Parasitic drain on 12V battery

[decrep]

Hi, Back to the 12 volt battery dying.
I have a 2021 MG HS PHEV. everything was fine until the service on the 20th January. Next time I came to drive, the car was dead.

I have heard, that when parts are in very short supply, the service people may sometimes swap the good part out from a new customer and put into one that's been waiting for a while.

With any luck they can continue doing this for a while, and keep charging for a new part that only gets used once, when it eventually arrives.

Hope this isn't what's happened to you, faults can appear straight after a service and it's just coincidence, but some times they've "accidentally" left a spanner in the works, means you'll be back for a new T-Box.

Sorry I just don't trust service organisations, some are fantastic, especially those in smaller towns that rely on local word of mouth, but I've been ripped off or attempted to be by larger franchises, that have a big brand clientele.

Unfortunately, BEVs are just about locked in to franchise dealers!

 

[Riversider]

Hi, I bought a brand new MGS5 Trophy 61kWh on 8th Aug 25, on the15th Sept 25 (a month later) the 12V battery was depleted. I don't use the car with just the 12V battery running, I make sure the car is in the ready mode. The AA said I have a parasitic drain on the 12V battery. MG had the car 6 days, said they fixed it and it drained again 5 days later. It's back in with the MG garage where I purchased it from, they have had it 3 weeks and still don't have a clue. The first garage I went to said they had another MGS5 and 2 BYD's with the same problem. Has anyone else been in this situation, with a brand new car. The garage has had the car longer than I've had it on the road.
TIA.

Hi there, did you ever get a resolution to this problem? I have the same car as you, got in October 25, battery drain problems started November 25 and it has happened now at least 10 times, car been into the dealer 3 times and I keep getting told that they cant find a fault. Just wondering if you ever got to the bottom of it?

 

[marcbesty]

Hi there, did you ever get a resolution to this problem? I have the same car as you, got in October 25, battery drain problems started November 25 and it has happened now at least 10 times, car been into the dealer 3 times and I keep getting told that they cant find a fault. Just wondering if you ever got to the bottom of it?

Hi,

I had the same issue. I went to the dealer to drop the car back for it to be looked at (3rd Time it was with them) and I asked for alternative options due to the amount of issues. I was offered the below.

Brand new S5 but I would have to pay an additional £2,500
A Hybrid ZS - straight swap - the car they said they would swap was a 75 plate with 9,000 miles

I sent a formal complaint email rejecting both options and requested a brand new car with no additional cost or a full refund (nothing taken away due to mileage etc). I quoted the Consumer Act and sent the below wording.

It is clear that the vehicle has suffered from the same fundamental fault repeatedly since the date of collection. Given the number of breakdowns, unsuccessful repairs, and the ongoing nature of the issue, it is evident that the vehicle was not of satisfactory quality or fit for purpose at the time it was supplied.

Consumer Rights Act 2015

Under the Consumer Rights Act 2015, goods supplied by a retailer must be:
Of satisfactory quality
Fit for purpose
As described
Where a fault develops within the first six months, the law presumes that the fault was present at the time of purchase, unless the retailer can prove otherwise.

As the vehicle has suffered multiple failures and repair attempts, I believe I am entitled to exercise my statutory rights.

I am now driving round in a 26 plate MG S5 and so far we have had no issues (touchwood).

 

[Shwd mae]

Problem has also been solved with me. Replacement of T Block, and I removed access to my MG account/MG I Smart account from my Rolec/EV charger, I believe this was the problem all along with the EV charger trying to 'communicate' with the car.

 

[marcbesty]

Problem has also been solved with me. Replacement of T Block, and I removed access to my MG account/MG I Smart account from my Rolec/EV charger, I believe this was the problem all along with the EV charger trying to 'communicate' with the car.

I have also not connected the new car to the app or my energy provider app.

 

[Riversider]

Hi,

I had the same issue. I went to the dealer to drop the car back for it to be looked at (3rd Time it was with them) and I asked for alternative options due to the amount of issues. I was offered the below.

Brand new S5 but I would have to pay an additional £2,500
A Hybrid ZS - straight swap - the car they said they would swap was a 75 plate with 9,000 miles

I sent a formal complaint email rejecting both options and requested a brand new car with no additional cost or a full refund (nothing taken away due to mileage etc). I quoted the Consumer Act and sent the below wording.

It is clear that the vehicle has suffered from the same fundamental fault repeatedly since the date of collection. Given the number of breakdowns, unsuccessful repairs, and the ongoing nature of the issue, it is evident that the vehicle was not of satisfactory quality or fit for purpose at the time it was supplied.

Consumer Rights Act 2015

Under the Consumer Rights Act 2015, goods supplied by a retailer must be:
Of satisfactory quality
Fit for purpose
As described
Where a fault develops within the first six months, the law presumes that the fault was present at the time of purchase, unless the retailer can prove otherwise.

As the vehicle has suffered multiple failures and repair attempts, I believe I am entitled to exercise my statutory rights.

I am now driving round in a 26 plate MG S5 and so far we have had no issues (touchwood).

Thanks so much for this, really helpful. I think this is now the route I am going to have to take as they are not listening to me. I've had the RAC out 3 times and have to carry a charger pack around with me, on car thats only a few months old. Madness!

 

[emmrecs]

Problem has also been solved with me. Replacement of T Block, and I removed access to my MG account/MG I Smart account from my Rolec/EV charger, I believe this was the problem all along with the EV charger trying to 'communicate' with the car.

Excellent news, since I was/still am in exactly the same situation, including the same charger. (I also suspected the charger was "communicating" with the car far too frequently and so draining the 12v.)

BUT, the replacement T-Box for me has, so far, failed completely to code to the car or the car to it so am currently driving an MG3 Hybrid+ loan car (and so spending a lot of money on petrol! Grrr. )

My local dealer has been in frequent contact with MG Technical and, I am now told, the issue has been escalated (by Longbridge) to the next level of technical support.

If, and when a resolution is found I will post back!