Charging system voltage is too high - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

azsig350 · 05-15-2012, 09:03 AM

This is my second alternator within a 2 month period and now after installing my new alternator while the car is on and the motor is running. I took a multimeter and put the leads over the battery terminals, and i'm getting 16+ volts i know this is too high, what do you guys think is the problem?

is there a way to lower the voltage output somehow?

thanks
-Tony

Zed Nismo · 05-15-2012, 10:53 PM

It sounds like your alternator is overcharging your battery. Are you sure the terminals are clean? If not then I would recommend you clean the battery terminals. If there is corrosion on them, then the alternator will not know when the battery is fully charged, and it will keep charging it. Either that, or you have a bad ground somewhere that causes the same affect. Although, if this was the case then your battery would blow before your alternator goes.

What made you change your alternator in the first place?

-Zed

roboticnissan · 05-15-2012, 11:25 PM

Maybe you have a bad battery. This can definitely be caused by a bad battery

azsig350 · 05-16-2012, 07:24 PM

sorry forgot to mention before, brand new battery, and terminal ends were installed when i replaced my alternator after it failed. then the new one failed. and now i have my in-warranty alternator in that's over chargeing now. whats also weird is my battery is over 12.6 volts wit the car off?

KiLLeR2001 · 05-16-2012, 10:08 PM

Nothing wrong with a battery being over 12V with the car off.

Lethal240SX93 · 05-17-2012, 12:35 PM

Could be another bum alternator. Wouldn't be the first time I've seen it. Where are these alternators coming from?

Other than that, check your grounds.

05-15-2012, 09:03 AM	#1
azsig350 Join Date: May 2012 Location: Gurnee, IL Posts: 6 Trader Rating: (0) Feedback Score: 0 reviews	Charging system voltage is too high This is my second alternator within a 2 month period and now after installing my new alternator while the car is on and the motor is running. I took a multimeter and put the leads over the battery terminals, and i'm getting 16+ volts i know this is too high, what do you guys think is the problem? is there a way to lower the voltage output somehow? thanks -Tony

05-15-2012, 11:25 PM	#3
roboticnissan Nissanaholic! Join Date: Mar 2007 Location: SOCAL/NORCAL Age: 32 Posts: 1,867 Trader Rating: (12) Feedback Score: 12 reviews	Maybe you have a bad battery. This can definitely be caused by a bad battery __________________

05-16-2012, 10:08 PM	#5
KiLLeR2001 Post Whore! Join Date: Jun 2007 Location: オーランドフロリダ Posts: 7,955 Trader Rating: (46) Feedback Score: 46 reviews	Nothing wrong with a battery being over 12V with the car off. __________________

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05-15-2012, 10:53 PM	#2
Zed Nismo Leaky Injector Join Date: Dec 2010 Location: Manteca, CA Age: 28 Posts: 63 Trader Rating: (0) Feedback Score: 0 reviews	It sounds like your alternator is overcharging your battery. Are you sure the terminals are clean? If not then I would recommend you clean the battery terminals. If there is corrosion on them, then the alternator will not know when the battery is fully charged, and it will keep charging it. Either that, or you have a bad ground somewhere that causes the same affect. Although, if this was the case then your battery would blow before your alternator goes. What made you change your alternator in the first place? -Zed

05-16-2012, 07:24 PM	#4
azsig350 Join Date: May 2012 Location: Gurnee, IL Posts: 6 Trader Rating: (0) Feedback Score: 0 reviews	sorry forgot to mention before, brand new battery, and terminal ends were installed when i replaced my alternator after it failed. then the new one failed. and now i have my in-warranty alternator in that's over chargeing now. whats also weird is my battery is over 12.6 volts wit the car off?

05-17-2012, 12:35 PM	#6
Lethal240SX93 Join Date: Feb 2012 Location: South Jersey Posts: 37 Trader Rating: (2) Feedback Score: 2 reviews	Could be another bum alternator. Wouldn't be the first time I've seen it. Where are these alternators coming from? Other than that, check your grounds.