Printer Friendly Forum Posts - voltage drop problem, what battery to buy?

Hello all,

I just installed a Sundown 1500D amplifier in my car along with a Sundown 50.4. I checked the voltage at the amp and its sitting at 11.5 V, with the amp gain turned ALL THE WAY DOWN! I can't even here the subs. The stock battery in my 2008 Commander just isn't hacking it. Which battery do you recommend I purchase that can still fit the tray?
Here are a few things to note:

1. A H/O alternator is out of the question. It requires fabrication, and no direct bolt in is currently available (the ones that advertised as being so are false and don't put out dirt at idle).

2. A second battery is out of the question, believe it or not, I don't have the space for it.

I'm not made of money either, so can we keep this somewhat cost affective? They will be drawing a tone of current considering the woofers hooked up to it are hungry and are wired for .75 ohms. Let me know what you guys think.

If you can not hear your subs, you must have one or more of them wired out of phase with the other(s)

No, its nothing like that. I can hear my subs easy, but I can't turn the gain up on the am without massive voltage drop (1.5 V). I need to get me a big beefy battery. But what kind will fit my 2008 Commander that can take the pull from a Sundown 1500D @ .75 ohm and a Sundown 50.4 bridged at 4 ohm?

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A new battery isn't going to be doing much good. The alternator is what powers the electronics in your car when the engine is running. So it is going to be the most important part of the charging system. Getting another battery is not going to give you a big improvement in your voltage.

The first thing I would look at is doing the "big 3" upgrade. I would also check the voltage at the battery and compare it to the voltage at the amp. If you have too big of a difference you may have a bad ground for your amps.

whiterob wrote:

A new battery isn't going to be doing much good. The alternator is what powers the electronics in your car when the engine is running. So it is going to be the most important part of the charging system. Getting another battery is not going to give you a big improvement in your voltage.

The first thing I would look at is doing the "big 3" upgrade. I would also check the voltage at the battery and compare it to the voltage at the amp. If you have too big of a difference you may have a bad ground for your amps.

Hello whiterob,

Perhaps I wasn't as clear in my initial post, but here, I'll clarify this again.

1. I CANNOT in any way get a H/O alternator. There are no direct bolt-ins available that work. They all have really low idles and take like 4000 RPMs to get up to where they need to be constantly. I'm not doing the whole fabricating route either.

2. The difference between the battery and and the amplifier is about 1 Volt, and the amplifier dips about another .5 volts when you crank it up. I'm trying to replace about a 2V differential then when I actually turn the gain up. I should be able to pull that with a big battery.

3. I also am considering running the ground right to the battery instead of the chassis. I do not, however, think it is smart for me to run the power directly, as I'd rather have it fused.

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Did you pick up on "The Big 3" comment...? Just curious...What size power wire did you run...? You defitnely need to keep it fused... posted_image You can use your meter to verify a Good Ground. The upgrade is cheap and easy,so why not...! After the upgrade is done...Then check voltage and go from there...! Here is a cool site to breeze through... https://bcae1.com/ ...

And the sticky for the upgrade... https://www.the12volt.com/installbay/forum_posts.asp~TID~73496~PN~1

...and for the ground... https://www.the12volt.com/installbay/forum_posts.asp~TID~49445~PN~1

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M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!

tommy... wrote:

Did you pick up on "The Big 3" comment...? Just curious...What size power wire did you run...? You defitnely need to keep it fused... You can use your meter to verify a Good Ground. The upgrade is cheap and easy,so why not...! After the upgrade is done...Then check voltage and go from there...! Here is a cool site to breeze through... https://bcae1.com/ ...

And the sticky for the upgrade... https://www.the12volt.com/installbay/forum_posts.asp~TID~73496~PN~1

...and for the ground... https://www.the12volt.com/installbay/forum_posts.asp~TID~49445~PN~1

Yes, I have already upgraded the big three with 0 gauge. Everything is 0 gauge, all the charging system and the wires running to the back (12 V). That 12 volt is in a distro block and is being split to both amps, 0 to the sub amp, 8 to the 4 channel.

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A bigger battery will not reduce your voltage drop.

If its your distro block, then replace it.
(Let me guess - it's a bling type with an ammeter? And guess what - it's a resistance/shunt ammeter and not a Hall Effect or similar? Now wth do people want to know what amperage they are using if they lose voltage because of it - because knowing amperage is more important than power output? Or maybe it has thermal breakers or fuses that have the same effect instead of magnetic breakers.)

Your best solution is double up on the big-3; that should halve your voltage drop. Or triple for one-third.

After that it gets academic - you are losing so much output because of the undersized alternator...
EG: you get 44% MORE output power by running at 14.4V instead of 12V (usually more in practice).

Odyssey and Northstar are a few brands a buddy uses for his competitions(group 31's...) I got a few for him this past year...Couldnt even find them for awhile...They said miltary was buying them up...! What size is the stock battery in those(group #)...There really is no upgrade for the alternator in those ...huh...? What about a "factory" upgrade alternator...(just throwing it out there) On a side note...Did you fuse the 8 gauge extension seperately(from the dist block)...?

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M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!

oldspark wrote:

A bigger battery will not reduce your voltage drop.

If its your distro block, then replace it.
(Let me guess - it's a bling type with an ammeter? And guess what - it's a resistance/shunt ammeter and not a Hall Effect or similar? Now wth do people want to know what amperage they are using if they lose voltage because of it - because knowing amperage is more important than power output? Or maybe it has thermal breakers or fuses that have the same effect instead of magnetic breakers.)

Your best solution is double up on the big-3; that should halve your voltage drop. Or triple for one-third.

After that it gets academic - you are losing so much output because of the undersized alternator...
EG: you get 44% MORE output power by running at 14.4V instead of 12V (usually more in practice).

Can anyone else verify this? I thought for sure that having a better battery would definitely help out and keep the voltage more stable around 12 V.

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tommy... wrote:

Odyssey and Northstar are a few brands a buddy uses for his competitions(group 31's...) I got a few for him this past year...Couldnt even find them for awhile...They said miltary was buying them up...! What size is the stock battery in those(group #)...There really is no upgrade for the alternator in those ...huh...? What about a "factory" upgrade alternator...(just throwing it out there) On a side note...Did you fuse the 8 gauge extension seperately(from the dist block)...?

