12v issues

[robertb]

I posted this elsewhere but I have a weird issue with my 12v battery.

The problem is that every time I charge the car, the 12v battery is slowly depleted unless I remove the charge cable right away.
The 12v battery holds it's charge no problem between charging sessions and tests fine outside the car.
I first noticed it a few weeks ago after I charged the car overnight. I came out the next day and the car was dead. It wouldn't open and was totally unresponsive.
After connecting my 12v booster pack, I got the car started and it immediately began charging the battery again.
Coincidentaly, the traction battery had been fully charged with no errors showing in the car or my Zappi charger.

Has anyone else had this happen? It's booked into the main dealer to be looked at under warranty as it's less than a year old.

 

[Buchanty]

I posted this elsewhere but I have a weird issue with my 12v battery.

The problem is that every time I charge the car, the 12v battery is slowly depleted unless I remove the charge cable right away.
The 12v battery holds it's charge no problem between charging sessions and tests fine outside the car.
I first noticed it a few weeks ago after I charged the car overnight. I came out the next day and the car was dead. It wouldn't open and was totally unresponsive.
After connecting my 12v booster pack, I got the car started and it immediately began charging the battery again.
Coincidentaly, the traction battery had been fully charged with no errors showing in the car or my Zappi charger.

Has anyone else had this happen? It's booked into the main dealer to be looked at under warranty as it's less than a year old.

Sorry to hear this. Never happened to me. Hope you get it diagnosed and fixed.

 

[5teep]

Sounds as if you might have a faulty 12v battery, not the first one reported, get your dealer to check it out.

 

[Deep purple]

When the car is charging the system also charges the 12 volt battery as you rightly say. If somehow the 12 volt charging system remains connected to the 12 volt battery when the main battery charge completes there might be a way for current to flow from the battery into the charging system ( a fault) which would explain why the 12 volt battery discharges if you don't disconnect the cable on completion of main battery charging.
Unless there is someone who has a detailed circuit diagram and an understanding of the logic of how the charging systems are controlled it will be difficult to get to the bottom of it.
I suggest that you connect the car to the charging system and start a charge. Monitor the 12 volt battery voltage which should go up to 13.5 - 14 volts as the 12 volt battery is charged. Then turn off the charger but leave the cable connected and see what happens to the 12 volt battery voltage. It should drop to 12.8 ish volts and stay there. If it drops and keeps on dropping then the battery is discharging and feeding power to something.

 

[Pebble]

I suggest that you connect the car to the charging system and start a charge. Monitor the 12 volt battery voltage which should go up to 13.5 - 14 volts as the 12 volt battery is charged. Then turn off the charger but leave the cable connected and see what happens to the 12 volt battery voltage. It should drop to 12.8 ish volts and stay there. If it drops and keeps on dropping then the battery is discharging and feeding power to something.

+1

 

[robertb]

I've found the issue. My V1 Zappi has a charge delay setting in the advanced menu. Zappi say if the setting is too high, it can sometimes cause the charger to keep polling the car which keeps it in a communication loop after charging. This obviously puts a drain on the 12v battery as the car is no longer charging it at this point. If left plugged long enough, the battery will eventually drain. I set the delay to 25sec and the issue has gone away.
I believe it's also a common issue with Kia's and Zappi chargers so not just an MG problem.

 

[Karsten]

I posted this elsewhere but I have a weird issue with my 12v battery.

The problem is that every time I charge the car, the 12v battery is slowly depleted unless I remove the charge cable right away.
The 12v battery holds it's charge no problem between charging sessions and tests fine outside the car.
I first noticed it a few weeks ago after I charged the car overnight. I came out the next day and the car was dead. It wouldn't open and was totally unresponsive.
After connecting my 12v booster pack, I got the car started and it immediately began charging the battery again.
Coincidentaly, the traction battery had been fully charged with no errors showing in the car or my Zappi charger.

Has anyone else had this happen? It's booked into the main dealer to be looked at under warranty as it's less than a year old.

I have the same issue. I have connected a 12v charger and disconnected the main charger and will se what happens. Anyways I am going to the dealer and have it diagnosed, as it is a new issue.

 

[robertb]

I have the same issue. I have connected a 12v charger and disconnected the main charger and will se what happens. Anyways I am going to the dealer and have it diagnosed, as it is a new issue.

The issue was with the wall charger. There was a communication setting that was constantly trying to communicate with the car and draining the 12v battery. Once changed, the problem went away.

 

[Karsten]

The issue was with the wall charger. There was a communication setting that was constantly trying to communicate with the car and draining the 12v battery. Once changed, the problem went away.

OK, I asked my provider and they denied any constant communication from box, but they mentioned, that third party apps can actually communicate, so the advice is: Only use the original app from box provider.

 

[johnb80]

The issue was with the wall charger. There was a communication setting that was constantly trying to communicate with the car and draining the 12v battery. Once changed, the problem went away.

When I first got my i3, 5 years ago I designed and built my own wallbox. The protocols for the very crude communications are published search for J1772 for the standard.

