Going away for a week's holiday - do I power off the MG4 completely?

[Rolfe]

Thanks.

 

[AndyL61]

Could you elaborate on that last bit? Sorry to be so ignorant but I've only had the car a couple of weeks. What happens when you check the car with the app, and if that does drain something, will it all be replenished next time the car is driven?

The 12v is charged by the HV battery when it is in ready mode (or driving) or if you are charging. It is not charged when the car is turned off and not plugged in. It should be fine if left for a few weeks just like any car. The app apparently wakes the car up when it scans so using the 12v slightly, so maybe it's best not to keep checking it on the app if you are not using for some time. But if your 12v is in good condition and you don't have anything that can drain it switched on then it should be fine to leave it for a few weeks as you would any other car.

 

[Rolfe]

Thanks again.

 

[Guru]

Not when the car is off though.

Yep, even when the car is off! We left ours for a few weeks and checking on the app I could see the 12v battery dropping down and then a couple of days later it was back up again. Main battery dropped by 1 or 2 % but the 12v was absolutely fine when we went back to it.
Our mk1 ZS on the other hand didn't do that and leaving that for more then a couple of weeks was tricky.

 

[tsedge]

I understand the 12v Battery is only used to power up the main console and hence open the software and screens so other main systems can be activated. When others have had problems with 12v flat battery the AA have just jumped charged with another 12V battery to get the car to wake up. Once its energised the car is good to go.
An ICE car requires a lot of starting current from the battery to overcome the friction and momentum to turn the engine over so the poissible burn outs in reviews may be on starting a large engine. However EV's dont have high torque starter motors and like I say the 12v battery is just mainly to get the cars main systems activated.
I have used the one I got to start my Triumph Stag 3.0 litre V8 and was fine.

Are you saying you used your MG4's 12V battery to jump start your Stag?

If so, I have heard that's one of the things expressly not recommended. The battery in the MG4 is small and weak for the purposes of cranking over an ICE engine and you may rapidly flatten it doing this.

 

[Rolfe]

I think he might be saying that he used the starter battery gizmo to jump start the Stag?

 

[Wudus]

On page 291 of the MG4 Manual it says
'If 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'.
Presumably that means it is OK to leave the battery connected when away for just 2 or 3 weeks.

 

[Rolfe]

It would seem so. I really ought to read more of the manual.

My ICE car was OK parked at Bristol docks for 10 weeks, but I had a lead/acid jump-starter battery kit in the boot just in case. When we got back to Scotland it transpired that my friend's ICE car which she had left in my garage was not OK, and we had to use the jump-starter kit on that. And then get help for a wheel that wouldn't turn due to the brakes binding.

 

[Tigger]

And then get help for a wheel that wouldn't turn due to the brakes binding.

Yes, my ICE car does that occasionally. I just give it a bit of welly, and it unsticks (and shoots forward, of course . . . ) I wish it was possible to leave it in park without the handbrake on, but it's too modern

As for the MG4, I've left mine for more than a week several times, and never had a problem, never lost any power.

 

[Rolfe]

My father, who learned to drive before there were such things as driving tests, told me always to leave the handbrake off if the car was in the garage. One, so you could push it out if the battery failed (although if you've reversed in that isn't really an issue), and two, so the brakes wouldn't bind.

I reversed my friend's car into my garage and deliberately left the handbrake off. The brakes bound anyway. At the docks in Bristol I forgot and automatically applied my own handbrake. I more or less got away with it, although I had to keep braking sharply as I drove from the secure car park to the pick-up zone to get them absolutely clear.

 

[Kithmo]

If I have to leave a car stood for a while, I make sure the brakes are warm first and leave the handbrake off if possible. That way it makes sure the brakes are dry and the shoes and pads shrink away from the discs or drums as they cool down.

 

[Alb]

I've always left the handbrake off on my petrol car when it was in the garage.

 

[PeteC]

On page 291 of the MG4 Manual it says
'If 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'.
Presumably that means it is OK to leave the battery connected when away for just 2 or 3 weeks.

I've just got back after leaving our car for 6 weeks and it was fine. It took a bit longer than usual for everything to fire up and READY appear so I guess it had shut itself down pretty well - I'd done nothing other than lock the car. The 12V battery is showing 12.4V in the app. The main battery had dropped about 5% in that time. I'd left it just under 60% charged.

 

[tsedge]

I've just got back after leaving our car for 6 weeks and it was fine. It took a bit longer than usual for everything to fire up and READY appear so I guess it had shut itself down pretty well - I'd done nothing other than lock the car. The 12V battery is showing 12.4V in the app. The main battery had dropped about 5% in that time. I'd left it just under 60% charged.

Good, it was just rousing itself from a deep sleep. That's how it should work.

 

[Kentboy]

Left my Trophy in the airport car park for 7 days on 45% and when I got back it was still on 45% and I had no problems getting moving.
This was in January with o/s temperatures of -3c to +5c
What I did like was that I could check it's status from the beach in Mallorca from my phone

Thanks! Mallorca in January is lovelyl

 

[RichardB]

Somewhat related to this .... I had an MG Smart alert today that there was an 'abnormal invasion' has triggered the alarm. I was only up the road so walked back and sure enough lights flashing, horn blaring. Unlocked it and locked it & no repeat so I'm assuming it was next door's cat jumping on it or a kids football as there's no sign of damage or forced entry (although would that count as a normal invasion?)
I'm going away for 7 days & parking at the airport and my concern is that it could happen in the car park. Is there a way to isolate it for that period? Obviously it would be powered down but presumably I wouldn't be able to isolate the alarm from Croatia?

 

[siteguru]

You can remote unlock/lock the car via the app.

 

[RichardB]

You can remote unlock/lock the car via the app.

Ta!

 

[Wudus]

Just trying to get clear when the 12V battery gets charged. I think it is only charged when the car is in ready mode, or plugged in, and also possibly topped up by the HV battery if necessary when the car is locked. So, for example, if you inadvertently left the car unlocked in a locked garage while away on holiday the 12V battery may go flat? Or does the HV battery keep the 12V battery topped up while you are away even if the car is unlocked and maybe the radio or something else is draining the 12V battery?

 

[stevegus]

'Don't leave it with a full battery?' Sorry don't understand. Why? What level of battery is good? I'd normally leave it at the usual 80%. Yes - saw those power bank things. Sound a good idea.

You are not supposed to leave the car for long periods with a fully charged 400v battery. Apparently degrades it