I will look into these brands. A factory upgrade alternator isn't really going to work, considering that if they took the alternator apart and increased the number of windings, I wouldn't get that much more considering that the alternator already has no room barely for any additional windings (just in stock configuration). I don't know the stock battery size at the moment.

Also, the distribution block for power is fused, both the 8 and the 0 guage are on separate fuses as part of the fused distro block.

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michigan_tech wrote:

Can anyone else verify this?

I hope so! It's called Ohms Law.

But I'm talking about the voltage drop after the battery - ie, the 1.5V - not the hold-up voltage available.
A battery will not reduce this 1.5V drop.

Sure, a bigger battery will stay closer to 12.7V for longer, and AGMs like Odyssey etc have lower internal resistance hence a higher output voltage, but I figure it's cheaper upgrading the big-3 than an expensive AGM battery. (Isn't cost an issue here?)

Or if it is the distribution block that is causing the drop, how much are magnetic breakers compared to an Odyssey battery?
Else what is the total load Amperage - maybe it's better sizing the main fuse for the load rather the cable, thereby possibly avoiding the smaller branch fuses. (Unless you require discrimination - but usually all or nothing should be fine for car power-amplifier systems. No??)

oldspark wrote:

michigan_tech wrote:

Can anyone else verify this?

I hope so! It's called Ohms Law.

But I'm talking about the voltage drop after the battery - ie, the 1.5V - not the hold-up voltage available.
A battery will not reduce this 1.5V drop.

Sure, a bigger battery will stay closer to 12.7V for longer, and AGMs like Odyssey etc have lower internal resistance hence a higher output voltage, but I figure it's cheaper upgrading the big-3 than an expensive AGM battery. (Isn't cost an issue here?)

Or if it is the distribution block that is causing the drop, how much are magnetic breakers compared to an Odyssey battery?
Else what is the total load Amperage - maybe it's better sizing the main fuse for the load rather the cable, thereby possibly avoiding the smaller branch fuses. (Unless you require discrimination - but usually all or nothing should be fine for car power-amplifier systems. No??)

Well if I already had upgraded the charging wire to 0 gauge, what more can I do to upgrade the big 3?

The SAZ 1500D has 4x40 A fuses
The SAZ 50.4 has 2x25 A fus

I have a distroblock that has a 250 A fuse between each one.

0 gauge in, 250 amp fuse to 0 gauge out (1500D)
250 amp fuse to 8 guage out (50.4)

Hopefully this can help some. What is a magnetizing breaker by the way? And what did you mean by sizing the main fuse for the load rather the cable? The load is two Dual 3 ohm voice coils wired parellel down to .75 ohms. They can handle 2000WRMS all day.

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The big 3 - like I said - duplicate what you have.

But you need to determine where the biggest voltage drop is occurring - ie, battery to chassis, chassis to amp, battery to distribution block, the distribution block, or d-block to amps etc.

If for example your drop is 1V in the ground and to the d-block, and say 0.5V across the d-block, then duplicating your battery to chassis and battery to d-block (2 of the big 3) will HALVE that 1V drop.
IE - two parallel 0 gauge cables will halve the resistance of a single 0 gauge cable (of the same length).

A magnetic or Hall-Effect ammeter or circuit breaker is one that senses current WITHOUT using a series impedance.
Traditional breakers and ammeters use at least a shunt resistor - eg, say 1 milli-Ohm for 10-500A, or a 0.25V drop for a 250A amp load (ie, 0.25V & 62.5 Watts lost). Magnetics don't - they sense the e-mag field - not the voltage drop or heat given off.

Usually to overcome the long cables from the alternator and main battery, a second battery is located next to the load (amps etc), or the main battery is moved there. But you say you do not have the space. (And if you can fit a capacitor, use a small AGM/VRLA battery instead - a small 12V 4AH or more common 7AH (usually the same price or cheaper than a 4AH) battery provides at least 1,000 times the storage of a more expensive 1F or similar cap.)

Fuse sizing:
You have 2 series 250A fuses. (That is strange - normally it'd be say 250 followed by 125A or smaller, or 500 by 250 etc.)
If 250A is enough to protect the 8G cable, then just use a single 250A fuse at the input to the 0G cable. That halves that resistive loss.

But say your load is 4x40 + 2x25 = 160 + 50 = 210 Amps total.
A 200A fuse is probably ample, but the 250A fuse will certainly handle the max load with a bit of headroom.

8G is about 0.000641 Ohms per foot, & 0G about 0.000100 (nominal ratings of about 45A & 170A depending on application).
Or 8G has over 6x the resistance of 0G.
Or at 250A, 8G drops .16V per foot and 0G drops .025V per foot etc (V=IR).
So keep your 8G as short as possible (unless you split the 0G into at least 6 8G cables - ie, 8G has 6x the resistance....).
And if the 8G is short, you do NOT need fuses to protect it - the theory being there is little chance of a short to ground (aka physical security - no fuse type protection needed).

And if you have an 8G short to ground, although it is rated for a nominal 50A, it should carry enough current long enough to blow or trip a 250A fuse/breaker. EG - assume a 300A current - that's .000641 x 300 x 300 = just under 60 Watts of heat per foot (P=RxIxI) - which shouldn't generate too much heat.

So hence why not use a single 250A fuse rather than two? (That halves fuse losses.)
And double your existing big 3 (or 2/3rds anyhow) since that will halve ground losses to the amp/s, and power losses to the distribution block.

Forgive my long examples, but it shows how a physical layout can be manipulated for best outcome - in this case, minimal voltage drop along the conducting path.
Most wiring protection (fusing etc) is designed to protect downstream wiring. But sometimes the wiring isn't worth protecting. [Or the wire itself is the protection - remember those primitive "wire" fusible links? (Not that that is a good example...)]

And all those calcs are just Ohm's Law V=IR and Power P = VI, and substitutions to get P=VV/R = IIR.

Easy isn't it?

