Fast charging and Low Voltage battery warning?

[Evgen K]

Aha, so perhaps in a strange way the car is warning that now you have finished your charging, but you still have the plug fitted, you’re depleting your 12V system without the HV being able to top it up?

I'll check it out next time when i do a fast DC charge. But if I remember correctly, even if I unplug the charging station cable, the car will have these warning lamps on until I press the brake pedal to put the car into READY mode.

 

[ReintjeWA]

I'll check it out next time when i do a fast DC charge. But if I remember correctly, even if I unplug the charging station cable, the car will have these warning lamps on until I press the brake pedal to put the car into READY mode.

I remember it being the same way, but it could also be by just sitting on the seat (and activating the car). I'll pay attention to it as well next time I charge, and we can compare our findings like proper scientists haha!

It might also be that the HV stays disconnected until you ask for it by pressing on the brake pedal. We'll have to see what happens.

 

[Evgen K]

Anyway, it's strange that the car is showing both warning lamps. From my point of view "Power Battery Cut-off" would be enough. Why it's showing "Low-voltage Battery Charging System Malfunction Warning" lamp? It's obvious that low-voltage battery charging system doesn't work because main battery is cut-off, isn't it?

 

[pollenface]

ACC means Adaptive Cruise Control ... what you intending ACC to mean please?

In the olden days it meant the "Accessories" key position.

 

[Kithmo]

ACC means Adaptive Cruise Control ... what you intending ACC to mean please?

Accessory mode, I'm surprised you didn't know that.

 

[siteguru]

I've never ever heard position 1 of an ignition referred to as that - ever. And I'm nearly 60 and have held a full driving licence since 1988.

 

[Kithmo]

I've never ever heard position 1 of an ignition referred to as that - ever. And I'm nearly 60 and have held a full driving licence since 1988.

It was actually written on the steering lock/ign switch on some cars I've had.

 

[tsedge]

I've never ever heard position 1 of an ignition referred to as that - ever. And I'm nearly 60 and have held a full driving licence since 1988.

I'm familiar with it, but it isn't consistent on all cars, probably depends what you have driven.

 

[pollenface]

Such a key position would allow you to turn on your radio without any other systems active.

 

[siteguru]

Such a key position would allow you to turn on your radio without any other systems active.

I know what it is, and what it is for ... I've merely never seen or heard it referred to as the ACC position until this thread.

 

[Evgen K]

I'll check it out next time when i do a fast DC charge. But if I remember correctly, even if I unplug the charging station cable, the car will have these warning lamps on until I press the brake pedal to put the car into READY mode.

So, i did experiment and i can say that after Fast DC Charging when car was not locked the HV battery stay disconnected and you see these two warning lamps even if the CCS2 plug was removed from charging port and even if driver is sitting in driver's seat. You have to step on break pedal to move the car in READY mode and connect the HV battery to car's system.
I still think that this is weird behavior and i hope this issue was fixed in some firmware update (mine is R40).

 

[Martinonline]

My Trophy showed a low-voltage battery charging problem when I went to drive it yesterday. The car was showing 11.9V. I've had this before and then after a quick power on and granny-charge the error disappeared. However this time I could not cancel it, a quick drive saw the voltage drop to 11.7V. I am away from home but tried to charge with the hotel's 16amp EVSE. Car would not connect and usual fixes failed. Drove to a 50kW charging station and tried DC but again no joy. (100% level set, no schedules.)

Back at the hotel the battery level was 11.5V. So I unpacked my Noco battery booster and connected it to the battery (with clicking (relay) noises coming from a unit to the right of the battery). The battery reached 14.2V and after I disconnected the booster went to 14.3V. I shut down the car and left it overnight during which time the battery went down to 12.5V.

This morning I powered up the car and it showed no faults and the expected 14.2V charging level. I connected it to the hotel's EVSE and it started charging with no issues.

I don't know if the fault would have corrected itself without the booster but I am just grateful to those posters who recommended carrying one.

 

[ReintjeWA]

My Trophy showed a low-voltage battery charging problem when I went to drive it yesterday...

How old is your battery? I think I remember reading they don’t last very long in our MG4s (the 12V ones that is) it may be age related?

 

[Martinonline]

I bought the car in April 2023. I think it was manufactured in November 2022.

The battery may be failing but I think the problem was that the charging circuit was not connected and hence the fault icon and fall in battery voltage. It is holding its charge now. However I will be keeping my eye on it.

 

[Coulomb]

Consider checking the battery terminals. It seems like the DC-DC is intermittently not charging the 12V battery. The battery terminals and connections are easy things to check, and have been known to cause problems before.

 

[Martinonline]

Battery connections fully tight. I think it was a software glitch recognised by the car that it was not charging the battery, possibly detecting a relay not closed. If so, the car was showing the battery voltage rather than the charging voltage on the driver's display as it was less than the 14.2V I usually see with the car powered on.