Alternator Draining Battery? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

kingsol · 06-07-2005, 11:59 AM

i found out that my car had a bad alternator, so i replaced it with a remanufactured alternator. Everything was fine the first day, but after the second night my car wouldn't start, so i thought it was the battery. i then replaced the battery, and again it was fine for awhile till i left it overnight, when it died again.

i then used a voltmeter to check the battery and began checking the fuses. the volts stopped dropping when i took out the alternator fuse. i left the car overnight without the fuse and it put it back in the morning when i started it up, and it started. so i'm guessing my alternator somehow has been draining my battery. so what could be making the alternator suck the battery dry?

PROJECTRB240SX · 06-07-2005, 12:53 PM

You Probably Have A Short On The Alternator Field Generator Circuit. Either The Internal Windings Of The Alternator Are Grounding Out Or There Is A Frayed Wire.

kingsol · 06-09-2005, 01:47 PM

i just checked all the connections and everything seems fine... guess i'll do another sweep
also, how many volts should i be getting from the battery when the car is off?

*NemeGuero* · 06-10-2005, 02:05 AM

your alternator itself wouldn't drain the battery. like was suggested, it's most likely a short in the alternator harness. Did you properly ground your alternator when you replaced it? start there and maybe clean the connections with that spray shit.. forget what its called

PROJECTRB240SX · 06-10-2005, 06:43 AM

A Good Idle Battery Should Have 12 -14v And Should Be Able To Output At Least 90% Of Its Amp Rating.

kingsol · 06-13-2005, 11:51 AM

ok, so i found out that it's one of the 2 grounds that is giving me problems. everytime the ground touches the alternator it quickly draws power from the battery. it's a single lead coming from the lower harness, so... why is it sucking up so much power, and where is the other end of that ground?

PROJECTRB240SX · 06-13-2005, 02:17 PM

When You Ground A Power Source It Transfers All The Energy To A Metal Dispersment Source. Grounding Your Generator Out Will Suck All The Available Power From The Battery And Transfer It To The Ground Source. Most Ground Sources Are Negative Battery Post (not Going To Be Your Problem), Engine Block, Or Chassis (frame Rail.... This Is Most Likely Your Problem Area).

kingsol · 06-13-2005, 02:36 PM

thanks man for all your help. i'm having a problem understanding the last part of your last post though... so what exactly do i need to do?

i'm thinking that there can be 2 problems with the ground and it has one end or the other. obviouly it's not the one connected to the alternator, so it has to be the other. but i can't find the other end because it gets lost in the lower harness. do you know where the other end of the ground is (if that's my problem)?

and is the ground draining the power because the other side is improperly grounded? do you think maybe the reman alternator could be bad?

also, what did you mean by the frame rail most likely being the problem?

PROJECTRB240SX · 06-14-2005, 06:56 AM

Those Are The Three Common Locations For Grounds On A Vehicle. Neg Battery Post, Engine Block, And Frame Rail (or Other Chassis Location). The Only Time Your Alternator Should Have A Complete Circuit (power Through The Alternator To Ground) Is When You Turn The Key On. It Sounds Like You Have A Crossed Wire, Shorted Wire, Or Possibly A Bad Alternator. I Would Check The Wire The Connect To The Alternator To Rule Them Out Then I'd Swap The Alternator Out. Is This In An Engine Swap? If It Is Did You Use The Swapped Engines Lower Harness Or Adapt The Ka Harness? If You Used The Ka Harness Besure You Didn't Mix Two Wires Up, If You Used The Engines Original Harness Make Sure You Used The Proper Connections At The Fuse Box.

kingsol · 06-15-2005, 07:06 PM

it was the reman alternator... thanks for all the help

skiboard06 · 06-15-2005, 07:43 PM

hey i have a question along the same lines thought id just post in this thread. i have a '90 240sx with a redtop sr20det swapped into it and my car is draining all the power out of my batt. i have a new batt and when i run the car eventually the battery light will come on and i have to go home and recharge the batt. Im assumming this means my alternator is bad anything else that could cause the alternator to not get power to the batt to recharge it? also what alternators from other cars could be used on a sr (i.e. ka24de alternator).

loser101 · 06-16-2005, 02:12 AM

take it to kragen they can test it for you

PROJECTRB240SX · 06-16-2005, 07:27 AM

Does It Lose Charge Overnight Or Just When You Drive?

skiboard06 · 06-16-2005, 08:35 AM

just when i drive it loses charge and battery light comes on after about 25 min. which makes me think im running on the battery alone

PROJECTRB240SX · 06-16-2005, 10:34 AM

You Are Not Getting The Proper Charge Fromt He Alternator.... You Need A New One. If It Isn't Draining The Battery Overnight And Only While Driving That Leads Me To Believe Its Not A Wiring Problem And Once There Is Load On The Electrical System The Alternator Can't Keep Up.

kingsol · 06-16-2005, 10:42 AM

you should get a voltmeter and test the chrages while your car is on. use the battery for the positive and the alternator for the ground.

this was my problem before the new alternator, so you'll most likely need a new one.

skiboard06 · 06-16-2005, 11:46 AM

fair enough i am just gunna get a new alternator i guess do you know if the ka alternator will work on the sr20det redtop engine if not do you think i could get my alternator rebuilt ?

