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Car audio voltage drop question

S/K Commodore

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Hey guys,



Have a voltage drop question due to a minor drop I would think.

I will start with the system I am running and the equipment I have, then onto the problem I’m dealing with.

BTW the car is a S2 VT V6 sedan



Equipment/accessories-



Dual 12” kicker compR subs in ported box (500wrms each- 1000wrms total) @2ohms.

Kicker cxa 1200.1 two channel 1200wrms @2ohms mono block amp.

Front P16-S (6” Rockfords with splits) 60wrms @4ohms (Components).

Rear P16 (6” Rockfords) (Coaxial) 60wrms @4ohms.

Pioneer GMA6704 1000watt 4 Channel amp at 60wrms per channel.



Power-



Front is 120amp alternator (brand new).

Yellow top battery (6 months old), have had both tested and in good working condition.

Big 4 upgrade using 0AWG copper.

Main power 0AWG copper.

Power from distribution block to both amp is 4 AWG copper.

2 main earths from chassis to distribution block 0AWG copper.

Earths from distribution block to both amps is 4 AWG copper.

In the car I have 3 LED volt meters set up,

1 is for the battery on 24/7 and the other 2 are for the amps, (1 each) that are wired to the remote on each amp.





Problem-



I been dealing with a volt drop for months now but have been getting there slowly even tho I have gone through like 6 sets of from speakers.

When car is off, battery voltage is about 12.6.

When I turn the car on, battery volts sit around 14.4-14.6 and the amps meters sit around 14.1-14.3,(no music).

Then I crank the music with bass, battery volts remain around the same sometimes down a little bit no lower than 14.2-14.3 and the amps meters will hang between 13.7-14.1. (That’s driving).

Come to a stop at lights or something with heavy bass, all 3 volt meters, so battery and amps will drop to around 12.5-12.8 or 12.9v and that’s with music right up, at idle.

But then I start driving again, they come right up again.

Now not sure if that’s normal/ok or not, but need peoples thoughts.

So far people say it’s fine as long as they stay above 12.4v, others say second battery and others also say capacitor.



Now I hear secondary battery is good due to holding more power, But really only designed for sound comps or when listening 2 music with car off as it holds more current and releases it slowly.

Where a capacitor is either useless,

but also good as they store extra current, due to sitting close to the amp so they allow a better and smoother current to the amp.

They provide extra power to amps when sudden bass hit so feeding the amp with that bit of extra current, but I really don’t know, I have the time and knowledge to do what is needed but not the funds to keep buying and trying till I get it so I would rather do 1 thing to fix problem maybe 2 depending on what funds is like.



Any help or opinions on either a secondary or a capacitor or anything that would help would be much appreciated. I would love people thoughts from personal experiences and have seen. Even if it’s not the same set-up but close to the same size set-up in rms and power supply.



Thank you.
 

Skylarking

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Don’t know as I’m no expert in crazy loud sound systems.

As is, you have 1200 + 4x60 W RMS which equates to 120A at full tilt on a 12V system.

Interestingly, @ engine idle, the 120A alternator won’t be providing the max 120A, which may be why you see the battery voltage drop a little. But is that causing sound issues or is it that you are just seeing the voltage drop which is annoying you?

If you’re simply chasing voltage drops because you’re annoyed at seeing the voltage dip at idle, you probably need to look at the current flowing through your system, especially at the battery with music playing (both at engine off and at idle). And measuring the current that the alternator can provide to the battery when the engine is idling and your sound system is pumping would also be of interest.

Think of it as the battery being a bucket of water, the sound system being a hole and the alternator being a tap. It the tap can’t fill the bucket at the same or higher rate then the hole drains the bucket, the bucket level will drop. Getting a bigger bucket doesn’t change the situation. Getting a bigger tap does…

Adding a capacitor is like adding another battery, that is it’s like connecting a hose to the hole in the bucket and plumbing it into a smaller bucket that then feeds the amp via a hole in the small bucket. The amount of water flowing hasn’t changed as the tap is the limiting factor here.

So I’m wondering what the Ah and CCA rating of your battery is, what current your sound system draws when you’re playing music and what current your alternator can supply when your idling the engine and playing music. If the alternator current supply is close to the required amp current draw, a bigger capacity battery may be able to help, marginally, but the real solution is to sort the alternator.

Maybe changing pulley size (smaller) will allow the alternator to provide more current at idle ;)


 

Jeda

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Don’t know as I’m no expert in crazy loud sound systems.

As is, you have 1200 + 4x60 W RMS which equates to 120A at full tilt on a 12V system.

Interestingly, @ engine idle, the 120A alternator won’t be providing the max 120A, which may be why you see the battery voltage drop a little. But is that causing sound issues or is it that you are just seeing the voltage drop which is annoying you?

If you’re simply chasing voltage drops because you’re annoyed at seeing the voltage dip at idle, you probably need to look at the current flowing through your system, especially at the battery with music playing (both at engine off and at idle). And measuring the current that the alternator can provide to the battery when the engine is idling and your sound system is pumping would also be of interest.

