Battery - Alternator HELP

[cbuts 10+ year member]

just installed my 275A singer alternator, took off the small pulley that came with it and used the bigger one that also came with it and my stock belt.

install went fine, except my voltage isnt right.

when im driving it reads 14.9, but when i stop at a light it goes straight to 13, and slowly decreases to about 12.4

also when in park it sits around 13ish

PLEASE HELP.

battery is a new red top that i bought the other day, and it reads 12.7 when engine is off. light wasnt on before alternator upgrade, and new battery was put in prior with no problems

vid of alternator running,seems to be very hot too

https://www.dropbox.com/s/sx7bcxmxijgxkjd/VIDEO0058.mp4

Click to read more...

 

[gckless 5,000+ posts]

What car do you have? And why did you take off the small pulley that came with it? If you use the larger pulley, the alt will spin slower, and possibly make it shut down when your engine is running slower. Which is what you're seeing.

 

[cbuts 10+ year member]

What car do you have? And why did you take off the small pulley that came with it? If you use the larger pulley, the alt will spin slower, and possibly make it shut down when your engine is running slower. Which is what you're seeing.

i didnt have a smaller belt at the time, its an 06 malibu 3.5l

 

[gckless 5,000+ posts]

i didnt have a smaller belt at the time, its an 06 malibu 3.5l

Well get one, put the smaller pulley on, and see what happens then.

 

[cbuts 10+ year member]

Well get one, put the smaller pulley on, and see what happens then.

yeah i guess ill have to try that... but what if it dosnt work.. lol

thx for the posts

 

[gckless 5,000+ posts]

yeah i guess ill have to try that... but what if it dosnt work.. lol
thx for the posts

Well then go from there. If it's not that, chances are it's your car. Were you monitoring voltage before you put the alt in? Did it do this?

I'd bet it's the pulley though.

 

[NASTY08IMPALA 5,000+ posts]

Well then go from there. If it's not that, chances are it's your car. Were you monitoring voltage before you put the alt in? Did it do this?
I'd bet it's the pulley though.

not the pulley ...its the car ..before i externally regulated my impala ..it would drop to 12.9 its computer controlled u will have to externally regulate it to keep 14.4 or higher

 

[bubbagumper6 5,000+ posts]

Your alternator was designed to run with that smaller pulley...

 

[cbuts 10+ year member]

Well then go from there. If it's not that, chances are it's your car. Were you monitoring voltage before you put the alt in? Did it do this?
I'd bet it's the pulley though.

no everything was completely fine before the install, and after starts up fine, i notice my voltage sitting at 14.8 from what it was before like 14.2 and then after a minute i noticed battery light on, and voltage now sits around 13 when idling in park, and goes down to 12.4 while at a stoplight(no accessories)

i really hope your right with the pulley, this is really bugging me, i hope i dont have trouble finding one

 

[NASTY08IMPALA 5,000+ posts]

yeah i guess ill have to try that... but what if it dosnt work.. lol
thx for the posts

sry its the car ..blame chevy

 

[cbuts 10+ year member]

So you install the alternator incorrectly then wonder why it doesn't work...

elaborate?

 

---------- Post added at 09:44 PM ---------- Previous post was at 09:43 PM ----------

 

not the pulley ...its the car ..before i externally regulated my impala ..it would drop to 12.9 its computer controlled u will have to externally regulate it to keep 14.4 or higher

where would i find an external regulate?

 

[bubbagumper6 5,000+ posts]

elaborate?

I revised my post, I just meant the alternator was designed to produce output at certain RPM's and by changing the pulley to a larger one you slow down the alt and probably decreased it's output.

 

[gckless 5,000+ posts]

not the pulley ...its the car ..before i externally regulated my impala ..it would drop to 12.9 its computer controlled u will have to externally regulate it to keep 14.4 or higher

Bad news bears right there.

He said it wasn't doing that before though. Are these the same models? Yours is 2 years newer so it's possible they updated the computer in that timeframe. I don't know either way though.

 

[cbuts 10+ year member]

I revised my post, I just meant the alternator was designed to produce output at certain RPM's and by changing the pulley to a larger one you slow down the alt and probably decreased it's output.

Okay, i just figured it came with a big one so why not try it.. my 110 stock alt idled and drove around 14 v and dropped 13.5 when bass hit, if i change the pulley will this idle like its supposed to..

nasty thinks otherwise.. really mind boggling and FRUSTRATING

 

[NASTY08IMPALA 5,000+ posts]

elaborate? 

---------- Post added at 09:44 PM ---------- Previous post was at 09:43 PM ----------

 

where would i find an external regulate?

i have a transpo bout 125 bucks ..

 

---------- Post added at 10:48 PM ---------- Previous post was at 10:48 PM ----------

 

elaborate? 

---------- Post added at 09:44 PM ---------- Previous post was at 09:43 PM ----------

 

where would i find an external regulate?

i have a transpo bout 125 bucks ..