Flat Battery

[bluenose1940]

Hello folks, when I went to use the car this morning I found that I had a completely flat Battery and so that was that!  I think that the problem revolves around the fact that I must have unknowingly altered the settings on my DashCam  and the parking mode has gone beyond the safety cut-out mechanism resulting in the dud Battery.

Some time ago I connected a Battery charger to my 12v Battery on a semi-permanent basis to help me overcome such a situation.  Fortunately I am able to get at the charger via the rear seats and have connected it all up.  What is concerning me at the moment is the fact that there is a constant buzzing at the front of the car that I cannot explain, it is quite noticeable if I put my ear close to the radiator grille.  If this buzzing was coming from the actual charger I wouldn't be quite so concerned.  Anyone have any thoughts on this please?

The Battery is so flat that I can't even get any ignition lights on and cannot open any windows to put the lead through rather than leaving the door slightly open.  Also I cannot open the tailgate which would have given me easier access to the Battery.  Is there a way to open this without power?  I would have struggled somewhat if I hadn't fitted the charger when I did.

Any help/guidance will be much appreciated.  Thank you.

[ColinBarber]

In this situation I would recommend charging the Battery disconnected from the vehicle to avoid the vehicle's electronics trying to power up on the charger which cannot supply enough current and voltage is too low whilst the Battery is in a heavy state of discharge.

You should either connect another battery/jump pack to the charging/jump connector in the engine bay. That will allow you to unlock the vehicle and open the tailgate to then disconnect the Battery -ve terminal. If you don't have another Battery to jump the vehicle from then you would need to use the manual release on the inside of the tailgate - the procedure is different depending on the design and if you have a power tailgate but initially involves removing the access panel:

 

The full procedure is in the owners manual.

[bluenose1940]

Hello ColinBarber, thank you for your help with this, as always, much appreciated.  As I mentioned in my first post, I was able to connect the charger via the rear seats which helped enormously.  Because of this I was able to leave it on until there was enough charge for me to open the tailgate.  I had my fingers crossed that I didn't have to get into 'The great escape' mode and wriggle my way into the boot to get at the release mechanism for the tailgate.

All is well now thank you.  Whilst not using the car much during the lockdown, I must keep my eye on things a little better.

Thanks again for the help.  Enjoy the sunshine.

[paulrnx]

1 hour ago, bluenose1940 said:

Hello ColinBarber, thank you for your help with this, as always, much appreciated.  As I mentioned in my first post, I was able to connect the charger via the rear seats which helped enormously.  Because of this I was able to leave it on until there was enough charge for me to open the tailgate.  I had my fingers crossed that I didn't have to get into 'The great escape' mode and wriggle my way into the boot to get at the release mechanism for the tailgate.

All is well now thank you.  Whilst not using the car much during the lockdown, I must keep my eye on things a little better.

Thanks again for the help.  Enjoy the sunshine.

Can I ask how long you’d left the car unused for? I’m trying to form a view for myself of how long is enough to cause this problem.

[Rosella]

1 hour ago, paulrnx said:

Can I ask how long you’d left the car unused for? I’m trying to form a view for myself of how long is enough to cause this problem.

When mine failed it was a exactly 7 days

[ColinBarber]

2 hours ago, paulrnx said:

Can I ask how long you’d left the car unused for? I’m trying to form a view for myself of how long is enough to cause this problem.

Paul, this is going to be a difficult thing for you to judge based on people's responses. You don't know the state of charge of their Battery before it was left. Given the current situation people just aren't using their vehicles enough to ever fully charge the Battery - and therefore sit in various degrees of discharge, which gets worse over a number of weeks - then if it is left a bit longer than normal the Battery may be too flat to unlock the vehicle.

In the normal situation where people are using their vehicles on an almost daily basis, no one had problems leaving their vehicle for two week when flying away somewhere on holiday. At present, if most people left their vehicles for two weeks they would experience a flat Battery.

[paulrnx]

3 hours ago, ColinBarber said:

Paul, this is going to be a difficult thing for you to judge based on people's responses. You don't know the state of charge of their battery before it was left. Given the current situation people just aren't using their vehicles enough to ever fully charge the battery - and therefore sit in various degrees of discharge, which gets worse over a number of weeks - then if it is left a bit longer than normal the battery may be too flat to unlock the vehicle.

In the normal situation where people are using their vehicles on an almost daily basis, no one had problems leaving their vehicle for two week when flying away somewhere on holiday. At present, if most people left their vehicles for two weeks they would experience a flat battery.

I’d still like to know. If say the minimum is 7 days and the maximum is 14 days I’ll know it’s somewhere in between. It’s not an exact science I understand this but it would be useful to know the range of days inactive that it happens.

[Grumps]

Our NX was 2 years old when we went away for 28 days during February 2020 and it was fine when we got back. I understand last February was cold and wet so was pleased there were no issues.

[Tel]

Mine was left on the drive for 5 days after I had valeted the interior & then painted the wheel patches on the garage floor.

The car stood in sub-zero temperatures for 4 nights with the dashcam on stand-by.

For the first time ever the car did not start @ the first attempt.

I conclude my weekly 12 mile Covid  blast keeps the Battery in satisfactory condition but is not sufficient for all circumstances.

Tel

[Superduner]

I don't know anything about the NX300H, but an hours work on the inside of my RX400H with the doors open is enough to seriously deplete the "little" Battery.  sometimes to the point of it not starting.

I've just fitted a new Bosch Battery, fully charged, and I'm going to take readings every day to see how fast it drops voltage while in the car.  So far, after 4 hours, it's reading 12.4v