V2L function to power the house?

[Everest]

the earth stake does nothing

I disagree.

The earthing rod connects the earth and neutral supply from the vehicle (or generator) to ground on the supply side of the RCD. If a human then touches a faulty device (i.e. one whose external metal casing has become live), some current will flow - via the human - to ground. The RCD will detect the resulting imbalance in current between live and neutral and cut the circuit.

 

[Rolfe]

I realise I'm late to this party, but it might be worth mentioning that I have that bog-standard cheapo VtL adaptor from eBay. I have run a 3 kw kettle from it many many times, and it boils just as quickly as it does when plugged into the mains. I have also run an 800 watt microwave which nominally draws 1.2 kw, and an induction hob rated at 2 kw. I also run smaller stuff like a pump for an airbed and the charger for my e-bike. I once accidentally ran both the kettle and the airbed pump at the same time.

I've mostly done this while out camping, but a couple of times I have run an extension lead into the house and run the kettle and the microwave from this. (One at a time, obviously.)

I haven't had any issues at all and everything seems fine. I'm currently having thoughts about maybe running the extension lead into the house to run a 2 kw electric heater during the day, on 3.5p/unit night-time electricity, given the price of fuel oil this month!

Obviously this has its limitations and is likely to constitute a trip hazard, but it's a hell of a lot better than nothing in a power cut. I think I could probably run the wifi router, my computer, a table lamp and the TV together, continuously (heating is otherwise catered for), and maybe unplug a couple of things to run the kettle or the microwave or the induction hob. I could also plug in the fridge and freezer overnight, I imagine, and if I only opened them momentarily during the day, stuff would probably stay fresh for the duration.

 

[Catsailor]

I realise I'm late to this party, but it might be worth mentioning that I have that bog-standard cheapo VtL adaptor from eBay. I have run a 3 kw kettle from it many many times, and it boils just as quickly as it does when plugged into the mains. I have also run an 800 watt microwave which nominally draws 1.2 kw, and an induction hob rated at 2 kw. I also run smaller stuff like a pump for an airbed and the charger for my e-bike. I once accidentally ran both the kettle and the airbed pump at the same time.

I've mostly done this while out camping, but a couple of times I have run an extension lead into the house and run the kettle and the microwave from this. (One at a time, obviously.)

I haven't had any issues at all and everything seems fine. I'm currently having thoughts about maybe running the extension lead into the house to run a 2 kw electric heater during the day, on 3.5p/unit night-time electricity, given the price of fuel oil this month!

Obviously this has its limitations and is likely to constitute a trip hazard, but it's a hell of a lot better than nothing in a power cut. I think I could probably run the wifi router, my computer, a table lamp and the TV together, continuously (heating is otherwise catered for), and maybe unplug a couple of things to run the kettle or the microwave or the induction hob. I could also plug in the fridge and freezer overnight, I imagine, and if I only opened them momentarily during the day, stuff would probably stay fresh for the duration.

Same plan for me. No intention of trying to replace my electricity supplier except during a power cut and then only for minimal power.

 

[T1 Terry]

I disagree.

The earthing rod connects the earth and neutral supply from the vehicle (or generator) to ground on the supply side of the RCD. If a human then touches a faulty device (i.e. one whose external metal casing has become live), some current will flow - via the human - to ground. The RCD will detect the resulting imbalance in current between live and neutral and cut the circuit.

Where does the supply, the MG4, connect to the ground? There is no link back to a substation, a transformer earth stake, only the house earth stake maybe ..... neither line one or line 2 are connected to the earth, so there is no active or neutral, just a floating line 1, line 2 and earthing cable on an appliance that has an outside metal surface the user can come in contact with ...... so with the user getting connected across line 1 and line 2, the supply just sees another appliance, there is no path for the imbalance between line 1 and line 2, if the metal case comes into contact with line 1 or line 2, there is already a path back through the earth cable and the earth stake, how is a second earth stake going to improve this situation?

