voltage problem

3

351w fastback

New Member

Jul 25, 2004

91

0

0

Jun 24, 2005

#1

• Jun 24, 2005

• #1

i have added a taurus electric fan and a 130 amp alternator. when i first start the car, the voltage reads about 14 but when i turn on my fan, lights and stereo it reads 12.6. is this ok or will it run my battery down?
thanks

 

shotsy

New Member

Apr 8, 2005

233

0

0

Oklahoma City

Jun 24, 2005

#2

• Jun 24, 2005

• #2

Bump the throttle up and watch the voltage gauge, On mine it wont start charging untill I get it over 1200 rpm or so, other than that it should read about 14.4V

 

2nd Mustang

Founding Member

Feb 24, 2002

2,488

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46

Southern California

Jun 24, 2005

#3

• Jun 24, 2005

• #3

If it's charging 14 volts when you start it and then drops to 12 when you start turning on accessories, then it can't keep up with the load. I'm assuming it's an internally regulated alternator, maybe a one wire type? 130 amps sounds like more than enough, unless you have a stereo that needs a tremendous amount of juice!

 

B

blk 02

Founding Member

Aug 5, 2002

57

0

0

Shreveport, La

Jun 24, 2005

#4

• Jun 24, 2005

• #4

Just a guess but depends on how everything is wired, the 130 alt is plenty big enough... If you are pulling the power for your accessories from the fuse box in side the car you are probably close to burning the car down. I'm not sure of the gauge of the wire feeding the fuse box but it’s not big enough to run all of that stuff causing the wire to heat up and creating a voltage drop. I would make sure that there is at least a 8 gauge from the alt to the battery and then run all of your extra accessories off of an extra fuse box switched by a relay. There was a post a couple days ago on how much of a difference it made by putting the headlights on a relay drawing the power from the battery directly.

Graham

 

S

streetgrande69

Founding Member

Nov 2, 2002

976

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16

Splendora, Tx

Jun 24, 2005

#5

• Jun 24, 2005

• #5

sounds really strange with the 130 amp alternator. bu if the battery doesn't need 14 volts, your voltage reg won't give it.

anyway i'm really interested in how close the fan comes to the waterpump pulley. i love to see a pic if you have one. i picked one of these fans up a year and a half ago and was disapointed to see it hit my pulley so i scraped the idea. can you either post or send me pictures?

 

shotsy

New Member

Apr 8, 2005

233

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0

Oklahoma City

Jun 24, 2005

#6

• Jun 24, 2005

• #6

I've got about 3/8th of an ich on my 351C

Another Angle

 

2nd Mustang

Founding Member

Feb 24, 2002

2,488

0

46

Southern California

Jun 24, 2005

#7

• Jun 24, 2005

• #7

Does the voltage increase to 13-14 volts if you increase the rpms after turning on your lights, fan and stereo?

 

B

blk 02

Founding Member

Aug 5, 2002

57

0

0

Shreveport, La

Jun 24, 2005

#8

• Jun 24, 2005

• #8

hey Shotsy I think the reason your alt doesnt charge its because your missing a wire to your alt. the on on the side currently is going to batt power right? the terminal next to it sould be the field, if you hook that terminal to either a switched 12v source ot hook the alt light. The light will be hooked to switched 12v + and the other side of the light will hook up to the empty terminal on the alt. clear as mud right??

 

shotsy

New Member

Apr 8, 2005

233

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0

Oklahoma City

Jun 24, 2005

#9

• Jun 24, 2005

• #9

Mines not the one with probs, it's working fine, I was just putting up the clearance pics for streetgrande69. My setup is a GM 12si with the one wire setup

here's the info

 

B

blk 02

Founding Member

Aug 5, 2002

57

0

0

Shreveport, La

Jun 24, 2005

#10

• Jun 24, 2005

• #10

shotsy said:

Bump the throttle up and watch the voltage gauge, On mine it wont start charging untill I get it over 1200 rpm or so, other than that it should read about 14.4V

Click to expand...

Was just pointing out why yours isnt charging until you rev it over 1200rpm.

Thanks for the pic though I couldnt remember what the exact printing on the back of the alt.. probably doesnt mater anyways because 351w fastback is probably running a ford alt lol

 

shotsy

New Member

Apr 8, 2005

233

0

0

Oklahoma City

Jun 24, 2005

#11

• Jun 24, 2005

• #11

Roj I'm a dumb A$$ and a bit tired So if I hook up the lite the GM alt will charge at idle?