So you're saying I need to double the zero gauge from my alternator to my battery, from my battery ground to chassis, and engine ground to chassis? Also, if I change the 8 gauge on the 4 channel to a 4 guage on the 4 channel, does that help or hurt me? The 4 gauge will have less resistance in theory I believe, but won't it allow it to draw more current and hence suck more life from the battery? Also, how do I hook that up on the distribution block? My block is set up like this:

ANLFUSE1 ---> (0/4/8)
0 --> Dist.BLK
ANLFUSE2 ---> (0/4/8)

You said to use a single 250A fuse. How do I do this given the way the block is?

Also, do you recommend running a direct ground to the battery for the sub amp? I thought you weren't supposed to have long grounds on sub amps, even if its 0 gauge.

By further upgrading the big 3 and changing this fusing/grounding, do you think I can achieve stable voltage?

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Cables don't drain batteries - it's the overall load that drains a battery.
Ideally cables would have zero resistance (aka super-conductors) so there is no power loss.
Using the water analogy, whether you water your garden with a 10' or 1/2" diameter hose doesn't make much difference to the flow - it's the nozzle at then end that determines that.

Fattening your pipe (cable) reduces your transmission resistance hence reducing voltage/power losses, hence your load (amplifiers) get more voltage/power.

As to "stable voltage" - this merely reduces voltage drops.
With a fixed resistance (ie, 1, 2 or 10 parallel 0G cables etc), the voltage drops vary with the load current.
So is that stable? The load voltage will still vary, but with lower transmission losses, its variation will less.
The battery will dip.
A large AGM battery might have 5mR internal resistance, hence it drops 200A x 0.005R = 1V.
A larger (Odyssey 75/86-PC1230) is 2.5mR hence a 0.5V drop at 200A.
Then there is the batteries capability...

For now, keep it simple and try to minimise your losses.
Later you can decide if are you concerned with voltage losses (resistance), or voltage dips (from varying current with power output)?
And if concerned about dips, why? (Keeping in mind you are already down at least 1.5V for high power outputs because your alternator isn't big enough.)

As to running a "direct ground to the battery for the sub amp" - only if you have a high resistance chassis or connections. But I would be surprised (read: worried) if a cable had a lower resistance than a car chassis. But all those voltages are easy to measure with a voltmeter anyway. And there is unlikely to be much difference in length between chassis and cable anyhow (who cares? and why?)
Normally I'd say the more parallel cabling the better, but not for a metal chassis (unless cable-connector-chassis joints have a higher resistance than end-to-end cable).

For more info though, I suggest experienced gurus. Whilst I keep hearing things that seem strange to me (like single cables not paralleled, or ground loops, or antennae planes etc), I don't have the practice.
And they can advise of the best equipment and fusing etc. I'd run the fattest cable as far as possible. And if lower gauge fanouts are short and secure, they need not be fused.

The rest of the crap below is optional detail. Feel free to ignore it!

EG: Lets assume you measure a 2V drop with the amps using 200A - ie, the battery as 12V; the amp as 10V; 12-10 = 2V.

Your Amp is consuming 10V x 200A = 2,000W = 2kW (P=VI).
Your cable is dropping 2V @ 200A = 2x200 = 400W (20% of 2kW the same as its 2V drop is 20% of 10V.)

What resistance is the cable (including fuses etc)?
V=IR hence R=V/I = 2V/200A = 0.01 Ohm = 10 milli-Ohm.

That's the equivalent of 100' of 0G cable (from 0G = 0.0001 Ohms per foot).
I'll use "R" to represent "Ohms".

You might then find that the distribution block is dropping 1.5V and the cable 0.5V.
So the d-block is 1.5V/200A = .0075R = 7.5mR.
The cable is 0.5V/200 = .0025R = 2.5mR.
The total "transmission" resistance is cable + d-block = 7.5mR + 2.5mR = 10mR (same 10mR as original (1.5V + 0.5V) 2V at 200A.

Say if you halve the transmission resistance.
Instead of 0.01R we have 0.005R.
The voltage drop is V=IR = 200A x 0.005R(ohms) = 1.0V.
That's half of the original 2.0V drop. (As we'd expect - we halved the resistance & since V=IR and we made 1/2 x R, that means 1/2 x V where V is the voltage (drop) across the Resistance R with current I running through it.

So now you have one extra volt for your amps. But that's looking at it in simple terms. The lowered cable & d-block resistance means more current will flow - eg V=IR hence I=V/R = 12V/(50+5)mR = 218Amps (where 50mR is the effective amplifier(s) resistance - ie, 10V/200A) so hence you now lose 1.1V across the cable & d-block, and the amps get 10.9V or 0.9V (~10%) more than it did. (1.1+10.9 = 12V = battery voltage.)
In practice, the battery voltage will drop a bit due to the increased current, and amplifiers may not behave like a resistor....
But the main point is that by reducing your transmission losses aka resistance, the amps get more power.

So are you saying I SHOULD use the 4 gauge on the 4 channel? Also, how do I hook up a 4 gauge input with a 0 gauge input and only use one fuse? Remember, this is how it looks in my vehicle right now:

ANLFUSE1 ---> (0/4/8)
0 --> Dist.BLK
ANLFUSE2 ---> (0/4/8)

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No - I'm saying that to reduce your voltage drops, you need reduce you resistances.

How you best do it is a design issue.
Are you designing for bling and hence want the best looking system, or maybe the loudest system? (Both IMHO&E usually resulting in poor sound quality.)

Maybe you might want minumum voltage drops hence 0G (0.1mR/ft) splitting into two equal loads with 2 x 3G (0.2mR/ft), or into 2G & 4G (.16 & .25 mR/ft) for a 40/60 load split. (But why not 0G splitting into 0G? See below...)

But if I understood you correctly, you have a single 250A fuse on your 0G (presumably near the battery!) which then feeds 2 downstream 250A fuses at each split?
If that is correct, then why have the downstream fuses - they are meaningless. (Did I miss the obvious or misunderstand?).
IOW - remove them. Get another disto block or bypass them or short them with cable.

