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Discussion Starter #1
Okay so I joined to get opinions/facts from others who love car audio to in full understand what, and why. For starts, I have all old school components, minus head unit, 6.5’s and 1 10” sub. (Quantum Q1500/10S subs x2, QS1500D amp and QA2160. My car is a 06 cobalt LT with maybe 7 month old 110A alternator and 2 batteries, ones 3 months old other is maybe 8. QA draws 30A, QS draws 100A power. Volt meter helps monitor. Alt jumps between 14.1-15.2 when first started. Drops to 13 unless something was left on or amps playing. both have VD under my cruising sound level (not clipping or distorted, but not anywhere near low). I only run one system at a time, as there separate lines. With the QS on, sometimes my alt stays steady Feeding power with a .5 max VD To car. Others, under bass drop. I’m down to 12.8, lights dimming to hell, windows barely rolling up, car trying to stall if at idol. QA sometimes gives me .2-.4 VD (my alternator is weird with its feeding power, can’t say what exact volts as I always see 14.1-15.7 max) now. I want to get opinions on WHY. Why the voltage jump at different times with alt, why severe VD, why do I sometimes run 13.3 max unless cars restarted and others 15+ with QS thumping, next to no VD. just. Why... Ground is great, sanded, self tapped, below that 18” length and branched by ground distribution block, good and snug at amp whole 9 yards. 4g AWG OFC to QS, 8AWG CCA to QA. Both amps are AB so of course there’s heat, but not thermal overload (protect mode) amounts no matter what volt. If we can’t piece together why on here, other than new alternator as I just don’t have the money for a high output one. Can we figure out a how to make it better and chill out that VD a little. Whatever you need to know just ask and I’ll relay the info. Just please, anybody. Help me further understand what my issue here could be.
 

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Iit could be some combination of an intermittent load that surges, and a voltage regulator?
 

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I’m sorry but I’m just not understanding. I’ve never taken the time to look into electrical charge systems, VD, or anything in those lines. I’ve been told by my pop (20 plus year GM certified mechanic) as long as I see over 12.9V I got nothing to worry about. But now that 12.8-13.1 is becoming a constant after a few minutes of running. Doesn’t drop below 12.9, with or without amp on. But still, at that voltage amp isn’t overheating, car isn’t dying. Next to positive my alternator is just about on the fritz.
 

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I highly doubt your alternator is on the fritz.

Why don't you ask Pops about the voltage regulator and how it works?
And what effect that surging loads might have?
 

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Get a current clamp and start investigating. Question how much load charging two batteries at once is putting on that alternator. Also, why 2 batteries?

Ge0
 
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So he went to say the alternator has a regulator built into it, another Added would almost be pointless. As well as surging loads, that would only have added stress on the alternator. Making it work almost double the time than what it wants too, shortening its life severely. Making me fear it even more since my amp alone, is the alternators output. But at that, wouldn’t my class AB be over heating, distorting, clipping?
 

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Discussion Starter #8
I’ll see if my pop has one, and I went and did the second battery kinda for shits and giggles of assisting the power issue, as I was gonna do a capacitor till I came to find out most caps today are overdrawn bs that usually don’t work or worse. Than I found out caps throw out that difference in voltage to the amp when it drops, assisting to keep input voltage stable. With VD there’s already low voltage. Than adding on something that’ll need to charge constantly while the already amp/voltage hungry amplifier drains on the system. It was a given it was pointless. I was hoping the added amperage from the batteries would be what I needed in the quest of stable system voltage, dimming lights and all that good stuff. Worked for about 2 months, now we’re a little bit worse.
 

