MG4 Dead !!

Lovemyev · Jan 17, 2023

Chr1sB said:
Something like this ? ... or should I look for a higher 'peak' output ?

Amazon product ASIN B0BLNJWV6X

Depending on your budget, I would go for the most powerful one that you can afford.
Here is the one that I have, it has a large reachable battery and includes a built in tyre inflator pump.
If you shop around, you can find it cheaper.
Don’t laugh, sometimes QVC the shopping channel have them on a promotion.
Halo is an American brand.

HALO Bolt Compact Portable Car Jump Starter - Car Battery Jump Starter with 2 USB Ports to Charger Devices, Portable Car Charger - Navy https://amzn.eu/d/aE69tzw

Auto Surgeon · Jan 17, 2023

The noco boosters are really good, gb40 onwards. My gb40 will start from a completely dead battery on a 2.5 diesel.

Chr1sB · Jan 17, 2023

Auto Surgeon said:
The noco boosters are really good, gb40 onwards. My gb40 will start from a completely dead battery on a 2.5 diesel.

As it happens I am looking at the GB40 as seems to get very good reviews and should also be able to start my wife's 2 litre diesel X1 if it came to it. Bit pricy though !!

Auto Surgeon · Jan 17, 2023

They have a higher amp range than most, great bit of kit & sometimes can be found on eBay cheaper.

Lovemyev · Jan 17, 2023

Chr1sB said:
As it happens I am looking at the GB40 as seems to get very good reviews and should also be able to start my wife's 2 litre diesel X1 if it came to it. Bit pricy though !!

Buy cheap, buy twice I say !.
I guess something is better than nothing though ?.
Purchase the largest one your budget will allow.
That heavy 2.0 Litre oil burner will take some winding over in cold weather, so you need a decent size pack that can stand the huge drain.
The first time you use it, you will be glad you bought it.
Could save a LONG wait from the recovery people, just to carry out a 30 second jump start.

Chr1sB · Jan 18, 2023

Lovemyev said:
Buy cheap, buy twice I say !.
I guess something is better than nothing though ?.
Purchase the largest one your budget will allow.
That heavy 2.0 Litre oil burner will take some winding over in cold weather, so you need a decent size pack that can stand the huge drain.
The first time you use it, you will be glad you bought it.
Could save a LONG wait from the recovery people, just to carry out a 30 second jump start.

Very good points.
Given the thousands of good reviews for the GB40 I took the plunge last night ... and hey presto, it's just turned up. Looks like a quality piece of kit and is on charge already !
I did look at eBay and other outlets, but at the moment Amazon was as cheap as anywhere really, so went with what I knew works.
If others are interested .. here is the link to it ..
Amazon product ASIN B015TKUPIC

Loved these reviews too ..

avhation · Sep 20, 2024

Finally I believe that MG have solved my phantom load problem after 4 very flat 12v battery events when the car had not been used for a week or two. The car is a batch one MG4 Trophy LR Oct 2022. I invested in a new 12v Bosch (£60) to eliminate the fault without success. The dealer could not find any faults so I added a battery monitor (£20) which showed a steady loss of voltage with time which I offered as evidence. The dealer then replaced the internal camera which monitors driver fatigue, but the symptom returned immediately. MG UK decided that instead of investigating further the system should be isolated. Now the 12v battery is holding 12.23v almost constantly after being parked for 7hr which is a vast improvement and acceptable given its earlier abuse.

It remains to be seen whether the intelligent charging system works any better than before.

And · 2025-04-26T02:45:12+0100

Disconnect the + terminal and charge the auxiliary battery. A booster wont work, use a 12v charger.
My story: I left my OBD2 scanner plugged in overnight and it killed everything.

pjmmk · 2025-04-26T06:33:00+0100

EV's and hybrids can be a bit of a culture shock to people used to the humongous 12v batteries in your average diesel engined car. Activities that your diesel's battery wouldn't even notice can completely flatten a hybrid's 12v battery.
I thought an EV would keep it's 12v battery charged from the HV battery though, at least for a while.

Ian Key · 2025-04-26T07:11:57+0100

pjmmk said:
I thought an EV would keep it's 12v battery charged from the HV battery though, at least for a while.

I would have thought so too. I know my MG4 does as looking at the 12V battery readings in the app while the car is switched off they vary between 12.3V and 14.5V even when it's been left standing for a couple of days.

avhation said:
Finally I believe that MG have solved my phantom load problem after 4 very flat 12v battery events when the car had not been used for a week or two. The car is a batch one MG4 Trophy LR Oct 2022. I invested in a new 12v Bosch (£60) to eliminate the fault without success. The dealer could not find any faults so I added a battery monitor (£20) which showed a steady loss of voltage with time which I offered as evidence. The dealer then replaced the internal camera which monitors driver fatigue, but the symptom returned immediately. MG UK decided that instead of investigating further the system should be isolated. Now the 12v battery is holding 12.23v almost constantly after being parked for 7hr which is a vast improvement and acceptable given its earlier abuse.

It remains to be seen whether the intelligent charging system works any better than before.

I guess you have one of the first MG4s with the fatigue camera on top of the steering wheel binnacle. I thought one of the software updates was to disable it anyway as it was too sensitive.

ReintjeWA · 2025-04-26T07:42:19+0100

Ian Key said:
I would have thought so too. I know my MG4 does as looking at the 12V battery readings in the app while the car is switched off they vary between 12.3V and 14.5V even when it's been left standing for a couple of days.

I think the HV only tops up the 12v when the HV is above 50% soc. My source is a vague recollection from reading it somewhere on here so it may be nonsense.

MG4 Dead !!

Lovemyev

Distinguished Member

Auto Surgeon

Standard Member

Chr1sB

Established Member

Auto Surgeon

Standard Member

Lovemyev

Distinguished Member

Chr1sB

Established Member

avhation

Standard Member

And

Novice Member

pjmmk

Established Member

Ian Key

Distinguished Member

ReintjeWA

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