Think of it as the battery being a bucket of water, the sound system being a hole and the alternator being a tap. It the tap can’t fill the bucket at the same or higher rate then the hole drains the bucket, the bucket level will drop. Getting a bigger bucket doesn’t change the situation. Getting a bigger tap does…

Adding a capacitor is like adding another battery, that is it’s like connecting a hose to the hole in the bucket and plumbing it into a smaller bucket that then feeds the amp via a hole in the small bucket. The amount of water flowing hasn’t changed as the tap is the limiting factor here.

So I’m wondering what the Ah and CCA rating of your battery is, what current your sound system draws when you’re playing music and what current your alternator can supply when your idling the engine and playing music. If the alternator current supply is close to the required amp current draw, a bigger capacity battery may be able to help, marginally, but the real solution is to sort the alternator.

Maybe changing pulley size (smaller) will allow the alternator to provide more current at idle ;)



Dude, you need a 2 Farad capacitor for the 1200.1.
Your electrical system can't supply the power that amp needs when your subs are hitting. I ran a 1 Farad cap using the kx 1200.1 driving 2 12" comp r subs and it was just enough. Ideally I would have ran 2 farad.
You'll notice more punch from the subs when they hit too.
 

Skylarking

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Sweet, I’ll admit I’m not an SPL doof doof expert.

However, if it was so simple, people wouldn’t be on the hunt for more powerful alternators. They’d simply buy big arse 18F capacitor and stick with their wheezy 60A factory alternators…

So, show me something other than marketing fluff, that clarifies how a capacitor resolves the current shortfall when an alternator can’t provide the required juice. Remember it’s just a simple solitary capacitor that some people add, not a complex high frequency boost buck converter circuit used to step up the voltage…

But much of these debates are like the debates about gold plated oxygen free copper video or audio cables that are wound by naked virgins. It’s sales and marketing fluff to make people with poor eyesight or poor hearing feel better about their spend. Its almost a where’s my cars styled fight which I don’t really have the patience for…

 

S/K Commodore

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my battery is a yellow top battery putting out 750CCA and 55.0AH.

Also regarding to having have compR subs and having the 1 farad cap, what electrical set up did you have as in battery type, alternator size, wiring size right through and was it copper or CCA? As mine is all copper right through and except from the distribution blocks to both amps which is still copper but 4AWG absolutely everything else is 0AWG
 

S/K Commodore

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Also the sound is fine, it’s the voltage drop at idle that is the problem, I have gone thru enough from speakers due 2 clipping due to voltage drop enough, I rather spend 1 lump $$ and add/fix something to fix voltage drop and stop clipping completely rather than leave it and keep spending $$ to replace blown/clipped out speakers coz one day it won’t be the speakers, it will be the subs. (Excuse the French but **** that)
 

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Honestly, I think your at the point of either a high capacity alternator or a second battery, if not both.

A cap is a bandaid, which will never fix your low output on idle, only keep the hits from dimming lights/removing power to critical engine electrics.

A visit to a couple of pro audio shop should get you on track, and hopefully they give similar advice
 

S/K Commodore

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I must also admit and say, it’s not every single time on idle it happens, I mean only on idle but not every time I come 2 an idle as sometimes it remains fine and doesn’t drop at idle and only certain songs it does it 2 not every song and every time at idle, I had a decent bass song this morning and voltage remained fine at idle at a stop sign intersection, so it’s not a major or huge problem in all honesty, really I see it as a good kink in the hose at a certain point with certain songs and not bad all the time to the point that it’s not a big ass problem that requires big $$ for big modification. Just something 2 help that kink come good, I’m seeking advice from everywhere, I just don’t wanna have 2 spend big $$$ on equipment that I don’t need and only spend what I have 2 just 2 fix this problem, yeah I agree if I had a huge system like for comps and **** wanting 150.0+DB them yeah big $$ is required for it but mine isn’t what you call “huge” and I had it tested a few months ago and it was hitting 138.8DB and with the mods I have made, now probably around 140.0DB so it’s not huge like 150.0+DB so with my setup and power set-up, I can’t imagine I need much 2 get it right, at the start I had a voltage drop of 1.5v and did a lot and got it down to .4 of a drop so under the max voltage drop now I don’t more mods, I honestly can’t see that I need much or go big $$ to fix and go all out as if I still had 1.5v or more of a drop or bigger system. And tbh I am seeing a lot of pros and cons on secondary battery, capacitors and either bigger alternator or smaller alternator pulley. Does any1 at all know any1 at all that has either the same or close 2 the same set-up as myself that has been in this position and has tried multiple solutions and found the right one? If so can you please let me know as it would be much appreciated.

Cheers guys
 

Jeda

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While a cap won't solve all your problems, it will definitely help get the most out of your sub set up.
Read below.


Stiffing capacitors store electricity, which they can discharge very quickly unlike the vehicles battery and alternator. They give your amplifier quick jolts of power when the bass hits to cover the amount of current it requires for musical transients.
 
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