does big 3 require a high output alternator?

[mrpep]

So here's what I have so far and tomorrow at work I plan on busting out the multimeter but for now, theirs a dial in my dash that reads battery voltage and it reads over 14 volts and when I'm driving with music at a low level and then when I turn it up loud , the dial goes below 12 so I can see the draw of current going down. Interesting for sure but still not sure how to trouble shoot until I measure with meter, even then I am not sure what my next step will be and I think we all can see what the results will be.... a definitive drop in voltage. Will this mean the big 3 or a HO alternator or both? Just preparing for what may come.

 

[nowhere 10+ year member]

it could be more than just the stereo. Might be a bad alt, something wrong in your elecrical somewhere, battery dying, hid lights, misc lights in the car, etc. It could be a lot of things. Dropping from 14v to 11v is not usual. Just do the grounds from car to battery and engine block to battery and see how it goes first. Usually alt to battery is the most difficult for most people to run.

Also, how many watts are you running, what kind of car, how many amps does stock alt provide?

 

[n2audio 5,000+ posts]

11.6 at idle tells you your alt isn't doing anything.

They can be intermittent when they're going bad.

But if I were you I'd be planning for an alt replacement in the very near future.

Big 3 never hurts, but it doesn't do much in a stock electrical system. It's just an effort in reducing impedance in the power/ground of the electrical system -- slightly. Any improvement would be difficult to measure, impossible to hear.

 

[Jeffdachef 5,000+ posts]

I understand that you don't want voltage to drop below that, and OP should probably reduce his gains, but I've run my truck for 3 years with voltage dipping into the low 11s when the bass hits. Any articles I could reference that would explain why this would go as far as frying electronics? I'm curious now.

Amp rated for 2000 watts at 14.4 V. You set it for 2000 watts on the DMM. Voltage drops, and your amp is only capable of 1700 watts but you are still forcing it to do 2000 watts which leads to clipping and distortion.

This is assuming people are noobs and do not understand this concept or when to back off on their bass. I'm sure you know your limits, but others might not.

 

[Jeffdachef 5,000+ posts]

OP, i'd pull up to an autozone to get that battery checked out pronto. Could be a bad batt. It could also be the vehicle's computer not telling the alt to charge. It could also be a crappy alternator. Many variables still untested. Narrow it down before something starts failing.

 

[mrpep]

it could be more than just the stereo. Might be a bad alt, something wrong in your elecrical somewhere, battery dying, hid lights, misc lights in the car, etc. It could be a lot of things. Dropping from 14v to 11v is not usual. Just do the grounds from car to battery and engine block to battery and see how it goes first. Usually alt to battery is the most difficult for most people to run.
Also, how many watts are you running, what kind of car, how many amps does stock alt provide?

I am running a Alpine mrx m1000 watt mono block on a 600 watt RMS 10'' W6 JL audio and then a second amp which is a kicker 4 channel amp and Im pushing 4 speakers approximately 75 watts each so a combined 300 watts totaling 900 watts. It is a conversion van so has a LED tv, blu ray player and they run off of an AC to DC converter . The van also has a separate stereo and ceiling and wall lights but I don't even have any of this on when I'm driving for the most part. Its just me and my sounds and if I have my headlights on it dims when the bass hits but it dims real hard and tehn my 4 channel amp shuts down until I lower the volume then it turns on again. I drive a Chevy EXPRESS 1500 VAN. One thing I notice a lot is I always get a shock when I touch the metal on the car, its really weird. Do you think a 145 amp alternator would do?

 

[wew lad 5,000+ posts]

The shock you're getting could be normal static from moving on the seat, or it could be from mounting your amps directly to metal, don't do that. Another culprit could be a bad battery to ground, bad alternator to ground, or both.

The power you're pulling from your electrical is not the RMS rating of your sub, amp, or anything inbetween. Remember amplifiers are not 100% efficient and because of that they will pull significantly more power than what your speakers are getting. Efficiency is not constant either, although it tends to get better at higher power with class D circuits IIRC.

Let us know when you get some testing done with your multimeter or getting your battery checked... we could talk about possibilities all day long but there are tests we asked you to do for a reason.

 

[wew lad 5,000+ posts]

Amp rated for 2000 watts at 14.4 V. You set it for 2000 watts on the DMM. Voltage drops, and your amp is only capable of 1700 watts but you are still forcing it to do 2000 watts which leads to clipping and distortion.

Wouldn't this only be for regulated amplifiers? I don't recall any information on unregulated amplifiers designed with internal circuitry that increases the output or gain when the voltage drops. I'm thinking that you'd only get less output, and the separation from clipping would remain proportionally the same. Is it possible that amplifiers clip sooner if the voltage is also low? (i.e. a 14.4v amplifier system gain is set to produce 200w and clips at 220w but a 12v input into the exact same system will output 170w but clips right at 170w).

 

[Jeffdachef 5,000+ posts]

Its the same for most amps out there. Lower voltages lead to heat, clipping and distortion. You dont hear distortion in bass most of the times so there's no way to tell by ear but on an oscope, it will show.

 

[nowhere 10+ year member]

I am running a Alpine mrx m1000 watt mono block on a 600 watt RMS 10'' W6 JL audio and then a second amp which is a kicker 4 channel amp and Im pushing 4 speakers approximately 75 watts each so a combined 300 watts totaling 900 watts. It is a conversion van so has a LED tv, blu ray player and they run off of an AC to DC converter . The van also has a separate stereo and ceiling and wall lights but I don't even have any of this on when I'm driving for the most part. Its just me and my sounds and if I have my headlights on it dims when the bass hits but it dims real hard and tehn my 4 channel amp shuts down until I lower the volume then it turns on again. I drive a Chevy EXPRESS 1500 VAN. One thing I notice a lot is I always get a shock when I touch the metal on the car, its really weird. Do you think a 145 amp alternator would do?

Alright with that equipment, you shouldnt' be experiencing that kind of voltage drop. You have an electrical problem somewhere. The amps mounted to the metal body of the van could be causing the shock, but I'm thinking you have a short somewhere. Go get your batt and alt checked out, check all the wiring on your system, check your power and ground on your amps, and do the big 2 (grounds). See what happens after all that is done. If your still seeing a problem after all that, then your gonna have to diagnose your electrical in the van.

 

[mrpep]

So I didnt have time to test but will try tonight , I did go to Autozone and they tested my battery and my battery results were " bad battery". I was told that the optimal battery is a good one , see link, what do you guys think?

OPTIMA Batteries - AutoZone.com

 

[nowhere 10+ year member]

So I didnt have time to test but will try tonight , I did go to Autozone and they tested my battery and my battery results were " bad battery". I was told that the optimal battery is a good one , see link, what do you guys think?
OPTIMA Batteries - AutoZone.com

You can double check the batt at home if you have dmm. A good battery should measure 12.6v.

Consensus around here for optima, is you can get better for the money or less.

 

[mrpep]

I Get 11.6V so must be weak , what battery do you recommend? I want top and side post cause my cables are side and it's hard to get 4 gage on that

 

[adulbrich 5,000+ posts]

No to the Optima. New ones are made in Mexico, and don't last. There's a whole thread of horror stories on CACO

 

[poolman966554]

No to the Optima. New ones are made in Mexico, and don't last. There's a whole thread of horror stories on CACO

interesting. i was just getting ready to use the $50 off at advanced auto for a yellow top, as it expires on the 30th..

Suggestions for a GOOD AGM dual purpose battery?