Jump Start

[APH]

Maybe a daft question, and most likely been asked before…….. can you use your MG4 EV to jump start another car (standard petrol) Which has a flat battery.

 

[Lovemyev]

I would say in theory - Yes ?.
As you are simply using one standard 12 volt battery from one car, to jump start another 12 volt battery on another car ( be it a ICE car).
However, give some consideration to the fact that your EV may not be so tolerant in receiving a power spike from the ICE car when it jumps in to life.
Also, turning over a very cold heavy ICE unit from the battery in your EV could leave you with a flat battery yourself very easily !.
I would steer away from getting into this type of situation personally myself.
I would favour purchasing a 12 volt jumper pack and store it under the drivers seat of your car.
It is then on hand to use on your own car or other people’s car, without compromising your situation.

 

[mtmg]

I jumped one yesterday with no issues. A 1.6 diesel ford focus. I’d be a bit apprehensive to jump anything over 2 litre though.

 

[Rolfe]

Nooooooo! The manual specifically says Do Not Do This. The 12v battery of an EV isn't rated to turn over an ICE and it could be damaged.

 

[dsimpkins]

I would say in theory - Yes ?.
As you are simply using one standard 12 volt battery from one car, to jump start another 12 volt battery on another car ( be it a ICE car).
However, give some consideration to the fact that your EV may not be so tolerant in receiving a power spike from the ICE car when it jumps in to life.
Also, turning over a very cold heavy ICE unit from the battery in your EV could leave you with a flat battery yourself very easily !.
I would steer away from getting into this type of situation personally myself.
I would favour purchasing a 12 volt jumper pack and store it under the drivers seat of your car.
It is then on hand to use on your own car or other people’s car, without compromising your situation.

Yes, I keep a jumper pack in the car, bought one after seeing a few people have 12v battery problems. Managed to get one while they were on offer.

 

[Chequers]

Disconnect the +ve on the EV otherwise the voltage drop on the EV's 12V battery will most likely start up the DC-DC converter when the BMS senses the sudden voltage drop.
This could damage the DC-DC converter and possibly other components in the circuit.
It's not like jump starting an Ice to Ice car where you would have your engine running backing up the 12V via the alternator.

 

[APH]

Thanks everyone, im not going to risk it… i will buy one of the Halford Smart Chargers to get the wife’s petrol car started.

 

[Lovemyev]

I guess you are intending to buy a booster pack ?.
You can use this on all 12 volt battery systems on EV and ICE.

 

[ging353]

I guess you are intending to buy a booster pack ?.
You can use this on all 12 volt battery systems on EV and ICE.

Just been caught out this morning with a totally flat 12 volt battery. Got in the car using the key but the door closed behind me and I couldn't get out. None of the internal door catches or windows would work. Sat there for almost an hour in the sun and almost passed out when a neighbour saw me and came to my help opening the driver's door from outside. Called AA and the guy said the 12 volt battery was completely flat. He charged it up and said he didn't think the battery was at fault as it was holding charge, but that some software was draining the 12 volt battery.
Contacted the dealer and they said that the internal door catch should release the door even with a flat battery. Car is now going in to the dealer for investigation.
Can anyone recommend a good battery booster as I'm not getting caught out again like this. It was terrifying !!

 

[Lovemyev]

Just been caught out this morning with a totally flat 12 volt battery. Got in the car using the key but the door closed behind me and I couldn't get out. None of the internal door catches or windows would work. Sat there for almost an hour in the sun and almost passed out when a neighbour saw me and came to my help opening the driver's door from outside. Called AA and the guy said the 12 volt battery was completely flat. He charged it up and said he didn't think the battery was at fault as it was holding charge, but that some software was draining the 12 volt battery.
Contacted the dealer and they said that the internal door catch should release the door even with a flat battery. Car is now going in to the dealer for investigation.
Can anyone recommend a good battery booster as I'm not getting caught out again like this. It was terrifying !!

