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#1
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power wire questions
with all the hype about large guage power wire i have a few questions.
tell me why i would need heavy guage power wire tell me why i should switch from 8 guage to 4 guage if i'm not blowing 40a fuses then in reality the 4 would be a waste, right how many have really checked the amps while running your system 40 amps is alot of power, my home theatre is only on a 15 amp breaker. just some good answers would help |
#2
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power wire questions
those questions are pretty vague but generally (someone correct me if i am wrong) 8g is good up to 600w, 4g is good from 600-1200w, and anything bigger 1/0...all depends on which amp u plan to run -- Highrollerii ------------------------------------------------------------------------ Posted via RealCarAudio.com - The checkmate of the caraudio community. http://www.RealCarAudio.com Highrollerii's Profile: http://www.realcaraudio.com/forums/m...fo&userid=1673 View this thread: http://www.realcaraudio.com/forums/s...threadid=10103 |
#3
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power wire questions
i dont know how you can call your self "TWEVOLTMAN" (12 volt man) and you
have very little idea what you're talking about.. 8 guage is ok for small amps/crossovers/eqs/etc... for larger amps and more things you will need to step in guage. There is no "hype" you WILL need large sized wire if you are running decent brand powerful amps. if you're system is working fine and you dont see any problems than you will not need to upgrade the wire size. Blowing fuses has nothing to do with it... the wire size generally wont make a difference on blowing fuses unless ofcourse you are over heating the wire and fuse in which case- you're a dumb ass for not getting right size from the start. While running my system at half volume which is peak listening volume the amps are 157.. i have 2 150 amp alernators and a very large battery. 40 amps is NOT alot of power for DC.. you have no idea what you're talking about. 15 amps is alot of power for AC, yes.. becuase if you look at the size of the power wires coming off you're reciever, its probly only 18-16 guage wire to power that thing. if you look at an amp in a car you are looking at 8-4-2 guage wire.. i run 2 guage wire to my amps.. which will soon become 0 guage becuase i'm upgrading my front stage amp. Sorry if this sounds rude but.. there is no reason to say that large wire is a "hype" becuase its not... Serious systems need serious power.. DJ TecThreat "TWEVOLTMAN" wrote in message ... with all the hype about large guage power wire i have a few questions. tell me why i would need heavy guage power wire tell me why i should switch from 8 guage to 4 guage if i'm not blowing 40a fuses then in reality the 4 would be a waste, right how many have really checked the amps while running your system 40 amps is alot of power, my home theatre is only on a 15 amp breaker. just some good answers would help |
#4
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power wire questions
While running my system at half volume which is peak listening volume the
amps are 157.. i have 2 150 amp alernators and a very large battery. What are you running?? |
#5
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power wire questions
Amps - 3 PPI 2600s 1 A/D/S P450.2
Subs - 3 JL Audio 15W3's Front stage is Infinity separates.. soon to adding some ID tweet and ID Mid Bass. Also have various Processors/X-overs/EQs etc.... around the vehicle. The amperage is most defintly different now... i changed out some different things recently. but for the most part, that was what it read last time it was checked. - Does it sound off to you mark? DJ TecThreat "Mark Zarella" wrote in message ... While running my system at half volume which is peak listening volume the amps are 157.. i have 2 150 amp alernators and a very large battery. What are you running?? |
#6
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power wire questions
The amperage is most defintly different now... i changed out some
different things recently. but for the most part, that was what it read last time it was checked. - Does it sound off to you mark? I can possibly see transients giving you that reading for some reason (depending on the equipment), but I don't suspect that's the real current draw when you're listening to it. |
#7
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power wire questions
40 amps is alot of power, my home theatre is only on a 15 amp breaker.