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Okay so I joined to get opinions/facts from others who love car audio to in full understand what, and why. For starts, I have all old school components, minus head unit, 6.5’s and 1 10” sub. (Quantum Q1500/10S subs x2, QS1500D amp and QA2160. My car is a 06 cobalt LT with maybe 7 month old 110A alternator and 2 batteries, ones 3 months old other is maybe 8. QA draws 30A, QS draws 100A power. Volt meter helps monitor. Alt jumps between 14.1-15.2 when first started. Drops to 13 unless something was left on or amps playing. both have VD under my cruising sound level (not clipping or distorted, but not anywhere near low). I only run one system at a time, as there separate lines. With the QS on, sometimes my alt stays steady Feeding power with a .5 max VD To car. Others, under bass drop. I’m down to 12.8, lights dimming to hell, windows barely rolling up, car trying to stall if at idol. QA sometimes gives me .2-.4 VD (my alternator is weird with its feeding power, can’t say what exact volts as I always see 14.1-15.7 max) now. I want to get opinions on WHY. Why the voltage jump at different times with alt, why severe VD, why do I sometimes run 13.3 max unless cars restarted and others 15+ with QS thumping, next to no VD. just. Why... Ground is great, sanded, self tapped, below that 18” length and branched by ground distribution block, good and snug at amp whole 9 yards. 4g AWG OFC to QS, 8AWG CCA to QA. Both amps are AB so of course there’s heat, but not thermal overload (protect mode) amounts no matter what volt. If we can’t piece together why on here, other than new alternator as I just don’t have the money for a high output one. Can we figure out a how to make it better and chill out that VD a little. Whatever you need to know just ask and I’ll relay the info. Just please, anybody. Help me further understand what my issue here could be.
A lot of modern cars have computer controlled charging that emphasizes fuel economy, I'd bet this is causing your problem. 12.9-13.1 volts should be the resting fully charged voltage of your battery. I believe you can disable that behavior somehow, but I can't tell you how. One of the high output alternator companies may be able to help you.
 

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Discussion Starter #10
So. He asked me to explain more on how and what was happening. He came to explain it was not the alternator being on its last leg, its the alternator being overloaded producing whatever amount of amps and volts to the system in a stable manner. shortening its life drastically, but with it looking to be newer I’m hoping I still got a fair amount of time on it as they last up to 4 years under proper output. Than went to explain even tho my alternator only is good for 110A, the batteries would dissipate the lacking amperage to amplifier/ charge system assisting my ol gals electronics anyway it can. It just would be far slower than a capacitor, being able to dissipate the voltage difference to an amplifier The second it drops. “helping” the alternators stress levels. (A cap will be dead if left off power source in no time at all, What goes out must be pulled back in to keep the output voltage available for use. to where a battery could have a bank good up to an hour Under load). That being said, the battery’s don’t request to see charge until they are below 12.7 volts. And there main goal/reason of being there is to feed DC power and high amount of amperage threw the Sitting electronic system, allowing the electronics plenty of cranking amps and voltage to turn the vehicle over, said Being when the alternator tells batteries to step aside, taking over DC current production of “14.4v” powering electronics and getting batteries back up to a full charge. He said the only real option is a high output alternator, or I could simply downgrade/remove the amp (not an option) depending the Amperage output it might not fully solve the VD. He also went to say it sounds as if the alternator is creating overworked current in a stable Manner, giving him reason to believe it’s not on its last leg which is a great thing. Now with all this said, is my amplifier being fed it’s amperage needs/wants stably? As It doesn’t over heating or really get hot to the touch at all as I got fans tied in to keep it cool and doesn’t distort or clip my output sound. Will the 13V of power put my old 2004 class AB QS1500D In ANY sort of circuitry failure. (it’s already been blown or damaged, needing/being repaired. 3 capacitor and Several replacement parts on the power side of the amplifier board concluded that) all in all, I want/need to know if my one of a kind QS is in any form of danger. To hell with the car and alternator. I’m worried about my amplifier hahaha
 

