Alternator issues?

[Pidsley]

Hi all. I've been having multiple battery issues, both starter and leisure.

This might be due to low charge from the alternator. Whilst engine idling it read 12.2v at the starter battery terminals. Hardly enough, I'm told, to re charge the starter and definitely not enough to allow the Sterling battery to battery charger to start charging the leisure battery.

However, when being recovered by road assist last week for a flat starter battery, the reading was 14.8v.

My question is two fold.. can the alternator output voltage vary or be intermittently faulty? Secondly, if so, does that mean a new alternator is needed?

T6.1 2021PLATE. Revolution Ricos conversion.

 

[manfrotto]

Does the voltage go up to a good charging voltage when you rev the engine a bit, and stay at that voltage when the engine comes back to idle?

 

[Dellmassive]

There is a very complex power system.

The alternator output is computer controled from 12v to 15v depending on what's needed.

If you turn on the headlights and Blu-ray fans you should see the higher voltage.

 

[Dellmassive]

Thread 'Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?'

30 Apr 2018

So

With all the talk regarding the Bluemotion thing and regen breaking and leisure batteries our T6 has finally arrived.

The first thing we done was to checkout the factory fitted setup,......
Stop/start=check,
Regen Braking=check,
AGM starter battery=check
leisure battery under passenger bench-standard lead acid=oops!
standard relay and fuse holder for charging thge leisure battery=check . . . hmmm?

So the factory standard setup is stop/start/regen with AGM starter battery, ok, so i ask the sales guy why i haven't got a second AGM battery under the passenger seat, (for balanced...

• Dellmassive
• battery sensor dc - dc charger stop/start
• Replies: 115
• Forum: Electrics, Lighting, ICE, Security

• 

 

[Pidsley]

Does the voltage go up to a good charging voltage when you rev the engine a bit, and stay at that voltage when the engine comes back to idle?

Hi thanks for replying. Just checked that. No the voltage remains the same. 12.1. Is that good or bad?

 

[Pidsley]

There is a very complex power system.

The alternator output is computer controled from 12v to 15v depending on what's needed.

If you turn on the headlights and Blu-ray fans you should see the higher voltage.

I tried with headlights on full beam ,,,internal heater fans turned to max. Reved the engine. No change in the voltage. Maybe dipped a bit, but only maybe from 12.1 to 12.05v.

Does this suggest failed alternator or is it the control module of some kind? Thank you.

 

[whodat]

You will need to plug in a Carista or similar device to get some error codes.
These days things don't seem to go mechanically wrong as quick as some sensor or computer chip exposed to heat/cold/heat/cold/wet/dry/heat/cold cycles etc does. A carista or other OBD device is as (if not more) important than a socket set nowadays.