Car dead after 2 weeks, won't open

[Rolfe]

Good point. If I leave my car much more than about 24 hours it stops paying any attention to the app because it's snoozing. Which is a bit of a pain if I then want to use the app to pre-heat it on a snowy morning, but that's a topic for another thread. That the OP was able to check the car at intervals that must have been more than a couple of days, and the car responded to the app, doesn't sound right.

Parasitic drain might be an explanation I suppose.

 

[siteguru]

FWIW I've not used my car for a few days - I've just checked via the app and it scanned the car OK.

 

[Rolfe]

Have you done anything at all to wake the car up, though? I opened my boot to get something out, and that was enough to wake it up and get it responding to the app.

 

[siteguru]

No - I've not unlocked it or been into it for a few days - last Thursday evening I think. I have checked the app though (maybe on Saturday, and then today).

 

[Rolfe]

Maybe you've checked often enough to keep it awake?

 

[siteguru]

 

[tsedge]

Maybe you've checked often enough to keep it awake?

Unfortunately we don't know the exact criteria to get it to go to sleep, but mine seems to do it repeatably.

 

[halogen]

i dont have access to ismart app yet..
but can we turn on the car with the app. something about preheating or cooling cabin...

then we could turn the car on with hetinf/cooling maybe once every 3 days for a good 10 minutes or something.

 

[JonnyG]

My old car used to disable all online communication when the battery was below a certain voltage ?

 

[Rolfe]

i dont have access to ismart app yet..
but can we turn on the car with the app. something about preheating or cooling cabin...

then we could turn the car on with hetinf/cooling maybe once every 3 days for a good 10 minutes or something.

You only need to scan it to wake it up, I think. But the problem is that if you keep doing that you'll flatten the 12v battery.

 

[Mickky]

I'm guessing it was the 12V battery. It is mentioned in the manual that you need to "turn on" the car to charge the 12V battery regularly, I don't remember the timescale but seem to think it was about 2 weeks. Checking via the app will discharge a small part of 12V battery each time, which won't help, also you may have had plenty of charge in the HV battery but this doesn't top up the 12V battery unless the car is "switched on".

It should do as long as the traction battery is at a reasonable charged state and there's not a fault in the system see MG4 manual page 23 Intelligent Charging.

 

[TassieDi]

The car is supposed to go into a deep sleep within 48 hours when you leave it. In this state the app will not work. It isn't a good idea to keep checking on it with the app when leaving it as this will stop it going into the deep sleep state - and thus promote battery drain.

It should keep the 12V battery topped up of you have more than 50% SOC, but if you leave it with less than that then the deep sleep is essential to stop the 12V from being discharged.

MG recommend if leaving the car for a month or longer disconnecting the 12V battery to preserve it.

If this has happened to your car then it should come to life immediately when you connect another 12V battery to 'jump' it into life.

General recommendation for an airport trip is:

• Leave the car with between 60-80% SOC.
• Do not use the app to check on the car while it is away.

Hi there, I'm visiting from the MGZS forum. I don't recall seeing anything in the MGZS manual about going into a deep sleep. Do you know if this applies to the ZS, and do you have a reference for it? Thanks.

 

[dspencer12345]

Left my ZS in an airport car park for a week. After a couple of days, lost contact with it using the app. And no, it wasn't in Luton! So yes, maybe they do go to sleep?!

 

[drugrunner]

Hi. I had the same problem, returned to Gatwick South car park after a 7day holiday and the car was dead. I wrote about this on this forum.
The car has just come back from MG Hendy Poole and they diagnosed the issue as a problem with the BCM module - Body Control Module, which had switched on by itself whilst parked. This should not have happened. MG are aware of the issue and have sent an update for the BCM Module which is what the service team applied. Hope that helps

Thread '12v dead battery and wife locked in the car! - Welcome home!!' 12v dead battery and wife locked in the car! - Welcome home!!

 

[Jto]

It won’t unlock: is the battery in the remote dead?
Plenty of charge left in the car: at what percentage ?

The car will top up the 12v battery but it’s not certain when and how long for. And as @MuzGB1970 stated, even the manual does say to have the car on and in READY mode for at least half an hour every week. Basically if you don’t drive it much. This isn’t so critical when the 12v battery is in a good state of health and charge.

If your 12v battery wasn’t in a good state of health I’m afraid these things happen.
12v batteries must be kept at 100% as much as possible. But if they’ve never been charged to 100% properly then they will struggle to keep the charge.

Luckily you can now buy LFP 12v batteries. Whether those are compatible with the MG4 I don’t know.
View attachment 21049
View attachment 21050

This seems not to be working to top up the 12v battery automatically? Why not I would suggest all MG4 drive if you had this problem or not take your cars to back to your dealer and have this checked out. All that have had drained battery write to MG and include a copy of this and make a complaint as this happens too much. The more noise that came be made more chance they may do something about it.

 

[Starplots]

There could be an easy fix for this an inline cut off switch. Maybe this should be fitted as standard now to all new vehicles.

You wouldn’t be able to access it if there was one fitted - no alarm/immobiliser whilst parked and the doors would be unlocked! It needs 12v battery power available for all of these functions.

My concern about the cheaper one was that people were saying that if you forgot to charge it and it completely discharged, it would brick and you'd never charge it again. The expensive one is reported to be more robust in that respect.

I think that’s only because it has a bigger battery. just set a reminder in your phone calendar to recharge it every 2 months - it’s normal for lithium batteries in power packs to need this (which is why my phone backup power pack is dead, no travel during Covid restrictions and I forgot about it )

Hi. I had the same problem, returned to Gatwick South car park after a 7day holiday and the car was dead. I wrote about this on this forum.
The car has just come back from MG Hendy Poole and they diagnosed the issue as a problem with the BCM module - Body Control Module, which had switched on by itself whilst parked. This should not have happened. MG are aware of the issue and have sent an update for the BCM Module which is what the service team applied. Hope that helps

Thread '12v dead battery and wife locked in the car! - Welcome home!!' 12v dead battery and wife locked in the car! - Welcome home!!

Interesting- happened to me in Shannon in September, 68% charge in the main battery, 12V fully charged when I left it. Only away for 2 days but arrived back at 11.30pm in freezing rain and was locked out. Had to call the AA out and iphe said half his calls were to EV’s of all marques with dead 12V batteries.
I’ll contact MG Ireland and ask about this update, thanks!

 

[tsedge]

Hi there, I'm visiting from the MGZS forum. I don't recall seeing anything in the MGZS manual about going into a deep sleep. Do you know if this applies to the ZS, and do you have a reference for it? Thanks.

I don't know anything about the ZS, sorry.

 

[Jto]

You wouldn’t be able to access it if there was one fitted - no alarm/immobiliser whilst parked and the doors would be unlocked! It needs 12v battery power available for all of these functions.

Would be better if there was a point on the outside of the car that a power pack could be connected to put power into the 12v battery with out having to get doors open, just plug in and charge for ten minutes to get you started then open up. Also you charge the battery once a month to keep it topped up and in good condition.

 

[Rolfe]

I think that’s only because it has a bigger battery. just set a reminder in your phone calendar to recharge it every 2 months - it’s normal for lithium batteries in power packs to need this (which is why my phone backup power pack is dead, no travel during Covid restrictions and I forgot about it )

I don't use my phone calendar. Years of experience have taught me that if it isn't written in ink on the calendar, it won't happen.

 

[siteguru]

But since you're using your phone more now, a reminder in your digital (phone) calendar will pop up on screen to let you know.