Looking to put together a minimal 500 watt RMS build. Have been on the fence if I need to pay significantly more for the oxygen free copper wire than the inexpensive clad copper wire.
I know the conductive properties for copper is much higher than aluminum and that the cca wire will run hotter and less efficiently, but is it truly necessary under a certain wattage for the benefits to make a difference or should you be using the better wire just for peace of mind?
what type of wire are you guys running and what are your opinions on the subject?
thanks!
I'm not sure why you'd want to use cca instead of plain copper - Al has only about 2/3rd the electrical conductivity of Cu.
As to OFC vs normal copper, early marketing blurb claimed that that OFC was a much "cleaner" sound because it didn't have the domains of plain copper (the names escapes me - domains, as in inter "crystal" barriers). But that has since been totally blown out of the water. (Yes, I helped the blow - just as I do now with "smart" battery isolators and a few dozen other things being advertised under false pretenses.)
I was quite anti-OFC.
However, OFC does have a lower resistance than ordinary copper.
But that is often trivial, else can more economically be overcome with a thicker gauge of wire - or a parallel run - both of which can be cheaper than OFC.
Of course if the car-audio world were that concerned about resistive losses, they wouldn't be using 1 & 2 Ohm speakers. Nor would they mount their frigging dc-dc converters IN the amplifier (it should be up front near the alternator and battery!) [ dc-dc conversion is required for >~200W into 1 Ohm, or 400W into 2, or 1600W into 8 Ohm etc (for 12V systems). ]
But 500W is not that much, and IMO losses with standard copper should be trivial - assuming the correct or bigger wire gauge is used.
[ However I am one for minimising voltage drops. I tend to exceed the gauges often provided in tables etc - unless cost or size/weight are an issue. But I prefer an "infrastructure" that exceeds equipment requirements and performance (rather than the other way around). ]
And that caraudiomag article does not mention OFC. As to "full spec", I'm sure the cca wires is also "full spec", but it is full spec to its size with its reduced conductivity. That's a case where the user had to be aware - it is not a "fault" of the cable.
However, if the manufacturer etc claim excessive specs (as if it were 100% copper), that's a different issue and one for the courts (misleading or fraudulent advertising etc).
It's like caraudiomag saying that 100% normal wire copper is not "full spec" because OFC has a lower resistance.
Oops - did any of that help?
But be aware of the difference between your OFC vc CCA question and caraudiomag's Cu vs CCA. Note too that Garry (caraudiomag) wrote as I did about going up one gauge etc, but that that might cost. I wonder if he is arguing against OFC? (LOL!)
As an aside (more for the experts on this forum), I often read car audio forums stating that the lower the Ohmage of a speaker, the BETTER the sound quality. That is the opposite to what I recall, but maybe their "quality" means loud and distorted (and expensive) rather than "clean".
Sorry - that's a bit of a hijack as it's not directly related to your question, but that's been bugging me and - geez - how many things can those forums get completely r's about? Heating batteries for greater capacity; a capacitor or batteries rather than a copious alternator... (Though those issue I do understand quite thoroughly!)
thanks for the responses, very informative! I just purchased some kicker ofc 4 gauge wire, which should be plenty for my 500W setup. Most people just buy cheap cca kits from ebay and are getting what they pay for... extra insulated, poorer conducting wire.
I spent a little more than I first planned but atleast got a well known: https://i.imgur.com/jgfKj.jpg
Everyone else feel free to chime in and add some thoughts/criticisms this is very interesting stuff! Never knew wiring made such a difference...
Not that I want to scare off or substitute for others...
(Wot? Me! That's as ridiculous as me rambling. And rambling!)
And (PS), I missed dragon's response. (And only skimmed the links - & I wondered if my aforementioned "copper (molecular) domains" was mentioned in those 1980's articles - ha ha.)
But IMO wiring is simple.
Find its resistance - eg,
powerstream.com-Wire_Size, though others hereon have links to others (better or more applicable?).
EG - Ohms per length times length (= Ohms resistance).
The voltage drop across it is simple Ohm's Law: V=IR (Voltage across something equals the current through it (I, in Amps) times the resistance of it.
FYI - it's Volts, Amps and Ohms. But that's equivalent to working in milli-Volts (mV), Amps, and milli-Ohms.
Decide if that voltage drop is acceptable - eg, 100mV (0.1V), 1V, 3V...?
The loss is also simple - P=VI, Power (Watts) = Voltages times Current (across & thru it). The Watts is heat for wires. (And heat & light for lights, etc.)
This next is a bit more complicating FYI stuff (though its use can make things much easier!)
The above V=IR and P=VI can be combined to yield P=VV/R or P=IIR. That's convenient if you know 2 of the 3 (V, I or R).
