Anyone using car battery to power house ?

[siteguru]

All the caveats apply ... the installer seemingly connected the supply that way for convenience. It's not normal (to my knowledge).

 

[Bam Bam]

Ah. Mine is plugged into a 13A socket. Does that mean it's OK for V2L, or do all the same caveats apply?

Oh, I see, then your question makes more sense.

I have never seen this and used to rent so have lived in quite a few places. Only ever seen them connected directly to a fused switch in the wall and thus assumed this was a regulation.

I think the recommendations about plugging in boilers will still be much involve much higher safety standards than plugging in other things. For instance, should you run a boiler off an extension lead?

 

[TimothyN]

When you talk about running a boiler off an extension lead, bear in mind that this is a gas boiler, so its only use of electricity will be for things like timers, control circuits, igniters, possibly pumps, we are not talking about a high power consumption unit.

 

[wattmatters]

When you talk about running a boiler off an extension lead, bear in mind that this is a gas boiler, so its only use of electricity will be for things like timers, control circuits, igniters, possibly pumps, we are not talking about a high power consumption unit.

In which case the likelihood that the electrical stuff is doubly isolated is higher but frankly I do not know. I would read the specification / user / installation manual for the unit to see if it suitable for use without residual current protection.

Here in Oz regulations require small electrical water boilers (e.g. 25-50 litre) with the option to have a plug to connect to a regular power outlet be used on a circuit with an RCD. Indoor gas water heating with electrical ignition/control is uncommon other than in utility rooms of apartment blocks for common supply.

we are not talking about a high power consumption unit

The potential for exposure to mains voltage is independent of the rated power draw of the appliance.

 

[TimothyN]

The potential for exposure to mains voltage is independent of the rated power draw of the appliance.

Of course; I was just wondering what was the rationale for questioning the extension lead and thinking that it might have been related to perceived current draw...

 

[Gomev]

It's a question I had thought about several years ago running the boiler with the aid of a battery power station, one of the EcoFlow type etc. It may have the same problem with a V2L supply, maybe ??
Researching discovered that often the boiler simply wouldn't work. The answer was because of the earthing. Apparently as was mentioned earlier in this thread it had to do with floating earths.
This was a solution I discovered and I quote it, it is not mine as it was a theoretical exercise for me. I am also not an electrician so provide this with no authority or knowledge whatsoever, and have no idea about it's legality or safeness.

'The reason they will not power the ignition on many combi`s is because the inverters and generators have whats called "floating earths" Even if their bodies are earthed with a rod they often will not power the ignition system properly.

I had a three pin plug fitted to my boiler instead of it being directly wired to the mains .

You need to use a short extention lead from the boiler to the power source , ( inverter or generator) but the Neutral and Earth of the lead need to be bonded (connected) .This then fools the clever ingition electronics into recognising a true earth and will fire up properly.

This is legal and proper as long as it is only used for the intended purpose .

Remember never to use this modified extention lead connected to the mains circuit. Label it in someway . N&E BONDED

I wanted mine done properly so I had a registered electrician supply the short bonded lead . He said he had not come across a request like it but thought it a cool idea and totally safe .'

 

[TimothyN]

I think I’ll wait for one of the tame gurus before doing that!

 

[mg4mc]

I tested our boiler (which is on a regular plug/socket) on V2L and it ran fine (self contained pump).

I also think all the piping may be connected via a plastic manifold block, though I'll double check when I get home next week. I had to replace it once as the original has been made out of some water soluble plastic!

 

[EvTek23]

I came across this YouTube article that goes some way to explain V2L, V2G, and V2H although it is with respect to Zaptec go 2 EVSE. Safety aspects and the necessity to have a separate earth are also discussed.

 

[wattmatters]

The MG4's V2L already has an E-N bond. That's why you can't use it to power a home because there must only be one spot where the E-N bond is made and homes will already have that in their main circuit board.

Backup generators without the E-N link are designed for use in powering homes which already have the Main EN link. Connect up a generator with an E-N link to a home and it will likely shut down with a fault, just like the MG4 will.

You could use the MG4's V2L to power a home but as the video mentions it will require not only full isolation but breaking the MEN link and a means to correctly earth the isolated system in the absence of the MEN.

It's not a cheap thing to do.

 

[Everest]

I'll chip in again here with some feedback to the recent questions / observations...

Given that V2L is consumer electronics and that this is a potentially lethal use case that could easily be done in all innocence, where is the information that it's not a great idea promulgated?