There is plenty to choose from online, this one is a popular choice just to get you started.
Topdon is popular in the trade.
The capacity is more than you require for you to boost your EV - but it will handle boosting large ICE cars as well.
I keep mine stored under the drivers seat.

TOPDON 1500A Car Jump Starter Pack Booster Battery Charger Power Bank JS1500 UK | eBay

Alongside a UL2734 certification, this car battery jump starter boasts 6 built-in smart protections against reverse polarities, short circuits, over currents, and more. Manufacturer‎TOPDON. You even get a heavy-duty Nylon storage bag as a gift!

www.ebay.co.uk

 

[DixieTGS]

Sat there for almost an hour in the sun and almost passed out

It's worth learning how to operate the emergency boot release for this situation. At least 3 of the cars I've had have had a way of exiting the boot from inside, but don't know if it is a requirement on all vehicles.

Look up emergency tailgate opening in the manual. You will need either the key blade hidden inside the fob or a suitable sized screwdriver kept in the vehicle somewhere.

I would practise getting over the seats and into the boot in benign conditions as it is not easy for everybody, and you may prefer to sit it out in a real situation.

Contacted the dealer and they said that the internal door catch should release the door even with a flat battery.

The problem here is the MG4 seems to deadlock even when locked from the inside sometimes. When deadlocked I think you are not supposed to be able to open from the inside to meet the Thatcham security requirements - or I might have made that up ?.

To make it worse I think the alarm goes off if you try and the battery is not flat.

 

[ging353]

It's worth learning how to operate the emergency boot release for this situation. At least 3 of the cars I've had have had a way of exiting the boot from inside, but don't know if it is a requirement on all vehicles.

Look up emergency tailgate opening in the manual. You will need either the key blade hidden inside the fob or a suitable sized screwdriver kept in the vehicle somewhere.

I would practise getting over the seats and into the boot in benign conditions as it is not easy for everybody, and you may prefer to sit it out in a real situation.

I am nearly 73 years old with mobility issues and there is no way I would be able to climb over the seats to get to the boot. I couldn't even get out from under the steering wheel as my driver's seat is electric and would not move.
The dealer said that even though there is no power the driver's door should release from the inside.
They are going to check the door latch to see if there is a problem with it.
Not what you'd expect on a £35,000 car, is it !!

 

[Martinonline]

DVLA had MG issue a recall to stop the previous lock-in problem. From reading this Forum - 'Locked in ...' thread from 01/11/2022 - the issue related to not being able to open a door even when powered up. Access from the outside was also stopped. It seemed this was related to the deadlock/alarm system. Again, if I remember correctly, the solution was only a software upgrade. However deadlocking as an anti-theft protection still meant you could not unlock the car from the inside if the car had been electronically locked. (Having broken a window for example.)

Your problem is an extension and of the same importance to my mind because it maybe that the driver's door level is mechanical only if the key fob/button/iSmart electric unlocking has been done which disables the anti-theft/deadlock. Using the emergency key may just allow outside access. I assume your neighbour did not need to use the emergency key again.

Note that if you lock the doors using the inside button or the auto locking feature the car is not deadlocked and doors can be opened from inside.

We need a brave soul plus partner to carry out a trial.

EDIT: Further thought - what occurred must be expected behaviour in that the anti-theft system stops the use of the inside door handle. If disconnecting the 12v battery allowed the doors to open then all a thief has to do is to pull the bonnet lever and get their partner to disconnect the battery. (However since they broke into the car they must have an exit anyway.)

 

[ging353]

DVLA had MG issue a recall to stop the previous lock-in problem. From reading this Forum - 'Locked in ...' thread from 01/11/2022 - the issue related to not being able to open a door even when powered up. Access from the outside was also stopped. It seemed this was related to the deadlock/alarm system. Again, if I remember correctly, the solution was only a software upgrade. However deadlocking as an anti-theft protection still meant you could not unlock the car from the inside if the car had been electronically locked. (Having broken a window for example.)

