Potential alternator issue

[GingerDub]

Hi - for the past two weeks I’ve had to jump my T6 2017 T28 stop/start on random occasions.

Today it happened again and then starts fine.

I put a multimeter across the battery whilst running and not running and found the voltage hitting 20 when it was running.

I’m suspecting a faulty alternator but confused by the randomness of when it needs a jump.

Any other ideas out there?

 

[Dellmassive]

Add a battery monitor to see what's going on with the voltage.

Thread 'Battery Monitoring -- How I Done It --'

22 Oct 2019

Battery Monitoring -- How I Done It --

Part #1

Battery monitoring is a very important part of your 12v system . . . . whether its just the vans starter battery or your leisure setup keeping an eye on the power in your battery bank will keep you from breaking down and make sure your weekends are not cut short from lack of power.

Battery monitoring is even more important with Lithium Lifepo4 batteries as the voltage stays fairly constant for 90% of the capacity.

first off lets look at a few basic 12v meters.

here a great little unit that I've been using for ages....

you can plug it...

• Dellmassive
• battery sensor dellmassive how to guide
• Replies: 333
• Forum: Electrics, Lighting, ICE, Security

• 

 

[GingerDub]

Thanks for the reply but monitoring it isn't going to help diagnose the problem - it will start or it won't. I have a NOCO jump battery for that scenario.

I'm concerned why I was measuring such high voltages in the first place - surely the alternator is cooking my battery?

 

[GingerDub]

I'm now suspecting a faulty voltage regulator - has anyone changed theirs?

 

[Dellmassive]

You need some data ..

What's the battery at rest voltage?

What's the battery voltage while cranking over?

What's the voltage of the battery when the engines running but we've accessories off.

What's the voltage of the battery with the engine running and all the accessories on.

A standard T6 smart alternator will push out 15.0 volts... When charging the battery or regenerative braking.


A T6 battery rest voltage will normally be around 12.3 volts.

A standard T6 battery will show when the engines running 12.6 so 13.2 volts.


....


If you're battery voltage is showing 20.0 volts while the engines running, then that might be a sign that the alternator, itself is faulty.

 

[GingerDub]

You need some data ..

What's the battery at rest voltage?

What's the battery voltage while cranking over?

What's the voltage of the battery when the engines running but we've accessories off.

What's the voltage of the battery with the engine running and all the accessories on.

A standard T6 smart alternator will push out 15.0 volts... When charging the battery or regenerative braking.


A T6 battery rest voltage will normally be around 12.3 volts.

A standard T6 battery will show when the engines running 12.6 so 13.2 volts.


....


If you're battery voltage is showing 20.0 volts while the engines running, then that might be a sign that the alternator, itself is faulty.

AS above, when running without accessories it was reading 20.....

 

[Dellmassive]

the highest i saw on a T6, was 15.0V

standard alternator is a 140A LINBus,

the uprated is an 180A LinBus,

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

•