12v Battery Charging

[seibegee]

Well iSMART must be lying to me every time I charge my car at home and do a scan of the car ... it always shows 13.xV (typically 13.9V) whilst on (HV) charge.

If you believe it's the app then force stop it after each use so it doesn't try to connect to your car in the background

Yep a warning just momentarily popped and disappeared 2 seconds later on my mobile !

Went outside to the car and noises again like relays were coming from under the bonnet. Ismart version 1.1.13 running on Android. Wonder if that's causing a flat battery?

 

[Martinonline]

I always get this message when I shutdown the app. I have had no problems with my 12v battery. Mind you I always power off my phone at night.

 

[seibegee]

I always get this message when I shutdown the app. I have had no problems with my 12v battery. Mind you I always power off my phone at night.

Thanks for that, I'll cross the app off the list of possible causes. Back to the AA breakdown man who suspects the key is stored too close to the car. He recommended something to put the key in ?

 

[Martinonline]

As far as I know the car is not continually communicating with the key as some cars do, so that the car will automatically lock/unlock. I believe the car is running a low power receiver and is just looking for the signal from key when the unlock button is pressed. Likewise for an iSmart remote unlocking.

 

[seibegee]

Just ordered a couple of faraday pouches for the keys. Apparently they can stop your car from being stolen as well, (my flat battery takes care of that.)

 

[JuziWomble]

Just to add my 2pence here

Mine is booked in for a suspected leaking 12v Battery as I have had to call the AA a few times and now MG/Garage are going to 'investigate leakage' - Its already had c/o the last investigation the latest (at the time) BMS patch - Roll 4 months and boom parked for 3 days and dead as a door nail - once again - So dealership will have for a period of Days the car to 'monitor' investigate..

I will also be Expecting a decent update (I hope c/o the R46 s/w update) as I shall be adding to the 'investigate list' - Bluetooth drop off's / Poor touch response A/C controller - iPhone Carplay yes no yes working - Car announcing 1st Jan on start ups occasionally & not having a clue re the correct date... That Seems to correct its self moments later - If I hold the Home key and restart the system - 80% of the time these issues stabilize but I often have to 'repeat the 'reboot'
(All Front Infotainment System issues)

 

[Martinonline]

Further to my post above, the car must transmit to the key fob when you push the button on the door handle. If the key is in a Faraday pouch or out of range (within about 150cm for my test) then the button does not work. I keep both my keys in Faraday pouches.

 

[seibegee]

Interesting the list I have does have infotainment issues too Fm radio and DAB goes blank no stations no volume. No DC rapid charging. 'No comms' issue displayed on rapid charger screens. 'Home screen reset' make no difference. Disconnecting the -ve battery post fixes it more often than not until the next time. Would like to hear what the 12v leak check reveals.

 

[seibegee]

Car spent a couple of days with the dealer who carried out R16 s/w update. The battery drain issue is a known issue so as per MG technical a BCM reset was performed. Time will tell if the battery goes flat again but for the first time the app showed the battery being charged when it dipped to 12.1 volts all the up to 12.3 volts . After 2 days on the drive without use.

 

[Captain]

Last night when I checked the 12v battery voltage on the iSmart app it was showing 12.2v. This morning at 7:00am it had gone down to 12.1v.
I haven't driven the car or unlocked it since yesterday afternoon and the last time it was on charge was 6 days ago. I've just checked it again (10:00am) on the iSmart app and it's showing 14.7v
Finally proof that the car charges the 12v battery even when it isn't on charge.

View attachment 19608

Oh to have a working app

 

[pollenface]

Oh to have a working app

I have never even paired my phone to the radio

 

[Vingnut]

As far as I know the car is not continually communicating with the key as some cars do, so that the car will automatically lock/unlock. I believe the car is running a low power receiver and is just looking for the signal from key when the unlock button is pressed. Likewise for an iSmart remote unlocking.

The low power reciving aside, the keyfob when pressed yesterday I tested for reach up to 300m + (when using the head amplifying trick). Impressive.

 

[GameZone]

What tool to use to remove battery connectors? 10 or 12 mm?

 

[siteguru]

Maybe use an adjustable so it won't matter.

 

[Jto]

10mm

 

[pollenface]

I keep a 10mm in the glovebox and a spare key battery

 

[GameZone]

I keep a 10mm in the glovebox and a spare key battery

Christ, there almost no room to get the 10mm off the battery

 

[Martinonline]

The low power reciving aside, the keyfob when pressed yesterday I tested for reach up to 300m + (when using the head amplifying trick). Impressive.

The low power refers to the power the receiver draws from the 12v battery not its sensitivity. I can unlock my car with the keyfob from a distance. The transmitted power is there, I assume, so that you can use the 'which one is my car' function in a crowded carpark. Obviously my car is the best-kooking car. However, the keyfob has to be nearer the car to use the door-buttons.

 

[PristDean]

So this guy has found the cause on his Ioniq 5, as I suspected, let the high voltage battery get too low and your 12v is neglected by it. I know some thought this was complete nonsense, just goes to show !

 

[Rolfe]

That's extremely interesting, but it still leaves a couple of questions unanswered.

First, there's the issue of what SoC the car needs to be at in order for the 12v battery to be charged from the HV battery. He reckons 20% in the Ioniq, as he saw it charging at 23%. However your dive into this in the MG4 seemed to suggest that it had to be 50%. I think this is what people were questioning, not the principle itself. If you can't leave your car for a day or two at less than 50% charge, this is a problem, much more so than at 20%.

There's also the question of how fast the 12v battery is running down if it's not being topped up by the HV. He said he had just returned from a long trip, so the 12v should have been fine at the end of that irrespective of the state of the traction battery. Nevertheless it went flat in a few hours, while the car was waiting to be charged at the off-peak rate. This sounds like a fault to me.

I was struck that his monitor showed the 12v going down quite fast and being topped up frequently from the HV. Surely that's a weak battery? I know ICE car batteries are more robust, but even so. We wouldn't expect an ICE car battery in good health to fail in a few hours and surely EV batteries can't be that much worse. A decent ICE car battery will hold enough charge to turn a cold engine over for months, not days, with no boost whatsoever.

I think that, quite apart from the SoC issue, he has a dodgy battery. A good battery shouldn't be losing charge like that. I also think that if the MG4 won't top up its 12v battery when it's under 50% on the traction battery, that itself is a problem.