If I had such a system, I'd have the 250A fuse near the battery (obviously) into 0G going as far as possible - right to the loads if they handle it.
For the split to each load I'd use some heavy secure cable joiner or clamp (twin screws; pressure spreaders; insulation clamps etc).
Or for Mr non-Bling Cheaps8t me, maybe at least two hose clamps or U-bolts - with maximum cable-cable copper interweaving - in an insulated box or surrounded by copious insulation.
If my splits are long runs and their gauge was too unsafe at the "master fuse" rating (250A), and assuming I couldn't split into 0G and then the smaller G at the last few inches, I'd install fuses at the splits as per normal practice, else guarantee physical security.

[FYI - These audio systems are similar to traditional telephone exchanges us DC power at HUGE currents. They use copper busbars and NO fuses - instead relying on physical security and maintenance procedures. If a fault happens, they burn to the ground (as did some New York exchange a few decades ago). But they have no choice - you cannot safely break (fuse) DC loads of several thousand Amps. And the practice works - despite the odd short circuit that usually vaporises whatever metal ladder or crowbar or nose-ring that somehow managed to touch both busbars, rarely has an exchange burnt due to shorts.]

But as I said, you need a designer.
If you understand what I have said, you should be able to do it yourself. (Hence my sample calcs & analysis.)
It's Ohm's Law (V=IR) for given cable sizes & lengths and the "combining resistor in parallel formula". But the latter is simply "half the resistance every time you parallel the same sized resistor" (eg if a cable is 12R, two in parallel is 6R, two of those = 4 in parallel = 3R etc).

There is a bit more circuit theory (sum of load voltages = source voltage; sum of parallel currents = source current; and the same total current flows thru a circuit, and at a given connection point, all voltages are the same)...
But all the above are really just interrelations of the same V=IR Ohm's Law.

But instead you could just keep improving your system.
If you find your biggest single voltage drop is from battery negative to to chassis, double the cabling. That will halve the resistance and hence halve that voltage drop. If it's still the highest, double again, or add as much as you can - the fatter the pipe, the lower its resistance.
If it's the distribution block, then overcome it somehow. If you can't, its loss has to be accepted. (Not that anything is ever acceptable!)

Eventually though you hit a limit - you can't attach a 1' diameter cable to a battery etc.
Or it is cheaper buying a vehicle that can accommodate battery(s) next to the loads, etc etc.
Or cheaper using a AC system....

That's all design & installation stuff which is why we have talented installers.
I'm not one of those (nor talented). I "merely" expanded the simple Big-3 principle in reaction to what I considered unacceptable voltage drops.

My experience does however include people that install expensive batteries for no significant gain, or even install capacitors to (quote) "increase alternator output voltages". (I think they need a true-RMS voltmeter if that's what they really did measure!)
And lots of people that think having a HUGE battery can overload their vehicle, or that a HUGE alternator can blow their battery etc. (Noting that eg batteries may have charge-rate limitations, but that's usually not the issue....)

I think a retro encabulator will help with the voltage drop.

https://video.search.yahoo.com/video/play?p=retro+encabulator&ei=UTF-8&fr=yfp-t-701&tnr=21&vid=0001534693733

Brilliant!
I used to work for Allen Bradley - I wonder if they still discount?

And that dude (Carnes?) explains it so well. If only I could do the same with my plasmic recycler.

I would like to thank the previous two men for their sarcasm, it hasn't benefited me.

Anyways, I ran a 4 gauge wire from the battery to the grounding point in the back (negative terminal on the battery) where the two amps are grounded too. It was somewhat more stable, but still chilling at 10.5 Volts measured at the sub amp. The guy i'm working with insists a bigger battery will surely help me here, and he's not a salesman, he's just saying it would. My battery light came on too, and after 10 minutes of charging with the system off it stayed on, but turned off when I restarted the vehicle. What gives?

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Did you crimp and solder all conections? When the voltage is dropping down to 10.5 volts, is that at the amp or at the battery? If at the amp, what is the voltage dropping to at the battery? Did you ground the amp to a seat or a seat belt bolt?

Again, what can I say?

I bigger battery WILL NOT reduce your voltage drops.

It will provide a higher source voltage for a longer period of time.

If his solution solves your problem, do it.

If you still want to reduce those losses later, hopefully all that I have said other than my last compliments to Rockwell have been beneficial.

If not, let me know so I can delete my posts to save space, boredom & confusion.

ADDENDUM re charging:
Your system probably dropped below some threshold voltage.
Some charging systems need a higher voltage or a re-start to initiate charging again (ie, ignition off-on).

Whilst your charge light is on, your system is not charging, hence no higher voltages etc.

(Charging systems vary. For most you must have a charge lamp (or similar trickle path) to ensure charging is initiated. For some you can disconnect the charge lamp once charging is initiated, etc etc...)

A bigger battery will last longer, but it too will discharge if the alternator isn't big enough.

i'm new to the forum but if i may say i would take the car to a local auto shop or like an autozone to have the alternator checked to be sure it isn't defective because to me it sounds like you have a weak alternator. a new bigger battery will not "give" you a higher voltage it will only hold the higher voltage for longer. if you can't replenish that power in the battery it will cause a voltage drop. now in my experience with both car audio and with automobiles i have also had this problem and found that the problem for the voltage drop was due to a failed voltage regulator in the alternator itself. this will allow sometimes allow the alternator to still charge the battery for starting purposes but as soon as a load from like an amplifier is put on it, it can not keep up with the current demands.

all in all remember that the alternator is what makes this higher voltage so therefore it is the brain of the charging system.

Hey BigTime - you may be new but what you said is something others often do not seem to grasp.

An alternator that cannot keep up with demand typically means a 1.5V system drop which is at least a 20% drop in audio output and spark power (assuming non-SMPS nor CDI etc).

A voltage drop due to inadequate cabling (from the battery/alternator) has the same effect. And the battery/alternator will not change the cable's drops & losses.

At least the cabling is cheap & easy to solve.

I this case, it seems cheapness is a priority and no extra equipment can be fitted.
But unless the battery is faulty, there is little point upgrading it.

If the regulator is faulty, it needs to be repaired anyhow. And that probably means replacing the alt/reg, so why not with a larger unit? These days many vehicles have 120A and larger alts.

