MG ZS EV 2024 charging port door won't open (dead 12V)

[MG ZS EV 2024 PH]

Hello everyone
We came back after a months vacation and now my 2024 MG ZS EVs charging port door won't open, it is still under full warranty (6 months old) and MG assist towing company says they can't tow an EV since parking brakes are engaged, It looks like the 12V battery that powers up the central computer is dead so no signal is sent even for the charging port door to open, I unlocked the door manually btw, so am I right here guys... Any suggestions please. The car was charged to 87% before I left and parked in my covered garage. Please help!!

Connected a battery booster just to unlock the charge port door (no other way) and have started charging it, 12V battery was dead and the main battery it looks like is just fine with alarm and flashing lights which were a welcome sight, hoping the green indicators on the charge port start blinking green for now it shows the portable charger is charging...

 

[hmadsen]

That's pretty normal, if you leave for a month you should put the 12V battery on a battery tender.

Sadly the ZS EV does not measure the battery voltage and top it up when it gets low, using the traction battery, like other car brands do.

 

[Gadget Geek]

The 12V battery will need replacing. Will still be under warranty, so sooner than later.

 

[MG ZS EV 2024 PH]

That's pretty normal, if you leave for a month you should put the 12V battery on a battery tender.

Sadly the ZS EV does not measure the battery voltage and top it up when it gets low, using the traction battery, like other car brands do.

There is a trickle charge from the main battery to the 12V I believe for this car so are you saying that I need an externally connected trickle charge as well for the 12V please when it is left unattended for over a week?.

 

[BOB353]

I would not worry about it unless you intend going away for 4 weeks or more.

Last time we did a 3 month tour of eastern Australia I fitted a 5 stage charger via a time clock that was set to 15 minutes per day to my wife's ICE car that had a suss battery.on arriving home it started first go.

 

[hmadsen]

There is a trickle charge from the main battery to the 12V I believe for this car so are you saying that I need an externally connected trickle charge as well for the 12V please when it is left unattended for over a week?.

Nope

The charger that charges the 12V battery is drawing power from the high voltage battery and to do that it needs the contactors to be pulled in (Make contact) and this only happens when the car is in "Ready" mode.

If you don't believe me, try attaching a voltmeter to the 12V battery with the car off, and then put the car into ready mode and you will see the voltage rise because the charger is then charging.

If it were trickle charging even with the car off, the battery would not run out of electrons

 

[MG ZS EV 2024 PH]

Yes that is so true, the trickle charge in OFF position is not in place (maybe to safeguard the main battery).
I ended up replacing the 12V with a DIN65 AGM battery since the stock SAIC battery is really "suss" even in a new car, doubt it is AGM.. godd news for me was that after replacing it there were no alarms or notifications which I expected to see based on some earlier comments.. maybe the newer models have that issue fixed.
All good and it was really an easy switch over the hardest for me was just the sheer fear or uncertainty, keep my dealership in loop who assured me no other warranties would be voided if I chose not to run with stock SAIC,.
Thanks guys good learning for me.

 

[Data]

Nope

The charger that charges the 12V battery is drawing power from the high voltage battery and to do that it needs the contactors to be pulled in (Make contact) and this only happens when the car is in "Ready" mode.

If you dont believe me, try attaching a voltmeter to the 12V battery with the car off, and then put the car into ready mode and you will see the voltage rise because the charger is then charging.

If it were trickly charging even with the car off, the battery would not run out of electrons

Ok, so my car manufactured September...ish 2024, an MG ZS LR Trophy Connect spent the day with my dealer yesterday having a complete software upgrade under warranty to solve a minor issue caused by having some warranty work carried out to the car's paintwork. We think the body shop may have disconnected the 12V battery with the car still running. This caused some glitches with the telematics & particularly the MG App. It's like shutting down your Windows computer by pulling out the wall plug, which can cause some hd corruption. The software upgrades were indeed very significant. More about those in another thread.

Anyway, to upgrade, the car was left running in the accessory ignition position for some of the time. This ran the 12V battery down quite a bit. When I collected the car the 12v battery was showing 12.1V. quite low. My 6 mile drive home charged it to 12.3V.

