Technical Stop Start Story

[306maxi]

Giat basically bolted the stop start system into existing technology so the cars use a regular starter motor and a regular alternator.
Better systems use a combined uprated generator/alternator which is also used as a motor to spin the engine up. This system uses less fuel to start the car because it doesn't need to pour fuel in to get ignition it can slowly drip the fuel in till it fires as the motor is more than powerful enough to turn the engine at full speed. This type of starter is also better suited to a deep cycling battery so the battery can be more designed like a leisure battery for longevity and long power delivery, better for when the car is stopped, and the alternator/generator is designed to deliver much higher currents to properly charge the battery when the car is running.

I suspect you mean a combined starter and alternator/generator. The system that Fiat has used is just fine for regular ICE engines that don't have any sort of hybrid drive.

The reason why a alternator never does as good as a battery charger is that in a stop/start application it gets interrupted, has some of it's current drained for use on lighting,radio, steering etc etc whereas a battery left overnight is doing nothing but charging.

 

[Mercky]

FIAT made it worse, with an Update (it allows also to switch Off S&S permanently - this is good), from now S&S also kicks in case rear window heater is on and/ or wiper is active on high speed, what was not the case before the Update, resulting in high battery drain, if engine stopped.

When you say switch off permanenly do you mean via the switch on the dash or is there a way to switch off via software?

 

[larslarsen]

When you say switch off permanenly do you mean via the switch on the dash or is there a way to switch off via software?

With the switch on the dashboard.

 

[Mick F]

If you switch it off, it isn't "permanently" at all.
It's only temporary, because next time you start the car, you have to press the switch again.

I'd prefer it to be a menu item like the daylight running lights.

Cheers,
Mick.

 

[Mercky]

If you switch it off, it isn't "permanently" at all.
It's only temporary, because next time you start the car, you have to press the switch again.

I'd prefer it to be a menu item like the daylight running lights.

Cheers,
Mick.

Hmm, I think you need a software update, I recall this was a change in a later version that stores the setting as all recent cars do. It also may well sort out other SS issues for you like having rear window on etc

 

[Mick F]

Hmm, I think you need a software update, I recall this was a change in a later version that stores the setting as all recent cars do. It also may well sort out other SS issues for you like having rear window on etc

Software eh?
How much does an update cost?
Surely not free gratis and for nothing when the car is out of warranty.

Ta,
Mick.

 

[jrkitching]

Software eh?
How much does an update cost?
Surely not free gratis and for nothing when the car is out of warranty.

You're not wrong there.

Like all things related to franchised dealer servicing, it depends on your negotiating skills. For example, you might be able to get an update thrown in free if you pay for a service.

On its own, perhaps not much less than the price of a new battery, which would IMO be a far better way of spending the money.

You'd also need to check first what updates the hardware in your car is able to accept.

 

[Mick F]

........... Like all things related to franchised dealer servicing, it depends on your negotiating skills. For example, you might be able to get an update thrown in free if you pay for a service.

On its own, perhaps not much less than the price of a new battery, which would IMO be a far better way of spending the money. ..........

Hopefully, the new battery will arrive Monday or Tuesday.

What I'm REALY looking forward to, is going round to the two places I had the old battery tested at, and telling them that what their equipment told them is actually WRONG.

What are these places going to do in the future about battery testing, when all they do is give a print-out pertaining to run-of-the-mill bog standard batteries?

How can they test (properly) a S/S battery and give a meaningful report?

Regards,
Mick.

 

[jrkitching]

Hopefully, the new battery will arrive Monday or Tuesday.

Keeping my fingers crossed that this works for you.

If it doesn't, I'm going into hiding.

 

[Mick F]

Rest assured, I will be reporting here!

When it arrives, I'll charge it up with my Ctek, and hopefully it won't take long.
Then, I'll fit it and go for a drive, let Rosa warm up, and find somewhere to stop. I will be taking a stop watch with me.

Fingers crossed.
Mick.

 

[jrkitching]

Rest assured, I will be reporting here!

When it arrives, I'll charge it up with my Ctek, and hopefully it won't take long.
Then, I'll fit it and go for a drive, let Rosa warm up, and find somewhere to stop. I will be taking a stop watch with me.

Fingers crossed.
Mick.

All I'd add is that once it's charged, let it stand for an hour or so to let the surface charge dissipate before you put it in the car.

It may take a day or two for the IBS to learn the parameters of the new battery.

 

[Mick F]

Ta.

When I charged Rosa's battery recently, I disconnected the -ve terminal completely, and charged across the poles. Basically a bench charge as the battery was isolated from the system.

After charging, I reconnected and had to reset the date and time, but other than that, nothing. First time I went out, (after warm-up) S/S worked almost perfectly. This didn't last long, as within a day or two the S/S only worked for 15secs maybe 20secs.

