Fuses, Cable Gauge, Capacitors… [I]
I'll bet you think your amplifier fuses are there to protect you amplifier to avoid failure, right? WRONG! While properly fused electronics can save the product if there is a problem, this is not why fuses are required. The reason fuses are so important is because they are what can save your vehicle from a meltdown!
How many times have you had an amplifier keep blowing a 20-30 amp fuse? How many times have you just put the next size higher in the fuse holder? If you answered 1 or more, slap yourself dummy! It is critical that all electronics be fused and with the Proper size fuse. A fuse too small my blow prematurely or frequently. A fuse too big may allow the product to damage your vehicle. Let's face it, it's easier and cheaper to replace an amplifier than it is to replace a vehicle or at least its fuse panel and wiring. Now, some amplifiers do not have fuses on them. If this if your case, call the manufacturer and ask them what size fuse is required. If you have multiple amps and they are all fused at the amplifier, is all well and done? NO! Regardless of how many amplifiers you have, you MUST have a main in-line fuse from the power cable to the battery. This fuse needs to be within 18” of the battery, no exceptions! If you have 3 amps with a single 25 amp fuse, dual 40 amp fuses and a single 80 amp fuse, then what size do you use for the main fuse under the hood? Simple, add them all up to 185 amps. Since you will not find a 185 fuse, it is okay to add up to 20%, but no more than that or you're defeating the whole idea of protecting the vehicle. We know we can buy 80, 100, 150 and 200 amps fuses at any local shop. A 200 amp fuse is only 8% above the total fuse rating for the system. If you do not listen to the system at full volume all of the time, you can also put in a 150 amp fuse which is only 19% lower than the 185 amp rating and you be in an even better place as far as protection goes, and you never notice the difference…
[I]Cable Gauge… [/I]
Do you ever wonder why some people use massive cable and wire in their vehicles when smaller cable also works? Because they're smart! In a system like we mentioned above, 185 amps of current is A LOT of power. That is why the cable from an alternator is typically 4 gauge. Here is the common problem… People buy 4 gauge thinking that because it is fairly hefty, that they can build whatever system they choose and power it with this 4 gauge power cable. To carry 185 amps of current, 4 gauge cable should not be used for any length! If your cable length is about 12'm, say for a pick-up truck, the cable needs to be 1/0 gauge! Now, let's say you're a genius and you have a more common system with a badass Soundstream 5-channel Tarantula TRA880.5 Amplifier. This amplifier requires a single 100 amp fuse. You can use 4 gauge power cable for this amp, as long as it is within 6 feet of the battery. Since you're hopefully not installing this on a motorcycle, you'll need approximately 12' for a small car or pick-up truck, and 18-20' for a larger car where the amplifier will be in the trunk. Based on the length requirements and 100 amps of current, you'd have to use a minimum of 2 gauge for the smaller vehicles and 1/0 gauge for a larger vehicle. Being cheap and skimping on the power cable size is foolish because if you run cable too small, you won't be able to pass enough current for the amplifier to operate at full potential. Please refer to our Gauge Chart to see what your system requires…
[/I]No not the flux capacitors in Doc's time machine! I'm talking about power reinforcing capacitors. Some people call them “stiffening caps”. Regardless, they do have their place in a system if used properly.
Charging capacitors properly is important so let's take a second to talk about the proper sequence. With the amplifier not hooked up to power and ground, first connect power from the capacitor to the amplifier. Second, connect the ground from the chassis or battery to the amplifier. Third, connect the ground from the amplifier to the capacitor. Fourth, place the charging bulb between the positive from the battery and the capacitor. When the capacitor is fully charged, the bulb will go out. At this point remove the bulb and attach the positive from the battery to the capacitor. There are right and wrong ways to make these connections. Please see schematics at the end of this article.
Caps do not make a system louder and is not a substitute for an auxiliary battery. Larger systems can put a power demand on the vehicle that the vehicle is not able to yield sufficiently. You will know if this is your problem because your lights will dim and the sound will become distorted due to amplifier clipping. SO, how much auxiliary capacitance do you need? The rule of thumb is to have a minimum of 1 Farad per 1000 watts, however, the more the better. Large capacitors can resolve this problem to an extent. The questions is, when to add a 2 nd battery and when to add a cap. A battery can cost considerably less, but the problem is that the battery needs to charged properly. Vehicle manufacturers do not give you a bigger alternator than you need. So adding another battery can put a heavy load on the alternator which can cause it to fail prematurely. Adding a high output alternator will resolve this problem, but can be expensive. Caps were introduced to market as a less expensive alternative, but are not as effective. Regardless, large caps can make a noticeable improvement in midbass and mid-high transient response. If your system requires slightly more power than the vehicle can produce or if you are just hearing a bit too much distortion due to amplifier clipping from a lack of sufficient power, than a cap(s) are the hot ticket. If you're building an SPL system, then caps are not a good substitute for batteries.