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Discussion Starter #11
Get this. That 13v stable happened and lasted all day Yesterday and good portion of today Even after checking/ re-tightening all connections to both ground and power. no matter how many times I restarted the cobalt or powered up different things on top of my 100A current hungry monster Of a “1500w” amplifier (alternator only produces peak output when asked for by electrical system) as of tonights car ride that lasted about an hour, and a little increase with low pass Filter. Behold. Damn 13.7-14V with a peak of 14.7 till I got the rpms over 2000, turning on the amplifier and it produced sound, close to 4 minutes. Next to no VD. Next to no dimming from lights even under deep drops, motor isn’t attempting to stall. WTF IS MY ALTERNATORS ISSUE. oh wait, my issue is it’s a GM! Hahaha! This puzzles me. How why and what. None of it adds up. Also went as far to get exact temp of the amp seconds after shutting off the system. 109 was the maximum temperature presented. That’s way, WAY cool for a quantum audio class AB amplifier since they were always known to have a high operating temperature. I just know AB amplifiers power ratings are generated off 14.4v ratings, and for the most part 14.4v is what AB amplifier ask of or else higher heat levels come into play (most of the time sending amplifier into protect fairly quick depending on your wire gauge, if your ground Is solid or good enough to make it function, gain and bass boost setting, forcing you to replace with less powerful amp or add extra current drawing fans to help move air on/around the board. along with a lot more opportunities for complete and total failure being presented within the amplifier. Now you (I) get to live hoping and praying on My QS1500D dating 2004 on the board, completely irreplaceable already being rebuilt once by quantum audio them self’s and would be quite expensive to have repaired again doesn’t blow under these operating conditions. I know my fans will keep heat at a minimal, elimination of thermal deviation to circuitry as 1 hour of slamming only created 109 degrees in one small area and 106 with the rest of the amp. Score! Now, the remaining fears of different input voltages damaging/ shortening the life of my old gal. Again it’s from 2004, been blown/damaged/upgraded once already. Almost every power transistor (minus 4 originals, WHY THAT CORNER CUT QUANTUM) replace one replace all. Along with 3 capacitors and a few other parts (still learning names of each and every piece) have been replaced, cool. It’s old so that give more reliability, right? Absolutely, Till you learn Dumbass before me for a few years he said, ran it with 13.8V of power, in a poorly vented environment going into protect a lot, 4x30A fuses when rated at 25A, complete shit ground doing some work on the plastic around the ground terminal, even adding damage from to amplifier board at the ground terminal and by the fuse slots. To top every last wrong move, 1.3 ohms was his final load to amplifier. It’s only rated for 2 stable being class AB disliking a lower than rated final load entirely. whole damn point of the repairs/rebuild done before he got it just about ruined. Making me fear a shorter than expected life in my possession due to total abuse threw its life. My main objective in this thread is to learn any, and every way I can prevent Added chances of failure To all of my old school high amperage AB quantum Audio amplifiers. I know some ways, but I’m only human and don’t know all. Any type of opinion, fact, “what your buddy told you” or what you overheard once about keeping old class AB amplifiers living just a smidge longer is much wanted and needed. Please and thank you!
 

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Maybe see if it correlates to certain types of music, or certain songs?

And see if Pops can opine on speed at which the output current ramps up, and then ramps down with a load that is surging?
 

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you should make your life goal to not have verbal diarrhoea... Jesus that’s hard work to read!

what I did gather is you think a battery has to get to 12.7 before an alt starts charging, this isn’t correct an alt will always try and keep the voltage at it’s set point... the set point can be adjusted by the car and put up or down if it’s been made in the last 15-20yrs, but it will always try and stabilise the voltage as that’s how it charges the battery, by increasing the cell voltage over 2.1v a cell

it’s likely a combination of smart charge and low revs meaning your voltage drops, have you done the big 3 on the engine? 0.1v here or there may not seem much but it adds up

do the engine to chassis, chassis to battery and alt positive to battery positive connections in some bigger cable and then see how the voltage holds up
 

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It's the morning of my fathers funeral, and I'd just like to say thank you for making me laugh with your thread title...

One of his army stories was about one of the guys in his unit who'd caught "VD" and got treated by the MP's vet rather than the doctor so he didn't get into trouble...

