13.5volts at idle with 250amp alternator normal?

[Supergumby5000 5,000+ posts]

Electrical:

-250amp mechman alternator

-(2) Kinetik 2400's

-(1) Kinetik 800

-1pos/1grnd run between each battery

Anyways, at idle, im sitting around 13.5volts at the front battery (kinetik800)

Is this normal? I always see people with HO alternators sitting closer to 15 volts. Then again, i've also heard that voltage really isnt as im portant as amperage (its better to have 4000amps at 13 volts than 2000amps at 15 volts)

Would getting a smaller pulley change this?

Im new to the whole HO alternator thing if you guys cant tell. Fill me in!

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[duece212 5,000+ posts]

Mine will do 14.2 to 14.5 when its cold.....when it gets hot it will only do about 13.5 or so at any RPM.

 

[DB_DRAG_SPL 10+ year member]

Most HO alts don't start cranking out power until you put a load on it (i.e. 2k rpms+)

 

[Just_Crazy 10+ year member]

It's the voltage regulator in the alternator not the alternator itself

 

[Supergumby5000 5,000+ posts]

It's the voltage regulator in the alternator not the alternator itself

well yeah i figured that much

the sheet sent with my alternator said the regulator was set around 14.8 volts though, im guessing thats what it may do cold then?

I just tested my voltage after driving to my girlfriends after school, then home, so it was perdy warm.

 

[DB_DRAG_SPL 10+ year member]

well yeah i figured that much
the sheet sent with my alternator said the regulator was set around 14.8 volts though, im guessing thats what it may do cold then?

I just tested my voltage after driving to my girlfriends after school, then home, so it was perdy warm.

14.8 @ idle?

 

[groundpound4200 5,000+ posts]

How did you measure the voltage?

 

[Supergumby5000 5,000+ posts]

14.8 at idle yes

I just emailed mechman though, and they got back to me in literally 10 minutes lol. They said they do their testing cold, at the terminals on the alternator, so testing my front battery when warm probably is why i have such a big different.

Tested with a fluke multimeter.

 

[duece212 5,000+ posts]

well yeah i figured that much
the sheet sent with my alternator said the regulator was set around 14.8 volts though, im guessing thats what it may do cold then?

I just tested my voltage after driving to my girlfriends after school, then home, so it was perdy warm.

Let it sit and completely cool. Start it up cold and immediately test it to see what it does

 

[Supergumby5000 5,000+ posts]

Let it sit and completely cool. Start it up cold and immediately test it to see what it does

Yeah, i'll probably do that in the morning tomorrow before class. I park in a garage that usually rests around 65 degrees (its like 40 degrees outside right now) That should give me a pretty good idea.

 

[TurdFergueson2 5,000+ posts]

Mine usually starts at about 14.2-14.7 @ idle when cold. It will hang around 13.8-14.4 while driving and about 13.5-8 when warmed up at idle. WHen I got it metered, it dropped to the high 12s/low 13s at full tilt. But that was off my HU voltage readings.

 

[Supergumby5000 5,000+ posts]

Mine usually starts at about 14.2-14.7 @ idle when cold. It will hang around 13.8-14.4 while driving and about 13.5-8 when warmed up at idle. WHen I got it metered, it dropped to the high 12s/low 13s at full tilt. BUt that was off my HU voltage readings.

What does your electrical consist of and what kind of wattage are you running?

I could care less if im sitting at 13v or 15v, just as long as i dont damage any of my equipment when i get everything hooked up. I'll be seeing a total of around 4200rms

 

[TurdFergueson2 5,000+ posts]

What does your electrical consist of and what kind of wattage are you running?
I could care less if im sitting at 13v or 15v, just as long as i dont damage any of my equipment when i get everything hooked up. I'll be seeing a total of around 4200rms

I was just about to say...............

2200 watt AQ amp, red top up front, Kinetik HC800 in the rear. Big 3 done. I saw total wattage is like 2900 with my eclipse xa4000 amp and my kx 200.2, but I never play everything at full tilt.

 

[GlocksRock 10+ year member]

sorta off topic, but I was just checking the voltage at my amp with the car running at idle, and was wondering what kind of difference in voltage I can expect to see when the car is actually driving, since I have no way of measuring it while I drive. Does the voltage go up or down as your are driving?

 

[terra 5,000+ posts]

Mine does 15 when cold..14.4-14.6 when hot.