P=IV P=15A (120V) P=40A (12V) 40 amps in not alot of power its alot of current |
#8
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power wire questions
"TWEVOLTMAN" wrote in message
40 amps is alot of power, my home theatre is only on a 15 amp breaker. it would take almost 150 amps to run your home theatre in your car (if it was pulling 15amps from the ac mains).. now tell me is that alot of amps? thats the differance in a 120 ac and 12 dc. |
#9
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power wire questions
What you really are asking is when to I need to use heavier Power/Ground
wires? It all comes down to Volt/Amp requirements of a particular system setup. There is also one other caveat. You do not want to **starve** your audio system for its power. There is an equation that you might want to keep in mind when sizing your wiring: Power out (Watts) = Power in (Watts) - Losses (Watts) ; Losses being the one that always trips everybody. No amplifier is ideal wherein all power into it comes out of it and no wire is ideal with zero resistance/ft. So, most class AB amplifiers are only about 50% efficient and all wire exhibits some resistance/ft. When should a Power or Ground wire size be increased? Simple, when the calculated or measured voltage drop between the amplifiers terminal and the battery's terminal is greater than .25 Vdc. The .25 Vdc figure is the generally agreed upon industry standard. When you calculate the voltage drop for a wire, length of wire now becomes an issue. Remember wire has resistance/ft. So now another equation is needed, V= IR. Where V is the voltage difference for one end of the wire to the other. I is the **maximum** current through the wire. R is the total resistance in the wire. To find I, we must now calculate the maximum input power requirements for an amplifier. If a stereo amplifiers maximum output is 500 Watts/channel, then the total output for this amplifier is #channels x 500W, which equals 2 x 500W or 1000W. This is the amplifiers total power output, not its input power (which comes from the power source). The input power is equal to the amplifiers total output power times the reciprocal of its efficiency. So if this amplifier is 50% efficient, then its power input requirements will be 1000W x 1/.5, or 2000W! We can now calculate the amplifiers current (I) requirements with the equation P=VI, where P is the amplifiers power requirement, V is the source voltage( usually a 12V battery) and I is the current draw from the voltage source (battery). We rearrange the last equation to read I=P/V. Now, I = 2000W/12 V. This gives an current draw of 167 Amperes. We can now solve for the maximum **total resistance** for the Power/Ground wire run. We know the voltage drop, .25V. We know the maximum current requirement, 167A. So, ..25V=167A x R which reduces to R=.00149 Ohms or 1.49E-3 Ohms. BTW you cannot measure this resistance with a standard multimeter. It is far too low a value. We can now determine what wire size is appropriate for our application. If we know the length of our wire run in feet and the total resistance of this run, we can now consult a table or chart of "resistance per foot for standard wire gauges". Look around, they exist. Or, call your wire supplier. For this application we would be looking for a Ohms/ft of 1.49E-3 Ohms / length of run or **lower**. I stress lower because your caluculated value might not be exactly that of a standard wire gauge. If you use your chassis as the return ground, you will not be able to empirically determine the total resistance for this run. Also, you must calculate this value for every amplifier in your system. And if you intend to use only a single wire run from the battery to a terminal distribution block, then this wire run will have to have a resistance/ft of the summation of all individual wire run resistance in parallel. This is given by the formula of 1/Rt = (1/R1+1/R2+1/R3+......1/Rn), where Rt is the total effective resistance and R1 thru Rn are the individual total resistance of the individual wire runs. Hope this helps! Taffer Garrett "TWEVOLTMAN" wrote in message ... with all the hype about large guage power wire i have a few questions. tell me why i would need heavy guage power wire tell me why i should switch from 8 guage to 4 guage if i'm not blowing 40a fuses then in reality the 4 would be a waste, right how many have really checked the amps while running your system 40 amps is alot of power, my home theatre is only on a 15 amp breaker. just some good answers would help |
#10
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power wire questions
thanks ! yes it does help. btw this is the answer i was looking for, an
infomanant answer with no bull****, unlike the other posts. and i *though this was a ng to seek answers..............well a ton of bull and 1 real answer, thanks taffer ! |
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