Dead car / flat 12 volt battery 😰

[Archev]

I bought a porringer (or double boiler for those without a clan affiliation!) a few years back - when I've time to use it, makes fabulously creamy porridge.

Och my wife isn’t a porridge person so I just use a short range single cylinder jug

 

[Archev]

Statutory porridge break over, I’ve just checked the car. So it’s on speaking terms with me this morning. It reads 72% and the 12 volt side is showing a healthy ? 14.2 volts.
I’ll still have it checked and chase up one of those booster units.

 

[AnonymouseDriva]

Ours is a long range exclusive.

Hmm That's interesting. From P9 of the LR Exclusive manual:

so I would have expected, given that you have the top spec (same as me) that this should have kept your 12v battery going. the * indicates optional or on certain vehicles in the range, but I can't see this being an 'optional extra' and there is no guidance in the manual about which models it applies to.

What was the state of your HV battery?

Only other think I can think of (assuming this feature is actually active) is that the 12v battery voltage dropped quite sharply with the draw from the lights and the cold weather so by the time the system realised the battery needed topping up, it was already below the voltage required to throw the relays (or whatever it does to connect the HV battery).

 

[AnonymouseDriva]

Statutory porridge break over, I’ve just checked the car. So it’s on speaking terms with me this morning. It reads 72% and the 12 volt side is showing a healthy ? 14.2 volts.
I’ll still have it checked and chase up one of those booster units.

Best to check the 12v in accessory mode rather than ready mode, otherwise you're just seeing the net effect of the voltage that the HV / LV converter (or whatever the technical term is) is putting across the battery.

 

[Alb]

Correct, the 14.2V you are reading is not the battery voltage but the charging voltage.

 

[Kithmo]

Why is there no timeout on the lights/electrics? As some ICE do have this run for 15mins then goes into ECO mode to save battery. Also it would not take too much to monitor 12V and when it gets to a low voltage it shuts down.

No timeout on the parking lights so you can park where there is a requirement to leave parking lights on.

I suppose technically, a pair of 20W LED bulbs could be left on for twice as long as 60W Halogen HB3 bulbs before draining the 12V battery

The headlights go off when you turn the car off anyway, even if you have switched them on manually, only the parking lights will stay on.

 

[Archev]

Best to check the 12v in accessory mode rather than ready mode, otherwise you're just seeing the net effect of the voltage that the HV / LV converter (or whatever the technical term is) is putting across the battery.

How do I get the accessory mode figure then?

 

[Alb]

Just press the start button twice without touching the brake pedal.

 

[AnonymouseDriva]

How do I get the accessory mode figure then?

press the start button without the brake held down. That'll put the car in 'ACC' mode and start some things up but won't connect the HV battery. Pressing again will put it in 'On' mode and that fires up a few more systems, but still leaves the HV battery disconnected. From memory you need to be in 'on' to fire up the screen and see the true 12v battery state. Press again to turn everything back off.

The HV battery only connects if you have the brake applied when you press the button. Once the HV battery is connected though, you'll see the voltage jump up on the 12v battery, rising slowly as it recharges.

 

[Archev]

press the start button without the brake held down. That'll put the car in 'ACC' mode and start some things up but won't connect the HV battery. Pressing again will put it in 'On' mode and that fires up a few more systems, but still leaves the HV battery disconnected. From memory you need to be in 'on' to fire up the screen and see the true 12v battery state. Press again to turn everything back off.

The HV battery only connects if you have the brake applied when you press the button. Once the HV battery is connected though, you'll see the voltage jump up on the 12v battery, rising slowly as it recharges.

View attachment 6253

Many thanks I shall double prod the machine and see what it tells me

 

[Lovemyev]

I’ll still have it checked and chase up one of those booster units.

Good shout @Archev .
Do it before you forget .

 

[Edoc16]

Ours is a long range exclusive.

Poser...

 

[deviousrich]

Which model of the 5 do you have? Some models will monitor the 12V battery state even when 'off' and top it up from the main battery. I'm assuming the LR Exclusive does, but don't know at what spec level that applies to as it's not clear in the manual. It has a * to say not all models, but nothing more specific than that.

a good shout, mine is a LR Exclusive. i did wonder if the main battery had kicked in, it was only the parking lights that it had on when i returned to it.
the main battery didnt have any noticeable degradation in % (as i was tight on miles id have noticed a few % loss) but it was only about 8 hours and only parking lights so not massive current id imagine

i was in such a panic that id been such a numpty that i didnt take notice of the 12v battery readouts unfortunately but it was a pleasent surprise that i hadnt knackered myself!

 

[Archev]

Poser...

He he - don’t worry - I was brought back down to earth with the fitting of coarse hair upholstery and a thorny steering wheel

 

[Archev]

Many thanks I shall double prod the machine and see what it tells me

So I’m getting 12 volts in the accessories mode then 14.3 volts in ready.
The car’s booked in for a check up on the 20th.
The driver seems way beyond any sort of help unfortunately

 

[bwanamdevu]

Aye the car was collected in September. It was sitting for almost two days since last use so that’s concerning.
We went over to the Stirling hub last night for a free charge and had 70%in the traction battery and 14.2 in the 12 volt when we parked up back at home. I’ll check it after I’ve enjoyed my porridge (pinhead oats, water no salt and cooked in the old tradition of the clans - in the microwave )
As an aside, last night there were three CCS chargers in use when we arrived We set about using the fourth but the girl on number 3 said it wasn’t working. I phoned CPS and the guy said #4 had been reported earlier in the day and was scheduled for attention.
We waited 15 minutes and plugged in as a car left. As we sat a car drew in and parked at the dead unit. Low and behold it was the SWARCO engineer . I was going to go and have a word with him but he was finished and gone when I looked round again.

Phoning the Crown Prosecution Service - the CPS - over this is surely going overboard! LOL!

 

[Archev]

Phoning the Crown Prosecution Service - the CPS - over this is surely going overboard! LOL!

No no no it was our very own Charming Power Society for jocular top ups. A wistful wish with everyone watt.

 

[Edoc16]

So I’m getting 12 volts in the accessories mode then 14.3 volts in ready.
The car’s booked in for a check up on the 20th.
The driver seems way beyond any sort of help unfortunately

Self praise is no honor Archie - must meet up for a coffee soon along with any other of the MG clan who might want to join.

 

[Lovemyev]

So I’m getting 12 volts in the accessories mode then 14.3 volts in ready.
The car’s booked in for a check up on the 20th.
The driver seems way beyond any sort of help unfortunately

That sounds about right to me ?.
The ZS EV is similar.
In accessory mode is battery state, then in full driving mode, the traction battery is providing about 14 volts to charge the 12 volt battery .

 

[Archev]

Self praise is no honor Archie - must meet up for a coffee soon along with any other of the MG clan who might want to join.

Sounds like a good idea but we’d better invite any MG addicts with serious tea addictions as well I suppose. Have you noticed any fine dry days foretold in your almanac? Or anyone else’s?