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Nanbakat Unregistered guest | I will be hooking up two amps (1000W and 500W) in my new install. 1500 total amps divided by 12 = 125A. Right? Power wire will be 4 gauge. Now should I put a 125A fuse on the powerline or 120A or 130A? I would think that a 120A fuse would protect the powerline best because it would cut the power supply before it reached the maximum. Is this line of thinking correct? Obviously, I dont need to protect the amplifiers because they have their own fuses for that. What do the experts say? |
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Silver Member Username: Matt12490Benicia, California Post Number: 388 Registered: May-05 | I'm not quite sure on the fuse part but i think you should run 2 gauge to the 1000w amp, and 4 gauge will be fine on the 500w |
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Silver Member Username: Matt12490Benicia, California Post Number: 389 Registered: May-05 | I'm not quite sure on the fuse part but i think you should run 2 gauge maybe even 0 to the 1000w amp, and 4 gauge will be fine on the 500w |
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Silver Member Username: Matt12490Benicia, California Post Number: 390 Registered: May-05 | oops |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 11068 Registered: Dec-03 | actually.. http://www.glasswolf.net/caraudio/charging.html go there to calculate your current draw. the circuit breaker or fuse at the battery should be rated for the peak current capacity of that gauge wire (see here: http://www.the12volt.com/info/recwirsz.asp) then use a fused distro block, and where you have one fuse for each amp's power line, you can use individual fuses rated for the current draw at the loads presented to each amp.. like a class D 1Kw wamp at 2 ohms would use a 100A fuse, etc. the battery fuse is to protect the wire. the smaller fuses near the amps are to protect the equipment. |
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Nanbakat Unregistered guest | Thank you for your replies. Okay this is starting to make more sense to me. Using your equation, Glasswolf, I have recalculated the amperage of the system to be 158A. 100A for the 1000w Class-D amp powering sub 58A for the 500W amp powering comps According to the webpage on recommended wire sizes, I should be using at least 4 gauge wire with a 150A fuse protecting the powerwire at the battery. Right? Or should I allow a higher amperage to go through by switching to 2 gauge wire? I guess it never hurts to have thicker wire (apart from your wallet). When I hit the distroblock I'll need 4 gauge for the 1000W amp (protected with a 100A fuse) and 8 gauge for the 500W amp (protected with a 60A fuse). I have one more question: I have a 1.5F stiffening capacitor that I'd like to add to the system. Does it make sense to wire it parallel to both amplifiers or should I hook it in directly inline only with the 1000W amplifier? If I wire it parallel does it get put in before the distroblock? I think that it would be a nightmare to put it in after the fused distroblock because of the different gauges of wire going to both amps. (The capacitor won't take the place of an electrical system overhaul. I may need to get the alternator rewound or a higher output alternator installed. I have a Nissan Xterra with a 130A output alternator so maybe this won't be necessary.) |
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Silver Member Username: N2audioLawrence, Ks USA Post Number: 565 Registered: Mar-04 | I would expect your alt to get it done, but there's no guarantee. I think you'd be best with the cap connected only to the sub amp. The comp amp isn't going to have the big v-drop associated with bass like the sub amp will. Power wire size - I would recommend 2 ga from the battery to the d-block for that size of truck. I'm guessing the length of the wire will be no less than 15'. I think you're piecing it together pretty well though. |
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Nanbakat Unregistered guest | Thanks Optidriven. Like you said...there's no way to be sure about the alternator providing enough juice until the stereo is installed in my truck. I'll also be running Hella driving lights (at times) so I may need to upgrade anyway. |
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Silver Member Username: N2audioLawrence, Ks USA Post Number: 568 Registered: Mar-04 | Well, if you were to drive with your extra lights on, and the system absolutely blasting for an extended period of time I could see a problem there -- maybe, but a 130A is a good sized alt. There would have to be some pretty unusual circumstances for it to be a problem. How many lights do you have? Are they standard 55w bulbs? |
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Nanbakat Unregistered guest | I have a pair of Hella black magic lights. They are 55W. I also have OEM fog lights and I upgraded the bulbs on my headlights to high output xenon (not HID). I do a lot of off-road stuff so I need to be able to see where I'm going. :P Now that I think about it, I shouldn't have a problem unless I'm running around in the woods with all my lights on and blasting some rap music at 110db. If it ever comes to that (not likely)...I'll just check the voltage meter on my capacitor or amps and find out if I'm drawing down power from the battery. In that case, I can lower the volume or turn off the lights. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 11081 Registered: Dec-03 | cap would go in parallel with the sub amp. helps act as a filter for AC ripple from the regulator, and helps to reduce propagation delay. |