Totally agree.
This is really interesting stuff.
I would also like to know if there is anything else (normally in a house) apart from a boiler that we shouldn't plug into our cars?

I agree that more should be done by the suppliers of V2L-capable vehicles to advise users on the dangers and what should or not be allowed to be connected directly - i.e. without having a sparky implement a more sophisticated / safe supply.

It's a complicated area, but IMHO, the vehicle supplier should categorically state that only class II (double-insulated) devices should be used with a supply that has no direct earth connection and no RCD protection. It is simply not safe to connect a class I devices (i.e. one that requires earthing) to a V2L supply without additional protection. There are some good points made in this article, if you are interested, as the same principles for portable generators apply to V2L.

MythBusters #6

This month, James Eade looks at his specialist subject of temporary power and, in particular, the earthing of temporary generator sets.

electrical.theiet.org

How would a common, educated but non-expert, person like me know that the combi boiler is unsafe for V2L? I mean, it's great that we have the level of expertise we have on here, but apart from that, is there any obvious documentation to say that a coffee machine, freezer or tumble drier is OK, but a boiler is not?

Freezer or tumble drier are not OK without earthing or RCD protection.

If it has never occurred to you that it is any different to plug the boiler in than, say, a kettle, then how would you be supposed to know, if you don't know to ask?

The simple answer would be to look at the device's electrical specification tag, that will show a symbol of a square within another square to indicated a double-insulated device. It is likely that a coffee machine, laptop etc. would be double-insulated, as will most outdoor tools, e.g. strimmer etc.

Otherwise, yes there is obvious documentation in the form of the installation manual for the product you intend to use. For example, picking a random Worcester-Bosch Combi boiler you will see something like this...

Clearly stating that the appliance must be earthed and that an RCD must be present - neither of which apply to a V2L supply source.

Similarly, looking at the installation manual for a Beko Fridge-Freezer states... "Warning! This appliance must be earthed" in bold in the first few pages.

Ah. Mine is plugged into a 13A socket. Does that mean it's OK for V2L,

No, for the reasons mentioned above.

 

[EvTek23]

The official discharge cable from MG includes an RCD on the double 13A outlet, but it is rather pricey.

Going back to the thread "MG4 discharge cable" @CrustEE has made some measurements of the AC output when in V2L mode and posted the following on post #23 an excerpt from which I have included,

"This is supported by measurements that I made using a multimeter at the MG V2L via a cheap ebay adapter. No load connected.
L to N: 222Vac
E to N: 26Vac
E to L: 196Vac
This does indeed indicate that the E (PE) connection is not tied to N and not to a mid-way point either."

However in this thread at post #130 @wattmatters says "The MG4's V2L already has an E-N bond".

If that were the case I would have expected to see 0V between E to N not 26Vac. I'm not sure if this is due to some sensing within the car inverter, which would then cut the output under certain conditions, or what the effect is on the output is if there is a E to N bond present.

Those who have used V2L have used it in the way MG probably intended, either literally out in the field, or in a household powering individual pieces of equipment via a 13A distribution block for several pieces of equipment in the same way where the earthing issue is less of a problem, and @ReintjeWA talks about those in Australia who use the V2L to charge storage batteries that run the house, but is still isolated by the storage battery charger from the house earth arrangement.

 

[wattmatters]

If that were the case I would have expected to see 0V between E to N not 26Vac. I'm not sure if this is due to some sensing within the car inverter, which would then cut the output under certain conditions, or what the effect is on the output is if there is a E to N bond present.

That was the no load condition. But then I don't know what V2L adapter they used.

The official discharge cable from MG includes an RCD on the double 13A outlet, but it is rather pricey.

We don't get that here, just a simple single outlet and limited to 10 A, ~2.2 kW. To get higher power output requires a custom cable unsupported by MG.

 

[Gomev]

...
The simple answer would be to look at the device's electrical specification tag, that will show a symbol of a square within another square to indicated a double-insulated device. It is likely that a coffee machine, laptop etc. would be double-insulated, as will most outdoor tools, e.g. strimmer etc.

Otherwise, yes there is obvious documentation in the form of the installation manual for the product you intend to use. For example, picking a random Worcester-Bosch Combi boiler you will see something like this...

View attachment 39723

Clearly stating that the appliance must be earthed and that an RCD must be present - neither of which apply to a V2L supply source.

Similarly, looking at the installation manual for a Beko Fridge-Freezer states... "Warning! This appliance must be earthed" in bold in the first few pages.

