Charging 12v battery using a V2L lead connected to the same car?

wandle MG4 trophy

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There are a few threads on here about MG4 12v battery failures that have caused numerous issues. I park my car well away from any plug that I could use for a battery charger so I am wondering if I could use my V2L cable connected to my car to attach a battery charger to charge my 12v battery?

Obviously the traction battery would need sufficient charge..

Presumably if the 12v battery were dead, the keyless entry would not work so I would need to use the blade key to open the car and lift the bonnet. Would the blade key also unlock the boot where I keep my V2L cable?
 
I like your idea but I think the problem might be is that the infotainment screen won't be working either so you can't tell the car to use the V2L.

Another thought. The main battery charges up the 12v battery when the car is on. Sitting in the driver's seat switches the car on. So if the 12v battery is flat would entering the car using the physical key and sitting in the driver's seat for 30 minutes charge the 12v battery?

Another option is to keep a lithium ion jump starter battery pack in the car to connect to the 12v battery like this one from Amazon
 
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As a matter of interest, has anyone any idea what the 12v battery voltage minimum voltage needs to be in order not to cause problems?
A little off topic, but I've just had a dashcam installed and chose not to have it wired to the permanent live feed because whereas the voltage regulator on the camera feed cable has a voltage drop cut-off, it's 11v, which seemed to me could be low enough to cause problems.
 
If the 12v battery voltage drops too low does the HV battery kick in to charger it up?
 
The manual offers this advice:

Note: It is recommended to set the power mode to READY for more than half an hour every week to help extend the service life of the battery. When the vehicle will not be used for an extended period (more than 1 month), it is recommended to disconnect the battery negative terminal clamping pile head. Make sure that the vehicle power system has been turned off before connecting or disconnecting the negative battery cable.

I'd just put ot to 'ready mode' for a bit
 

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