Is the stop start system in my Honda Jazz more trouble than it is worth?

I have some doubts about the benefit of this facility. Every time I come to a stop with foot held on the brake the engine stops and release the brake and the engine fires up. This means that the battery has to start the engine many more times than with the facility disabled. As I understand it, continually stopping and starting the car degrades the battery thus shortening its useful life. My 2 year old battery was recently checked by the A A and it was found to be in only "fair" condition, pretty poor for a battery of that age. Also every time a car is restarted there is a spike in petrol usage--this facility seems to cause more problems that it solves, I now disable it before I drive. I would appreciate your comments and advice

Asked on 4 March 2024 by John Hughes

Answered by David Ross
Stop start systems offer a particular benefit in urban traffic, allowing the engine to automatically switch off to reduce fuel consumption to zero while the car is stationary. The saving on fuel in urban traffic is reported to be anywhere from 8% to 15% depending on the traffic density.

On the downside, a vehicle with stop start does use the battery more frequently which can result in a shorter battery life. We would not expect any spike in fuel consumption upon restart to be greater than the amount of fuel saved while the engine is switched off. Ultimately it is a matter of personal choice whether to disable the system or otherwise in terms of balancing reduced fuel consumption and environmental impact versus component longevity.
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