So, Voltage Drop, Verbal Diarrhoea or Venereal Disease?

Who's got what and which is worse?
 

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Ge0
 

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Get this. That 13v stable happened and lasted all day Yesterday and good portion of today Even after checking/ re-tightening all connections to both ground and power. no matter how many times I restarted the cobalt or powered up different things on top of my 100A current hungry monster Of a “1500w” amplifier (alternator only produces peak output when asked for by electrical system) as of tonights car ride that lasted about an hour, and a little increase with low pass Filter. Behold. Damn 13.7-14V with a peak of 14.7 till I got the rpms over 2000, turning on the amplifier and it produced sound, close to 4 minutes. Next to no VD. Next to no dimming from lights even under deep drops, motor isn’t attempting to stall. WTF IS MY ALTERNATORS ISSUE. oh wait, my issue is it’s a GM! Hahaha! This puzzles me. How why and what. None of it adds up. Also went as far to get exact temp of the amp seconds after shutting off the system. 109 was the maximum temperature presented. That’s way, WAY cool for a quantum audio class AB amplifier since they were always known to have a high operating temperature. I just know AB amplifiers power ratings are generated off 14.4v ratings, and for the most part 14.4v is what AB amplifier ask of or else higher heat levels come into play (most of the time sending amplifier into protect fairly quick depending on your wire gauge, if your ground Is solid or good enough to make it function, gain and bass boost setting, forcing you to replace with less powerful amp or add extra current drawing fans to help move air on/around the board. along with a lot more opportunities for complete and total failure being presented within the amplifier. Now you (I) get to live hoping and praying on My QS1500D dating 2004 on the board, completely irreplaceable already being rebuilt once by quantum audio them self’s and would be quite expensive to have repaired again doesn’t blow under these operating conditions. I know my fans will keep heat at a minimal, elimination of thermal deviation to circuitry as 1 hour of slamming only created 109 degrees in one small area and 106 with the rest of the amp. Score! Now, the remaining fears of different input voltages damaging/ shortening the life of my old gal. Again it’s from 2004, been blown/damaged/upgraded once already. Almost every power transistor (minus 4 originals, WHY THAT CORNER CUT QUANTUM) replace one replace all. Along with 3 capacitors and a few other parts (still learning names of each and every piece) have been replaced, cool. It’s old so that give more reliability, right? Absolutely, Till you learn Dumbass before me for a few years he said, ran it with 13.8V of power, in a poorly vented environment going into protect a lot, 4x30A fuses when rated at 25A, complete shit ground doing some work on the plastic around the ground terminal, even adding damage from to amplifier board at the ground terminal and by the fuse slots. To top every last wrong move, 1.3 ohms was his final load to amplifier. It’s only rated for 2 stable being class AB disliking a lower than rated final load entirely. whole damn point of the repairs/rebuild done before he got it just about ruined. Making me fear a shorter than expected life in my possession due to total abuse threw its life. My main objective in this thread is to learn any, and every way I can prevent Added chances of failure To all of my old school high amperage AB quantum Audio amplifiers. I know some ways, but I’m only human and don’t know all. Any type of opinion, fact, “what your buddy told you” or what you overheard once about keeping old class AB amplifiers living just a smidge longer is much wanted and needed. Please and thank you!
Please start by breaking up your thoughts into paragraphs. This is nearly impossible for me to read.

Ge0
 

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Your alternator is likely turning off, a strategy to reduce parasitic drag on the motor once the battery is adequately charged.
 

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Your alternator is likely turning off, a strategy to reduce parasitic drag on the motor once the battery is adequately charged.
I'll bet a dollar you are correct.

Ge0
 

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Your alternator is likely turning off, a strategy to reduce parasitic drag on the motor once the battery is adequately charged.
Good luck... he is conviniced his alternator is on the way out.


I'll bet a dollar you are correct.

Ge0
But... I was hoping his Pops was going to tell him.
 
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