I know I am just expanding what you said, but some readers are like old keyboards - you have to punch the information in.

Welcome to the site!

thanks for the welcome. on what you replied i could not agree more. i have installed quite a few car audio systems with good luck and you would not believe how many people would want to run the biggest baddest system and completely neglect the fact that the stock charging system of almost any vehicle is only about big enough to run what comes standard on that vehicle let alone a subsonic bass producing power hungry amp. i always tell people the same thing. you are only as strong as your weakest component. you wouldn't build a mansion on a crumbled foundation would you

The problem is not a weak alt(well it is but not because it is defective). The problem is, that it is the new BS type wind with onstar running through it. It sucks so much life out of the power it is making. You would be lucky to be able to run a 500rms mono block off it let alone the load you are trying to run. Getting a rewind is not going to get you much more output if any. the onstar regulates it output and a new alt is not possible to get unless from the factory. Even then there so called "OPTIONAL" H/O alt is the exact same part number as the none H/O. About the only thing that can be done is add an alt for a dedicated audio charging system. Simply removing the old one and replacing it with a regular style wind is not possible either. The onstar runs trough everything and is and regulates the alt. With out it able to pass through the alt it wont work. At least to my knowledge and the last time i talked to Dominic Iaggi. So other then adding an alt you are SOL at the moment.

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posted_image

M tech . I would listen to these guys they know what they are talking about trust me a bigger battery is gonna leave you stuck somewhere on the curb.I had a factory alt. 140a on a bigger the recommend battery 800/1000 and after having 3 amps and other junk wired to it the alt left me stuck and the car shut off. They do sell. Ho alts that fit your factory specs. Highoutputalternatorscom sells them they aren't cheap but they look like thwe orginal . You can also find a local shop in your area and they will make a custom oem fitted alt. no brackets or special belts. You can go on and on and not listen but doubling your big3 and swapping batteries is not going to solve your problem. The alt keeps the car running after the battery starts it.

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1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
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12.5 VGA flip down
Nettop pc w/10" touch screen
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Xtx-500.5
"Take the faceplate off get the jumperpack"

Looks like Iraggi now has them as well In 3 flavors for a for a direct bolt up for a commander. 220A, 260A and 300A he has a store on the bay and and he is who I use for all my alts. Guess i need to call him about my 300c again.

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posted_image

So what is general consensus here? I got one guy saying that my car has something to do with OnStar and all the alternators in the world won't make a different. Then another guy says that the alternator will make the world of difference.

Which is the right answer?

Also for Dominick, how do I get ahold of him? Can someone PM me his information? Which other HO alternators can I get for this thing that are direct bolt ins? I haven't had any luck and the ones I have found have very low idle output.

Here is the lone exception (EXCEPT its for the Grand Cherokee, but I think that works for Commanders too):
https://www.dcpowerinc.com/alternators/jeep/2007-2010-jeep-grand-cherokee-4-7v8-260-amp-high-output-alternator.html

Its still extremely expensive though. I'd like to hear what Iraggi has available though.

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michigan_tech wrote:

So what is general consensus here? I got one guy saying that my car has something to do with OnStar and all the alternators in the world won't make a different. Then another guy says that the alternator will make the world of difference.

Which is the right answer?

Also for Dominick, how do I get ahold of him? Can someone PM me his information? Which other HO alternators can I get for this thing that are direct bolt ins? I haven't had any luck and the ones I have found have very low idle output.

Here is the lone exception (EXCEPT its for the Grand Cherokee, but I think that works for Commanders too):
https://www.dcpowerinc.com/alternators/jeep/2007-2010-jeep-grand-cherokee-4-7v8-260-amp-high-output-alternator.html

Its still extremely expensive though. I'd like to hear what Iraggi has available though.

If dominic Iraggi is making them now then the onstar running through it is not going to affect it as was originally thought or they have now found the way around it. The big problem with these types of alts is the case is very small to the way it is wond. Adding wind to it was and is not easy. Hints to the price of the few that are out now. That and they are a fairly new style. Last time i checked. Mind you quite some time ago in the end of '07 beginning of '08 there was no one doing winds or after markets for these types of alts. It was also thought that the onstar and PC were regulating the voltage. You had to add alt/s for a dedicated audio charging system for anything of moderate to high end power.

Iraggi can be found quite easily on the bay. store name Iraggi Alternator And Electronics. Email is dominick@tds.net Phone 651-287-7991 he is open M-F 9am-6pm He can answer any questions about which alt you need and about the onstar. I need to call him as well the last time i did there was nothing availible for me at that time. But he does have them now.

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posted_image

michigan_tech wrote:

So what is general consensus here? I got one guy saying that my car has something to do with OnStar and all the alternators in the world won't make a different. Then another guy says that the alternator will make the world of difference.
Which is the right answer?

I thought most were in agreement.
We have discussed TWO problems:-

(1) Each time you double your power cables, you halve your cable resistance thereby halving the voltage drops. V=IR. I don't think anyone disputes that.

(2) When(ever) your alternator cannot supply enough current, your alternator voltage drops until your battery takes over. Nobody should dispute that either.

Both above in your case where about 1.5V.

Certainly IMO a 1.5V cable drop is too big and should be reduced. 0.75V may be acceptable. And that should be cheap - merely double the cabling. Is doubling again from 0.75 to 0.33V worth it? Probably not.

The alternator is a contentious issue. Many people say get a bigger battery etc. All that does is take longer to flatten.
It will NOT give you more output power when the load exceeds alternator capability.

A bigger alternator keeps the voltage high for higher loads (and usually lower RPM).
And undersized alternator means audio output drops by at least 20% - eg from 12V to 14.4V means at least a 44% increase in amplifier power output.

Keep in mind the two separate parts above. IMO neither can be disputed (except by those without reasonable understanding of them).

Another confusing issue is that changing the current available does NOT change the losses along the way - ie, the cable & distribution voltage drops. Whether you have a 100AH battery or a 10,000 AH battery will not change your 1.5V cable losses. (However, a better battery may have or hold a higher voltage at its output - ie, lower internal resistance etc. But that should be insignificant to 1.5V drops whether through cabling or undersized alternators.)