The solution is an RVD, it looks for more that 30mv on the earth circuit, if it sees that, it trips, whether the faulty appliance causes it or a bared live cable and there is a connection back to something connected to the earth circuit .... the RVD will sense more than 30mv and break the circuit, no current had to run through the person because, without either line one or line 2 being connected to the earth cable, these is no circuit between the two live cables .....

It can be hard to get your head around when you have only ever worked with mains power, but I had to learn it all when I did the electrical and computing diploma at TAFE ..... well, the first 3 yrs squeezed into 1 yr, about then the Electrical Engineer who was teaching us told us what we could be earning after we accumulated 7 yrs worth of study ..... I was already making near double that, so I didn't return ... I never did get my head around calculus ....... so I was never going to be advancing on to quantum computing, nor did I have an interest in how to write formal reports that no one would read unless something went wrong and they were looking for someone to blame ......

T1 Terry

 

[JimJ]

In the aftermath of Cyclone Alfred when we had no grid power for eight days. From a 2kW generator we ran an extension lead to a small power board in the kitchen. From that we powered our fridge and freezer and ran lights.

We did not run the genny continuously, but enough to keep things cold and frozen.
It had the same output as the MG V2L.

Since we have bought the ZS, we should be able to do the same if needed.

Meanwhile our solar panels enjoyed a rest. No grid reference, no solar power.

 

[Everest]

Where does the supply, the MG4, connect to the ground? There is no link back to a substation, a transformer earth stake, only the house earth stake maybe

That is NOT what I was saying... I specifically said ...

The earthing rod connects the earth and neutral supply from the vehicle (or generator) to ground on the supply side of the RCD.

You need to create a TT earthing arrangement for the RCD to work.

Maybe better explained using this extract from the excellent Victron "Wiring Unlimited" book. The right-most diagram is what I have been detailing in this thread.

 

[T1 Terry]

That is NOT what I was saying... I specifically said ...


You need to create a TT earthing arrangement for the RCD to work.

Maybe better explained using this extract from the excellent Victron "Wiring Unlimited" book. The right-most diagram is what I have been detailing in this thread.

View attachment 44842

See the centre image, it required an earth/neutral bond, there is no earth neutral bond in a floating system, so an RCD will not function, earth stake or not ....
An RVD in the circuit will trip if voltage is seen on the earth circuit, no need to wet the ground and drive in an earth stake. An RV does not have an earthing stake, an off grid house is unlikely to unless someone has made it into an earth/neutral linked system ....

In many ways, a floating system is safer than an earth/neutral linked system, as long as there is an RVD in the circuit .....

T1 Terry

 

[Everest]

See the centre image, it required an earth/neutral bond, there is no earth neutral bond in a floating system, so an RCD will not function, earth stake or not ....

Yes, obviously. Not sure why you posted that when I originally said and have repeated that a N-E bond must be made at the generation source...

For that reason, there must be a N-E bond at the generator/V2L source, together with an earthing rod, prior to the RCD device.

Regarding...

In many ways, a floating system is safer than an earth/neutral linked system, as long as there is an RVD in the circuit .....

RVD's seem to be an Australian thing and not generally available or used in the UK.

A floating system is relatively safe for connection of one device, but not when there are multiple devices connected to them, as discussed earlier in this thread.

 

[T1 Terry]

Yes, obviously. Not sure why you posted that when I originally said and have repeated that a N-E bond must be made at the generation source...


Regarding...

RVD's seem to be an Australian thing and not generally available or used in the UK.

A floating system is relatively safe for connection of one device, but not when there are multiple devices connected to them, as discussed earlier in this thread.

Maybe there is a difference in how the earth/neutral link is made.
In Australia, the earth/neutral link is at the powerboard, after the supply and before the RCD/RVD, but in an RV for instance, if you added an earth/neutral link after an RCD on the supply, like from a house or caravan park. that second earth/neutral link will trip the RCD on the supply side.

