Technical Smart alternator issue on Ducato 2021

[GauSte]

Hello,
I was on holidays with my 2021 Ducato Camper van during this summer, I bought it as a used one just one month before. I got another Ducato from 2017 before.

After a few days, the Ducato battery voltage was decreasing, and one morning I could'nt start.
As the van is 3 year old, I thought the battery was too old, so I went to a garage to change it.

Then I looked for some information on the Web, and discovered : the smart alternators of Euro6 !
So I discovered that it charges during a small minute when the engine starts, it charges when the van slows, and when the voltage is too low.
So it maintains a ~12.5 V (like a 50% charge).

But the battery didn't get charged any more (-> 11.5V). I thought It was because of the DC/DC converter which charges the leisure battery for the fridge, and consumes more current than the alternator provides.
I checked some items :
- My alternator charges (-> 14.4 V) for ~30 seconds when the engine starts -> OK
- My alternator charges when I slow while driving -> OK
- My alternator does not charge when voltage is too low !

I found a youtube video with Euro6 explanations, which shows how to force charging (like a stupid alternator...), by disconnecting the sensor on the battery (-).
I did it, but no charge.
So I think there is an issue. The ECU does not detect low voltage to drive the alternator...

Any experience or ideas ?
Thanks

 

[Reg 65]

Sorry for the late reply as I have only justseen this thread
I also have a 2021 Ducato (140) and in my experience
To check a smart alternator you need a voltmeter you can see when you are driving, because as you have observed it usually only charges fully when the vehicle momentum is turning the engine - which you won't see when the vehicle is stationary.
In any other circumatances iff the battery is over about 80% charged the alternator will stop charging till the battery is back down to 80%. So the battery is discharging when the engine is running, voltage may only be about 12 volts and this is normal.

 

[GauSte]

To check a smart alternator you need a voltmeter you can see when you are driving

Hi,
OK, it's what I did :
>> - My alternator charges when I slow while driving -> OK

if the battery is over about 80% charged the alternator will stop charging till the battery is back down to 80%.

The level is nearer to 50% (12.4 V)

voltage may only be about 12 volts and this is normal.

But my voltage is going down to 11.4V, which is not enough to start the engine, and this is not normal.

 

[jackwhoo]

Did the no start battery low happen with the vehicle being used regularly ?
Or after the vehicle being parked unused?

 

[GauSte]

Did the no start battery low happen with the vehicle being used regularly ?
Or after the vehicle being parked unused?

The van was used every day for 2 weeks, pluging to the mains only every 4 days.
I was on holidays in Ireland, very rainy... :-/

 

[jackwhoo]

Of course it rained a lot....

Has the new battery gone flat when in use every day?
Have you tried disconnection the dc to dc charger and seeing if that improves charging ?

 

[GauSte]

Of course it rained a lot....

Has the new battery gone flat when in use every day?
Have you tried disconnection the dc to dc charger and seeing if that improves charging ?

Just not to loose the new battery, I turned off the fridge while I was driving, so the DC/DC did not use as much energy from the vehicle battery.

 

[Reg 65]

Thanks for the clarification GauSte
I would suspect whatever accessories you have connected, disconnect them, and the battery after closing all the doors and waiting a minute for the computer to shut down, and then reconnecting the battery so the van is in its original state. Then try it.
I don't know much about DC to DC chargers. Most of the advice on the web is to use a DC to DC charger, which I suspect originates from experts who are selling them. (never ask a barber if you need a haircut) But I have never used one even with my smart alternator.

New Ducato Stop Start Alternator | FIAT Motorhomes / Campervans

Hi, Looking for help :o I'm needing to get a new van for a camper, where the only source of electricity will be the vans alternator. On older models I have fitted a second battery through a voltage sensing relay using 25mm2 cable so the X2/50 standard 150amp alternator charges both batteries...

www.fiatforum.com

I tried connecting the batteries in parallel with 25mm2 cable controlled by a 200 amp relay, operated by the ignition switch, or the D+ on the alternator - both worked well with my smart alternator for a couple of years. But then the relay started sticking (it was a cheapo unbranded job off ebay) so I eliminated the relay and now have all batteries permanently connected in parallel keeping therm equally charged. 1 x 020 battery 110ah and 4 x 019 batteries 100ah. (2 under each seat) - all standard flooded lead acid starter batteries. The most simple and efficient arrangement, making the most of regenerative braking and no current wasted in DC to DC chargers. As far as I can see the only downside from this simple arrangement is the risk of flattening all the batteries so I couldn't start. But with so much spare capacity I never come near to discharging them and carry a jump start pack just in case.

 

[Bogumil Dreliszak]

Hello GauSte,


I have a very similar problem with my Ducato. Did you manage to solve it in the meantime, or do you have any further information?


Everything you describe also happens to me. After about 3 years I also had starting issues – I noticed it especially when my leisure batteries were very discharged and pulled current via the booster from the starter battery.


Because of this I bought a new LiFePO4 as starter battery. At first I thought the issue was the battery itself, but with Bluetooth monitoring I can now actually see the charge and discharge currents. My leisure batteries are from the same brand, so I can confirm: while driving the alternator does not really charge, instead about 60A is drawn from the starter, and around 30A goes into each of the two leisure batteries. Only during braking the recuperation kicks in and charging increases for all batteries.


When starting the engine there is charging as expected, but it’s hard to measure while driving – the only reliable information I get is from the battery app showing the current flows.


I also spoke with a mechanic and he is convinced that this behavior is controlled by the start-stop system, which makes the alternator “smart” and leads to these problems.


Would be great to hear if you found a workaround or a proper solution.


Best regards,
Bogumil

 

[Bogumil Dreliszak]

Hello GauSte,


I have a very similar problem with my Ducato. Did you manage to solve it in the meantime, or do you have any further information?


Everything you describe also happens to me. After about 3 years I also had starting issues – I noticed it especially when my leisure batteries were very discharged and pulled current via the booster from the starter battery.


Because of this I bought a new LiFePO4 as starter battery. At first I thought the issue was the battery itself, but with Bluetooth monitoring I can now actually see the charge and discharge currents. My leisure batteries are from the same brand, so I can confirm: while driving the alternator does not really charge, instead about 60A is drawn from the starter, and around 30A goes into each of the two leisure batteries. Only during braking the recuperation kicks in and charging increases for all batteries.


When starting the engine there is charging as expected, but it’s hard to measure while driving – the only reliable information I get is from the battery app showing the current flows.


I also spoke with a mechanic and he is convinced that this behavior is controlled by the start-stop system, which makes the alternator “smart” and leads to these problems.


Would be great to hear if you found a workaround or a proper solution.


Best regards,
Bogumil

Update:
I disconnected the IBS (Intelligent Battery Sensor), which sits directly on the negative terminal of the starter battery. It normally measures current, voltage, and sometimes temperature, and sends this information to the ECU via LIN bus to control charging and start-stop functions.

The first time a fault appeared, but I cleared it with a Topdon scanner. After that I restarted the engine several times – no new errors came back.

The alternator charged the starter battery up to 100%, but the start-stop system still did not activate.

For now I’m satisfied with the result. I’ll keep posting updates here if anything changes.

Example of the IBS on a Fiat Ducato negative terminal:
Fiat Forum – What is this thing connected to my battery?