# Maintaining a Constant 14 Volts.



## jf2oo6 (Feb 17, 2010)

First off the car is a 2008 Altima. I will be running 2 amps in my system. Both are sundown. A 100.4, and 1200rms mono. The mono makes the 1200 watts at 12.8 volts, and it is supposed to do 1500rms and 14.4 volts. So now I want to get a constant 14.4 volts to that amp. I believe the stock alternator in the Altima is somewhere around 110-130 amps. So would just doing a big 3, and maybe adding another battery in the trunk do this for me? I know a new alternator would help a lot, but it would be nice to avoid spending that 5 or 6 bills. What do you guys think.


----------



## Oliver (Jun 25, 2007)

http://www.diymobileaudio.com/forum/diyma-spl-forum/71693-156-1-db-one-sub-no-wall-12v.html



> Man I am excited... 155.9 was my best before with two Nightshade 15s and four 3000s on an* 18v system.*



Without an adjustable voltage regulator ... no way !



> output voltage adjustable over a 1.2 to 37 V range. ...


----------



## gijoe (Mar 25, 2008)

How much are you willing to invest for 300 watts? The difference between 1200watts and 1500 isn't audible.


----------



## Cruzer (Jul 16, 2010)

gijoe said:


> How much are you willing to invest for 300 watts? The difference between 1200watts and 1500 isn't audible.


i agree, just do the big 3 as its not that much $ and be done with it.

i have a 130amp alt, stock battery, 2 amps, i get 14.4 volts to my AQ1200D and its running @1ohm 1200 watts or more and i dont even have the big 3 done...


----------



## MarkZ (Dec 5, 2005)

Increase your idle to about 1200rpm


----------



## jf2oo6 (Feb 17, 2010)

Well I dont want to go crazy trying to get 300 watts. This thread was pretty much asking what the options are to achieve the 14 volts. Just trying to see if someone has a simple, cost efficient solution. 

Do you guys think adding another battery would help? Can my stock alt charge 2 batteries ok?


----------



## 89grand (Nov 23, 2006)

Well, instead of trying to get a constant 14 volts which is not an easy task, you could sell those amps and run some amps with a regulated power supply like old School PPI's, or maybe one of the few new ones that have regulated supplies (don't know many news ones that do), then your power output wouldn't be dependent on input voltage, at least not from about 10.5 volts and up.


----------



## matt1212 (Jan 14, 2010)

gijoe said:


> How much are you willing to invest for 300 watts? The difference between 1200watts and 1500 isn't audible.


Agreed. Doubling power to a speaker only increases the spl by 3bd's and your not even close to that. Thats a marketing technique that companies use to make the amp sound better. The alternator runs at 14v but the battery and rest of the system are designed to stay at 12. I wouldn't worry about it. Besides, if you were able to get it to happen, you take a chance of frying all your cars other electrical components.


----------



## sqshoestring (Jun 19, 2007)

It is easier to get a larger amp. The extra battery will only help if you are dropping under 13v, or playing with car off, but I think a good idea. You will overcharge the batteries and all that too, just get more amp. Voltage regulators run higher the cooler they are, my car goes over 14.5 all the time in the winter.


----------



## SoundChaser (Apr 3, 2009)

40 farads would do it.


----------



## Knobby Digital (Aug 17, 2008)

Missing Link Audio

Dunno anything about them.


----------



## t3sn4f2 (Jan 3, 2007)

Difference between 1200 and 1500 watts? 1dB AT MOST under ideal power supply conditions. 

Decibel Watt Online Calculator

Play you system loud WITH MUSIC and HAVE SOMEONE lower the sub by 1dB without telling you. See if you can CONSISTENTLY tell when they do it. If you can't, then there is no point in changing anything since you won't have anything to gain.


----------



## cubdenno (Nov 10, 2007)

The MLA device listed above may help. What is going to happen is the alternator will provide all the current (amps) at its voltage 13.6-14.4 v.

At the point the audio system along with the car accessories draw more than the alternator is able to provide the supply comes from the battery at ~12.6 volts. this voltage will drop lower continuously if you are putting sustained loads in excess of the alternators capacity.

Upgrade the grounds. Don't worry about the positive from the alternator. 

Don't worry about upgrading amps to something with a regulated power supply. The draw from a bunch of class AB amps putting out the power you have on tap now would be even worse on your electrical. Plus you have the amps already. And they are great amps.

I run a bit more power than you on a stock electrical. Upgraded battery. Good cable runs. Upgraded grounds. I don't listen to a lot of rap but regular music never comes close to being a problem.


----------



## Cruzer (Jul 16, 2010)

I don't understand. I looked up my alternator what I read I have a 136amp alternator.

When I have truck running, hard hitting song, volume crankeð my voltage at the amp jumps from 14.2 to 14.4.

I have done anything to my electrical, not even a simple big 3.

Maybe I got a bigger alt than I think?


----------



## sqshoestring (Jun 19, 2007)

Voltage regs are imperfect, they change with temperature and load. When it senses a load it may produce slightly higher voltage, but you can be sure when you exceed the capability of the alternator voltage will drop. When you have too small of wire, voltage at the amp will drop but not as much at the battery. If this does not happen with the system at max volume playing material with bass in it, well then you have a large enough alternator and wire, at least until you turn other stuff on in the car.


----------



## Cruzer (Jul 16, 2010)

cajunner said:


> then you should have no more than 13.8V at the amp after a warm-up/charging phase is complete. When you first crank up and for several minutes, the voltage regulator brings the voltage up to 14.4V, or 14.6V, but not much higher than that.


This must have been it. i started the truck and cranked the volume. after the truck's rpms went down then i tested it. probably a whole minute after starting it but what ur saying is everyones car does that right after being started. 

guess i need to drive a little and after i get home, dont turn it off, and test it again?


----------