[ Ignore if too complex: Note that Power increases as a
square of voltage or current (VxV or IxI, aka VV or II) for a given resistance. Hence why (typically) 14.4V delivers 44% more power than 12V - ie, not simply 14.4/12 = 1.2 = 20% extra, but 1.2 x 1.2 or 14.4x14.4/(12x12) = 1.44 = 44% more! Sort of obvious if understood that V=IR means that V is proportional to I across a given resistance R - ie V=IR => V/I = R. But that assumes a constant resistance load. ]
This next may be complex, but illustrates how easy - or applicable - the above can be.
Will a 1.5V battery across a speaker blow it?
Let's see - worst case is highest current which means lowest impedance (~resistance) speaker - eg, 1 Ohm.
P = VxV/R = 1.5V x 1.5V /1 Ohm = 1.5 x 1.5 = 2.25W.
Round 2.25W up to 3W (to be conservative, aka add a safety margin - just in case).
Hence a 3W 1-Ohm speaker should handle a 1.5V battery.
So if your 1Ohm speaker is rated above 3W, it should be okay to use a 1.5V battery to test its connections (for continuity or (cone) polarity).
So please check that your speakers are above 3W. I'd hate you to blow your expensive subs etc. (That's a joke - ie,the "greater than 3W" - NOT the blowing bit!)
What voltage drop for 500W using 4G?
Let's assume 600W power input. (amp inefficiency)
4G is 0.2485 Ohms per 1000'; let's say 0.25. (From my link above.)
Hence from V=IR, V = I x .25R per 1000' (many use "R" instead of the Ohms Ω symbol) or mV = I x .25mR per foot - eg, 25mV per 100A per foot ( = 100A x .25mR = 100 x .25 = 25mV).
Though that may be too complex... (We need strike-thru formatting!)
Instead, 600W.
From P=VI, hence I=P/V = 600W/12V = 50A.
Assume 10' of 4G, from V=IR => V= 100A x 10' x 0.25R/1000' = 100 x 10 x .25/1000 = 1000/1000 x .25 = .25 => .25V
IE - 1/4 of a volt for 50A thru 10' of 4G.
Assume the same for the ground path => 2 x .25V = a 0.5V drop (between the alternator/battery and the amp).
If 0.5V is ok, then fine.
If close to ok, then consider that the might be less than he 4G resistance - ie, ground is a short length of amp-to-body 4G, 4G from battery to body (assuming you have ADDED that to existing battery-body grounds), and the body/chassis resistance
should be less resistance than the equivalent length of 4G.
Then again, the ground includes terminals/bolts to the body which have their (tiny?) resistance. But the 4G also has its "terminal" resistance.
That's where things get poopy - but we are ONLY considering the 4G resistance. It is up to the designer (you!) to factor in the (oft forgotten!) return/ground path, terminal resistances etc.
And experience soon learns connection resistances (ie, ignore. or are they significant?) and the importance of GOOD clean contacts!
But now I'm breaching into other contributions and the Rules Of Thmb or the knack of design that the experienced have.
Though in principle it is easy - THINK and break each "segment" down and find its contribution. (The same as with fault-finding.)
And I said "in principle" its easy - it may take a lot of time, but you soon(??!) learn what is important etc.
So, since I'm not one to ramble, I'll leave it here.
Besides, others and other links (on the12volt or other sources like
bcae1.com) do a far better job at taking people through the basics than I do. I prefer to "apply" those basics into reality - I often see (IMO)
the obvious that others seem to miss. (LOL - my today reply to a 2005 OP on mp3car.com (
here) being IMO an amusing case in point. Oh dear - the old complex yet flawed suggestions!)
And I have some common ROTs (Rules Of Thumb) and tricks - eg, divide amplifier output by 10 for input current. Much easier than /12V or /14.4V and it compensates for amp inefficiency. Though used for initial designs, its amazing how "real" it becomes (except in close-call and some cases) in part because you can't get the exact value you want (eg, wire resistance) hence you round up to what is available...
But I'm not one to ramble.
Hopefully you have censored the too complex bits. (My replies often take several re-reads! Same for their technical content. (LOL))
Now with all those fancy numbers can you tell me other then a measured with the proper equipment are you going to be able to here a difference in a double blind test?
That's what is comes down too. I am betting you will never here any difference. I have no doubt that you can see the difference but as far as where it counts an audible difference. Plus your in a car environment that's is a far cry from a anechoic chamber and even there it would be a far cry to here the difference.
As long as your running the proper ga wire for the power you running your going to be fine. I am not buying into special wire with magic properties.
If I am off my rocker then please let me know.
AAMP of America did some tests with CCA wire. They were thinking about using it in their power wire kits. I called my friend a few weeks after they were supposed to test it, I asked about the outcome of the test. He replied, we are not going to be using that stuff. We do not want to have to pay for a car. Apparently, if overfused (I know this will never be the case in the real world, because EVERYBODY knows how important a proper size fuse is) and the current capacity of the wire is exceeded, there is a VIOLENT disintegration of the wire, launching molten BBs of aluminum EVERYWHERE.
awesome information guys, thank you for putting some time and thought into your posts. Really appreciate the sharing of knowledge!