I would suggest that fitting a brand new perfect battery after taking the old one out the car will reset ..... and the date and time would need resetting too. I reckon that the new battery will work S/S as soon as the car warms up, but I'm willing to be proved wrong.

Stay tuned!
Mick.

 

[UFI]

What are these places going to do in the future about battery testing, when all they do is give a print-out pertaining to run-of-the-mill bog standard batteries?

How can they test (properly) a S/S battery and give a meaningful report?

You just need to go to someone who knows what they're doing

 

[PuntoHowTo]

I suspect you mean a combined starter and alternator/generator. The system that Fiat has used is just fine for regular ICE engines that don't have any sort of hybrid drive.

The reason why a alternator never does as good as a battery charger is that in a stop/start application it gets interrupted, has some of it's current drained for use on lighting,radio, steering etc etc whereas a battery left overnight is doing nothing but charging.

Hybrid drive isn't necessary for the more advanced system, the starters are powerful enough to spin the engine but not run the car. They tend to be belt driven so certainly not suitable for any hybrid purpose, where as hybrids can use their main drive motor to generate power.

Your reason for alternators In S/S set ups not charging as well as a battery charger is no different to can car, basically if the alternator is charging there will also always be something taking power away from the battery.
If you look at a battery charging curve, the closer to full a battery gets the harder it becomes to charge. If you have systems taking power as well the battery is even harder to charge, and alternators are no high powered battery chargers. So an off car bench charge is always going to be better.

Thank you for your helpful explanations, but for the above sentence I cant agree since I have read the opposite.

Without adapted alternator, starter motor and battery sensor S&S could not work at all.

In my TA it works, but not if cold outside, quite good (not below 0 Celsius).

The alternator in a fiat 500 with stop start is no different to a non stop start alternator, the starter motor may be a little more beefed up than non stop start models to cope with the extra starts but mechanically it's all the same.

All stop start systems switch off in low temperatures to prevent damage to the battery. Cold =slow chemical reactions which means the battery will discharge quicker, charge slower and not recover so quickly, after a couple of stop starts it will start to struggle. Plus drivers will have heaters fans and maybe lights running which all add to the load so it's deemed better to let the car just work normally without S/S

 

[Most Easterly Pandas]

Hybrid drive isn't necessary for the more advanced system, the starters are powerful enough to spin the engine but not run the car. They tend to be belt driven so certainly not suitable for any hybrid purpose, where as hybrids can use their main drive motor to generate power.

I think Maxi means hybrid system as in Smarts MHD system on their fortwos, not as in petrol/electric hybrid.

I could be wrong though.

 

[larslarsen]

.......


The alternator in a fiat 500 with stop start is no different to a non stop start alternator, the starter motor may be a little more beefed up than non stop start models to cope with the extra starts but mechanically it's all the same.


All stop start systems switch off in low temperatures to prevent damage to the battery. Cold =slow chemical reactions which means the battery will discharge quicker, charge slower and not recover so quickly, after a couple of stop starts it will start to struggle.
.....

I read that the TA alternator is CAN bus controlled, managed by S&S, able to deliver more charging current to battery after battery discharge in Stop period, controlled by battery sensor, measuring current into and out of the battery.

Additionally the alternator will stop to charge battery in case of strong acceleration and give more current to battery in case of deceleration.

May be this Information is wrong, but its from FIAT dealer manual....

I know that battery capacity depends on temparature (100% at 25C and aprox. 50% at -18C) and it sounds logical to deactivate S&S at lower temparatures.
Unfortionately FIAT put the switchoff threshold to very low temparature (-20C (?) my dealer told me but not sure remember correctly).

What is really annoying, is the automatic restart a few seconds after stop, what will discharge the already discharged battery more and more at each stop, instead to let the engine running. In first Winter after I bought my TA I could not believe that this is normal. In between I know it better.

No idea why S&S has been designed like this.

 

[Mick F]

You just need to go to someone who knows what they're doing

I suppose my real question is HOW?

Regards,
Mick.

 

[UFI]

May be this Information is wrong, but its from FIAT dealer manual....

It's not wrong. These profiles are easy enough to observe/test yourself.

 

[jrkitching]

It's not wrong. These profiles are easy enough to observe/test yourself.

UFI, have you done any experimentation with an integrating voltmeter/ammeter to look at power flows into & out of the battery over a typical daily cycle? I'm curious how this changes as the battery ages; I'm interested in finding out just how much more power is used by an older battery as opposed to a factory-fresh one.

 

[Most Easterly Pandas]

What is really annoying, is the automatic restart a few seconds after stop, what will discharge the already discharged battery more and more at each stop, instead to let the engine running. In first Winter after I bought my TA I could not believe that this is normal. In between I know it better.

No idea why S&S has been designed like this.

At a guess its because the system can't judge the battery condition with the engine and battery being charged? Turns of, checks battery, doesn't like it's level and so then restarts within a second or two?