PROJECTRB240SX · 06-16-2005, 12:06 PM

There Is A Place Called Tucson Electric Here In Arizona That Rebuilds Alternators/starters For Cheap, I Might Have There Number Somewhere. I Honestly Don't Know If The Ka And Sr Are Interchangable.

skiboard06 · 06-16-2005, 08:18 PM

thanks i will look for a place to get it rebuilt

withy · 06-16-2005, 11:29 PM

ka and sr alternators are interchangeable with a little slight modification to the mounting bracket i think it was....

06-07-2005, 11:59 AM	#1
kingsol Zilvia FREAK! Join Date: Jun 2003 Location: Berkeley/San Francisco Posts: 1,435 Trader Rating: (0) Feedback Score: 0 reviews	Alternator Draining Battery? i found out that my car had a bad alternator, so i replaced it with a remanufactured alternator. Everything was fine the first day, but after the second night my car wouldn't start, so i thought it was the battery. i then replaced the battery, and again it was fine for awhile till i left it overnight, when it died again. i then used a voltmeter to check the battery and began checking the fuses. the volts stopped dropping when i took out the alternator fuse. i left the car overnight without the fuse and it put it back in the morning when i started it up, and it started. so i'm guessing my alternator somehow has been draining my battery. so what could be making the alternator suck the battery dry? __________________ There is a time in every man's education when he arrives at the conviction that envy is ignorance; that imitation is suicide; that he must take himself for better for worse as his portion; that though the wide universe is full of good, no kernel of nourishing corn can come to him but through his toil bestowed on that plot of ground which is given to him to till. -Emerson

06-07-2005, 12:53 PM	#2
PROJECTRB240SX Zilvia Junkie Join Date: Dec 2003 Location: GILBERT, AZ Posts: 304 Trader Rating: (0) Feedback Score: 0 reviews	You Probably Have A Short On The Alternator Field Generator Circuit. Either The Internal Windings Of The Alternator Are Grounding Out Or There Is A Frayed Wire. __________________ IF I AM TYPING IN CAPS (LIKE NOW) I AM SORRY BECAUSE I AM AT WORK (DATA ENTRY) AND I HAVE NO CAPS LOCK BUTTON AND NO WAY TO CHANGE MY UPPER CASE LETTERING. SORRY!

06-09-2005, 01:47 PM	#3
kingsol Zilvia FREAK! Join Date: Jun 2003 Location: Berkeley/San Francisco Posts: 1,435 Trader Rating: (0) Feedback Score: 0 reviews	i just checked all the connections and everything seems fine... guess i'll do another sweep also, how many volts should i be getting from the battery when the car is off? __________________ There is a time in every man's education when he arrives at the conviction that envy is ignorance; that imitation is suicide; that he must take himself for better for worse as his portion; that though the wide universe is full of good, no kernel of nourishing corn can come to him but through his toil bestowed on that plot of ground which is given to him to till. -Emerson

06-10-2005, 06:43 AM	#5
PROJECTRB240SX Zilvia Junkie Join Date: Dec 2003 Location: GILBERT, AZ Posts: 304 Trader Rating: (0) Feedback Score: 0 reviews	A Good Idle Battery Should Have 12 -14v And Should Be Able To Output At Least 90% Of Its Amp Rating. __________________ IF I AM TYPING IN CAPS (LIKE NOW) I AM SORRY BECAUSE I AM AT WORK (DATA ENTRY) AND I HAVE NO CAPS LOCK BUTTON AND NO WAY TO CHANGE MY UPPER CASE LETTERING. SORRY!

