Do most cars run at 14.4v or less??

[ttran 10+ year member]

I was told that most amp manufactors rate their wattage going off 14.4v, but realistically our cars run less than that.

My amp is rated at 70w x 2 @ 4 ohms, but at 14.4v

45w x 2 @ 4 ohms at 12.5v

Does this mean I will most likely only get around 45watts? Is there anything to do to raise the voltage or is that even safe?

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[bryce-man 10+ year member]

my truck runs at 14.8 after big 3 with truck on

12.8 with truck off

 

[Stel 10+ year member]

A voltage regulator can raise the voltage to the amp, though I'm not sure how much one would cost that can handle the current. It would probably be cheaper to get a more powerful amp.

 

[Lakota 5,000+ posts]

Your voltage changes while the car is on. It will likely start with a higher voltage to help charge and steadily drop over time.

 

[jluv 10+ year member]

I was told that most amp manufactors rate their wattage going off 14.4v, but realistically our cars run less than that.
My amp is rated at 70w x 2 @ 4 ohms, but at 14.4v

45w x 2 @ 4 ohms at 12.5v

Does this mean I will most likely only get around 45watts? Is there anything to do to raise the voltage or is that even safe?

Yes. Chances are with your stereo cranked you won't see a consistent 14.4 volts.

It all depends on your electrical system and the load you have on it. If you run your A/C or heater, headlights, wipers, etc, that makes a difference, too. There are amps out there that have regulated power supplies and will deliver the rated power at even less than 12 volts, but the flip side to that is that they are harder on your electrical system. Basically, those amps (JL Slash series, for example), are going to get their power even if it means stealing it from the rest of your electircal system.

 

[AcidicDreams 10+ year member]

Wow people let's offer some real advice here:

A) Your alternator provides power at roughly 14.4-14.8v when of course the car is running (to spin the alt)

B) Your battery provides starting power at roughly 12.6-12.8v

The reason the battery is lower is because to charge it, it needs to be a lower voltage than your alternator.

Now, when you are running the car, are the alternator can provide enough power to the whole system then you are running at the 14.somethin voltage your alternator is providing. However if the car's combined draw is more than the alternator can provide the voltage drops until it gets to the battery voltage at which point both the battery and the alternator combined are discharging to cover the load presented by the accessories, ignition, stereo etc. When the voltage drops everything electrical has less output, hence the headlight dimming when you are overpowering the alt at night.

So those ratings @ 14.4v are valid when the engine is running, unless you are overpowering your alt.

 

[AcidicDreams 10+ year member]

Your voltage changes while the car is on. It will likely start with a higher voltage to help charge and steadily drop over time.

Why is it going to steadily drop over time?

 

[ttran 10+ year member]

ah ok, so I'll get the most wattage from the amp when the car is on and a little less with it off. Makes sense.

70w x 2 on

45w x 2 off

Is that not enough power going to some Phoenix Gold RSD6.5s?

 

[IgnoreMe 5,000+ posts]

Why is it going to steadily drop over time?

heat.

i have never seen my alternator run higher than 14.01V with engine fully warmed up and battery fully charged. most of the time it will run around the 13.8 area. this was with stock and aftermarket.

i have seen my voltage as high as i think 14.3 or so right after starting the car, but that is because the battery is slightly discharged and the alt is now charging it back up.

 

[jmanpc 5,000+ posts]

Most cars are 14.4 when you first start, and it'll go to 13.8 after a while.

 

[fived 10+ year member]

I range anywhere from 11.9-14.0 at tops.

 

[jnralp00 10+ year member]

Yeah mine runs at around 13.8

 

[jdawg 5,000+ posts]

heat.
i have never seen my alternator run higher than 14.01V with engine fully warmed up and battery fully charged. most of the time it will run around the 13.8 area. this was with stock and aftermarket.

i have seen my voltage as high as i think 14.3 or so right after starting the car, but that is because the battery is slightly discharged and the alt is now charging it back up.

right, you see this mostly on newer cars. Also has to do with outside temperature, most newer computer controlled cars have a battery sensor actually built into the computer. It will charge more when its senses extreme cold temperatures, or atleast try too. Most cars i have seen on factory stuff are generally around high 13 to low 14 most of the time. It really can vary greatly car to car.

 

[regal8r 5,000+ posts]

A voltage regulator can raise the voltage to the amp, though I'm not sure how much one would cost that can handle the current. It would probably be cheaper to get a more powerful amp.

unless you know your way around an alternator, if he has a GM, he wont be able to replace JUST the regulator...

 

[IgnoreMe 5,000+ posts]

right, you see this mostly on newer cars. Also has to do with outside temperature, most newer computer controlled cars have a battery sensor actually built into the computer. It will charge more when its senses extreme cold temperatures, or atleast try too. Most cars i have seen on factory stuff are generally around high 13 to low 14 most of the time. It really can vary greatly car to car.

i actually was running with that idea. had no proof, no one suggested it (until you right now), but i noticed that. seemed to charge somewhat more at my apartment (deserts basically) than it did at my girls and families house (very close to the coast with sometimes a 15-20 degree difference in temp). good to know that i had the right idea.

edit: sorry my post is backwards. i meant deserts charged lower, coast charged higher.