Converting a non working V2L to a 7kW supply from my MG4

[T1 Terry]

First, apologies but I copied and pasted this here from the AEVA forum Converting a non working V2L to a 7kW supply from my MG4 - AEVA Forums cause I doubt I could get it right a second time, I had to redo it so many times to get that one sort of readable.

This is not intended as a guide or instructions on how to make a 7kW V2L on the cheap, this is just how I did it. If anyone chooses to follow this path, it's on you to do it safely and on your head if it doesn't work out as intended and becomes an electrical hazard ..... you have been warned

Ok, this is what I started out with https://www.aliexpress.com/item/1005007 ... 18026JBBa7 and looked remarkably like this one https://www.ebay.com.au/itm/37626173781 ... R_rIp5HiZQ
and naturally, it didn't work

A few hrs on Google looking at everyone's idea of what was safe, what worked and didn't work and what would happen if you didn't buy a genuine MG part, like your future birthdays would be cancelled or something ..... I lashed out and spent $4 on a mix of resistors, pulled the non working item to bits to find out why it didn't work, and discovered this

Cheap V2L reconstruction showing original resistor and diode connected to CP pin and earth pin.jpg (129.83 KiB)
Yeah, my shaking and clear photos don't go together real well, but this I believe is the set up to make the plug into a charger ..... seems they couldn't even copy the correct thing.

So I removed the link between the earth pin (PE) and the signal pin (CP) because the common consensus was this caused false tripping sometimes, and soldered a 470ohm 1W resistor between the PE pin and the PP pin

Cheap V2L reconstruction resistor connected to CP pin and earth pin.jpg (298.7 KiB)

and added some more heat shrink and liquid electrical tape in an attempt to avoid any shorting in the very confined enclosure

Cheap V2L reconstruction resistor connected to CP pin and earth pin with heatshrink and liquid electrical tape.jpg (328.02 KiB)
Now comes the tricky part of getting it back together. This photo is to help verify you have the correct pins in the correct holes.
Note: I changed all the incorrectly labelled photos from CP pin to PP pin, so hopefully it comes out correct on the forum

Cheap V2L reconstruction pins in their correct locations.jpg (217.46 KiB)
Next important step, fit the 3 screws before you try to feed the wire and pins through the body and get them located in their retainer spots and into the main body, it isn't easy once you have the wires in there

Cheap V2L reconstruction 3 screws fitted in the body first.jpg (347.78 KiB)
It should look sort of like this when you get the pins and wires and retainer in place

Cheap V2L reconstruction 3 screws showing with pins in place.jpg (279.96 KiB)


This is an attempt to get a photo looking down at where the screws go, just so you get an idea why I suggested to put them in first. Through the blurry photo, you can just make out the heads of the phillips screws and the now blank CP pin

Cheap V2L reconstruction 3 screws.jpg (172.62 KiB)
This is the socket in the MG4 so you get an idea of the pin placement

Cheap V2L reconstruction showing pin placement in vehicle socket.jpg (407.94 KiB)
You don't need photos of it screwed back together, but a note of warning, getting that multi fit socket to line up in the body without an edge catching and it buckling up, is an exercise in patience screwing each one of the 1.5 size multihex screws, one turn at a time, and tapping it every which way to get all the edges in .....

The cable to the motorhome plugged into the adaptor and into the car

Cheap V2L reconstruction powering motorhome rooftop rattler on heat cycle drawing for MG4.jpg (401.56 KiB)
The MG4 display showing the load

Cheap V2L reconstruction powering rooftop rattler on heat cycle draw for MG4.jpg (518.18 KiB)
and a photo of the airconditioner in the motorhome running on heat with the outside temp at 16.5°C:

Cheap V2L reconstruction powering rooftop rattler on heat cycle 16.5C.jpg (300.13 KiB)
This is powering the Victron inverter charger, so it is topping up the battery to power all the 12V lights and water pump, the aircon, microwave when we use it (had to try it out) the 3 way fridge on mains power, the hot water using the electric element, coffee maker, electric jug, toaster and the air fryer 9yeah tried them all, just to see if it could do it).

