How do I know if I have a variable voltage (smart) alternator?

[Munarer]

Hi, I have a 2011 Nissan Navara King Size Ute, 4X4 2.5 Turbo Diesel Auto. I'm considering a dual battery system. I checked the battery connection as I found out that a variable voltage (smart) alternator would rely on a sensor attached to the negative terminal of the battery.

There is no such attachment to my negative battery terminal, but how do I know if I have a variable voltage (smart) alternator for certain as the information I have is that they exist for Nissan Navara Model years from 2011?

Cheers

 

[bods]

Hey mate, I believe there should be a "green wire" attached to the back of the alternator. Apparently this is the smart alternator sense wire, from memory I thought it went to the positive battery terminal, but I don't have a D40 so can't confirm if this is the case...

 

[Old.Tony]

I could go out and check my alternator (not a smart alternator) but my engine bay needs a full de-dusting, we've just gotten back from a half-lap of the country and 3 days at Bathurst for the 12 Hour race ... so I'm not going to do that now, in the dark!

There is a way to tell, though. With a voltmeter set up so you can see if in the cabin, take the car for a drive. After about 5 minutes or so, the voltage should drop from around 14.4-14.7V down to under 13V if you have a smart alternator. If you have a normal alternator, the voltage will remain above 14V.

That's why there are differences in DC-DC chargers.

You can defeat the smart alternator by removing that green wire (just take it out of the plug, then wrap everything up to seal it from dirt/moisture). It then becomes a better alternator.

That may be the only time I say "dumb things be gooder".