For those relying on an RCD, there is a program in the Victron inverter that looks for an earth neutral connection, if it sees one on the supply, it will leave the earth/neutral linking relay open, if it doesn't sense a link and deems the supply is a floating system, it can be set to close the relay to make that connection, changing it from a floating system to a neutral/active system.
The catch there is, if the remote system has been running on the inverter, a floating system, and the earth/neutral link is made via the relay, as soon as shore power is connected, the shore power RCD sees a fault, the earth/neutral is connected and it sees that as an appliance fault, so it trips, the inverter doesn't see a shore power supply, so continues to run on the batteries. The RV user, now thinks they are receiving shore power that they are paying top $$ for, so everything gets turned on ...... and the battery drops out in the middle of the night .... no lights, nothing ....
Those who attempted to add an RCD after the inverter, so the supply would be cut if a fault was sensed, had a 50/50 chance of connecting the earth to the correct line, in a floating system, both lines are active, the problem occurs when the mains supply is plugged in and line connected to earth after the inverter is the active line on the supply ..... the smoke comes out ....
If the caravan park supply is a reverse polarity, because the lawn care and drain cleaner is also the handyman electrician, wires the replacement burnt out 15 amp socket with the active in the neutral spot and the neutral in the active spot ..... now the RCD upstream fails, so no power anyway.

This is why the RVD was originally designed, it is also an RCD and a reverse polarity detector, the ultimate safety switch.

Sadly, most of the people who make the rules regarding the Australian Standards, can't get their head around something new being introduce after they finished their training .... over here it is known as "professor syndrome", I'm the authority, I didn't study this new idea when I was trained, so it couldn't possibly work .....

T1 Terry

 

[suavecarve]

I've found Multiplus II pretty accommodating with gennys I've fed into it, it seems pretty resilient in overload state too, way more output than its rating. It's certainly a heavy piece of kit compared to many others.

Picking your brains as an obvious knowledge on charging house batteries from mg4.

Current set up is a fox 10kw battery with internal 3.4kw inverter to the house filled up overnight with 6.5p kw leccy. Topped up with 4.2kw of solar.

Having a vorsprung 7.4kw EV charger put in this week.

My theory is if I plug the EV to vorsprung charger, change the vehicle to discharge, I recharge my home battery at the inverter rate of the mg4 (2.2-3kw) then replenish overnight.

Am I wrong ?

 

[T1 Terry]

Picking your brains as an obvious knowledge on charging house batteries from mg4.

Current set up is a fox 10kw battery with internal 3.4kw inverter to the house filled up overnight with 6.5p kw leccy. Topped up with 4.2kw of solar.

Having a vorsprung 7.4kw EV charger put in this week.

My theory is if I plug the EV to vorsprung charger, change the vehicle to discharge, I recharge my home battery at the inverter rate of the mg4 (2.2-3kw) then replenish overnight.

Am I wrong ?

No, they are not a 2 way system. I'm assuming the 7.4kw charger is an AC unit and supplies enough current to max out the 7kw onboard AC charger.
The draw that 7 kw back out of the EV battery requires a resistor across the sensing pins and the earth pin, to tell the on board charger that is now required to be an inverter and supply up to what ever value resistor you use to control the inverter max output.

The two systems use the DC pins, not the AC, so much higher voltages at DC move backwards and forwards .....

T1 Terry

 

[Everest]

Am I wrong ?

Yes.

 

[suavecarve]

No, they are not a 2 way system. I'm assuming the 7.4kw charger is an AC unit and supplies enough current to max out the 7kw onboard AC charger.
The draw that 7 kw back out of the EV battery requires a resistor across the sensing pins and the earth pin, to tell the on board charger that is now required to be an inverter and supply up to what ever value resistor you use to control the inverter max output.

The two systems use the DC pins, not the AC, so much higher voltages at DC move backwards and forwards .....

T1 Terry

Should I have mentioned the vorsprung EV charger is bidirectional ?

The electricity would not go to the grid as I m not set up for export apart from excess solar. It would go to the house. The home battery is part of the house.

As far as I can see it's pretty similar to V2L apart from going through the EV charger instead of a 240 v socket allowing up to 3kw. If the house is using 500 watts then up to 2.5 kw to the home battery (if I set that to charge) just like my excess solar recharges my home battery rather than sending it to grid.