This morning I scanned the car with my app to find the battery now at 13v! So clearly the car does detect low 12V battery voltage & take action to remedy this. I appreciate this may not be the case with earlier cars. However, there may be a battery management software upgrade to correct this.

Just saying!

 

[hmadsen]

This morning I scanned the car with my app to find the battery now at 13v! So clearly the car does detect low 12v battery voltage & take action to remedy this. I appreciate this may not be the case with earlier cars. However, there may be a battery management software upgrade to correct this.

Just saying!

We dont have to agree, if your car does this, it is the only MG ZS EV i know of that does this., every other MG ZS EV 2022-2025 only charges the battery with the HV battery contactors energized and this only happens when the car is in ready mode.

 

[Data]

Ok but se

We dont have to agree, if your car does this, it is the only MG ZS EV i know of that does this., every other MG ZS EV 2022-2025 only charges the battery with the HV battery contactors energized and this only happens when the car is in ready mode.

Ok but it appears several of us on here have this feature where the car charges the 12V battery when it needs it. In my case there is no other explanation for it. It went from 12.3V to 13V overnight with the car switched off & locked. As I mention above. I appreciate not all cars may do this especially the early cars. It's not the first time my car has done this either. I have a friend who also reports his new ZS doing this.

 

[Data]

Ok, phoned dealer who has advised that the later cars charge the 12V battery with a trickle charge even when the car is turned off & locked, if the battery needs it. I'm pretty sure I wasn't talking to the cleaner, and they knew what they were talking about. Pretty sure I didn't misunderstand what they said. My car had a complete battery management software upgrade yesterday to a new version. However, even the older version allowed the 12V battery to charge from the main traction battery when the car is powered off. I witnessed this on three or four occasions. I don't know what years of car can do this but it's likely a software upgrade may enable some other cars to do the same. If I'm wrong, I'm wrong but how else did my battery charge itself up overnight?

Interestingly, although my car was brand new & bought by me on the 30th Jan this year, all 6 of the cars computer modules needed upgrading as it was running quite old software. The main telematics system was running version R25 software & this is now upgraded to R27. Once that was done the MG computer showed the technician five other significant software upgrades that could not be seen using R25.

Further, I was told my car would be able to charge at Tesla super chargers as it already had the upgrade for that. MG do listen it seems!

 

[fred12345]

Further, I was told my car would be able to charge at Tesla super chargers as it already had the upgrade for that. MG do listen it seems!

I'm sure MG listens and acts but it seems it all comes down to local MG garages not willing to update stuff unless someone pays for it... in some cases you can get some updates for free when the car is in for repairs and in some cases they won't do anything unless someone pays for the "computer time" ...

 

[hmadsen]

Ok but se

Ok but it appears several of us on here have this feature where the car charges the 12v battery when it needs it. In my case there is no other explanation for it. It went from 12.3v to 13v overnight with the car switched off & locked. As I mention above. I appreciate not all cars may do this especially the early cars. It's not the first time my car has done this either. I have a friend who also reports his new ZS doing this.

Well my car delivered in January 2025 had all modules updated as part of the preparation for delivery (Dealer said it was on their computer for several hours to update all modules) and mine does not do it still, even though it has the latest software. (or atleast i never saw it do this)

Might be tempted to throw a battery monitor on before we go on holiday, we will be gone for 14 days with the car in the driveway, to see if it will in fact now be able to measure voltage and charge if needed.

 

[Data]

Yes, you are right Fred. The updates to my car took over 3hrs. That's near 3 hrs of being hooked up to their computer. Expensive at £164+VAT per hour.

 

[hmadsen]

Yes, you are right Fred. The updates to my car took over 3hrs. That's near 3 hrs of being hooked up to their computer. Expensive at £164+VAT per hour.

Honestly, they would be taking the piss, if they charged you for 3 hours of service for that.

The mechanic would be able to do other things, not requiring the computer while the system was updating itself.

Probably needed a few "continue" clicks.

They should have charged you for maybe 1 hour.