I respect your knowledge and others on here and you clearly speak as a qualified person, however I speak as an unqualified lay person, and possibly as devil's advocate.

Firstly I would not read the installation manual for a combi boiler as I would get someone else to install it, as per previously mentioned I am not qualified to do so.

It's difficult enough to know what the washing labels mean on a clothing garment let alone what a square in a square means on an electrical device or frankly WTF does double insulated mean !!! (2 layers of plastic around the wire perhaps ??)
And just to add to my ignorance as a non electrical person as far as I'm concerned and I'm pretty sure I speak for the vast vast majority of everyone else who is not an electrician or qualified in that knowledge, the only instruction for my new fridge freezer, which I assumed rather than read the instructions, was ...... plug it in.

This is not a dig or meant to be insulting to anyone, I totally respect people with the knowledge by their trade, profession or learning that I don't have which is why I don't do electrical or gas work, or other stuff I won't go into .
I worked in IT and I did not expect others outside the industry to know what I knew, same for any profession/trade. It is easy to forget that those outside don't know what we have known forever and is completely obvious to us.

Simply when I'm sold something with an electrical socket (V2L adapter ?) I expect to be able to plug something into it. Equally if it has a plug (freezer ?) I expect to be able to stick it in a socket.

What I am not expecting to do is have to look for symbols that I didn't even know existed and then look to find out what they mean or have to understand expressions which are specific to a profession or trade.

Us general public clearly need to be told explicitly or we will continue to do it all wrong.

or is it just me ?

 

[decrep]

or is it just me ?

Totally not!
I have good electrical knowledge and I understand the problem now it has been explained fully, but I probably would have plugged the wrong thing in.
There should be a warning somewhere, but where? On the plug I guess but there are lots of manufacturers from different countries, how do you get them to comply?
In the manual on the front page would be really good.

 

[MG Clive]

In the manual on the front page would be really good.

But who reads the manual.

 

[MG Clive]

I bought this last year, just in case of emergencies, and I have to say that I'd just have assumed I could plug anything with a normal household plug into it.

 

[decrep]

So now we need to learn how to tell if an appliance needs an earth to be safe, or if it's double insulated.
I think you can assume if it only has a 2 pin plug it's OK. (Do you get them in GT Britain)?

I'd probably be happy if there was nothing conductive that you could come in contact with.

 

[siteguru]

We only get 2-pin plug devices for things like electric shavers and similar. But even some devices with 3-pin plugs aren't actually earthed ... for example I have a USB charger unit in my desk drawer that has an earth pin but it is made of plastic.

 

[Everest]

The official discharge cable from MG includes an RCD on the double 13A outlet, but it is rather pricey.

That's a step in the right direction and I can see how that could help in some failure situations. But, a bit like having an airbag in cars, it won't protect from every possible failure without connecting the Earth from the vehicle to ground via an earthing rod - which then comes back to my previous postings regarding needing to know existing earthing arrangements for your house and installing suitable transfer switch etc.

If that were the case I would have expected to see 0V between E to N not 26Vac. I'm not sure if this is due to some sensing within the car inverter, which would then cut the output under certain conditions, or what the effect is on the output is if there is a E to N bond present.

It is disappointing that the manufacturers do not give more info. Would a N-E bond external to the vehicle cause the V2L to shutdown? Or, worse, damage the vehicle's inverter?

It's difficult enough to know what the washing labels mean on a clothing garment let alone what a square in a square means on an electrical device or frankly WTF does double insulated mean !!! (2 layers of plastic around the wire perhaps ??)

I find IT, electronics and networking symbols much simpler than washing labels!

Double-insulation generally means there is an extra non-conductive protection around the device, so that a single failure of the device cannot create a condition that could cause a shock. However (and somewhat confusingly) a single layer of suitable reinforced insulation will allow the device to meet Class II / double-insulation category, like for example, a mains-powered power drill.

I worked in IT and I did not expect others outside the industry to know what I knew, same for any profession/trade. It is easy to forget that those outside don't know what we have known forever and is completely obvious to us.

Us general public clearly need to be told explicitly or we will continue to do it all wrong.
or is it just me ?

agree - I think the suppliers should provide more info about their V2L implementations and guidance for the usage of it. And it's not just MG; I had a look at BYD, Renault and the HMG's owners manual and similarly, not much practical info. Maybe that is because they are addressing worldwide markets and hence the differences between supplies can vary significantly across countries, esp. in USA with their split-phase supply