Wire Kit Warning
Thread Starter
500 Watt CAFz'r
Joined: Oct 2004
Posts: 870
I just had a customer bring an amp wiring kit for us to install.
It said 4ga right on the wire....we ran it thru the car, and when we went to crimp the ring terminals on....the wire inside the shiny insulation was only 8 ga!!!
Kit carries the name "Raptor".
The customer required 120 amps of current over 15 feet.
The 8 ga is good for about 50 amps only....sure way to destroy a perfectly good amp.
Make sure you are getting what you are paying for!
It said 4ga right on the wire....we ran it thru the car, and when we went to crimp the ring terminals on....the wire inside the shiny insulation was only 8 ga!!!
Kit carries the name "Raptor".
The customer required 120 amps of current over 15 feet.
The 8 ga is good for about 50 amps only....sure way to destroy a perfectly good amp.
Make sure you are getting what you are paying for!
Thread Starter
500 Watt CAFz'r
Joined: Oct 2004
Posts: 870
Running an amp designed to work with 12 volts plus on less than 4 volts will sure not be good for it!
The wire will Not carry the current...it will cause a voltage drop which will increase as the wire heats up.
The amp will struggle to maintain it's output (if it's a regulated power supply) and will over heat or exceed it's capabilities.
120 amps from a 12 volt source, means the internal resistance of the amp is 0.1 ohms at full pin.
A 1/4 ohms resistance from the 8 ga wire, in series with the .1 ohms of the amp means that the wire will drop 9 volts, and the amp gets the remaining 3 volts....do the math.
So even if the wire's resistance is 0.05 ohms, the amp will still only see 9 volts. Not a good thing.
[ April 20, 2005, 02:40 PM: Message edited by: Car Trek ]
The wire will Not carry the current...it will cause a voltage drop which will increase as the wire heats up.
The amp will struggle to maintain it's output (if it's a regulated power supply) and will over heat or exceed it's capabilities.
120 amps from a 12 volt source, means the internal resistance of the amp is 0.1 ohms at full pin.
A 1/4 ohms resistance from the 8 ga wire, in series with the .1 ohms of the amp means that the wire will drop 9 volts, and the amp gets the remaining 3 volts....do the math.
So even if the wire's resistance is 0.05 ohms, the amp will still only see 9 volts. Not a good thing.
[ April 20, 2005, 02:40 PM: Message edited by: Car Trek ]
Thread Starter
500 Watt CAFz'r
Joined: Oct 2004
Posts: 870
Oops...I was wrong. The resistance of 8 gu wire is .64 ohms per 1000ft, or .0096 over 15ft.
That results in a drop of 1.15 volts, not counting the resistance of the terminals, fuse holder, ground connection etc.
Add in another 5 ft of ground, and we up the loss to over 1.54 volts....probably over 2 after the rest of it.
Still not a good thing, if you thought you had 4 guage wire. The 4 guage only drops .61 volts, an 0 guage drops .24 volts.
The so called 4 guage was a bit loose in an 8 guage ring terminal, so I'm wondering if it was maybe a 9 guage.
Anyway, if that's what my competitors are using for power wire...well no worries here lol!
http://www.stealth316.com/2-wire-resistance.htm
[ April 20, 2005, 03:04 PM: Message edited by: Car Trek ]
That results in a drop of 1.15 volts, not counting the resistance of the terminals, fuse holder, ground connection etc.
Add in another 5 ft of ground, and we up the loss to over 1.54 volts....probably over 2 after the rest of it.
Still not a good thing, if you thought you had 4 guage wire. The 4 guage only drops .61 volts, an 0 guage drops .24 volts.
The so called 4 guage was a bit loose in an 8 guage ring terminal, so I'm wondering if it was maybe a 9 guage.
Anyway, if that's what my competitors are using for power wire...well no worries here lol!
http://www.stealth316.com/2-wire-resistance.htm
[ April 20, 2005, 03:04 PM: Message edited by: Car Trek ]
Yankee
Joined: Oct 2003
Posts: 3,599
I think you will find the in line resistance higher due to several factors (oxidation, poor crimps, some broken strands etc.) in almost any cable. But not significantly higher in most cases though it can creep up over time and connection torque can unload over time.
0 Watt CAFz'r
Joined: Nov 2003
Posts: 29
there are many amp kits on the market like that and many retailers do not even know that they are selling them.
the other sad part is many retailers do not know what happens when you use a crap kit like that on an amp that needs 4 ga and they do not care.in their eyes if the amp blows the distributor will pay for it.these are the same retailers that get mad when the distributor no longer wants to help them.
it is hard to find a retailer that knows what they are doing in car audio. oh ya bestbuy and fs are not the ones that know. they just like to miss lead
the other sad part is many retailers do not know what happens when you use a crap kit like that on an amp that needs 4 ga and they do not care.in their eyes if the amp blows the distributor will pay for it.these are the same retailers that get mad when the distributor no longer wants to help them.
it is hard to find a retailer that knows what they are doing in car audio. oh ya bestbuy and fs are not the ones that know. they just like to miss lead
I bought a lighning audio '8awg wiring kit' once.. Later I find out that only the ground wire was 8awg while the power wire was 10awg... [img]graemlins/freak.gif[/img] 
Limiting the voltage into the amp will only equate to less power out before supply collapses and the amp clips... it wont necassarily hurt anything...
Limiting the voltage into the amp will only equate to less power out before supply collapses and the amp clips... it wont necassarily hurt anything...
Thread Starter
500 Watt CAFz'r
Joined: Oct 2004
Posts: 870
The insulation was clear blue, the ground cable clear. The wire sure looked the same diameter as my 10 guage from the outside, and the magnifying effect of the insulation made it impossible to tell, until we stripped the ends....like I said, it fit a bit loose into an 8 guage ring terminal.
I couldn't say for sure if supplying a low voltage to an amp is damaging or not, and I'm not going to test the theory on my products....for sure the amp won't perform properly, and could damage the subs it's driving.
I've seen lots of systems where the subs oscillate to full excursion, even when played low, from under powering the amp. Severe problems when the amp motorboats (quickly cycles on and off).
I couldn't say for sure if supplying a low voltage to an amp is damaging or not, and I'm not going to test the theory on my products....for sure the amp won't perform properly, and could damage the subs it's driving.
I've seen lots of systems where the subs oscillate to full excursion, even when played low, from under powering the amp. Severe problems when the amp motorboats (quickly cycles on and off).