In reality they charged you for the 3 hours, and also charged the other person, whose car they worked on while yours stood unsupervised, doing the update, for 3 hours of labor.

But they do say a good technitian should be able to bill about 16 hours for every 8 hour workday

 

[Data]

Well my car delivered in January 2025 had all modules updated as part of the preparation for delivery (Dealer said it was on their computer for several hours to update all modules) and mine does not do it still, even though it has the latest software.

I don't dismiss what you say. I know most cars won't do this. But I'm finding this confusing. I've experienced the opposite of what you say. My car was not being charged, was locked, 12V battery at 12.3V. Yet by morning it had been charged to 13V Apparently some others have experienced this too. I'm an ex tech (retired) from many years ago (I know little about EV's). So I know it's possible. I would advise folks to assume their 12V battery WONT charge as mine clearly did.

Honestly, they would be taking the piss, if they charged you for 3 hours of service for that.

The mechanic would be able to do other things, not requiring the computer while the system was updating itself.

Probably needed a few "continue" clicks.

They should have charged you for maybe 1 hour.

In reality they charged you for the 3 hours, and also charged the other person, whose car they worked on while yours stood unsupervised, doing the update, for 3 hours of labor.

But they do say a good technitian should be able to bill about 16 hours for every 8 hour workday

I didn't pay anything. It was all warranty work. I'm a retired technician from many years ago so I know how it works.
The good news is your car should have the Tesla enhancement to allow you to charge at their super charger centres that are open to all makes.

 

[fred12345]

Yes, you are right Fred. The updates to my car took over 3hrs. That's near 3 hrs of being hooked up to their computer. Expensive at £164+VAT per hour.

well, considering a mechanic specialist software engineer has to keep pressing the space bar on the laptop and constantly monitor the progress for 3 hours, £164+ VAT p.h. is cheap.

They could just charge £100 or so and leave the car to update overnight when they are closed and the laptop is not needed elsewhere, assuming that's possible ...

 

[Data]

well, considering a mechanic specialist software engineer has to keep pressing the space bar on the laptop and constantly monitor the progress for 3 hours, £164+ VAT p.h. is cheap.

They could just charge £100 or so and leave the car to update overnight when they are closed and the laptop is not needed elsewhere, assuming that's possible ...

Yes, that's the issue. Someone has to interact with the car & MG's central computer at various points. It's not an autominous process. When I've done this on various cars if you don't pay attention the whole process can come to a stop wasting lots of valuable computer time.

 

[hmadsen]

I don't dismiss what you say. I know most cars won't do this. But I'm finding this confusing. I've experienced the opposite of what you say. My car was not being charged, was locked, 12v battery at 12.3v. Yet by morning it had been charged to 13v. Apparently some others have experienced this too. I'm an ex tech (retired) from many years ago (I know little about EV's). So I know it's possible. I would advise folks to assume their 12v battery WONT charge as mine clearly did.

Of course its possible, i also have an Elon-mobile and that one will certainly monitor and top up the battery....It kind of have to also, because the battery in that car is only about 6Ah and Lithium Ion to save on weight, so it would run out pretty quickly if it was not topped off whenever it was low.

I certainly hope the ZS EV has been updated to also do this, it's pretty crappy, that an electric car with 50+kWh of energy in one battery, would be immobilized because the other battery would be depleted.

I think all EV manufacturers should consider doing what the other car I have does and just replace the very heavy lead acid battery for one that is maybe 10-20 pounds lighter.

 

[hmadsen]

Yes, that's the issue. Someone has to interact with the car & MG's central computer at various points. It's not an autominous process. When I've done this on various cars if you don't pay attention the whole process can come to a stop wasting lots of valuable computer time.

What....So they need to sit and monitor the computer because otherwise it will time out ?

I would have imagines that it was like with a windows install, you start it and every 10 minutes you just press "Continue" and then it would do it, by itself and if you left it for 1 hour it would still happily continue after you pressed the button.

This method is so archaic, especially when other manufacturers have been able to update every bit of the car Over the air for longer than the ZS EV have been around.