Bad alternator

[Trekster]

My van turns over slowly on a morning. Quite sure the battery is not at fault. From looking at these graphs, would it indicate a faulty alternator. It sends charge but only so often. Never seems to fully charge the battery

 

[CJW]

Others here know more than me and will chime in if I’ve got it wrong but T6s have a smart alternator, which only adds load when the battery needs it and (I believe) will normally try to apply the load when braking, meaning that kinetic energy is recovered. The system is designed to not charge the battery above a certain SOC (80%?) so that there is room for this KERS charge.

They can also vary the voltage.

So what you’re seeing might be perfectly normal.

 

[oldiebut goodie]

Looks normal to me also - if the battery is good it would be time to check connections.

 

[Salty Spuds]

What van is it? If anything, it looks like it’s overcharging if it’s a Euro6/Bluemotion. 13.6V is well charged. Have you done a cranking test? If so, what were the results? If not, it would help if you did.

 

[Trekster]

What van is it? If anything, it looks like it’s overcharging if it’s a Euro6/Bluemotion. 13.6V is well charged. Have you done a cranking test? If so, what were the results? If not, it would help if you did.

Its the CXHA 150ps (smart alternator) Cranking voltage was 10.59 when I tested it. Charging test was 13.31v at idle and 13.44v on high rpm which apparently is a low charging voltage however this could be due to how the smart alternator works?

 

[Salty Spuds]

Its the CXHA 150ps (smart alternator) Cranking voltage was 10.59 when I tested it. Charging test was 13.31v at idle and 13.44v on high rpm which apparently is a low charging voltage however this could be due to how the smart alternator works?

The RPM won’t make much difference to the charging voltage. Try doing the same test with some load on the battery, heated seats/screen, blower on full, headlights on etc. this will force the alternator to kick in.