12v battery and Noco booster

[Martinonline]

I have just returned from a break that meant my Trophy was left at 72% charge from 3.00pm Monday till 10.00am Friday. I did check the car via the app on Thursday afternoon and it reported 12.4v for the battery which seems to be normal for it.

 

[tsedge]

Thanks for your feedback everyone.

I'm planning to leave the car unused for 48 hours to see if the problem reoccurs. I'll have driven roughly 100 miles in the week beforehand, and I'll leave it not charging, with less than 50% in the HV battery.

However, I want to be absolutely sure that I'm not inadvertently leaving something on which could drain the 12V battery. Does anyone have a "turning the car off fully" checklist? e.g. Select parking brake, get out, close door, lock with key fob. Also, is there anything I should avoid doing during that 48 hour period that might unintentionally wake the car?

Thanks!

I recommend:

• Leave it with more than 50% in the battery, some report the car doesn't top up the 12V battery if the HV battery is below that.
• Avoid using the app, this will wake it up.
• Disconnect any USB connected devices.

Then, just lock it with the key, as normal.

 

[siteguru]

As per above (unless the 48 hour leaving is being done as a test, in which case having an SoC of less than 50% would be a useful check). Just park up, press the P button, get out, close the door, lock with the fob or door button then walk away. Don't check the car with the app. Have a 12V booster handy when you return to the car just in case.

 

[Martinonline]

Plus check that all the lights are off in case you've accidently set manual lights control. Unless, that is, you've set Follow Me Home.

 

[JonnyG]

Edited as already said above ?

 

[OriginalBigAl]

As per above (unless the 48 hour leaving is being done as a test, in which case having an SoC of less than 50% would be a useful check). Just park up, press the P button, get out, close the door, lock with the fob or door button then walk away. Don't check the car with the app. Have a 12V booster handy when you return to the car just in case.

If you are doing a check like this, is it possible to leave the bonnet on the latch, not closed , so access to the battery is easier should the worst occur, or will the car not like that?

 

[mg4mc]

It won't like it

 

[Coulomb]

is there anything I should avoid doing during that 48 hour period that might unintentionally wake the car?

Yes, going near it with the key fob.

 

[Coulomb]

It won't like it

Why not?

 

[mg4mc]

Why not?

Because the bonnet is on the alarm system like the doors and hatch.

BUT... I just tried it, and though the car doesn't like it - the horn beeps when you lock the car. The car does still lock, but presumably with the alarm disabled.

 

[Rolfe]

Well, if the car is in a secure car park, that could be a sensible option.

 

[mg4mc]

Could be, so long as something doesn't stay awake because there is an error condition.

 

[Rolfe]

Might be something to try out in safe conditions - i.e. when facilities are available to start the car if it all goes horribly wrong.

 

[johnb80]

Might be something to try out in safe conditions - i.e. when facilities are available to start the car if it all goes horribly wrong.

I'm not sure what the point is, is there not a manual lock on the MG4 that the conventional key opens, can the bonnet not be opened once inside when the battery is flat?

 

[WonkoTheSaneUK]

I'm not sure what the point is, is there not a manual lock on the MG4 that the conventional key opens, can the bonnet not be opened once inside when the battery is flat?

There is, hidden under the cover of the door handle

 

[johnb80]

There is, hidden under the cover of the door handle

I thought there would be hence why all the heartache of leaving the bonnet open, I dont see the point.

 

[OriginalBigAl]

Siteguru had suggested a 48 hr check , presumably on your driveway, if in this time the battery had drained below the threshold for booting the car up and boosting it was required then access would be quicker without the faddle of dismantling the key and door lock , although it could be good practice, hence my query as to what problems it may cause.

 

[johnb80]

Siteguru had suggested a 48 hr check , presumably on your driveway, if in this time the battery had drained below the threshold for booting the car up and boosting it was required then access would be quicker without the faddle of dismantling the key and door lock , although it could be good practice, hence my query as to what problems it may cause.

It would be much much easier to leave a pair of wires hanging out from under the bonnet to allow a battery charger or power supply to be connected. They could also be used for checking the battery voltage. By doing it this way the car can be properly locked and the appropriate systems allowed to sleep, rather than introducing unknowns.

 

[JonnyG]

Jusy a quick question : once the drivers door lock has been opened manually as in the above video , can you open all the other doors manually, from inside the car using the handles ? Presumably you could then easilily fold down one of the rear seats and access the boot too (or at least the boot area nearest the seats ?). If so you can leave chargers etc. in the boot ??

 

[Rolfe]

Good point.