Car battery

Mar 23, 2020 Last reply: 3 years ago 57 Replies

Changed my car a couple of weeks back and it has the push button start/stop rather than ignition key. It also cuts out if stopped at traffic lights and restarts when accelerator pedal is pressed.



All very well for saving fuel and I am sure the answer will be yes, but how much does this impact on the battery life with all the `extra`stop starts, or has the technology improved so that this has no adverse effect on battery life.



Most of our driving is around town.


The brochure for my car, which does the same, says the energy for restarting comes from braking stored in a supercapacitor. Battery not involved.

There's also a new 'breed' of batteries becoming available specifically designed to handle this, I think they're actually called 'stop/start' batteries. Yes, a quick search for 'stop start battery' brings up loads of hits.

Batteries for the automatic stop/start system are designed for that purpose.

My car has that system, but also has a button which disables it temporarily (pressing it again resets it). I find it helpful to disable it at junctions which are on a slope and you need to keep the brake on to avoid rolling forwards or back, and/or are very busy and when a gap appears you need to nip out quickly.

Oh yeah, are these the same super capacitors which were supposedly sold to CB radio people to make an inadequate power supply more beefy? If so then a lot of balderdash. Brian

We had a Polo with this many years back when it was a very new thing. I don't think I ever replaced the battery in a good number of years.

Not a problem with Jazz Hybrid, that starts of the "main" battery and motor/generator, although there is a small lead acid and conventional starter for backup.

It strikes me that these cars must have one hell of a starter motor! This is where an electric car can't be beaten.

Remember the amount of amps required to restart a hot engine (especially one tuned for stop start) is tiny compared to a cold start on a winter's day. And the batteries tend to have a larger capacity than a similar car without.

The batteries are designed for it, although they may cost more to replace than a "normal" one when the time comes.

Plus when the engine is stopped, the ECU ensures it stops in an ideal position to require minimal rotation to restart.

Unless you do a lot of start/start heavy traffic driving the fuel saving is minimal. It was only brought in by car manufacturers to artificially reduce CO2 emiisions to comply with EU regs.

Absolutely no effect at all. The engine leaves itself primed ready to fire and will restart again before you can even put it into gear. If the engine isn't warm enough to support fuel saving mode it will display an icon on the dash instead and keep running. If the engine block cools to a point where restart might be a problem it spontaneously restarts - which can be a little disconcerting the first time it happens to you.

Failure to use the car regularly and/or only ever doing very short journeys can be more of a problem for the battery life.

The main problem with modern electronic ignitions is that if the battery is borderline the immobiliser can panic when the starter motor current draw causes the battery voltage to collapse. I had that happen to me last month and was walking home when a friend stopped picked me up and we went with jump leads. But my solar panel recharger had actually put just enough into the battery in the couple of hours I had been walking to allow it to start so I should have just sat with it and waited.

My four year old Skoda Octavia with stop/start feature recently told me its battery was getting flat and a test at a specialist revealed it was indeed nearly dead. A new one was £90 which didn't seem TOO bad to me. They said batteries have an expected life of about 4 years.

... snipped

Is that true? I'm doubtful that it's possible for the ECU to stop the engine in a specific position WRT the cycle - happy to have my doubt corrected ...

I just whack the gear selector into "S" mode at tricky junctions, that disables the stop/start and you get a swifter throttle response when pulling away.

They use the normal pinion starter when the engine is cold, and use the alternator to start it via the belt once it's warmed up (oil less viscous)

Mine did have to have a new belt tensioner at under 2 years old.

What's the point of that? If it's easier for the alternator, it'll be easier for the starter motor too.

I had a courtesy car with that feature, it made a similar noise on automatic start to initial start. But I suppose there are various ideas about.

If you looked at the teeth on the flywheel on old cars, you could see that the engine stopped at certain places anyway.

(Wear pattern on teeth.)

Jeeze! I have usually had ten years out of a battery!

+1, assuming you mean your ICE car.

The engine still stops in certain places, just there's less wear on the flywheel.

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