Parasitic drain on 12V battery

[Lovemyev]

Eventually MG CS will “join up the dots” and realise that they DO have an issue with a batch of T box components in these cars.
Unfortunately for us owners and the dealers, they follow down the same laborious and time consuming route for all parties.
Making numerous appointments to finally conclude with the same diagnosis of the patient.
Until somebody at the mothership decides.
“Hey…… I had one of those issues only last week and the T box was the problem” .
Until the penny drops - get a booster pack !.

 

[emmrecs]

It is stupid that like you people are having to consider boosters to get running again.

Not stupid, in my opinion, just careful!

I bought my Battery Booster when I owned my previous MG5, and never needed it! Now, having needed it at least four times with my S5 I'm only too pleased to have it available.

 

[Hallix73]

About to exchange my MG4 for a S5. I have always had a 12v Boost pack in the MG4, never had to use it. However sounds a lot on here with S5 have problems. Early days with MG4 it was common that the 12v terminals were slack after transit.

What is a T-Box????

 

[emmrecs]

T-Box = Telematics Box.

 

[T1 Terry]

Has anyone else tried the fix @Big L thought might have sorted his battery hassles before he sold it Parasitic drain on 12V battery
Makes sense to me

T1 Terry

 

[Hallix73]

T-Box = Telematics Box.

Thank you and quick AI googles gives me this. Understand now.
In electric vehicles (EVs), a Telematics Box (or T-Box) is an automotive onboard unit that manages two-way communication between the car and external systems. While standard in many modern vehicles, it performs critical EV-specific functions related to battery management and connectivity.

Core Functions for Electric Cars

• Battery Health Monitoring: Tracks real-time data such as state of charge (SoC), discharge rates, battery temperature, and voltage.
• Range Management: Calculates remaining range by combining battery data with external factors like traffic, elevation, and weather.
• Charging Logistics: Helps drivers find available charging stations and allows fleet managers to schedule charging during off-peak hours to save costs.
• Remote Control: Enables "connected car" features through smartphone apps, such as remotely starting climate control (pre-conditioning) or locking doors.
• Emergency & Security: Automatically triggers emergency calls (eCall) during accidents and acts as a GPS tracker if the vehicle is stolen.