Getting the alternator to charge at a higher voltage

[KEVINL]

I have a fairly serious stereo system in my truck now and the alternator only charges to 13.5 volts it maintains it but all amps are rated at 14.4 now a days and everything will work better and stay cooler at the higher voltage.

My question has anybody installed one of these on a duramax equipped truck http://www.missinglinkaudio.com/id24.html

 

[THEFERMANATOR]

You have a newer style ECM controlled alternator, and that page says they don't support it(says expected late 08, but no mention of wetehr they have it yet or not). So you may need to go to an older style alternator with a built in regulator. I have heard good things about this place http://www.alternatorparts.com/ .

 

[hondarider552]

Type of system Kevin? Might not be the system, OE batteries?

Playin a little too much Michael Jackson?

 

[MadMaxx61]

I run dual alternators so I cant say but I have over 2500 watts RMS and it does a good job staying at 14.4v mind you I do need to add in a Cap. lol

 

[duratothemax]

You have a newer style ECM controlled alternator, and that page says they don't support it(says expected late 08, but no mention of wetehr they have it yet or not). So you may need to go to an older style alternator with a built in regulator. I have heard good things about this place http://www.alternatorparts.com/ .

....the fancy alternators, are only on the 2005+ HALF-ton trucks/SUV's with RVC (regulated voltage control). Those used a PWM signal from the generator/battery control module, which used an inductive loop/ring around one of the battery cables (it even communicated on the databus) to provide "smart" charging capability.

ALL duramax alternators are controlled by the ECM only, based on voltage alone.

The "AD" alternators have been on the duramax's since they first came out. Even back in 2001, they were controlled by the ECM. The alternators are still controlled in current HD's by the ECM, but they arent controlled via PWM by a "smart" generator control module. The ECM just sends a signal to regulate the alternator based on current measured battery voltage.

As far as I know, even the 2012 HD trucks still use the "old" style alternator with NO "smart feedback" system. The RVC is/was a half-ton thing. They only did it for better fuel economy...which is irrelevant on the HD trucks.

 

[KEVINL]

Type of system Kevin? Might not be the system, OE batteries?

Playin a little too much Michael Jackson?

I am running a Rockford Fosgate t600-4 for the highs Class AB amp

and a viper 600.1 D class amp running at only 4 ohms for 275 watts

I have 900 w rms right now but will probably be adding another 1500w+ to it

I run dual alternators so I cant say but I have over 2500 watts RMS and it does a good job staying at 14.4v mind you I do need to add in a Cap. lol

How do you get yours to charge at 14.4 the only time mine does that is when I first start the truck.


Is there anything that can be done in Efi live to tell the ecm to charge at a higher voltage

My other dmax did the same thing but I only had one amp so I didnt really care

 

[duratothemax]

on the gassers, the table is mapped out in EFILive....(commanded generator charge rate vs. voltage vs. rpm)....I doubt they would revisit the diesels to map out the table though, given the fact that there is little interest/demand for it.

 

[hondarider552]

GM offered a dual alternator upgrade for the LMM's correct Ben? Might be something to look into Kevin. My neighbor has a LBZ with dual alternators, and with a blow through box in the bed with 4 10's and a tv system, ive never seen it drop much voltage below 14v.

 

[KEVINL]

So it sounds like i am stuck with charging at 13.5 volts I don't need another alternator yet because i maintain 13.5 with everything off or everything on

i am reading the voltage from the obd 2 port is that a reliable place to get it

 

[hondarider552]

I would think so, system voltage will be 13.5-14.6 iirc.

 

[NAFLASH]

Are you having issues staying at 13.5 volts? Is it really worth it to have 1 more volt?

 

[duratothemax]

Kevin- Im sure a lot of car audio guys on the internet out there "think" and "say" that .9v is going to make a "big difference"..........but has anyone actually done any scientific tests, or have there been any official statements from the guys that actually engineered the amplifier in the first place?

