Disabled start/stop enables smart alternator on non-Adblue T6 | Broken V-Belt

[tondi]

Hi all,

It's been my 2nd V-Belt failure in last 2 months. Trying to find a source of the problem I remembered turning off the Start-Stop system via my Ross-tech OBD.

I have a Victron 50A DC-DC for my camper utilities and started noticing charging is weak. Opened the app and began measuring starter voltage.

Whereas previously it got stable 13.8V (If I remember correctly) now it varies a lot and on idle it's ~12.8V and jumps to more than 14V when braking.

Could that be the reason behind my V-belt issues? The car is an early 2015 produced T6 CAAC 140km (year model 2016)

 

[DaveD]

Could that be the reason behind my V-belt issues? The car is an early 2015 produced T6 CAAC 140km (year model 2016)

I've got a CAAC engine 2016 T6 and I switch the stop start off at the start of every journey, 9 years later it's on the second aux belt, and the first was only changed because I asked for it to be changed when it had a new cam belt. There is something wrong if your van is chewing through them at the rate you describe.
The "smart" alternator should produce more voltage under braking, as yours does, so nothing suspicious there;

Thread 'Battery charging through regenerative braking.'

9 Jul 2021

I'm led to understand that the battery doesn't charge from ticking over on the drive because the van uses regenerative braking energy to charge it. That's right yes?

I haven't used my van much over the past 18 months and predictably, the battery tends to be quite down on its SOC. (I base this on the speed the starter motor turns the engine rather than through a meter). I can also tell when the battery is sufficiently charged because my stop/start starts working!

Anyway, I decided to top the battery up by giving it a run down the motorway. Despite a couple of hundred miles the stop/start...

• Teesix
• Replies: 30
• Forum: Electrics, Lighting, ICE, Security

Are the pulleys all running smoothly and properly aligned?

 

[DXX]

Defective belt tension caused by defective alternator pulley clutch.
Plenty of youtube videos showing how to check the pulley clutch operation.
Best done through the RH (UK offside) front wheel arch with the liner removed but probably possible from under the van with the sump guard off (if fitted).
If no sump guard is fitted I would advise to fit one as it keeps the road dirt out of this important mechanism,

 

[tondi]

Thanks,

@DaveD I believed that my car doesn't have a smart alternator, since it's a non-AdBlue version. It produced steady values of 13.8V until recently. I think it changed with turning off the Start/Stop system as some voices on this forum say. I'm mostly looking for advice whether this correlation really exists.

@DXX
After the first failure I got all pulleys checked and was told it's alright. Then second time it happened it was burned, so all pulleys were replaced, alongside with tensioner and the AC was filled (it was missing pressure) well, I'll drive and see.

Can any of you help me measure the temperature of the belt with a laser thermometer? Mine is reaching about 80deg Celsius (176F) and aim wondering if it's a lot.

 

[DXX]

Mine is reaching about 80deg Celsius

That doesn’t sound correct at all, sounds like the belt is slipping and friction is causing the high temperature and failure.
Smart alternator or not it still has an alternator pulley clutch that needs to be checked for correct operation.
You mention the pulley check, was that just the ribbed belt idler and tensioner pulleys?

 

[DaveD]

@DaveD I believed that my car doesn't have a smart alternator, since it's a non-AdBlue version. It produced steady values of 13.8V until recently. I think it changed with turning off the Start/Stop system as some voices on this forum say. I'm mostly looking for advice whether this correlation really exists.

I might be wrong, and I don't have a method of measuring the voltage under braking, only when my van is static, so hopefully others might be able to offer advice.
This is an interesting thread on the subject and suggests that some Euro 5 (non AdBlue) vans might have smart charge alternators;

Thread 'Smart Alternator - all T6?'

20 Nov 2019

Are all T6 vans equipped with smart alternators, or is it only those with Euro6 cat engines?
I have a 2016 T6 Euro5 engine, (no adblue).

• OllieGBR
• alternator
• Replies: 27
• Forum: Electrics, Lighting, ICE, Security

 

[tondi]

@DXX This is from the last (2nd) failure:



This time I was told the belt burned, since some material remained between the pulley ribs. They changed everything - and I'm still not feeling comfortable, esp with that readout reaching 80 deg.
Everything was checked at the shop, same as first time. This time they suspected A/C compressor and filled missing liquid. All the pulleys - from alternator and from the engine were replaced and checked before belt was mounted. All running smooth so far. It's just my suspicion about the Start/Stop disabled that may be affecting alternator performance and maybe making it immobile and f*cking up the belt when I'm not braking?

@DaveD This is interesting - I wonder if a "Smart/Dumb alternator" is actually a matter of the software and it's possible to alternate between these two as my results suggest. Will have a detailed read. I'll probably also revert my Start/Stop disable and see if voltage stays fixed after that

Thanks both.

 

[DXX]

Just to let you know that the ribbed belt failure on a T6 can easily cause a damaged timing belt and catastrophic engine failure.
I suggest a different garage as it would seem that the one you have previously used has missed something critical.

 

[DXX]

This time they suspected A/C compressor and filled missing liquid

Hopefully they evacuated the system and filled the correct weight of refrigerant, I can’t see how the AC would affect the belt unless the compressor bearings are seized.
As above go to a different garage.

 

[jayc001]

I turned my stop start off 80k miles ago with VCP and smart alternator still functions correctly. Your belt issues sounds like a alternator pully issue as mentioned above. I had similar issue on my T5.1

If you want to disable smart charging for a test just plug the shunt lead on the negative battery terminal.

 

[Alster]

Was it a genuine/good quality belt?? As above I would be trying another garage

 

[tondi]

I disabled the setting and so far so good with the belt, albeit it's noisy when wet.

Went for a mechanical "memory" switch instead. Super simple to put in place, plug&play and solves the problem

Also, as you mentioned the car has a smart alternator indeed, the setting did not affect the output.