How a dc charger connects to the EV battery, forces the car to close the contacts? In practice I think there will be some warranty issues.

In theory, yes, but there are issues with power factor, and the fact that solar inputs to grid tie inverters expect a high impedance string of panels, not a low impedance power supply.

I would not do it.

How difficult it would be to increase the impedance of the power supply?