If you could reduce your cable losses by 1.5V and your alternator could supply full power, you would have at least a 60% audio output power gain (from a supply voltage POV).

There are other details - like lower alternator output at lower RPM, and resistance cause by ammeters and protection (fusing) etc. But let's KIS.

If there are any apparent contradictions, reply what they are and we'll go from there.

Here is the way i see it. Now maybe I am way off base here but the only thing in your vehicle that will produce electrical power is your alternator, there is nothing else not even a battery or a capacitor which are just to merely act as storage devices for the electrical power. Now with this voltage drop you are experiencing you are not only going to eventually due damage to you car audio components but you also run the risk of damaging the electrical components of your vehicle mainly you ecu. Your electronics in your vehicle come with a rated power that they need in order to operate properly. As your voltage drops your amperage is going to increase because the power remains constant. This is going to cause your electronics to get warm. You definitely do not want to burn up your ecu because it is the "brain" of your vehicle and they are very expensive.

With all that said before you go out and start spending hundreds of dollars on remedys lets start by doing a little self check. First with your vehicle running and your system off check your voltage at your battery with a multimeter. You should be producing somewhere near 14.4 volts. If you are lower than 13.8 volts with no load on the charging system your alternators voltage regulator is shot and it will need to be replaced regardless. Now if it comes back at near 14.4 volts and you turn your system on like maybe to half level and you are already down to say 12.5 volts I am willing to bet that the alternator is no where near big enough to handle the amp draw. If it all checks out fine at the battery than yes it is definitely an issue of to small of wire. Now also keep in mind that just because a manufacturer says a wire is 0 gauge and you paid $2 a foot for it you really got an 8 gauge wire with a lot of plastic coating. Remember you are only as strong as your weakest link. Good luck and feel free to shoot me any questions.

More agreement! Bigtime is saying the same thing in an alternator-itive way.

A clarification - current goes up if voltage drops only for constant power loads - eg SMPS (switched-mode power supply) etc.

Now - subject to correction by anyone with modern or specific examples.....
ECUs generally do not have constant-power supplies since their CPUs etc only require 5V or less. A supply of 8V or above is sufficient for even the oldest linear 5V regulators. (Devices like injectors & relays may require higher voltage, but they usually run off the raw supply - ie, 8V or above.)
Hi-power audio amps use SMPS (DC-DC converters) as they have to to get several hundred Watts (eg - above 200W onto 1 Ohm speakers).

Also, Mr Mich mentioned a 1.5V voltage drop which - as i understand it - is from distribution alone - ie, from the alternator/battery via the distribution block to the amp(s). That can only be improved by decreasing distribution resistance.
If Mich's Sundowns are SMPS or equivalent, as BigTime says, with decreasing supply/battery voltage, the current increases thereby INCREASING the distribution voltage drop.
That is in addition to undersized alternator considerations.

If the vehicle's electrics could be transferred to where the amp is - including the alternator's "sense" wire, the alternator will keep that voltage at 13.8-14.4V whatever - ie, overcome the distribution drop of 1.5V etc. But apart from other consideration, unless what I, Mr Big & others are saying is understood, I would NOT attempt any such modification.

I still am confused on what you all are recommending I should do. Here are the facts once again:

1. Voltage drop of 1.5 V from the Battery to the Amp.
2. A distribution block exists at the back of the vehicle that takes in the 0 gauge from the battery and splits it into 0 and 8 guage (sub amp and 4 channel amp, respectively).
3. The big 3 all are ran at 0 gauge, and there is an additional 4 guage wire ran from the negative terminal of the battery to the grounding point in the back where the amps are also grounded.

Dominick Iraggi has a direct bolt in alternator available for me. It is pricey, but I can get 180A, 220A, 260A, 300A, or 320A. Does going too high on an alternator (Amperage wise) possibly HURT the electrical system by putting too much out?

So my question is this:
1a. Do I get the alternator?
1b. If so, does this mean I have to upgrade the battery too?
2. Do I get just a bigger battery?
3. Do I do something else with my charging wires?

Thank you

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Well I'm not the smartest guy on here but what I would do is get the alt. The biggest your car can take as well as your pockets. But don't short change your self on this upgrade. As for a battery if its fine leave it be. Big alt small battery fast charge but on a big battery you won't have starting issues as well with a small battery and a system you might. Someone else chime in

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1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
alpine v60
12.5 VGA flip down
Nettop pc w/10" touch screen
78nova
5-re audio 5x7 ,10" sub &
Xtx-500.5
"Take the faceplate off get the jumperpack"

Your problem with your voltage drop between your battery and your amps is due to the wiring configuration. Your supply wire to the distribution block need to be bigger than the wire that go to your amps. You need your wire to the distribution block to have an equal or lower resistance per foot than the combined total of the resistance of the wires that it is supplying. Your supply wire is probably getting pretty warm to the distribution block because of this voltage drop. Now I can relate to this because I once had a 4 gauge power wire that ran to a distribution block and then a 4 gauge to one amp and a 10 gauge to another and the supply wire got so hot that you could actually smell it burning the plastic coating off of the wire. To remedy this I put in a 0 gauge wire from the battery to the distribution block and the problem went right away.

So all in all in your case i would either double up the wire going from your battery to the distribution block or take it out all together and put in a triple 0 gauge single wire. Now with that said that will take care of your voltage drop their but if your one amp requires a 0 gauge wire to power it that means it likes a lot of current, way more than your stock alternator would ever dream of putting out.

So in the end the only way I see to properly solve your problem you are going to need to change your wire between the battery and amps or use a larger one and you will also need to go to a much larger alternator. Either that or you will need to change your sub amp to a much smaller one.

Good luck michigan_tech and if you have any questions I would be more than happy to help you.

Mr. Big

As far as me needing larger than 0 gauge from the front to the back, that doesn't make sense to me. I've ran bigger amps in other cars with only 200A alternators and never had an issue. In my last vehicle, I had 0 ga from the battery to the D block and then 0 and 4 out of the block. I certainly don't think that for these two amps it causes the need for 00 or 000 gauge, I never needed those for amps that were bigger than these amps in the past.

