Hi, 

I just replaced my alternator as the pulley went bad. However, I have noticed that the charging voltage is around 13v during warm day and only gets upto 14.4v when I first start it in the morning. As the engine gets hot, the charging voltage drops. My battery only gets charged up to 12.4v.
 

The alternator has 1 pin plug and when I unplugged it, the voltage went up from 13.2v to 13.8v. I am wondering if it’s okay to run without that plug connected? 

thank you 🙂 

Hi JB, it sounds like you have an alternator smart charge fault.

Removing the smart charge control wire from the alternator will cause it to go in to the 'default failure charge' which is 13.8V

Running like that for a short time is not a real problem, but long term it can result in the battery being over charged, or at time of high electrical load (example, heated rear window) then the battery will be under charged.

I would check all battery terminals very carefully and make sure they are clean and tight. Check also the smart connector for signs of corrosion.

It is also possible that your battery is just getting to the end of it's life and has a high internal resistance which would cause the smart charge system to limit the charging voltage.

 

17 hours ago, unofix said:

Hi JB, it sounds like you have an alternator smart charge fault.

Removing the smart charge control wire from the alternator will cause it to go in to the 'default failure charge' which is 13.8V

Running like that for a short time is not a real problem, but long term it can result in the battery being over charged, or at time of high electrical load (example, heated rear window) then the battery will be under charged.

I would check all battery terminals very carefully and make sure they are clean and tight. Check also the smart connector for signs of corrosion.

It is also possible that your battery is just getting to the end of it's life and has a high internal resistance which would cause the smart charge system to limit the charging voltage.

Hi, thank you for the reply. I have checked my battery and it’s reading 12.45 after two short distance trips. The car is starting fine and all electric features in the car seems to work okay. I will keep an eye on it I guess. Thank you 🙂 

On 5/9/2022 at 3:48 PM, Eric Bloodaxe said:

Yes, all the discussions we've had on here lately served to remind me that batteries don't need to be particularly low (in voltage terms) before they are effectively "flat".

 

On 5/15/2022 at 10:04 PM, unofix said:

 

I’m going to get my battery tested tomorrow as the seller said I can get it replaced if it’s bad 🙂