06-13-2005, 11:51 AM	#6
kingsol Zilvia FREAK! Join Date: Jun 2003 Location: Berkeley/San Francisco Posts: 1,435 Trader Rating: (0) Feedback Score: 0 reviews	ok, so i found out that it's one of the 2 grounds that is giving me problems. everytime the ground touches the alternator it quickly draws power from the battery. it's a single lead coming from the lower harness, so... why is it sucking up so much power, and where is the other end of that ground? __________________ There is a time in every man's education when he arrives at the conviction that envy is ignorance; that imitation is suicide; that he must take himself for better for worse as his portion; that though the wide universe is full of good, no kernel of nourishing corn can come to him but through his toil bestowed on that plot of ground which is given to him to till. -Emerson

06-10-2005, 02:05 AM	#4
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	your alternator itself wouldn't drain the battery. like was suggested, it's most likely a short in the alternator harness. Did you properly ground your alternator when you replaced it? start there and maybe clean the connections with that spray shit.. forget what its called

06-13-2005, 02:17 PM	#7
PROJECTRB240SX Zilvia Junkie Join Date: Dec 2003 Location: GILBERT, AZ Posts: 304 Trader Rating: (0) Feedback Score: 0 reviews	When You Ground A Power Source It Transfers All The Energy To A Metal Dispersment Source. Grounding Your Generator Out Will Suck All The Available Power From The Battery And Transfer It To The Ground Source. Most Ground Sources Are Negative Battery Post (not Going To Be Your Problem), Engine Block, Or Chassis (frame Rail.... This Is Most Likely Your Problem Area). __________________ IF I AM TYPING IN CAPS (LIKE NOW) I AM SORRY BECAUSE I AM AT WORK (DATA ENTRY) AND I HAVE NO CAPS LOCK BUTTON AND NO WAY TO CHANGE MY UPPER CASE LETTERING. SORRY!

06-13-2005, 02:36 PM	#8
kingsol Zilvia FREAK! Join Date: Jun 2003 Location: Berkeley/San Francisco Posts: 1,435 Trader Rating: (0) Feedback Score: 0 reviews	thanks man for all your help. i'm having a problem understanding the last part of your last post though... so what exactly do i need to do? i'm thinking that there can be 2 problems with the ground and it has one end or the other. obviouly it's not the one connected to the alternator, so it has to be the other. but i can't find the other end because it gets lost in the lower harness. do you know where the other end of the ground is (if that's my problem)? and is the ground draining the power because the other side is improperly grounded? do you think maybe the reman alternator could be bad? also, what did you mean by the frame rail most likely being the problem? __________________ There is a time in every man's education when he arrives at the conviction that envy is ignorance; that imitation is suicide; that he must take himself for better for worse as his portion; that though the wide universe is full of good, no kernel of nourishing corn can come to him but through his toil bestowed on that plot of ground which is given to him to till. -Emerson

06-14-2005, 06:56 AM	#9
PROJECTRB240SX Zilvia Junkie Join Date: Dec 2003 Location: GILBERT, AZ Posts: 304 Trader Rating: (0) Feedback Score: 0 reviews	Those Are The Three Common Locations For Grounds On A Vehicle. Neg Battery Post, Engine Block, And Frame Rail (or Other Chassis Location). The Only Time Your Alternator Should Have A Complete Circuit (power Through The Alternator To Ground) Is When You Turn The Key On. It Sounds Like You Have A Crossed Wire, Shorted Wire, Or Possibly A Bad Alternator. I Would Check The Wire The Connect To The Alternator To Rule Them Out Then I'd Swap The Alternator Out. Is This In An Engine Swap? If It Is Did You Use The Swapped Engines Lower Harness Or Adapt The Ka Harness? If You Used The Ka Harness Besure You Didn't Mix Two Wires Up, If You Used The Engines Original Harness Make Sure You Used The Proper Connections At The Fuse Box. __________________ IF I AM TYPING IN CAPS (LIKE NOW) I AM SORRY BECAUSE I AM AT WORK (DATA ENTRY) AND I HAVE NO CAPS LOCK BUTTON AND NO WAY TO CHANGE MY UPPER CASE LETTERING. SORRY!

06-15-2005, 07:06 PM	#10
kingsol Zilvia FREAK! Join Date: Jun 2003 Location: Berkeley/San Francisco Posts: 1,435 Trader Rating: (0) Feedback Score: 0 reviews	it was the reman alternator... thanks for all the help __________________ There is a time in every man's education when he arrives at the conviction that envy is ignorance; that imitation is suicide; that he must take himself for better for worse as his portion; that though the wide universe is full of good, no kernel of nourishing corn can come to him but through his toil bestowed on that plot of ground which is given to him to till. -Emerson

06-15-2005, 07:43 PM	#11
skiboard06 Leaky Injector Join Date: Mar 2005 Location: Cincinnati Posts: 115 Trader Rating: (0) Feedback Score: 0 reviews	hey i have a question along the same lines thought id just post in this thread. i have a '90 240sx with a redtop sr20det swapped into it and my car is draining all the power out of my batt. i have a new batt and when i run the car eventually the battery light will come on and i have to go home and recharge the batt. Im assumming this means my alternator is bad anything else that could cause the alternator to not get power to the batt to recharge it? also what alternators from other cars could be used on a sr (i.e. ka24de alternator).