 

[T1 Terry]

Should I have mentioned the vorsprung EV charger is bidirectional ?

Might have helped :lol: Then, I don't have a clue, is it AC or DC?

T1 Terry

 

[suavecarve]

Might have helped :lol: Then, I don't have a clue, is it AC or DC?

T1 Terry

AC

 

[Everest]

Should I have mentioned the vorsprung EV charger is bidirectional ?

Are you sure? + can you send us a link to the charger's technical specification. If so, it will need to be ENA type tested and require G99 approval prior to connection to the grid.

It would also need to rectify and re-invert the V2L output to be grid-tied. I don't see that likely, unless it costs several thousand £££

 

[suavecarve]

Are you sure? + can you send us a link to the charger's technical specification. If so, it will need to be ENA type tested and require G99 approval prior to connection to the grid.

It would also need to rectify and re-invert the V2L output to be grid-tied. I don't see that likely, unless it costs several thousand £££

You make a fair to reasonable point.

My error here was googling "best bidirectional EV chargers" and hitting the first link (which if I find it I will post it (with a warning))
Then trusting the top 10 best bidirectional EV chargers would actually be bidirectional, then going to Amazon and ordering the same model

I ve just gone through the gumpf below and no mention of it being biderectional. Looks like I LL be doing V2L and extension lead then

(Unless you look through it and tell me I have found unicorn poo)

https://www.amazon.co.uk/VORSPRUNG%C2%AE-Ethernet-Tethered-Charging-Protection-Black/dp/B0FKTLT5NN

You make a fair to reasonable point.

My error here was googling "best bidirectional EV chargers" and hitting the first link (which if I find it I will post it (with a warning))
Then trusting the top 10 best bidirectional EV chargers would actually be bidirectional, then going to Amazon and ordering the same model

I ve just gone through the gumpf below and no mention of it being biderectional. Looks like I LL be doing V2L and extension lead then

(Unless you look through it and tell me I have found unicorn poo)

https://www.amazon.co.uk/VORSPRUNG%C2%AE-Ethernet-Tethered-Charging-Protection-Black/dp/B0FKTLT5NN

Please note the EV charger is not bidirectional or biderectionable for those too embarrassed to ask for Viagra over the counter

And here is the website of the best 10 "bidirectional EV chargers"

Our 10 Best Bi Directional Ev Charger for 2026 [UK] | CompareBuddy.co.uk

Compare and review the 10 best Bi Directional Ev Charger for 2026 at CompareBuddy.co.uk. Find top-rated picks with detailed insights to help you choose the perfect one for you!

comparebuddy.co.uk

NB I bought it prior to April 1st

 

[Everest]

You make a fair to reasonable point.

My error here was...

Definitely not bi-directional at that price

You mention it is being installed next week - assume you have a sparky to do that for you as you've bought it via Amazon. Assume also you are aware of the DNO requirements for either approval vs. install and notify depending on supply adequacy / MD of 60A or less etc.

 

[johnb80]

If you have the option, cancel / return that wallbox. Units like this and many others are not recognised by the top EV tariff providers and therefore you wouldn't be able to use them. Intelligent Octopus GO is currently one of the cheapest at 3.49p off peak for 6 hours as well as other charging sessions during peak hours under their control. You can make good use of this by charging house batteries at the same time if IOG has given you extra sessions. You do need to use one of these:-
Ohme (ePod & Home Pro)
MyEnergi Zappi
Wallbox (Pulsar Max/Plus)
Hypervolt Home 3 Pro
Easee One

My favoured one is the Zappi, it's the most widely accepted wallbox amongst energy suppliers. It also integrates really well with Solar and energy diverters etc.

 

[suavecarve]

Definitely not bi-directional at that price

You mention it is being installed next week - assume you have a sparky to do that for you as you've bought it via Amazon. Assume also you are aware of the DNO requirements for either approval vs. install and notify depending on supply adequacy / MD of 60A or less etc.

All sorted with relatives