Somebody explain*** New Car***Voltage Questions

[eztrez2013]

I have a 2014 Infinity Q50S AWD. The car has a stock 150 amp alternator. The resting voltage varies greatly. I can drive down a busy street and at the first red light I'm resting at 13.6V. The next red light I'm resting at 12.6V and the next red light I'm resting at 14V. So on and so forth, It doesn't seem to matter whether I'm full tilt or music off. When at full tilt I see up to a .5 voltage drop with a Fosgate T1500bdcp at 1 Ohm. Problem is the drop is always about .5 whether I'm at 12.6, 13 or 14.4. What causes this??? AND What can I do to regulate and keep the voltage on the higher end. It's driving me crazy always checking my meter to see if I'm safe to rail on it.. I'm assuming it being regulated by a module of some sort but what's the get-around? Someone help...Not sure if it matters or not..But big 3 (plus a couple extra grounds in 1/0) AGM is front and a big 140 AH AGM in back...Need some help... Thanks in advance

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[hispls 5,000+ posts]

911-02 R Regulator [911-02R] - $110.00 : H2O Instruments & Marine Electronics, H2O Makes Everything Go!!!

This is what most people use to externally regulate. Just be sure to have a very solid +12 and ground connection to it and you can dial it right in to where you need.

Definitely sounds like a control module issue, probably some sensible reason for why it does what it does but it doesn't help you so much trying to really push the limits with audio.

 

[sam_b03 10+ year member]

Nissan uses a clutch in the alternator for fuel efficiency. It doesnt charge when the battery is full. You can rev the engine and kill it and hear the alt continue to spin after every thing stops. It sounds kind like a high pitch whine almost turbo like.

 

[eztrez2013]

Thanks, both of your responses make sense, but would the clutch in the alt still overrule the external regulator?

 

[phemps 10+ year member]

My 2007 impala does the same. Annoying as fuck