06-16-2005, 02:12 AM	#12
loser101 Leaky Injector Join Date: Oct 2003 Location: sf Posts: 122 Trader Rating: (1) Feedback Score: 1 reviews	take it to kragen they can test it for you __________________

06-16-2005, 07:27 AM	#13
PROJECTRB240SX Zilvia Junkie Join Date: Dec 2003 Location: GILBERT, AZ Posts: 304 Trader Rating: (0) Feedback Score: 0 reviews	Does It Lose Charge Overnight Or Just When You Drive? __________________ IF I AM TYPING IN CAPS (LIKE NOW) I AM SORRY BECAUSE I AM AT WORK (DATA ENTRY) AND I HAVE NO CAPS LOCK BUTTON AND NO WAY TO CHANGE MY UPPER CASE LETTERING. SORRY!

06-16-2005, 08:35 AM	#14
skiboard06 Leaky Injector Join Date: Mar 2005 Location: Cincinnati Posts: 115 Trader Rating: (0) Feedback Score: 0 reviews	just when i drive it loses charge and battery light comes on after about 25 min. which makes me think im running on the battery alone

06-16-2005, 10:34 AM	#15
PROJECTRB240SX Zilvia Junkie Join Date: Dec 2003 Location: GILBERT, AZ Posts: 304 Trader Rating: (0) Feedback Score: 0 reviews	You Are Not Getting The Proper Charge Fromt He Alternator.... You Need A New One. If It Isn't Draining The Battery Overnight And Only While Driving That Leads Me To Believe Its Not A Wiring Problem And Once There Is Load On The Electrical System The Alternator Can't Keep Up. __________________ IF I AM TYPING IN CAPS (LIKE NOW) I AM SORRY BECAUSE I AM AT WORK (DATA ENTRY) AND I HAVE NO CAPS LOCK BUTTON AND NO WAY TO CHANGE MY UPPER CASE LETTERING. SORRY!

06-16-2005, 10:42 AM	#16
kingsol Zilvia FREAK! Join Date: Jun 2003 Location: Berkeley/San Francisco Posts: 1,435 Trader Rating: (0) Feedback Score: 0 reviews	you should get a voltmeter and test the chrages while your car is on. use the battery for the positive and the alternator for the ground. this was my problem before the new alternator, so you'll most likely need a new one. __________________ There is a time in every man's education when he arrives at the conviction that envy is ignorance; that imitation is suicide; that he must take himself for better for worse as his portion; that though the wide universe is full of good, no kernel of nourishing corn can come to him but through his toil bestowed on that plot of ground which is given to him to till. -Emerson

06-16-2005, 11:46 AM	#17
skiboard06 Leaky Injector Join Date: Mar 2005 Location: Cincinnati Posts: 115 Trader Rating: (0) Feedback Score: 0 reviews	fair enough i am just gunna get a new alternator i guess do you know if the ka alternator will work on the sr20det redtop engine if not do you think i could get my alternator rebuilt ?

06-16-2005, 12:06 PM	#18
PROJECTRB240SX Zilvia Junkie Join Date: Dec 2003 Location: GILBERT, AZ Posts: 304 Trader Rating: (0) Feedback Score: 0 reviews	There Is A Place Called Tucson Electric Here In Arizona That Rebuilds Alternators/starters For Cheap, I Might Have There Number Somewhere. I Honestly Don't Know If The Ka And Sr Are Interchangable. __________________ IF I AM TYPING IN CAPS (LIKE NOW) I AM SORRY BECAUSE I AM AT WORK (DATA ENTRY) AND I HAVE NO CAPS LOCK BUTTON AND NO WAY TO CHANGE MY UPPER CASE LETTERING. SORRY!

06-16-2005, 08:18 PM	#19
skiboard06 Leaky Injector Join Date: Mar 2005 Location: Cincinnati Posts: 115 Trader Rating: (0) Feedback Score: 0 reviews	thanks i will look for a place to get it rebuilt

06-16-2005, 11:29 PM	#20
withy Leaky Injector Join Date: May 2005 Location: wichita, ks Age: 39 Posts: 120 Trader Rating: (0) Feedback Score: 0 reviews	ka and sr alternators are interchangeable with a little slight modification to the mounting bracket i think it was....