MG4 12Volt battery not charging

[thowi02]

Red battery indicator came on and in the manual it advised to take it it the service department , did so and was advised that because the car was only 50% charged it needed to be 100%, They suggested leave it with them that evening and they would charge overnight. I was dubious that this would cure the problem. On the way to the service dept warning beeps and messages regarding the battery kept popping up and then the car just stopped. I was then left on a main road with no power. Rang the assistance (AA) who came within 15 mins. Diagnosis was that the inverter was not charging the battery. Coincidentally the car had a software update a few weeks previous.
The car is now with the service department.

 

[tsedge]

Red battery indicator came on and in the manual it advised to take it it the service department , did so and was advised that because the car was only 50% charged it needed to be 100%, They suggested leave it with them that evening and they would charge overnight. I was dubious that this would cure the problem. On the way to the service dept warning beeps and messages regarding the battery kept popping up and then the car just stopped. I was then left on a main road with no power. Rang the assistance (AA) who came within 15 mins. Diagnosis was that the inverter was not charging the battery. Coincidentally the car had a software update a few weeks previous.
The car is now with the service department.

There have been a few issues with the 12 volt battery. I think someone had loose terminals on theirs. Others have doubted the quality of the 12V battery itself.

First I have heard of a software fault causing it not to charge.

 

[Les burrows]

Car needs to be at 100% to charge the 12 volt what a load of B-S you say you had a software update recently can I ask what was that for thanks. Also which model of the 4 was this
Les

 

[siteguru]

I tend to notice that when my car is on charge (at whatever state of charge) and I check the app, the 12V battery voltage tends to be 14+V, so topping up.

 

[the briggie]

And it won't be the "inverter " as that is dc to ac... it could be the dc to dc converter not supplying to the 12v battery.

 

[tsedge]

And it won't be the "inverter " as that is dc to ac... it could be the dc to dc converter not supplying to the 12v battery.

Agreed but is this considered a single module?

 

[the briggie]

Agreed but is this considered a single module?

Could be within the same hardware depending apon design if that is considered a module.

 

[siteguru]

Just checked my app ... car is at 100% SoC but not charging from (or plugged in to) the wall box; battery shows 12.4V

 

[the briggie]

Let's be honest the 100% hv battery required to allow 12v charge was so much bull that even a bull would deny it on bullseye with a bully in its hoofs....

 

[Jef]

Car charged to 100% yesterday, used for a short journey this morning, SOC now 93% 12v battery now showing as 12.6v. MG4 SE-SR.

 

[thowi02]

Car needs to be at 100% to charge the 12 volt what a load of B-S you say you had a software update recently can I ask what was that for thanks. Also which model of the 4 was this
Les

Software update was for doors locking problem. Car is SE.

And it won't be the "inverter " as that is dc to ac... it could be the dc to dc converter not supplying to the 12v battery.

The AA guy wrote in his report "Inverter not charging 12v battery and vehicle cut out."

 

[the briggie]

As stated inverter is dc to ac...if the dc to dc converter is built into the same unit then maybe he was using a generic term...but it must have two separate functions.

What is an inverter? An inverter, otherwise known as a power inverter or frequency inverter, is an electronic device or electronic circuitry that is designed to transform direct current (DC) into alternating current (AC) and at any frequency and voltage.

DC-to-DC converters are devices that temporarily store electrical energy for the purpose of converting direct current (DC) from one voltage level to another. In automotive applications, they are an essential intermediary between systems of different voltage levels throughout the vehicle.

 

[rmoyao]

The minimum voltage for the 12v battery to charge is 13.85 VDC. If voltage on the 12v battery goes under 11 VDC then the DC to DC converter (buck converter) should kick in with 13.85 VDC or a little more. If not the problem could be cabling harness or the buck converter.

 

[thowi02]

Red battery indicator came on and in the manual it advised to take it it the service department , did so and was advised that because the car was only 50% charged it needed to be 100%, They suggested leave it with them that evening and they would charge overnight. I was dubious that this would cure the problem. On the way to the service dept warning beeps and messages regarding the battery kept popping up and then the car just stopped. I was then left on a main road with no power. Rang the assistance (AA) who came within 15 mins. Diagnosis was that the inverter was not charging the battery. Coincidentally the car had a software update a few weeks previous.
The car is now with the service department.

Car was charged overnight and checked, no fault found ! Hopefully problem will not recur on the motorway.

 

[bowfer]

First I’ve heard of this on the 4.
It’s one of very few common faults on the Leaf and it’s easily fixed with a new 12V battery.
But it has to be said it usually takes several years to become an issue on the Leaf, not a few months.

 

[amdmad]

Happened on our Leaf24, 2 years into ownership, new 12v battery all was well.

 

[OJEastwood]

Could someone be kind enough to detail the specs of the 12V Battery, please? We're STILL waiting for our car but I'm thinking I may swap the 12V out for a slightly better, and hopefully future proofing it a bit. Probably a little drastic but hopefully it'll be one less issue further down the line.

Thanks in advance!

 

[the briggie]

Can you look under the bonner to read the existing battery manufacturer, model number etc.

 

[OJEastwood]

Can you look under the bonner to read the existing battery manufacturer, model number etc.

I would but I don't have the car yet

 

[the briggie]

So why not wait? Confused...as MG4 battery drain issue has not even started to crawl never mind stick its head above the parapet yet. Battery drain on an EV is the same as an ICE car just that you can't momentum bump an EV. I honestly would suck it and see