What size power wire to run in an 850W amp?
07-02-2012, 03:03 PM
#1
What size power wire to run in an 850W amp?
I just picked up an Alpine MRV-F450: 850W unit. Is 8 guage wire enough or should I use 4 gauge for power. The amp will have a 50A fuse inline with it. Thanks
Do I need a capacitor to? If so what kind/type?
Do I need a capacitor to? If so what kind/type?
07-02-2012, 03:09 PM
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Re: What size power wire to run in an 850W amp?
I'd say go with the 4 guage wire, and def use a capacitor. Unless you want to have a 2nd battery.
07-02-2012, 04:13 PM
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Re: What size power wire to run in an 850W amp?
I'm not no expert but 4 gauge would do you pretty good I think . I have a 750watt JBL amp and I got 4gauge wires
07-02-2012, 06:36 PM
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Re: What size power wire to run in an 850W amp?
Voltage X Amps = Watts
Or what you want to know,
Watts divided by voltage = Amps
850 divided by 12 volts = 70.83333333 Amps
Wire being what it is and the usage in your case, by gauge 12 gauge = 20 amps
10 = 30
8 = 40
6 = 60
4 = 80
As far as wire for this purpose you want a fine stranded 4 gauge wire like as in a welding cable or heavy duty jumper cable. I would also solder the connectors rather than just crimp them.
Or what you want to know,
Watts divided by voltage = Amps
850 divided by 12 volts = 70.83333333 Amps
Wire being what it is and the usage in your case, by gauge 12 gauge = 20 amps
10 = 30
8 = 40
6 = 60
4 = 80
As far as wire for this purpose you want a fine stranded 4 gauge wire like as in a welding cable or heavy duty jumper cable. I would also solder the connectors rather than just crimp them.
07-03-2012, 08:32 AM
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Re: What size power wire to run in an 850W amp?
You'd also want to keep the distance in mind as well. I've enclosed a chart for reference (on this or other projects).
07-05-2012, 02:00 PM
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Re: What size power wire to run in an 850W amp?
never hurts to run bigger than u need right now you never know if u might upgrade!!! ive also found all wire is not created equal cheep brand 4 gague is smaller then rockford fosgate 4g wire i usualy go for big and cheep like my...... ahhh thats another discussion
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07-06-2012, 04:17 PM
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Re: What size power wire to run in an 850W amp?
Not trying to step on anyone's toes, but a good formula for finding what ampere fuse to use is Wattage / Voltage / Amplifier Efficiency.
As a rule of thumb, Class AB amps are ~65% efficient. Class D ~80%
I normally use 13.6 volt DC because a fully charged battery will cause the alternator to put out about that voltage. Even if the alt is putting out max voltage, it's not uncommon to see ~1 volt drop with hard bass notes.
850 watts RMS / 13.6 volts = 62.5 amperes
62.5 amperes / .65 = ~96 amperes (Class AB)
62.5 amperes / .80 = ~78 amperes (Class D)
That's why Class D amps are more desirable for bass. They make more wattage with any given amperage.
As a rule of thumb, Class AB amps are ~65% efficient. Class D ~80%
I normally use 13.6 volt DC because a fully charged battery will cause the alternator to put out about that voltage. Even if the alt is putting out max voltage, it's not uncommon to see ~1 volt drop with hard bass notes.
850 watts RMS / 13.6 volts = 62.5 amperes
62.5 amperes / .65 = ~96 amperes (Class AB)
62.5 amperes / .80 = ~78 amperes (Class D)
That's why Class D amps are more desirable for bass. They make more wattage with any given amperage.
Last edited by AJ_92RS; 07-06-2012 at 04:20 PM.
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