Nissan voltage regulator FYI

[Taxed1]

Hello all again. This is just an fyi. I just finished installing a system in my son’s 2012 Nissan Altima. Big3 completed, XS power batteries front & back. After it was all done I wanted to check what the voltage was from the alternator to the front battery. I told my son to start the car & then by the time I got my probes on I was reading 13.6 & fluctuating. Immediately I was like ok, the alternator is the stock alternator from 2012, never replaced. I searched & did find a thread over at the Nissan forums about a regulator on a 2013 & most of the thread spoke about it being attached to the negative post right at the battery but this 2012 did not have anything attached to the negative at the post. So I figured it did not have one so new alternator it was. I pondered a high output alt but for a 1200 watt system before rise I was like no way, especially after I saw the prices all starting around $359. So I purchased a new non-refurbished factory OE alt for $149. We installed it today. Set up my Fluke & told him to start it & bam 14.29 then another bam, 13.6 then fluctuating 13s. WTF. So I followed the negative factory wire & there it was. About 10 inches down near the bottom of the battery tray was this black box that encircled the negative with a 2 wire plug attached. I did read over at Nissan that one guy just unplugged & removed the one that was attached up at the post but mine is not removable but the 2 wire plug is. I am still wondering why I never saw it when I swapped the battery to an XS power one. Anyways, after simply unplugging the connector on that black regulator & retesting now I have a mostly constant 14.29-13.9. Also no computer complaints nor check engine lights.

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[mastershake575]

Alot of cars from 2010 onwards have voltage regulators, it's unfortunate for car audio purposes (lower voltage) but the manufactuers do it so they can pad there MPG rating.

Reason why alot of those alts you were looking at are $350+ is because they do way better amperage at idle, they actually use upgraded bearings which is what you need with a smaller pulley, and some of them even bypass the voltage regulator (usually the common trick is the more expensive alternators will come with a harness that has a resistor wire, the restitor will basically trick the power controll module into thinking that the alternator always needs a max load so the alternator will run at full tilt at all times).

Seems like you found a way to manually bypass the PCM (wording towards the end was confusing but i'm assuming that's what you did, it's usually either removing a wire or on some older cars you can simply remove it from the fusebox)

 

[BigRod420ziljian]

I need help with my 2023 Nissan Sentra. I put a taramps 3k smart and 2 xs power batteries d3400

can't seem to find out why the voltage continuously stays at 12.6 when idle, when on the highway , voltage reads 13.3 volt when I let off the gas and then when I accelerate it goes back down to 12.6 and fluctuates a little by little until I let off the gas and it goes all the way up. I believe it's a voltage regulator on the new vehicles. has anybody gotten past this problem

 

[1aespinoza 10+ year member]

I believe it's a voltage regulator on the new vehicles. has anybody gotten past this problem

I have read on this site that some vehicles "disconnect" the alternator under acceleration to lighten the load on the engine. I think the AC compressor switches off as well. IIRC it has something to do with fuel economy.

 

[Bass Addict 10+ year member]

On 2012 frontier,there was a plug on a bracket not too far from my battery from factory.THAT was what was limiting my alt to batt charging.been unplugged now for over 8 years.before i unplugged it,i was having the same scenerio as the other posters.