12 volt battery

[John1941]

MG4 locked overnight, lights seen on in morning then went out. Had to open door manually.
12 volt battery flat, how could this happen?

 

[siteguru]

Lights switch knocked to be manually on?

 

[Rolfe]

If the car was awake, surely it should have kept the 12V topped up from the HV? Or maybe not if it was at a low SoC?

 

[John1941]

Lights switch knocked to be manually on?

Thanks, this was possible but I thought all was switched off when doors locked.

If the car was awake, surely it should have kept the 12v topped up from the HV? Or maybe not if it was at a low SoC?

Car was well charged!? See my other reply, thought all switched off when doors locked, including light selections.

 

[Rolfe]

Not if the lights aren't on auto. I noticed this in a car park where I'd switched off the auto lights because they came on going up the entrance ramp. I thought I'd put them back to auto but I'd actually put them at on. As I walked away from the locked car I saw its lights blazing at me. There was a warning on the dashboard screen, but it only appeared when I locked the car so I didn't see it!

 

[Grriff]

I'm not sure the interior lights will turn off, if turned on manually. They will drain a battery overnight.

 

[John1941]

Not if the lights aren't on auto. I noticed this in a car park where I'd switched off the auto lights because they came on going up the entrance ramp. I thought I'd put them back to auto but I'd actually put them at on. As I walked away from the locked car I saw its lights blazing at me. There was a warning on the dashboard screen, but it only appeared when I locked the car so I didn't see it!

Thanks, reckon some re-progamming needed!

 

[Rolfe]

I'm not sure the interior lights will turn off, if turned on manually. They will drain a battery overnight.

Not if you've replaced them with LEDs they won't. And even if you haven't, the originals are so weak I'm doubtful.

 

[Kithmo]

Not if you've replaced them with LEDs they won't. And even if you haven't, the originals are so weak I'm doubtful.

I've replaced mine with LEDs and they do turn off after about 30 minutes when the car is turned off.

I'm not sure the interior lights will turn off, if turned on manually. They will drain a battery overnight.

With the factory fit, two 5W filament bulbs in it would take over 50 hours to drain the 12V with the interior lights on.

 

[DaevM]

I've replaced mine with LEDs and they do turn off after about 30 minutes when the car is turned off.

With the factory fit, two 5W filament bulbs in it would take over 50 hours to drain the 12V with the interior lights on.

Doesn't it just require enough taken off the top to stop things working, i.e. about half an hour or so? I had this with my last ev. Never had a problem with it in 5 years then when cleaning it to trade in had all the doors and boot open while vacuuming etc. for about half an hour or so and required a charge to get it going again.

 

[Grriff]

My old Jazz had a battery similar the MG4's and the interior lights drained it overnight.

 

[Kithmo]

Doesn't it just require enough taken off the top to stop things working, i.e. about half an hour or so? I had this with my last ev. Never had a problem with it in 5 years then when cleaning it to trade in had all the doors and boot open while vacuuming etc. for about half an hour or so and required a charge to get it going again.

If it was an ice car where it has to turn a starter motor yes, but not in an EV. It only takes a few amps to flip a relay and engage the HV battery so I can only assume either your 12v was on its last legs or it was low on charge to start with.