DIY V2L cable

[Ayoull]

@Ayoull and @DangerousDoug , many thanks for your erudite explanations and warnings associated with the mis-use of the V2L feature provided on our cars.
Hopefully they will cause people to think twice before mistakenly thinking that V2L (vehicle to load) and V2H(vehicle to home) are one and the same.
So far, only a few vehicle manufacturers provide true V2H and MG is not one of them.

Not a problem, I've been both sides of the fence, started as an electrician and then retrained at the DNO so can see how both sides are at odds at times, but ultimately want everything to be safe and compliant.

V2L was a stop gap measure that personally I don't think should have been introduced, due to the potential issues already discussed, but people view it as the holy grail of power in a blackout which V2H won't provide as it will have to comply with G98/G99 which require disconnection of supply on loss of mains.

 

[Sloucher]

Are v2l cables universal? That is, could I use a cable from a 4 on, say, a leaf?

The answer is no, they're not universal. The type 2 end of the cable contains a resistor. Every manufacturer has its own protocol for the car to recognise when a v2l cable is present and will have their own value for that resistor. Hence a Hyundai cable wouldn't be recognised by an MG and vice versa.

 

[Greenie]

The answer is no, they're not universal. The type 2 end of the cable contains a resistor. Every manufacturer has its own protocol for the car to recognise when a v2l cable is present and will have their own value for that resistor. Hence a Hyundai cable wouldn't be recognised by an MG and vice versa.

 

[Geoffree]

I've noticed that there are discharge adapters on eBay for about £30. Some actually mention they are for MG4. Only a single 3 pin plug sockets but you could plug in an extension cable. Search for: MG4 Vehicle to Load Type 2 UK.

 

[Ayoull]

I've noticed that there are discharge adapters on eBay for about £30. Some actually mention they are for MG4. Only a single 3 pin plug sockets but you could plug in an extension cable. Search for: MG4 Vehicle to Load Type 2 UK.

They're not waterproof those generally

 

[Sloucher]

I've noticed that there are discharge adapters on eBay for about £30. Some actually mention they are for MG4. Only a single 3 pin plug sockets but you could plug in an extension cable. Search for: MG4 Vehicle to Load Type 2 UK.

I have one of those. It was supplied with a 1K resistor which I changed to 470 ohm but have since swapped out for 2K to restrict the output to 16A.

 

[skynett]

I have an Hybrid Inverter with an EPS input, I suppose there is a way to wire this so I can power the Inverter from the Car and perhaps Charge my Inverter Battery from the Car when the Sun is not out. Anyone done this before?

At the Moment I just use an extension lead to power 1 or 2 devices when needed, but because I have an off peak Octopus Rate, I am looking at getting the extra benefits using the Car battery even more through my Inverter EPS input.

 

[Mick b]

Thanks for the reply, sounds like you are trying to do something similar to me but are a few months ahead.

My biggest issue with the manual changeover is the multiple Raspberry Pies I have running to control the home automation, the heating control system (Underfloor) and my MQTT server.

Sadly Raspberry Pie's do not always take well to power interruptions which can corrupt the boot disk, not great when all your automation is running on them so I need to do a controlled power down and then reboot after switch over.

Trying to build a UPS for the Pi's that will also do a controlled power down but not there yet.

On a different note, I keep hearing that the MG4 cannot be locked when in V2L mode and that the 12V battery discharges as the car is still on. Have you had any experience of this?

I lock my MG4 when discharging with no problem

 

[DangerousDoug]

Thanks for the reply, sounds like you are trying to do something similar to me but are a few months ahead.

My biggest issue with the manual changeover is the multiple Raspberry Pies I have running to control the home automation, the heating control system (Underfloor) and my MQTT server.

Sadly Raspberry Pie's do not always take well to power interruptions which can corrupt the boot disk, not great when all your automation is running on them so I need to do a controlled power down and then reboot after switch over.

Trying to build a UPS for the Pi's that will also do a controlled power down but not there yet.

On a different note, I keep hearing that the MG4 cannot be locked when in V2L mode and that the 12V battery discharges as the car is still on. Have you had any experience of this?

I, too, use Pis around the house (phone system, ad blocker, etc) and I've made simple low voltage UPSs for them. A simple arrangement with 3 x 3A diodes and a resistor is all you need, along with a 15v psu (many 12v psus run at 15v, and there are a lot of old laptop PSUs on ebay which give a very stable 15v (or you can drop a bit with a couple of extra diodes). so, forward biased diode from supply to load, forward biased diode from 12v lead-acid battery to load, then resistor from supply to lead-acid battery through a third forward biased diode. This gives 14V from the PSU while mains is on, with battery taking over when mains fails. Then all you need is a step-down BUCK converter from ebay (about £3) to give 5V at 3A to your pi(s). Simples ;-) We have a solar and PV installation, which cuts over in case of loss of mains supply, but the cutover takes around a second. So everything in the house is UPS protected.

 

[dawson2099]

Made up my V2L cable tonight based on info from elsewhere in the group.

Bought a 5m 16A type 2 Cable with a wired end from AliExpress.

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View attachment 12579

some 470 ohm 1w resistors
10 x 470 Ohm 1W Metal Film Resistor 1% Tolerance (Pack of 10) Amazon.co.uk
View attachment 12580

And a double waterproof plug socket

Double Outdoor Socket Waterproof Outside Plug Socket Weatherproof IP66 Wall Electrical Outlet, 13Amp 2Gang Storm Switched Power Socket Box. Amazon.co.uk
View attachment 12581

You need to change the internal resistor inside the type 2 plug from 680 ohm to 470 ohm.
Which is just a case of opening it up and cutting the resistor out of the thin blue wire.
View attachment 12582
Then replace it with the 470 ohm version, making sure to heat shrink the soldered connections and the resistor itself like the one you remove.
View attachment 12585
Then put it back together and move to the socket end.
Putting the cable through the waterproof connector seal in the housing and trimming the end of each wire (earth, live and neutral, which are all tagged for you on each wire, I also soldered the ends up for better connection) ready for fitting to their relevent fittings on the back of the socket
View attachment 12583
There is also a thin grey wire that needs to be cut and shielded as it won't be used (see looped wire in pic above)
Once all connected just fasten the plug socket to the housing and screw in each corner then fitting the screw covers.
View attachment 12584
That should be it....
The test will be tomorrow when I bring my car home and give it a whirl.

I'm sure it will be fine I've checked, double checked and triple checked all the connectors.
Will post back tomorrow with an update on whether it works, though it should be fine, the resistor carrys very little, it's just there to tell the car that it's a discharge cable, MG use a lower ohm resistor than normal, hence the switch from 680 to 470 ohm. (Probably so they can sell their own cables as others won't work)
All in its cost me around £70, which is much cheaper than the competition.

Or try an adapter like this, £13 on eBay:

EV Cable Adapter Discharge V2L Vehicle to Load Type 2 UK Power​

 

[Stitchriddle]

Reading around seems these adapters are not working on MG4 MY23 models...Basically those built after end of March 2023. Anyone know if there's a way around this? Not sure if its to do with the new ones being single phase only affecting the connections? I have no knowledge on this stuff, just trying to see if there's another option?