Flat Battery - Fiat/Carado 2023

[Dean68]

Hi,
Hopefully somebody may have advice on my dilemma. I have a 2023 Carado T459 on Ducato chassis . All was perfect for ten months from new then one day having driven 200 miles to a campsite in York on arrival the motorhome would not restart after checking in at reception. I left it a while and then it started. Had Fiat assist out who could find nothing wrong. Drove to Scotland, same thing happened, arrived at campsite and van would not start. We had to push motorhome to its pitch! I had jump leads and was able to start the motorhome from friends battery and all was fine for rest of the trip.

I bought off Amazon a 12v plug in voltage indicator so I could monitor voltage during future trips.

For info I have also taken the motorhome to Fiat twice to get smart alternator and battery checked and each time they can find nothing wrong (very frustrating).

I am now in France and twice so far motorhome has not started after long journeys! Short journeys of less than 3 hours seem to be fine.

What I have noticed so far with 12v plug in is that when I start the van from cold normal running voltage seems to be either 13.4v or 14.2v and when you let off accelerator it increases sometimes as high as 15v. This from what I have read is normal. The abnormal operation I have experienced is as follows:

(1) After the first breakdown in France I got a guy in a van to assist me with jumpstart. Once started the voltage meter stayed at 14.2v constantly for 3 days travelling to Alps. Had no problems starting but fuel consumption was down to 26mpg when normally about 29. It then dropped on the fourth day to 13.4v constantly. When I say constantly I mean when you let off the accelerator it does not jump higher.

(2) After first four days it seemed to start working normally, starts at 13.2-13.4 and flicks up to 15 when letting off throttle. However what I have noticed now is that if I drive for 3-5 hours the voltage slowly drops and on one occasion went as low as 11.9v. It still flicks up to 15 when you let off. When it’s down as low as 11.9v when I stop Motorhome won’t re-start. I now have a jump start pack which I use to jump start and once started it then seems to restart quite easily!

It’s driving me mad. My plan is to go to Chelston Motorhomes motorhomes where I bought it and get a fuse pulled so that the habitation battery is not being charged by van. If issue stops I will know it’s the habitation side causing issue. If it continues I can focus on the Ducati van, or Fiat can!

If anybody has any experience, ideas or strategies to resolve I would be extremely grateful.

 

[Cush]

Could it be an earth fault that only surfaces after a long trip where things in the engine bay get affected by heat. I a, certainly no expert but I would be checking the alternator and cab battery earth straps. Wise will be along soon.

Oh, and welcome. Always good to do an intro message

 

[Jev88]

11.9v???

Battery kapput.

Do check earth straps and battery / starter motor terminals. Adding extra earth from battery to engine block if possible but I am more familiar with older vans.

 

[gus-lopez]

hat if I drive for 3-5 hours the voltage slowly drops and on one occasion went as low as 11.9v. It still flicks up to 15 when you let off. When it’s down as low as 11.9v when I stop Motorhome won’t re-start

I would say that it is a smart alternator fault as it is not charging correctly if it is dropping that low?

 

[Lenny HB]

I also reckon it's an alternator problem.
Smart alternators normally keep the battery around 12.-12.5v only going a bit higher on start up and a lot higher on engine overrun.
The fact that the battery is down at 11.9v after a long drive would imply the alternator is packing up when it gets hot.

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[Dean68]

Could it be an earth fault that only surfaces after a long trip where things in the engine bay get affected by heat. I a, certainly no expert but I would be checking the alternator and cab battery earth straps. Wise will be along soon.

Oh, and welcome. Always good to do an intro message

Thank you, I discussed with Fiat as this is often mentioned on forums. This was checked out by Fiat and deemed to be good as new and no issue. Once I get to the bottom of the problem I’ll post again. Thanks for your thoughts.

 

[Dean68]

11.9v???

Battery kapput.

Do check earth straps and battery / starter motor terminals. Adding extra earth from battery to engine block if possible but I am more familiar with older vans.

It was 11.9v on the display whilst engine running which I’m told was system operating voltage not the exact battery voltage. But it can’t be far wrong as van didn’t start! Once jump started and run for a few minutes van restarted fine. Annoyingly I have to jump start direct to the battery under the floor in the cab as the terminals provided under the bonnet are too far apart for the little nico jump started gadget’s cables. I will post again when I get to the bottom of it. Van still has a years warranty so I’m on the case. FIAT although helpful always defer back to you need to get the habitation side checked. Chelston say nothing wrong with habitation so go to Fiat!

 

[Dean68]

I also reckon it's an alternator problem.
Smart alternators normally keep the battery around 12.-12.5v only going a bit higher on start up and a lot higher on engine overrun.
The fact that the battery is down at 11.9v after a long drive would imply the alternator is packing up when it gets hot.

 

[BouncyBoatFolk]

I also reckon it's an alternator problem.
Smart alternators normally keep the battery around 12.-12.5v only going a bit higher on start up and a lot higher on engine overrun.
The fact that the battery is down at 11.9v after a long drive would imply the alternator is packing up when it gets hot.

I would agree with this, the insulation around the windings is breaking down as the alternator gets hot. When it cools it's resealing itself. I've had this on a previous [ non smart ] alternator, but exactly the same fault. Additionally, if the fridge is sucking away current as well that's adding to the cabs battery lack of input.
Mike.

 

[Dean68]

That is my diagnosis as well. Ideally I need to do a two hundred mile drive, arrive at Fiat with voltmeter showing 11.9v and the van running and let them diagnose. I have a lot more real time info now so I’m hoping when I get back to Uk I can drive home the issue and get some action from Fiat. I will post again when I get resolved as if this can help somebody in the future shortcut the problems I am having my work will be done!

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[Lenny HB]

If you have had to jump start it a few times it's going to need a new battery I wouldn't trust it but that's another problem.

Might be worth a trip to Adams Morey at Portsmouth they are one of the best Fiat dealers and very helpful.

 

[Dean68]

I would say that it is a smart alternator fault as it is not charging correctly if it is dropping that low?

I think it’s that as well. The fact it ran at 14.2 constantly for 3 days was bizarre. I was pleased at the time as despite fuel consumption at least I knew the van would start! Also I thought it would be easy for Fiat to diagnose the issue as something was broken. I was very disappointed it started to work normally again!! I’m hoping that when they plug in there diagnostic device that there will be loads of voltage error messages and issues that may lead them to the problem. I will post again when I get to the bottom of the issue. Thanks for your input.

 

[Guigsy]

How powerful is your B2B? There were problems a few years ago when smart alternators became the default and manufacturers weren't fitting B2Bs. People with 3 way fridges were finding the fridge on 12v would pull more from the cab battery than the alternator was supplying. So they'd go for a drive and end up with a flat battery.