Your problem is an extension and of the same importance to my mind because it maybe that the driver's door level is mechanical only if the key fob/button/iSmart electric unlocking has been done which disables the anti-theft/deadlock. Using the emergency key may just allow outside access. I assume your neighbour did not need to use the emergency key again.

Note that if you lock the doors using the inside button or the auto locking feature the car is not deadlocked and doors can be opened from inside.

We need a brave soul plus partner to carry out a trial.

EDIT: Further thought - what occurred must be expected behaviour in that the anti-theft system stops the use of the inside door handle. If disconnecting the 12v battery allowed the doors to open then all a thief has to do is to pull the bonnet lever and get their partner to disconnect the battery. (However since they broke into the car they must have an exit anyway.)

Someone needs to be accountable for this. This is extremely frightening and dangerous. I dread to think what would have happened had it not been for my neighbours son releasing me.

 

[Martinonline]

I suggest you vent your feelings to the dealer who may tell MG. The fact that nowhere is there a warning not to close the door is a worry.

I suspect the original thinking was for the situation where the keyfob battery was flat and you needed to get into the car (as in all the videos I've seen) for a new battery (required if the keyfob battery fails whilst you are out). Or you needed to pop the bonnet to access the 12v battery.

MG will probably say that you could exit the car through the boot but, as you say, that is not a proper solution.

I keep a spare PAYG phone in the glove compartment along with a hammer and battery booster in the centre storage.

 

[Ian Key]

It's interesting that the neighbour could open the door from the outside but @ging353 couldn't open his ZS EV from the inside. I wonder if it's a fault with his car or with all ZS EVs and is the MG4 susceptible to the same problem?

 

[Martinonline]

I posted believing @ging353 had an MG4. However I believe my analysis to be what will happen in an MG4.

Please see below. A warning is required if there is any doubt as to the state of the 12v battery.

Our biggest problem occurred after a 10-day stay in Gatwick car park. We returned to the car, Husband pressed the key fob, the wing mirrors didn't come out, oddly, but the doors did unlock. He got in and shut the door, ready to start up. The car locked around him & he couldn't get out, despite having the key with him & clicking it furiously. He was trapped in a hot car & would soon run out of oxygen! I called the fire brigade. Then we hailed a man in a van who had jump leads, & who got Husband to pull the bonnet lever so that he could attach the leads & spark the car back into life, releasing the doors. Now we understand from Facebook that some MG drivers keep jump leads in the car in case the 12V battery dies. But would that help if you were trapped inside? Why would you buy a £30,000+ car and feel the need to drive with jump leads on board or with the window half down in case you get trapped? The AA came out this morning & found the battery to be functioning normally. But we can't get anyone from an MG dealership to inspect the car until five weeks' time.

 

[Martinonline]

@ging353, did you ever get to the bottom of the failed door unlocking from the inside with the car having a flat 12v battery? Could be important for those intending to sleep in the car though they probably could exit through the boot.

 

[pjmmk]

I thought it was mandatory for all cars with electric door locks/releases to have an easy to use mechanical emergency release backup in place. If it's not working or missing, that's a very serious issue. It's certainly something I'd expect MG/your dealer to prioritise.

 

[ging353]

I suggest you vent your feelings to the dealer who may tell MG. The fact that nowhere is there a warning not to close the door is a worry.

I suspect the original thinking was for the situation where the keyfob battery was flat and you needed to get into the car (as in all the videos I've seen) for a new battery (required if the keyfob battery fails whilst you are out). Or you needed to pop the bonnet to access the 12v battery.

MG will probably say that you could exit the car through the boot but, as you say, that is not a proper solution.

I keep a spare PAYG phone in the glove compartment along with a hammer and battery booster in the centre storage.

I have since invested in a battery booster and a sharp punch to shatter the window should it ever happen in the future.
I'm hoping never to have to use either.