Leaving the car for most of February

[My car]

Can anyone suggest the optimum charge to leave on the battery if the car is going to sit on the driveway unused for most of February?
Thanks

 

[Bricktop X PWR]

80%
Might also be tempted to leave the 12v battery on a trickle charger.

 

[My car]

Not sure how to leave the 12 volt battery on a trickle charge

 

[Bricktop X PWR]

Not sure how to leave the 12 volt battery on a trickle charge

Where are you leaving the car?

Ok re read, driveway.

Buy something like this.....

There are much cheaper alternatives available.

Get your extension lead and un ravel it.
Open bonnet.
Drop the plug to the floor under the car and plug it in.
Assuming you have an outdoor socket?
Connect trickle charger to battery.
Shut bonnet after you have checked its working.

Much cheaper

 

[My car]

Thanks for all that.

 

[Ian Key]

MG4s have been left for three or four weeks in airport car parks and started OK when the owners have got back from holiday.
If you are really worried about it starting when you get back leave the car at 80% charge and get yourself a lithium jumps starter just in case. The advantage over a trickle charger is you can use it away from home to start the car. Or call MG Assist to jump start it when you get back.

 

[JustAnotherMidlifeCrisis]

I live and work overseas and am in the UK only once every several weeks. I just leave the car with whatever level of charging happens to be there. No issues so far when I come back and switch it on.

 

[OriginalBigAl]

Take the 12v battery out and leave it in the warm house, the car will need to reset when putting back in, but in the meantime it can,t be nicked.

 

[mj224]

I left my MG ZS EV for 7 weeks with a full battery minus about 50 miles. No problem at all when I returned.

 

[ukslim]

I've returned to my old, second hand, ICE car after several weeks away, to find the 12v battery dead. But that was a long time ago, and the car was an old rust bucket.

The only way an MG4 is going to not work after 4 weeks, is if it has a fault.

Personally I wouldn't go out of my way to mitigate a fault I don't know exists - if I returned to find a problem, I'd be on the warpath to the dealer.

 

[Robf]

From memory the manual states that if left for long periods the 12v battery should be disconnected?

 

[ukslim]

From memory the manual states that if left for long periods the 12v battery should be disconnected?

There's nothing of the sort in my manual PDF, searching for "12v".

It mentions disconnecting it if the car's involved in a collision and won't start, and if the car gets immersed in water. Nothing about storing it for long periods.

The manual mentions that the car can top up the 12v battery from the HV battery ("Intelligent Charging"), so unless there's a fault, it should be much less likely to empty than an ICE.

 

[Robf]

There's nothing of the sort in my manual PDF, searching for "12v".

It mentions disconnecting it if the car's involved in a collision and won't start, and if the car gets immersed in water. Nothing about storing it for long periods.

The manual mentions that the car can top up the 12v battery from the HV battery ("Intelligent Charging"), so unless there's a fault, it should be much less likely to empty than an ICE.

There you go. for more than 1 month disconnect negative terminal, page 291

Note: It is recommended to ensure the vehicle is
placed in READY mode for half an hour every week
to help extend the service life of the battery. If the
vehicle is stored for more than 1 month, remove the
negative terminal from the battery. Make sure that
the vehicle power system has been turned off before
connecting or disconnecting the negative terminal.

 

[ukslim]

There you go. for more than 1 month disconnect negative terminal, page 291

Note: It is recommended to ensure the vehicle is
placed in READY mode for half an hour every week
to help extend the service life of the battery. If the
vehicle is stored for more than 1 month, remove the
negative terminal from the battery. Make sure that
the vehicle power system has been turned off before
connecting or disconnecting the negative terminal.

Good find.

Nice of them to describe it as "12v Battery" throughout the manual, except there

 

[RP67]

At the same time.... in the same manual....

"Intelligent Charging The 12Vbattery SOC(State Of Charge) is constantly monitored, when the vehicle is power OFF it is possible, under certain conditions, that the HV battery will automatically charge the 12V battery to ensure the vehicle starts. This function will activate and switch off automatically.
Note: The system will suspend intelligent charging if a fault is present, when starting or the vehicle is being charged by an external device.
Note: The driving range will be reduced after intelligent charging.
Note: The intelligent charging function is suspended when the high voltage battery is in a low SOC."

 

[Odin]

Not sure if this will help, but it's something that I have used to help keep the battery in good condition.
Hopefully the link will work.

https://www.amazon.co.uk/piece-Car-battery-cover-protection-thermal/dp/B00I8LG8HW/ref=mp_s_a_1_4?crid=21QKJC5A9S096&dib=eyJ2IjoiMSJ9.Q4O22JaK4Mm7a_VXjgiJ_7ccEc7pohzAPbDA0tNiGno8Pdqv5r8D9lssFA41XRjGUfF903V6jXMZ5aPhEiKl0lGf5_tPDGyzN5aOngzkUzykU_JqvjnBF9cBYuqfTrqc2ApjjEiPo0N_yWSbH7yBJg9z9EY--12gBbX9TiyriYb4dD5vcHA1zLnTVWnT-GEi-FMxQcfpAwhKOEQZNtr17Q.boKKoOcdhsKSaez43z5zuBgidwikcjMoWWcRgg-aU_I&dib_tag=se&keywords=12v+battery+cold+weather+cover&qid=1705761619&sprefix=12v+battery+cold+weather+cover%2Caps%2C104&sr=8-4

 

[Philz]

Can anyone suggest the optimum charge to leave on the battery if the car is going to sit on the driveway unused for most of February?

 

[rabacon001]

MG4s have been left for three or four weeks in airport car parks and started OK when the owners have got back from holiday.
If you are really worried about it starting when you get back leave the car at 80% charge and get yourself a lithium jumps starter just in case. The advantage over a trickle charger is you can use it away from home to start the car. Or call MG Assist to jump start it when you get back.

I left mine for 3 week last February at Heathrow and it was fine when I got back, best of all being bright orange it was dead easy to spot in the car park

 

[Rolfe]

I left mine for just over two weeks and the SoC was the same when I came back as when I'd left it.

 

[Philz]

Left ours at Canberra airport for 6 weeks after driving to the city (70km). Battery was about 70% when we let it, lost 12% in 6 weeks, 12V battery was fine.
I have a jump starter but don’t usually carry it with me.