I just have a hard time believing that .9v is really going to make a difference. If you do the math, thats barely 5 amps more current draw. And even then, its a wash...because there is no way your system is drawing (lets just say for arguments sake) 1500+ watts for more than a split second at any given time. An acceptable voltage level for a running car is generally accepted as anywhere between 13.2v and 14.7v. So anyone who is designing ANYTHING electronic for an automotive environment should accept that as a margin of error...and therefore the widget they are designing (whether its an amplifier or a lockup controller) should be able to operate at 100% capacity without any noticeable performance degradation or quirks if the input voltage is within that range.

IF the amp in question REALLY is going to perform noticeably differently, or there is going to be an impact in performance or reliability between operating on 13.5v vs. operating at 14.4v, then quite frankly, thats a really shitily (I know thats not a word) designed amplifier.

All im saying, is that I would like to see some scientific data from an actual amplifier engineer that says .9v is going to make a real difference.

Of anything in a vehicle, the most voltage sensitive (and electrical sensitive) components are the computers. If all of the electronics in our trucks can cope with a crappy power input source and work properly on anywhere from ~8v to 16v+, then im sure an amplifier is going to be fine.

As long as your electrical system isnt dropping below 13v continuously, I really wouldnt worry about it..........

 

[KEVINL]

its not a big deal it helps having higher voltage but is not critical you will draw less amps and get a little more power but is it enough to notice probably not.

I was just curious if it was something that could be done as long as i stay above 13v it wont hurt anything

 

[duratothemax]

And secondly, I did some quick reseearch, and from what I understand, both of those amps use regulated power supplies. Meaning regardless of input voltage, the same amount of voltage gets to the high voltage rail in the amp. Yeah at lower voltages (13.5 vs 14.4) the amp might draw more input current, but as long as your wiring can handle it, it otherwise doesnt make diddly bit worth of difference as to output of the amp.

As long as your voltage is above 10-11v, amps with regulated power supplies can cope, and will output the same ultimate power to your speakers.

AND. Even amps without regulated power supplies. STILL not gonna make a difference! I mean we're talking on the order of maybe 50 watts over the 1500watt capability of the amp, if your truck is running at 13.5v vs 14.4 volts! 50 watts difference is nothing a human ear is going to be able to discern against.

If you do the actual math for your specific system and amp setup..............I really think you are worrying for nothing. Your ears arent going to be able to tell the difference with an extra .9v, and the amp isnt going to run any "measurable" amount cooler. Im talking "real world" here...not going to make a difference in the real world.

 

[duratothemax]

its not a big deal it helps having higher voltage

ok, maybe on the order of 1-2%.

but is not critical you will draw less amps

as long as the wire going from your amp to your battery can handle the current without melting, its irrelevant.

and get a little more power

again, only on an amp with an unregulated power supply

I was just curious if it was something that could be done as long as i stay above 13v it wont hurt anything

Im sure "something" could be done if you wanted to make some custom fooler setup for the ECM so it will charge at a higher rate, etc....but really, its like asking "will my truck make more hp on shell or texaco diesel"

 

[Ian J]

Kevin I am a autosparky that specialises in certain areas that does not involve working on cars but power mangment is one of them
I aggree with every thing that has been mentioned above and would like to add that you are looking at a stable voltage what you need to worry about is unrestricted current flow at full load.
Its like supplying 20PSI to your CP3 at idle through a 1/4" line, it will go into suction when most needed.
What you need is like a 1 B&S cable to your batteries and then to your amps to handle handle peak current.
If you are running several amps you need to look at running a heavy line per amp and use a mega or Maxi fuse to remove volt drop under load
dont worry about using fancy coloured cable that the audio shops sell just the biggest cable that fits into the amp.

With the AD alts I just connect the warning light wire only through a light or resistor and then It will charge at the preset regulated voltage of about 14.4V