Speak EV - Electric Car Forums banner

1 - 20 of 36 Posts

·
Registered
Joined
·
549 Posts
Discussion Starter #1
Hi: the MG was used two days ago for a 40 mile drive, and still has a good 70% of battery. I tried to get in this morning, but the doors were dead: no response at all on any of them to either key. Its seven months old. Anyone have any ideas? And if the 12v battery has gone flat, which seems highly unlikely, how do I get in to charge it up anyway?
 

·
Registered
Joined
·
1,198 Posts
Maybe you left the car in auxiliary mode.
Use the emergency key hidden in your key fob to unlock the door:

then open the bonnet and manually release the charge port by pulling the wire release loop, and try charging the car which should charge the 12V (which will need the car to think it's locked).

if you have a 12V charger, use that.

or, carefully jump start the car. do not connect directly battery to battery, but 12V to 12V, and for 0V/ground connect chassis to chassis so as to reduce the current flow.
 

·
Registered
Joined
·
549 Posts
Discussion Starter #3
OK, thanks: I've managed to get into the car and I'm using a 12v charger from the garage: I'm assuming its OK to leave the car 12v battery in situ whilst trickle charging? Luckily I dont need the car today anyway,
 

·
Registered
Joined
·
1,198 Posts
I would say safe to leave car connected to battery whilst trickle charging - the battery will act as a voltage buffer. It shouldn't take too long before there will be enough power available to turn the car on fully (foot very hard on the brake) and turn on. then you can disconnect the 12V charger as the car will charge from the traction/HV battery.

I've got one of these, which tells me the 12V battery voltage (should be about 13V when fully charged, and 14.1 to 14.2 when on charge and nearly full). It also tells me the temperature inside and out.
https://www.aliexpress.com/item/32879769329.html
 

·
Registered
Joined
·
3,097 Posts
I’ve connected the 12v charger to the car, then started the car. Not aware of any issues. It’s a bit like jump starting it.

The 12v battery gauge shows the charging voltage when the car is in ready mode but I think it shows the battery voltage when not in ready mode.
 
  • Like
Reactions: Scally

·
Registered
Joined
·
549 Posts
Discussion Starter #7 (Edited)
Thanks Mike: mine just didnt start, even when connected, and the charger was showing 0.3% battery and not shifting: with voltage of 5.8.
I've ordered one of those
https://www.aliexpress.com/item/32879769329.html devices for future use.

. I found a vampire drain when I charged the 12v battery whilst still connected: the internal cabin fan switched on: no idea why but it is a warm day: rather odd ! But no way the car would start. So the charge didn't work: I've subsequently disconnected the terminals and the 12v battery is now charging properly, I think. Anyway its showing 10.3 volts now, but the battery % meter is still stuck at 0.03% rather strangely. Possibly a screwed 12v battery?

I did find a little pull cord thing inside right of the bonnet, but it didnt do anything: do you know exactly where the main charging flap release is located and what it looks like, please? I may need to resort to that.
 

·
Registered
Joined
·
1,198 Posts
I now remember, the little cord thing is an emergency release for the charging plug.

I'd have to check the instruction manual for the manual charge flap release
 

·
Registered
Joined
·
549 Posts
Discussion Starter #9
I now remember, the little cord thing is an emergency release for the charging plug.

I'd have to check the instruction manual for the manual charge flap release
Great thanks: voltage is now showing 11.5: I reckon I'll wait for it to go up to 13 or 14 and then reconnect and try to start again.
 

·
Registered
Joined
·
1,198 Posts
I assume you've got an ammeter, so when the 12V battery is charged you can see whether there's a big current draw when the car is idle. It will take quite a few minutes from closing the doors and locking them before the car goes into a deep sleep
 

·
Registered
Joined
·
212 Posts
did find a little pull cord thing inside right of the bonnet, but it didnt do anything:
I also tried pulling the "cord thing" when the charge cable got locked into the charge port on a faulty rapid charger and it did nothing. Can anyone shed any light on this? I may have to pull the plastic grill off one day and see how the mechanism works.
 

·
Registered
Joined
·
3,097 Posts
I also tried pulling the "cord thing" when the charge cable got locked into the charge port on a faulty rapid charger and it did nothing. Can anyone shed any light on this? I may have to pull the plastic grill off one day and see how the mechanism works.
Practice removing your type 2 or granny lead as well. I’ve not tried it, but it might take more of a pull to realise?
 
