Smart alternator woes? (2 Viewers)

[GoldenVision]

I have a voltmeter plugged into a cigarette socket to keep an eye on what's happening with the smart alternator/engine battery.

When driving normally (foot on accelerator) it shows about 12.5 v. Decelerating (foot off accelerator) it rises to around 14.5 v. According to the Fiat Forum (it's a 2023 Ducato) that is normal behaviour for a smart alternator.

However after driving for a couple of hours the vehicle battery shows 12.7 v.

Any ideas what the problem could be?

 

[Russell's Dad]

It's a smart alternator. I couldn't get my head around how it works, but the folk on this forum assured me all was well. I wasn't comfy with anything below 12.7 v but 12.4 is about normal apparently.
My advice is to stop looking at the stats. Unless, of course, it won't start.

 

[Tombola]

It's fine, it wont show highest voltages when it's powering things.
Then as it's smart, it will rise when it can

 

[Kannon Fodda]

Vehicle battery at 12.7V (at rest from charge discharge for at least 30 mins) would be fully charged given it is likely a lead-acid /agm type.

 

[Raul]

I have a voltmeter plugged into a cigarette socket to keep an eye on what's happening with the smart alternator/engine battery.

When driving normally (foot on accelerator) it shows about 12.5 v. Decelerating (foot off accelerator) it rises to around 14.5 v. According to the Fiat Forum (it's a 2023 Ducato) that is normal behaviour for a smart alternator.

However after driving for a couple of hours the vehicle battery shows 12.7 v.

Any ideas what the problem could be?

There is no problem, despite how hard you are looking for one, that’s just normal operation. Your battery will always be left without full charge, to allow for regenerative breaking to put some charge in. At 12.5v is voltage under load without alternator support as it does not need it, and as you switch off, the voltage bounces up as it’s fully charged and not under load anymore. All normal. Mine dips to 11.9v while driving, as I coast jumps to 14.2-14.5v.

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[GoldenVision]

Thanks for the replies.

A Victron B2B 50 amp is installed, and, according to the manual, that doesn't kick in until the vehicle battery reaches 13.3v. After 2 hours driving it still hadn't kicked in (except briefly while coasting).

Surely the vehicle battery should reach 13.3v under normal driving conditions - otherwise the B2B will never start and the (lithium) leisure batteries will never charge?

Really confused about this!

 

[Gromett]

Thanks for the replies.

A Victron B2B 50 amp is installed, and, according to the manual, that doesn't kick in until the vehicle battery reaches 13.3v. After 2 hours driving it still hadn't kicked in (except briefly while coasting).

Surely the vehicle battery should reach 13.3v under normal driving conditions - otherwise the B2B will never start and the (lithium) leisure batteries will never charge?

Really confused about this!

Have you seen this thread. Seems Guzziando had a similar issue?

Victron Energy Orion-Tr Smart 12/12-30A with Smart Alternator not working?!

I have fitted a Victron Orion B2B charger to my motorhome. The problem I am having is that I am only getting 12.4v coming from the alternator, and getting the notification in the app stating 'charge is disabled due to: input voltage lock-out Engine shutdown detected. I have a wire running from...

www.motorhomefun.co.uk

 

[LostInSpace]

Our Hymer fitted (Schaudt) B2B kicks as soon as I start the engine, presumably wired off the D+ signal). And this sounds right to me. Your documentation about 13.3 volts sounds wrong,

From your first post, I wonder if you actually have a problem or if you are worried about nothing. the voltages from a smart alternator are more complex than rocket science!

The vehicle battery will never be fully charged. (one of the features of a smart alternator - further reading required).

The two real questions are:-

does your vehicle battery always start the engine?​

does you leisure battery have a good charge?​

If your answers to both are yes, then stop worrying.

 

[GoldenVision]

Your documentation about 13.3 volts sounds wrong.

That's what it says in the manual - should be good for most smart alternators

the voltages from a smart alternator are more complex than rocket science!

Far too complex for my little brain!

The two real questions are:-

does your vehicle battery always start the engine?​

does you leisure battery have a good charge?​

Vehicle battery always starts the engine.

Can't answer the second question yet as the B2B was only installed yesterday.

BUT 2 hours in motorway driving yesterday the battery didn't rise above 12.5v (apart from regent).

AND today motorway driving showed 14v, so the B2B worked perfectly (nothing had changed).

So it would seem to be an intermittent problem with either the smart alternator or vehicle battery. And Fiats do seem to be prone to earthing problems...

 

[Derbyshire wanderer]

Thanks for the replies.

A Victron B2B 50 amp is installed, and, according to the manual, that doesn't kick in until the vehicle battery reaches 13.3v. After 2 hours driving it still hadn't kicked in (except briefly while coasting).

Surely the vehicle battery should reach 13.3v under normal driving conditions - otherwise the B2B will never start and the (lithium) leisure batteries will never charge?

Really confused about this!

After fitting a Victron B2B with a smart alternator and setting as instructed for the supposed compatibility it became clear that the low vehicle battery voltage kept switching off the B2B so I wired it with a D+ switched input and now working perfectly.
In addition, when wired as alternator sensing, the Battery Master via the solar charger would trigger the B2B without the engine running so again it was not correct.

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