Alternator issue


Mr.D

CarAudio.com Newbie
May 17, 2021
24
1
Miami
I just noticed today while driving that the alternator will go from 14.5v to 13.1v and sometimes get as low as 12.7v, then suddenly jump back up to 14.5 for a while then drop down again. Battery is a new XSpower D3400R, I tested the voltage when I got home with the car off and the resting voltage is 13v. Is this a sign my alternator is going out?
 

Dafaseles

CarAudio.com Regular
Nov 12, 2020
165
58
510
I just noticed today while driving that the alternator will go from 14.5v to 13.1v and sometimes get as low as 12.7v, then suddenly jump back up to 14.5 for a while then drop down again. Battery is a new XSpower D3400R, I tested the voltage when I got home with the car off and the resting voltage is 13v. Is this a sign my alternator is going out?
Could be, or it could be done kind of voltage regulator within the car. For example, my truck when I start it will be at 14.7, then drop to 13.8ish, then, when the battery needs a bump, it can jump up to 15.3ish. And that's normal. They do it for added fuel economy.
What kind of car is it and what year?
 

Mr.D

CarAudio.com Newbie
May 17, 2021
24
1
Miami
  • Thread Starter Thread Starter
  • #3
Could be, or it could be done kind of voltage regulator within the car. For example, my truck when I start it will be at 14.7, then drop to 13.8ish, then, when the battery needs a bump, it can jump up to 15.3ish. And that's normal. They do it for added fuel economy.
What kind of car is it and what year?
Thanks for the reply. It's a 2014 infiniti Q50. This happens with the sound system completely off
 

Bobbytwonames

Trigger Man!
5,000+ posts
Aug 28, 2018
6,839
-1,255
Vegas
Thanks for the reply. It's a 2014 infiniti Q50. This happens with the sound system completely off
You might need a new tensioner pulley. My mechman was squealing like a bitchh when I started my truck. And it took a couple of minutes to stop squealing and raise the voltage up to a decent level. I changed the tensioner pulley and everything is golden now.
 

Mr.D

CarAudio.com Newbie
May 17, 2021
24
1
Miami
  • Thread Starter Thread Starter
  • #5
You might need a new tensioner pulley. My mechman was squealing like a bitchh when I started my truck. And it took a couple of minutes to stop squealing and raise the voltage up to a decent level. I changed the tensioner pulley and everything is golden now.
Possibly new belt too?
 

Dafaseles

CarAudio.com Regular
Nov 12, 2020
165
58
510
Thanks for the reply. It's a 2014 infiniti Q50. This happens with the sound system completely off
Yeah, mine does it on its own also, no music or anything. It's just a factory thing they use to save fuel and bring up their fuel economy.
Do some digging around the internet, maybe find an infinity forum or Facebook group and ask people who now those cars inside and out. A lot of newer cars, such as yours, do things like that normally.
If it isn't normal, than yeah, it might be going out, or your pulley might not be spinning correctly. It's worth looking at.
 

Mr.D

CarAudio.com Newbie
May 17, 2021
24
1
Miami
  • Thread Starter Thread Starter
  • #7
Yeah, mine does it on its own also, no music or anything. It's just a factory thing they use to save fuel and bring up their fuel economy.
Do some digging around the internet, maybe find an infinity forum or Facebook group and ask people who now those cars inside and out. A lot of newer cars, such as yours, do things like that normally.
If it isn't normal, than yeah, it might be going out, or your pulley might not be spinning correctly. It's worth looking at.
Yeah I saw something about that. I also posted in a Q50 forum just waiting for their input. Kinda ***** for someone trying to have a subwoofer system if the xar regulates the viktage whenever it wants to
 

Dafaseles

CarAudio.com Regular
Nov 12, 2020
165
58
510
Yeah I saw something about that. I also posted in a Q50 forum just waiting for their input. Kinda ***** for someone trying to have a subwoofer system if the xar regulates the viktage whenever it wants to
I agree, but it could be worse, you could have a BMW lol.
Car companies don't care about us aftermarket stereo system guys because 95% of the people who are going to buy the car won't install an aftermarket system. They'll be wowed by the stock system because "it gets loud enough for me" and it plays into the 40 hz range at low volumes lol. Unfortunately, this is the new normal. But there's usually a fix... sometimes it's not worth the hassle or the amount of money you have to spend, but there's usually a fix.
 
  • Like
Reactions: Mr.D

Kickstand

CarAudio.com Veteran
Jan 1, 2021
867
275
Maple Ridge
I have a 2015 Q50s
Mine does the same thing
The whole car is one big computer so what your seeing are different accessories kicking in and out
Put it in ECO mode and watch what happens while it's regulating the output on the engine
I would love to see what the voltage is like on something like a 918
The whole car is adaptive and constantly adapting to your driving style
 
  • Like
Reactions: Mr.D

Mr.D

CarAudio.com Newbie
May 17, 2021
24
1
Miami
  • Thread Starter Thread Starter
  • #10
I have a 2015 Q50s
Mine does the same thing
The whole car is one big computer so what your seeing are different accessories kicking in and out
Put it in ECO mode and watch what happens while it's regulating the output on the engine
I would love to see what the voltage is like on something like a 918
The whole car is adaptive and constantly adapting to your driving style
If this is the case I'm ready to downgrade my system because no point in having such a large system if it's gonna do this crap
 

mastershake575

CarAudio.com Veteran
Mar 11, 2015
653
159
Dallas
If this is the case I'm ready to downgrade my system because no point in having such a large system if it's gonna do this crap
No you need to find out how to bypass it. Here's some information on the Nissan based voltage regulators http://www.nissantechnicianinfo.mobi/htmlversions/2016_Feb_March_Issue_6/VoltageControl.html

Since your car stereo system isn't directly tied to the cars computer system there's nothing telling the alternator and it's sensor (ECM) to kick on.

I would contact Singer alternators https://www.singeralternators.com/ He's really good at tricking OEM alternator regulators. On most car models he will sell an adapter kit that's easy to install (the adapter basically tricks the ECM into thinking that the car needs a maximum power/voltage draw at all times).

On some car models there's also the possibility of being able to turn it off somewhere else under the hood (for example on my old honda I could disable the voltage regulator by unplugging it from the main fuse box)
 
  • Like
Reactions: Dafaseles

Mr.D

CarAudio.com Newbie
May 17, 2021
24
1
Miami
  • Thread Starter Thread Starter
  • #12
No you need to find out how to bypass it. Here's some information on the Nissan based voltage regulators http://www.nissantechnicianinfo.mobi/htmlversions/2016_Feb_March_Issue_6/VoltageControl.html

Since your car stereo system isn't directly tied to the cars computer system there's nothing telling the alternator and it's sensor (ECM) to kick on.

I would contact Singer alternators https://www.singeralternators.com/ He's really good at tricking OEM alternator regulators. On most car models he will sell an adapter kit that's easy to install (the adapter basically tricks the ECM into thinking that the car needs a maximum power/voltage draw at all times).

On some car models there's also the possibility of being able to turn it off somewhere else in the car (on my old honda I could disable the voltage regulator by unplugging it from the main fuse box)
That would be great if I can do that. I will definitely contact him. Thank you
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.


Users Who Are Viewing This Thread (Users: 0, Guests: 1)



Latest posts

Newest threads

Most posts - Past 30 days

Latest classifieds