Alternator issue?

[dom14]

Hey guys,

My RB30 Patrol alternator(upgraded one from EF-EL Falcon 110 amp) is putting out 14.2-14.3 max volts regardless of whether it's idling or revving the life out it.

The other day, it had trouble turning over with one of the cranking batteries, so I thought it's the battery and removed it and bench charged while having the engine on the spare battery. With the non-cranking battery, it was showing 14v maximum regardless of the rev range(with that non-cranking battery). And showing 14.2-14.3 fixed voltage with the battery in it now.

It looks like the alternator regulator is putting out a fixed voltage, regardless of idling or revving high.

This can't be a good thing, right?

A dying regulator you reckon?

Thanx in advance for any advice from electrickery experts here.

[the evil twin]

No, thats what they are supposed to do, thats why they call them Regulators :-)

[mudnut]

How fast did it crank over with the second battery?

[dom14]

How fast did it crank over with the second battery?

Slightly faster, but the second battery is a stronger one with higher CCA capacity. The one that didn't crank over was a weaker $100 Autobarn special I bought around three years ago. Only reason it's still alive is 'cos I've been pulse charging it once a month or so.
But, it still passed the load test, so I reckon it's still good. For some reason it wasn't getting charged properly.

FYI, the alternator was always boost around 0.2V or so when I revved it high as far as I can remember, but it's "regulating" it perfectly. I smelled a rat for some reason. Battery ain't that bad. Something else was/is going on. I reckon it's the trailer wiring.

It didn't pop into my stupid head to do the voltage test of the non-cranking battery the moment it was failing to do that. I had the multimeter right next to me, but 'cos I got stuck in a tight spot with the damn trailer at the back, I got panicked. :)

I'm going through all the trailer wiring both in the vehicle and trailer now. I think the problem is there.

[dom14]

No, thats what they are supposed to do, thats why they call them Regulators :-)

Of course, but I have a clear memory of it's putting slightly more(0.1 to 0.2V) when I was revving high. It ain't doing it now, so I thought the regulator may be playing up a bit. :)

[the evil twin]

By changing the Battery you changed the load.

The manky battery was dragging down the Alt at idle RPM.

[dom14]

By changing the Battery you changed the load.

The manky battery was dragging down the Alt at idle RPM.

Yeah, you might be right. Another thing is that the highest alternator voltage(both idle and high revs in this case) is 14.1-14.3, depending on when I test it. It never goes upto 14.4 or 14.5 which it used to do.
Either way, if the battery is not the cause, it most certainly contributed to the issue.
I guess it's on it's way out now as a cranking battery, and turning into it's next life as a UPS battery. :)