Granny charging variability

[TimothyN]

I am sitting in the car during granny charging for the first time and witnessing that the charge rate varies between 2.7kW and zero (though more typically 0.3kW) on about a 30 second cycle.

I have a video if anyone would like to see it.

Is that normal?

 

[TimothyN]

I locked and unlocked the car and it's steady at 2.7kW now.

 

[salty]

To be honest, I've know idea what my Granny Charger does. I just know it charges the car. That's all I need to know.

 

[Everest]

Might be plucking at straws here, but could it be that when you were in the vehicle the HVAC was turning on and off, and hence using much of the power?

 

[EvTek23]

If its like the MG4 which it is heavily based on, when it charges from an AC supply the car has to be locked during the charge process. It may not go into full charge mode or keep on aborting when you are seated in the car as it now in partial ready mode with the HV battery connected. The HV battery is disconnected from the car while charging.
If you lock and unlock the car but are not seated in the car it is not in the ready mode. So will go into the charge mode. Unlocking the car during charging causes it to pause or abort as it says on the display but resume on relocking.
DC or fast charging is different as you turn the car off which disconnects the HV battery and can therefore sit in the car.

 

[Ruislip Resident]

Anybody have a suggestion for a good granny charger. The S5 I have ordered comes with a type 2 (which I already have one of). The dealer does not even have any grannys available to thow in. The ZSEV I am returning at the end of the PCP has one, but If I keep it, no doubt Santander will charge me for it. Nb I use the granny to charge when visiting my folks and at some holiday rentals. I always leave money for my folks for this and get pemission at tbe holiday rentals with an agreed cost (if they want anything).

 

[salty]

Very much doubt Santander would even notice, there was no granny charger.
But if you don't want to risk it, this is the one I got, from Amazon, it's been great.

 

[TimothyN]

I'm very happy with

https://amzn.eu/d/6pEE6fa

It goes to a true 2.7kW consistently, so may be a few percentage points better than the one Salty suggests, at the same price.

 

[MG Clive]

Anybody have a suggestion for a good granny charger. The S5 I have ordered comes with a type 2 (which I already have one of). The dealer does not even have any grannys available to thow in. The ZSEV I am returning at the end of the PCP has one, but If I keep it, no doubt Santander will charge me for it. Nb I use the granny to charge when visiting my folks and at some holiday rentals. I always leave money for my folks for this and get pemission at tbe holiday rentals with an agreed cost (if they want anything).

There are plenty of chargers available, but it's probably safest to stick with the genuine MG one > MG Granny Charger.

 

[salty]

There are plenty of chargers available, but it's probably safest to stick with the genuine MG one > MG Granny Charger.

That Is cheap for a genuine MG granny charger. I got the one from Amazon coz the supplied Granny charger wasn't long enough 4m for my needs. So got a 6m one from Amazon and it's been fine.
Personally don't think a genuine MG one
would be any safer, than a good aftermarket one.

 

[TimothyN]

Salty, what was the logic of going for one limited to 10A when 13A is available?

I have charged many nights at 13A/2.7kW and had no problems whatsoever, no heating of components, no cut-outs, and going 30% slower would be a pain.

 

[Everest]

Salty, what was the logic of going for one limited to 10A when 13A is available?

Basically for compliance with IET Wiring Regulations (722.55.101.0.201.1i), mandates a BS1362-2 EV compliant socket to supply max continuous of 10A for EV charging.

FYI; 'so-called' 13A sockets are only suitable for 13A for a short duration - e.g. 3 mins. kettle boiling.

Max should be 10A with BS1362-2 EV socket and dedicated final circuit.

Otherwise max 8A continuous use.

Otherwise, this may happen...

Post in thread 'Don't charge from a 3 pin plug when it's 27 degrees outside kids'

Jun 19, 2025

Have you got a picture of the 'granny's' plug?

It wasn't granny's plug thank god. It was an industrial extension cable approx. 25m long to a weather proof socket.

• Yorkshire Hillbilly

• 

See details on this page.. 13A EV Sockets Compliant with BS 1363-2 EV
or here https://electrical.theiet.org/media/2422/bs-7671-2018_a1_2020-inc-corrigendum-may-2020_read-only.pdf

 

[TimothyN]

I have now charged maybe 50 times, sometimes from 20% to 80% and it doesn't even get warm.

 

[Everest]

We seem to be going around in circles

You asked "what is the logic" - I have given you the answer with the technical & IET / BS7671 regulatory reasons behind it.

With all due respect I don't give a **** if you set your house on fire or electrocute your loved ones with your V2L 13A suicide cord or your lack of respect of earthing and RCD from your V2L thread.

Good luck and goodbye

 

[TimothyN]

To be fair, on your advice I dismantled the 13A to 13A cord and said I would desist from putting the boiler on it, even though it has a 13A plug.

So you are a very valuable person.

 

[Bantam]

That 13amp plug looks like the fuse was clipped onto contacts that where not clean ie rusty? water got on them? I have used a 13amp charge lead for 8 years now never had a problem like this photo, just chop off the plug put a new plug and fuse on the cable end. Make certain your socket contacts are good any slight movement of the square pins mainly the live pin can cause heat to be generated if you think this is bad I have seen plenty of photos of Rolex car chargers 7 kw with badly installed cables under screw terminals actually overheating and going on fire on the house wall!!! and most granny leads only use a max of 10amps.