Happy boxing day guys. You may have seen that I have posted about this issue. Had this car for nigh on two years. I can't seem to get it sorted. Anyway here is the latest. The stop-start only works very intermittently. Like once over a 200-mile journey. That can't be right surely ? Last year I had the main battery replaced. Thinking that might be the issue. At that time I was not aware of the second battery in the boot. Recently The garage replaced that. They told me it might be a few days before it was fully charged up. Anyway, two weeks have passed, and it still only stops/Starts very intermittently. So no change. so not happy still.
I have heard that the new battery(s) should be registered to the system of the car. Could this be the issue? Please help guys.
Thanks David.

Battery does not have to be registered. Get a Ctek MXS5 battery conditioner & leave it on until the first green light comes on.
However, the cold weather & darker days comes into play. With you using the heating/ lights/ wipers more, the car decides whether the stop start will be activated. Range Rover Sport: Mercedes S63 AMG Coupe: 992 Porsche Carrera 4S

Hi. Thanks for your reply. Yes, I am aware that the car decides if it has enough juice for the stop/start to work. But I had driven from Daventry (Northamptonshire UK) About 100 miles, Back home to Suffolk in the daylight. No rain, minimal heat, and the blower was on low. And it self-stopped/started just once, as I stopped to reverse onto my drive at home. I know lots of you don't like or use this feature. But I do. But even when I turn it off, after a while I look down, Why would that be?
and it's back on. Regarding the battery condition meter, They were recently checked by the garage. And showed both be ok.
David.

Put the car on a battery charger for 1 night and I’m pretty sure the stop start will work. It always makes mine work. I use a CTEK MX5. It has green lights on it to show you the state of charge of your battery. I read somewhere ages ago that the RRS needs a 4 hour drive to fully charge the battery. Don’t know how true that is though……

Thanks very much. I will do that. Thanks David

Hi Johnrrs. Ta for your sugestion. I did what you said. But before connecting my charger. I thought I would check what the Stop/Start battery voltage was. The engine was not running. Nor had it been running since the previous night. So it was cold. I don't know if I should have been pleasantly surprised. But it read 16 volts. Good or bad?
David.

16v is far too high ///it will gas and bubble from 14.5 V upwards . You have an alternator issue.

This is all rubbish about winter driving running the battery down . All the items mentioned are run from the alternator and the starting load is replaced within 1 minute

Get your facts right Always listen to old people or when they die you will live on in ignorance.
The avatar is a picture of the man with a big cock.
Learned to 4x4 on 100 mile beach and Frazer Island QLD
Dont spend money on old cars you will never get it back

Where are you checking the voltage of the battery?

Check the main battery with engine running at fast idle ..should not be over 14.4v.
Some voltmeters go crazy if the battery in them is low Always listen to old people or when they die you will live on in ignorance.
The avatar is a picture of the man with a big cock.
Learned to 4x4 on 100 mile beach and Frazer Island QLD
Dont spend money on old cars you will never get it back

The last time I checked my battery voltage I did it at the charging points under the bonnet. I was getting 13.1V with engine off and 15.2V with engine running

This is all rubbish about winter driving running the battery down . All the items mentioned are run from the alternator and the starting load is replaced within 1 minute

Get your facts right[/quote]

Perhaps you should get your facts right. Its called an intelligent stop/start & if you read the owners manual there are a few things in there which determine whether it should work or not Range Rover Sport: Mercedes S63 AMG Coupe: 992 Porsche Carrera 4S