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Eco start stop system

11011 Views 6 Replies 4 Participants Last post by  Bernard
So, eco start stop isn’t working, I tried charging the battery and still no luck. Then I tried using an older battery charger which seemed to do the trick and the eco start stop came back to life but only for about 3-4 days!
now as most people here agree I normally used to turn the system off as i honestly don’t like it, but wanted to check some things as I have some time on my hands now....
do You think it could be a battery issue where it’s not holding charge, or maybe I got a cell that’s gone? Or might it be the capacitor Of the start stop?

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Are you driving your car enough at the moment to keep the battery sufficiently charged? I'm certainly not (due to the lockdown). If it's a 2020 model you can see the battery state, if the starter battery is "partially charged" then eco stop/start will stay inactive.
It’s a 2016 one. I do try to drive a bit around but still not keeping much charge
Member Toobad posted this information that might be useful

Hope this helps
Do you think it could be a battery issue where it’s not holding charge, or maybe I got a cell that’s gone? Or might it be the capacitor Of the start stop?
Your car is the same age as mine. The battery is getting old and will not hold the same voltage as when new. A battery charger may allow a float charge which will temporarily let the Stop/Start system become available again but will decay very quickly to a level that the engine management system decides the function cannot be made available. I haven't seen Stop/Start being offered for nearly a year now. I am happy with this as it just saves me from switching it off manually every time I use the car.

There are 8 different and very diverse criteria that need to be fulfilled before the Stop/Start function shows as available by turning green on the screen. The amount of charge available from the battery is just one of them. There does not seem to be any consistency in these criteria being met hence availability can be offered within minutes yet may not appear for over half an hour the next day even though conditions appear to be the same. I really don't think the function has a major impact on real world fuel economy. I suspect it's true purpose is to inflate the official consumption figures whilst controlling emissions thus giving the copy writers in the marketing department something attractive to work with. The upshot is that the customer ends up paying over the odds for the car because the starter motor and battery have been uprated to cope with the increased duty cycles the Stop/Start system demands.

Stop/Start will be offered only when:
  • the indicator lamp on the ECO button in the centre console shows green
  • the outside temperature and the atmospheric air pressure is within the range that is suitable or the system
  • the engine is at normal operating temperature
  • the set temperature for the vehicle interior has been reached
  • the battery is sufficiently charged
  • the system detects that the windshield is not fogged up when the air-conditioning system is switched on
  • the bonnet is closed
  • the driver's door is closed and the driver's seat belt is fastened
If the problem is indeed with the "auxilliary battery" (capacitor), you will get a nag screen appear every time you start the car. Hope this helps.

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Hey Toobad,

I'm not a massive fan of the feature either, but I am keen to see the behaviour of the new 300e at some point. It seems to me that with a proper 48v battery behind it and the extra electric motor to both start driving off and spin up the petrol motor instantly then eco stop/start could finally be more efficient with no drawback.

Sadly I'm unlikely to own one anytime soon as I've only had the 300 for 6 months. :)
Thanks for the replies, basically I think it’s just the battery getting old like ‘toobad’ said as after a charge it works perfectly. Useless to change battery for that feature which I don’t like at least for now since it still does the job of starting my car 😂😂
Just was curious and wanted to find out why it doesn’t work. Anyways thanks again
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