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Have you checked to see if the voltage drop is on the power or the ground? Connect a Wire to the battery's positive terminal and run it to the back of the vehicle near the amplifiers. Connect the red meter lead to that wire. With the system playing where you experience the 1.5 volt drop, touch the black meter lead to the input terminal of the amplifier. What is the voltage? After getting that reading, move the black lead to the input side of the distribution block. What is that reading? These readings will only show the voltage drop on the power path to the amp. Then you can move the wire to the ground connection of the battery, and do the same thing, with the meter. First the ground terminal of the amp, then the grounding point at the chassis of the car. Whichever (the power or the ground) shows the greater reading, needs to be dealt with. There can be nothing else connected to the wire that you ran to the battery.

It's not that the amps require a bigger wire to supply the power your voltage drop is occuring across your distribution block because you are changing the resistance between the wires. If the power demand is constant and you change the resistance your voltage is going to change, thus you end up with your voltage drop. Just out of curiousity take a multimeter with your system on and your vehicle running and check your voltage to ground on both sides of the distribution block and see if that is where the voltage change occurs. If so then that will prove my theory.

As always good luck and I hope to hear from you!

Mr. Big

Are you both suggesting that wiring is my only issue and I don't need to upgrade my battery nor my alternator?

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You will need to check it. You must be playing it at the level in which you got the 1.5 volt drop. Playing it at a lower level is not going to tell you anything. Is it a fused distribution block? If so does it show any signs of melting the plastic around the fuse holder mounts? Checking from one end of the distribution block as he suggested will tell you if the distribution block is your problem. That test can be done in less than a minute. Once again, the system must be PLAYING to check this too.

Now I personally believe as long as your vehicle is starting fine your battery is the furthest from your problems. Your voltage drop I believe is a wiring problem and as far as your alternator goes if you have the potential to have over a 200 amp load there is now way your 140 amp alternator will even keep up let alone do it without a voltage drop, unless you are only gonna listen with the volume a quarter of the way up.

Mr. Big

i am an idiot wrote:

You will need to check it. You must be playing it at the level in which you got the 1.5 volt drop. Playing it at a lower level is not going to tell you anything. Is it a fused distribution block? If so does it show any signs of melting the plastic around the fuse holder mounts? Checking from one end of the distribution block as he suggested will tell you if the distribution block is your problem. That test can be done in less than a minute. Once again, the system must be PLAYING to check this too.

The Distro bock is fused and it uses ANL fuses, so your saying I should be looking for melting on the plastic around the centre of the fuse or burn marks on the fuse itself?

The amps run at 12 V when at no volume, but when I turn it up to 52/60 on my deck its sitting at 10.5 V. (I probably should have mentioned that before...)

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Earlier I asked if the 10.5 was at the battery or at the amp. I do not know if I ever got an answer. If that was the reading at the battery, performing the tests above will tell you if there is a voltage drop on your power wire or your ground path. And it will tell you which of the 2 is more the cause. If the voltage was 10.5 at the battery, you have charging issues.

i am an idiot wrote:

Earlier I asked if the 10.5 was at the battery or at the amp. I do not know if I ever got an answer. If that was the reading at the battery, performing the tests above will tell you if there is a voltage drop on your power wire or your ground path. And it will tell you which of the 2 is more the cause. If the voltage was 10.5 at the battery, you have charging issues.

I thought I said this clearly, but it was 12 at the front, and 10.5 at the sub amp when I was running 52/60 on my deck (cranking heavy bass).

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If what you stated is going on your wire is the problem. If you got cheap wire you get cheap results. Turn the car off check both ends of the wire and post your results. Another tet you can do is unplug the wire from your fuse to your distro block run a new test wire from your fuse to your distro . Have the wire outside the car for a easy test turn it up and post your resaults. I think your main amp wire is bad.

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1993 sdv
Alpine 4x6 6x9 5 1/4 swr-10d4
alpine v60
12.5 VGA flip down
Nettop pc w/10" touch screen
78nova
5-re audio 5x7 ,10" sub &
Xtx-500.5
"Take the faceplate off get the jumperpack"

I am sure you did mention it, there are a lot of posts to read through. Performing the test at the distribution block should be simple. One lead on the input of the block. the other lead to the output side of the fuse leading to the sub amp.

i am an idiot wrote:

I am sure you did mention it, there are a lot of posts to read through. Performing the test at the distribution block should be simple. One lead on the input of the block. the other lead to the output side of the fuse leading to the sub amp.

So I hook up a multimeter like you mentioned, and what do I look for? I do this with the volume cranked up right?

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You use you voltmeter or multimeter to find your biggest voltage drop - eg:
* in the ground circuit: chassis to engine block; battery- to chassis or engine; chassis (or whatever) to the amps.
* in the power circuit: alternator to battery+; battery+ to front/nearby fuse or distro block; across fuse/distro; distro to amps (or front fuse to rear distro; across distro; distro to each amp/load) etc.

IE - find the voltage drop across each section.
Tackle the biggest drop first. Doubling your copper (cable) across that section will halve that voltage drop.

That's your cheapest option.
And reducing that 1.5V drop is VERY worthwhile. (That's 150W lost per 100 Amps of load.)

You might then consider boosting your source voltage from about 12.7V to 13.8-14.4V with a bigger alternator.

oldspark wrote:

You use you voltmeter or multimeter to find your biggest voltage drop - eg:
* in the ground circuit: chassis to engine block; battery- to chassis or engine; chassis (or whatever) to the amps.
* in the power circuit: alternator to battery+; battery+ to front/nearby fuse or distro block; across fuse/distro; distro to amps (or front fuse to rear distro; across distro; distro to each amp/load) etc.

IE - find the voltage drop across each section.
Tackle the biggest drop first. Doubling your copper (cable) across that section will halve that voltage drop.

That's your cheapest option.
And reducing that 1.5V drop is VERY worthwhile. (That's 150W lost per 100 Amps of load.)

You might then consider boosting your source voltage from about 12.7V to 13.8-14.4V with a bigger alternator.

So here is the REVISED scoop.

