Concerns About Vehicle Battery Performance

[slowdriver]

Hi. Some advice. We are travelling to France Newhaven Dieppe this evening in a German pvc aLa Strada Avanti Eb on a Ducato Maxi chassis.The vans not been used much since September but has been on hook for long periods. It’s had a couple of decent 40- 100 miles plus round trips recently, all trouble free. The leisure and leisure battery is an AGM and the vehicle battery is lead acid - whatever was installed by Fiat/ the converter in 2020 when the van was built. It has a Votronics BDB. It has been on charge for the last week. Last night after I’d been doing a fair bit of manoeuvring and stop start I thought I detected a bit of weakness in the vehicle battery and therefore put it on charge via my Victron mains charger. It went from bulk to absorption to full and float in about 30 minutes.
We have just had a steady drive from Oxford to Newhaven and the engine battery is only on 12.4v

It’s 4 years old so I’d have thought it should have a bit more life in it.
It’s a Bank Holiday tomorrow in France so assuming it starts on the ferry! I was intending to head for Chartres 2.5 hrs or Orleans (5 hrs) first thing tomorrow -Monday - haul up there and take it on Tuesday morning to a Fiat dealer (they will presumably have a suitable replacement off the shelf )

Any better ideas, and any possible causes apart from just a failing battery

 

[slowdriver]

And I should add it had its 2 year service at Fiat professional last Tuesday..

 

[Lenny HB]

I think you have a smart alternator with a van of that year and converters don't normally fit a B2B unless there is a smart alternator.
12.4v is not uncommon for the battery to sit at if you have a smart alternator.

Not uncommon for a battery to be at the end of it's life after 4 years on a heavy diesel but first check if the alternator is charging. If it's not a smart alternator with the engine running voltage should be around 14v. Not so easy to check with a smart alternator it will only charge at 14v or more on engine overrun.

If you do need a new battery there are Battery Mega Stores in France they will be less than ½ the price of a Fiat dealer

 

[slowdriver]

I think you have a smart alternator with a van of that year and converters don't normally fit a B2B unless there is a smart alternator.
12.4v is not uncommon for the battery to sit at if you have a smart alternator.

Not uncommon for a battery to be at the end of it's life after 4 years on a heavy diesel but first check if the alternator is charging. If it's not a smart alternator with the engine running voltage should be around 14v. Not so easy to check with a smart alternator it will only charge at 14v or more on engine overrun.

If you do need a new battery there are Battery Mega Stores in France they will be less than ½ the price of a Fiat dealer

It is a smart alternator . So can I just check the engine running voltage with the multimeter across the battery terminals? Is there a way of simulating overrun? Revving and letting it die back to tick over? I have the victron battery charger cable hard wired to the battery terminals so I can check the battery voltage without taking the floor up using the pins in the connecting block so revving while holding the meter probes onto the terminals is not required .
Will the battery megastore fit the battery as well? I could do it but I’d be concerned about resetting stuff which I assume needs to be reset after a battery change. Plus there’s the possibility of a hernia getting it out.

 

[Lenny HB]

As you have a smart alternator the battery voltage you are seeing is probably OK.

Sorry not sure about checking out a smart alternator but if you can monitor the voltage while driving you should see the voltage go up and down.

Don't know if BMS would change a battery of well they would do it.
There is a procedure that is recommended but not essential.
After turning ignition off leave for 15min before changing batteries, then leave for 10 min after connecting new battery, then switch ignition leave for a couple of min then switch off. Then you can turn on and start the engine after 5min.

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[slowdriver]

Most helpful thx. I’ll pick up a voltage monitor cigar lighter dongle in France