For a standard (non DC rapid) wallbox, communication if you can call it that between the wallbox and the vehicle is done via the pilot line. The wallbox puts a 1khz squarewave on the pilot line and varies the pulse width to communicate to the vehicle what it's capabilities are. Here is the table:-

The vehicle can inform the wallbox about it's current state by increasing load on the pilot signal to reduce the voltage peak to peak. :-

So as you can see, there are no communications setting to adjust in the vehicle or the wallbox. The vehicle and wallbox dont 'poll' for comms.

 

[robertb]

When I first got my i3, 5 years ago I designed and built my own wallbox. The protocols for the very crude communications are published search for J1772 for the standard.

For a standard (non DC rapid) wallbox, communication if you can call it that between the wallbox and the vehicle is done via the pilot line. The wallbox puts a 1khz squarewave on the pilot line and varies the pulse width to communicate to the vehicle what it's capabilities are. Here is the table:-

View attachment 17809

The vehicle can inform the wallbox about it's current state by increasing load on the pilot signal to reduce the voltage peak to peak. :-

View attachment 17810

So as you can see, there are no communications setting to adjust in the vehicle or the wallbox. The vehicle and wallbox dont 'poll' for comms.

Very interesting read but I'll stick with the manufacturers explanation of events as their fix for it worked immediately after changing the setting.

 

[MikeMac]

I posted this elsewhere but I have a weird issue with my 12v battery.

The problem is that every time I charge the car, the 12v battery is slowly depleted unless I remove the charge cable right away.
The 12v battery holds it's charge no problem between charging sessions and tests fine outside the car.
I first noticed it a few weeks ago after I charged the car overnight. I came out the next day and the car was dead. It wouldn't open and was totally unresponsive.
After connecting my 12v booster pack, I got the car started and it immediately began charging the battery again.
Coincidentaly, the traction battery had been fully charged with no errors showing in the car or my Zappi charger.

Has anyone else had this happen? It's booked into the main dealer to be looked at under warranty as it's less than a year old.

Hi just dealing with the dead 12v battery. Had to jump start the car a dozen times whilst we waited for a service slot at Crawley MG. Now been told that before they can find the issues faults they need to replace the battery. They can’t replace it because MG does not have a part number and don’t supply them. In the meantime we have no car. Been informed that they will arrange a hire car but have got nowhere. Called MG customer care, they basically told me “it’s not our problem “ and was very rude and unhelpful on the phone. Service at MG Crawley is appalling, to the point that appear to be avoiding our calls and requests for updates.
Appalling service from MG.

 

[Wibble]

Got in the car early, pressed start and it said something like HV battery not activated. The 12v battery was showing 12.2v. Did the off on trick and the car went to Ready and the 12v battery quickly climbed from 12.2 up to 14v plus.

I drove 40 miles home with no issues and decided to see what if I switched off and back on again. It repeated the same thing as above. Multi meter showed 12.3v so I stuck a charger on it and in 2-3 mins it went to 14v. I turned the charger off then on and back to 13.7v it then slowly dropped to 13.1 before climbing slowly.

So clearly a 12v battery issue so I guess I'm calling the garage tomorrow. I only got it in May, 2nd hand, so hopefully they will sort it for free.

 

[Gomev]

Got in the car early, pressed start and it said something like HV battery not activated. The 12v battery was showing 12.2v. Did the off on trick and the car went to Ready and the 12v battery quickly climbed from 12.2 up to 14v plus.

I drove 40 miles home with no issues and decided to see what if I switched off and back on again. It repeated the same thing as above. Multi meter showed 12.3v so I stuck a charger on it and in 2-3 mins it went to 14v. I turned the charger off then on and back to 13.7v it then slowly dropped to 13.1 before climbing slowly.

So clearly a 12v battery issue so I guess I'm calling the garage tomorrow. I only got it in May, 2nd hand, so hopefully they will sort it for free.

Apologies for suggesting this but not pressing the brake pedal for sufficiently long before the start/stop is pressed and while the car does it's checks before saying 'Ready' would have the same effect. HV not activated and voltage at 12v. Press the pedal, push the button, car says ready, release pedal. Again apologies if you are doing this but thought I'd mention it. .

 

[Robf]

Hi just dealing with the dead 12v battery. Had to jump start the car a dozen times whilst we waited for a service slot at Crawley MG. Now been told that before they can find the issues faults they need to replace the battery. They can’t replace it because MG does not have a part number and don’t supply them. In the meantime we have no car. Been informed that they will arrange a hire car but have got nowhere. Called MG customer care, they basically told me “it’s not our problem “ and was very rude and unhelpful on the phone. Service at MG Crawley is appalling, to the point that appear to be avoiding our calls and requests for updates.
Appalling service from MG.

Eh?

They can't replace the battery because they don't have the battery part number? you got to be kidding?

 

[Wibble]

Apologies for suggesting this but not pressing the brake pedal for sufficiently long before the start/stop is pressed and while the car does it's checks before saying 'Ready' would have the same effect. HV not activated and voltage at 12v. Press the pedal, push the button, car says ready, release pedal. Again apologies if you are doing this but thought I'd mention it. .

The battery is showing too low even with the car off using a multimeter. Its not holding charge. I have got it on an battery optimiser right now so hopefully that will sort it out.