I went out and got a 320A Iraggi Alternator. I also changed the amps up from Sundown SAZ1500D's and SAX50.4 to Cadence Audio C9 and C5. The subs will now be wired for a 2 ohm load at the amp instead of 3/4, so this should be way more stable. The C9 will also put out more power than the SAZ1500D at 2 Ohms simply because it is a bigger amp (physically) and it is rated higher. The amps are wired like so:

Battery (+ and -) ---> C9 ---> C5

So essentially there is a direct Voltage line from the positive terminal of the battery to the +12V terminal on the C9 and a direct ground from the negative terminal to the C9's GND terminal (0 GA on both lines). From there, an 8 gauge wire was inserted in the power and ground terminals on the C9 and it was ran to the C5's +12V and GND terminals (respectively). These lines act like "jumpers".

According to one of the engineers at Cadence, the amplifiers need at least 11V to operate safely. My questions include the following:

1. Will my STOCK battery be able to run this entire system now that I have the tremendous charging upgrade or is there just not enough capacity there for the battery to provide power?

2. Someone was telling me I should establish a common "ground plane" between the head unit and the amplifiers considering the distance between them. Is this a valid point? He was saying I should run a small jumper line from the C5 (4 channel small amp) to the head units + and GND inputs on the back, then it all would be hooked up to the same voltage and ground plane. Does this make any sense? To be more explicit, he said that I would run a 20 ga wire in the + input on the C9 (which is being fed by an 8 gaug + input jumper from the C5) and run it to the + input on the head unit, and do the same with the negative for the GND terminals.

Please let me know what your thoughts are.

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There is no way to make it run 100% efficient. Most alternators will only produce 14.4ish volts at regualr operating speeds. You will have a voltage drop no matter what you do. To minimize it, minimize the amount of wire used...distance from battery to amp, the fewer the connections the better, the better the connections the better, the quality of the wire the better. The big question in my mind is...does that 1.5 volt drop change the sound quality so much that you would spend this kind of time chasing it?

and the battery is a 94R in case no one answered that already. Good luck sir.

The battery will provide enough power until it discharges to the point where - with voltage drops - the amp sees 11V.

I don't know how else to answer that part of your question....

oldspark wrote:

The battery will provide enough power until it discharges to the point where - with voltage drops - the amp sees 11V.

I don't know how else to answer that part of your question....

Well I had asked a few questions in there, and nobody has responded about the whole grounding plane idea.

At any rate, would my battery sustain that 13.8-12V charge considering how fast the alternator is recharging it?

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The ground plane depends what it is there for.
An antenna's radiation? A common ground to avoid ground loops?
If there is no need for it, then why have an extra connection point hence more resistance etc in the paths?

The battery does not sustain 13.8V etc. Excluding surface charge, a fully charged battery can only supply (sustain?) up to ~12.7V.

It is the alternator that sustains the load above the battery's voltage (eg, max 12.7V).
Below 12.7, it is the battery and whatever the alternator is supplying.

So however long your battery can sustain your load without the alternator is the minimum time the battery will sustain the load with the alternator.

Does that make sense?

The battery sustains the load until it is discharged - ie, ~12.4V for cranking batteries, ~11.6V or lower for deep cycle. (Those are internal cell voltages - ie, without the internal-resistance voltage drops. This may mean 11.4 or 10.4 or 9.4V at the terminals under load.) But your load will probably hit 11V before the battery is discharged.

oldspark wrote:

The ground plane depends what it is there for.
An antenna's radiation? A common ground to avoid ground loops?
If there is no need for it, then why have an extra connection point hence more resistance etc in the paths?

The battery does not sustain 13.8V etc. Excluding surface charge, a fully charged battery can only supply (sustain?) up to ~12.7V.

It is the alternator that sustains the load above the battery's voltage (eg, max 12.7V).
Below 12.7, it is the battery and whatever the alternator is supplying.

So however long your battery can sustain your load without the alternator is the minimum time the battery will sustain the load with the alternator.

Does that make sense?

The battery sustains the load until it is discharged - ie, ~12.4V for cranking batteries, ~11.6V or lower for deep cycle. (Those are internal cell voltages - ie, without the internal-resistance voltage drops. This may mean 11.4 or 10.4 or 9.4V at the terminals under load.) But your load will probably hit 11V before the battery is discharged.

So are you saying that when I'm driving and listening to my music that there could be a point where my battery runs out of potential and cannot sustain the load despite my alternator charging?

Also, do you surmise that there would be sufficient voltage fluctuation to possibly fry the connected equipment?

What I mean from GND plane is establishing a common 12V and GND signal from the amplifiers and the head unit. Is this a good idea by running the + and - wires for my head unit as jumpers from my 4 channel + and - ports?

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LOL! We are going in circles again!

michigan_tech wrote:

So are you saying that when I'm driving and listening to my music that there could be a point where my battery runs out of potential and cannot sustain the load despite my alternator charging?

No - you are suggesting that your alternator cannot always supply the load. You are hence discharging your battery.

michigan_tech wrote:

Also, do you surmise that there would be sufficient voltage fluctuation to possibly fry the connected equipment?

No - I am not familiar with the equipment. (You mentioned 11V etc.)

michigan_tech wrote:

What I mean from GND plane is establishing a common 12V and GND signal from the amplifiers and the head unit. Is this a good idea by running the + and - wires for my head unit as jumpers from my 4 channel + and - ports?

IE - a common ground, or ground bus etc.
Though I see reason for common ground point, I see no reason to introduce another one. What is wrong with the common point between the battery & body? (Or alternator/engine if you prefer?)

But irrespective of the commonality, as KLF wrote ((klferguson26; and just before 3AM too LOL!), you will have voltage drops to or from it. You can minimise the drops. And they may NOT matter anyhow.
(The common +12V is lesser issue since things are not referenced to it the same way as ground - ie, ground loops, not hot or +12V loops.)

I'm merely (re-)stating the basics. Re-read the thread (or my replies) if you don't understand that we are repeating the same.
EG - when the alternator can't supply the load, the battery discharges.
How long till it flattens? Refer to battery specs and discharge curves for your load (else approximate through AH ratings).