VW Polo - Auto Start-Stop

chriscatt said:
And you have proof that it's the start/stop causing this? You know batteries fail for other reasons don't you and I have never had one battery failure on the four cars we've had with the system and I don't expect to have any..
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The current draw to start an engine every few minutes in heavy traffic and then charging them to capacity in quick succession is not good for any battery. You don't need proof, it is how batteries react when used heavily. I will see how long mine lasts compared to the other cars with start/stopped enabled.
 
Finglonga said:
The current draw to start an engine every few minutes in heavy traffic and then charging them to capacity in quick succession is not good for any battery. You don't need proof, it is how batteries react when used heavily. I will see how long mine lasts compared to the other cars with start/stopped enabled.
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Wonder what the maths are for the loss for a lower battery life set against the fuel savings when idling.
 
I've always wondered about stop start in heavy traffic. Are you using more fuel starting it several times in a minute than you save having it off for 30 seconds every minute? I live in London and there are many times when you're spending 10-15 minute creeping forwards a car length and stopping over and over. My wife will probably go auto for the next time we get a car, but not one that has to stop and restart the engine every fifteen seconds.
 
Finglonga said:
The current draw to start an engine every few minutes in heavy traffic and then charging them to capacity in quick succession is not good for any battery. You don't need proof, it is how batteries react when used heavily. I will see how long mine lasts compared to the other cars with start/stopped enabled.
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Why don't we need proof? - specific stop/start batteries (AGM/EFB) are specifically designed for the workload of stop start:
http://www.yuasa.co.uk/info/technical/agm-efb-explained/

https://www.varta-automotive.com/en-gb/technology/agm-battery-technology
https://www.varta-automotive.com/en-gb/technology/efb-battery-technology
 
chriscatt said:
Thank you, that is proof indeed...
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I didn't say it was or wasn't proof. Just responding to the "you don't need proof" that start/stop kills batteries. Why would it kill batteries that are specifically designed for it? Maybe AGM/EFB batteries are still in their infancy and maybe do have issues, but look at how long it has taken conventional batteries to get to the performance/reliability that they are now
 
I'm a bit of a luddite - I like manual gears, carburettors, all that sort of thing.

I don't mind stop-start, I love anti-stall, I love auto hold - all things that make my life easier and the driving experience better without any side effects I can see. If I wanted to do a handbrake turn I'd still like a conventional lever though.

Incidentally I've never once been dazzled by a brake light - what are they, 20 watts or so? :p
 
chriscatt said:
Sitting stationary with your foot on the brake is just another lazy bad habit drivers seem to have gotten into, aside from being just damm inconsiderate..
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As said Audi/VW group cars have the brake light on with the auto hold, you are just going to stop staring ant the lights as it is going to be every car soon.
 
More on how start/stop systems preserve the life of components involved:
"One of the major enhancements made to allow the auto start/stop feature is more accurate crankshaft and camshaft position sensors. The ECU knows exactly what position (Cylinder at TDC) the engine has shut down at. When ready to start, it takes this position into account and uses the combustion process to aid with the restart using the relevant cylinder. This is why engines that have auto SS do not need as much starter cranking time versus older engines with antilog crank position sensors. This shorter "work time" allows for the smaller (or same) starter sizes. There are also more advancements in the rotor and starter design which allow for the starter to handle the extended workload. And yes, this feature was mainly created to lower emissions which will thus meet CAFE standards for the entire brand (and yes I am sure they market better MPG...)

Also, there are a lot of other parameters that the ECU calculates in order to allow for proper engine shutdown.
Engine coolant and oil temp, brake and throttle pedal positions, vehicle speed / rolling direction, 12V battery condition, HVAC requirements, steering wheel input just to name a few."
 
Steampunk said:
I've always wondered about stop start in heavy traffic. Are you using more fuel starting it several times in a minute than you save having it off for 30 seconds every minute? I live in London and there are many times when you're spending 10-15 minute creeping forwards a car length and stopping over and over. My wife will probably go auto for the next time we get a car, but not one that has to stop and restart the engine every fifteen seconds.
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Hybrids 'creep' without needing to start the engine. However all s/s and hybrids will need to run the engine once the battery is critical. There's a hybrid4 that peugeot do which has a motor for the back wheels and engine at the front.. gives traffic creeping and additional 4x4 when required. Although I'd still prefer a old 4x4 if that was the case it was used on bad ground.

However as chriscatt has said .. there's lots of reasons for the engine not stopping. The 3008SUV will start when a seat belt is opened or door and parking brake etc - perhaps to remind you.

I suspect that the diesel S/S also work something like that too - holding the engine at close to firing compression for restart speed. If the mixture is too cold then I assume it would also restart to prevent having to wait for the heating elements before the start would work.
 
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