  • Like
Reactions: Scally

·
Registered
Joined
·
549 Posts
Discussion Starter #13
Yay: 12v battery fully charged and now the car is working fine, and on the main charger. Hopefully that's the end of it: I've learned a lot: thanks for all your help and tips ;-)
Main thing is this: if there is a vampire circuit in operation that is draining power from the 12v: even just a wee fan, then you DO need to disconnect the 12v from the car first.
 
  • Like
Reactions: SkippyKitten

·
Registered
Joined
·
3,351 Posts
OK, thanks: I've managed to get into the car and I'm using a 12v charger from the garage: I'm assuming its OK to leave the car 12v battery in situ whilst trickle charging? Luckily I dont need the car today anyway,
While charging the battery in situ, and both main battery connections still in place, it is recommended to attach the red positive lead of the charger to the positive post on the battery, then the black lead of the battery charger to an earth point on the body shell of the car.
If you want to connect the leads of battery charger directly to the battery, then the battery terminals should be removed from the battery first.
This is seen as best practice I believe.
 

·
Registered
Joined
·
3,351 Posts
I found a vampire drain when I charged the 12v battery whilst still connected: the internal cabin fan switched on: no idea why but it is a warm day: rather odd !
I find this a little odd myself ?.
You would expect that the HVAC fan motor would only be active when the car is either fully booted to the READY position ( Foot applied to the foot brake when hitting the start button ) or in the STANDBY position ( Foot NOT applied to the foot brake when hitting the start button ).
When the car is FULLY powered down, then surely all the 12 volt supplied items are affectively dead ?.
Did you leave the car in the standby position when you left the car and locked it up ?.
This would account for the drain and the reason the cabin fan started up when you supplied enough power back into the 12 volt battery.
 

·
Registered
Joined
·
1,198 Posts
I think someone measured and reported the idle drain on the battery, can't remember if here on this forum or on the facebook group. The car has to run the remote unlock controller, the car alarm sensors, and also the battery charge port monitoring so that smart charging can work (the latter being a feature that was fixed with the January update, when the car was deep asleep it wouldn't wake up to charge)
 

·
Registered
Joined
·
3,351 Posts
Anybody spotted this one ?.
Over the last couple of weeks, I have noticed that when I first boot up the car, the 12 volt battery gauge in the dash has only ONE of the white bars above the centre line lite.
When I drive about 2 - 4 miles, it lights up the second bar above the centre line.
We made a day trip to Harlech and back yesterday, almost around 140 miles in total.
Booted up the car this morning, same thing.
One white bar above the centre line on the gauge.
Drove about 2 miles and the second bar was now lite.
Anybody else witnessed this type of thing ?.
The length of the journey appears to have no little affect on what I am witnessing.
OBTW - Bit of a observation, the car made the journey both there and back and we had around 27 miles left on the GOM.
Weather not great, but no HVAC required either way.
Pretty impressed with the range to be honest, the drive was really nice, the scenery was fantastic.
 

·
Zoe Devotee
Joined
·
9,215 Posts
@Scally plug in your home charger to the car, 10mins max and the 12v will be good to go. I did this last week after my unfortunate breakdown. Literally 10mins (and I had a flat HV and 12v) and the car was then showing 4% and able to boot up and start and move around again.

Been grand ever since.
 
  • Like
Reactions: Scally

·
Registered
Joined
·
549 Posts
Discussion Starter #19
Great thanks folks: I think the probable solution may be this: my wife drove the car to and from work the other day, and she probably inadvertently left it in Standby Mode by not depressing the brake pedal: the car was therefore left on for 36 hours, hence the 12v battery drained flat: it's the only explanation that makes sense, really. It's a bit of a drag that the car can't detect this itself, and charge the 12v from the main battery , but hey ho , there you go.
 
  • Like
Reactions: Paul M

·
Registered
Joined
·
549 Posts
Discussion Starter #20
We made a day trip to Harlech and back yesterday, almost around 140 miles in total.
OBTW - Bit of a observation, the car made the journey both there and back and we had around 27 miles left on the GOM.
Weather not great, but no HVAC required either way.
Pretty impressed with the range to be honest, the drive was really nice, the scenery was fantastic.
Yes, my wife is also reporting getting some great range: at least 160 miles, in this warm weather.
 
1 - 20 of 36 Posts
Top