I'm happy with the end result, it gives us a 51kWh electrical jerry can for when we are free camping, the MG4 can be set to any 8min SOC down to 20% before it disconnects the V2L, so there will always be battery power to drive to a charger if needed, and it all works seamlessly, when the V2L drops out, the Victron inverter will draw from the 600Ah @ 12V sodium ion house battery, so the electric blanket will still be working all night and the toaster, jug and coffee machine will all work before I need to step out the door to face the day

Although the Victron Multiplus have an auto earth/neutral link relay connection if it doesn't sense an earth circuit on the supply side, I'll add an RVD from RVDSafe to be sure to be sure, and to protect against reverse polarity supply at a caravan park .... had that quite a few times now, so better to protect against it

T1 Terry

 

[MG Clive]

Good work Terry.

 

[T1 Terry]

The MG4 was still at 49% this morning, started the experiment at 82% I think. Air con ran till around 11pm, it was getting a bit too hot by then.
Margaret has the air con heating from when she got up, the eleccy blankets ran all night along with the 3 way fridge/freezer, the battery charger, Margaret had a number of cups of tea, so at least 4 cycles of the jug and hot water stayed hot, this morning the jug and toaster and my coffee machine, and now the washing machine, all running of the MG4 battery, very happy with that performance.

T1 Terry

 

[MozFromOz]

Hey Terry. Just finished upgrading my V2L adaptor to 7kW. For those looking to copy, I take no responsibility for your assembly skills etc. Here I included a 32A breaker as an isolator switch. All stranded cable is terminated with bootlace ferrules to address the risk of loose strands causing hot joints. In my case I've used the same resistor as Terry but on light duty 250V rated flexible wire and zip tied in place inside a charging plug. Wires are crimped to the pins. The energy meter is a CT type with the CT coil threaded over the active wire inside the grey box.
The 15A outlet plugs also have the wires crimped with bootlace ferrules to mitigate hot joints under heavy load. Not sure if I will leave the breaker at 32A or change it to 25A as I don't know if the inverter/charger can handle the full 7kw for continuous use.

 

[T1 Terry]

Hi Ray, looks good, why the fancy readout box ...... because you could I guess
As I said at the Adelaide branch meeting of the AEVA, mine has worked flawlessly powering the motorhome with everything running, including the Victron inverter acting as a charger to make up what ever was remaining from the 7 kwW output to recharge the 600Ah of sodium ion house batteries.

I'm thinking of making a toroidal transformer to boost the 220VAC up to 240V or 250V, just so the inverter doesn't have such a hard time trying to make up any shortfall if we ask for more than the 7 kW from the MG .... it is not a happy chappy trying to make 220VAC to match the MG output, where it would normally be making 240VAC, but it can be adjusted up to 250VAC like is coming out of the mains here now that they fixed the burnt out neutral link at the pole transformer, sure makes the AC appliances take notice. Toast is done real quick and the 3 way fridge actually works like a proper fridge freezer ........, certainly reheats the hot water tank quickly as well

T1 Terry

 

[MozFromOz]

Hi Terry. I had one of the energy meters leftover from another project so I thought I'd add it to the box.
A quick question for you. I couldn't see it in your photos but did you change the 3 pin socket on your adaptor to a 32A one or did it come like that?

 

[T1 Terry]

Came like that, I did use a 20 amp male plug ..... but later discovered it wouldn't fit in a 15 amp socket if I wanted to use the same cord from a 15 amp outlet .... so the active and neutral pin had to be filed down to fit the 15 amp socket ......
Sounds completely the wrong thing to do, until you look at the end of the pin that the cable connects to

As can be seen, the tab on the end of the pin that the 5mm sq cable attaches to, is even smaller again, so no loss of actual conductor material was lost and the contact patch inside the "one size fits all" multifit socket on the adaptor, doesn't actually gain any contact area between the 15 amp width pins and the 20 amp width pins ........

When I remake the cable into the CCS plug, the 5mm sq conductors will go straight into the pins and be crimped on ......

T1 Terry

 

[MozFromOz]

Great work on the 20a plug. I guess it nevertheless won't be safe to run at 7kw for more than a few minutes given the limited grip on the pins in the socket and contact area. I always scratch my head at why the only enlarged pin on a 15A plug is the ground pin. It's why I decided to build mine the way I did so the load connection is distributed across the two 15a line sockets.