A Question on Power!

I read that if you provide an amp with 14+ voltage, it can provide alot more power than at 12volts. So can anyone please explain, is the battery voltage important when a fused is used, If I put in a 60A fuse, in my power cable before it travels to the amp, then does it matter if my battery produce 15volts or 12 volts? cos its still gonna be filtered out by the fuse. Will the power going to the amp be exactly the same regardless of the battery voltage?

Ok, here is the low-down on fuses and batteries.
If you add a 60-Amp fuse in line on your power cable to your amp, this means that only 60 amps of current may move through the cable. Any surges in current will blow the fuse. Voltage is NOT affected by a fuse rating. Your battery is a 12 volt automotive battery that when connected through the alternator and voltage regulators, is stepped up to a usable 14 volt source for your car's use. In order to get the full 14+ volts to your audio system you need to purchase another voltage regulator/step-up transformer. Such as the Jacobs Accu-Volt, or the Stinger Antidote.

On some amplifiers the extra voltage will give you better results. It all depends on the amp. Some amplifiers have regulated power supplies that make the amp produce the same power anywhere from 12-16 volts, and in this case it wouldn't do you much good. On high current applications (2 ohms or below) with an unregulated amplifier is where your voltage will be very important.

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Joseph Wade
http://listen.to/monte
"I'll be finished when it's perfect"

[Richard Clark]

Whether or not your amp will produce more power at 14 volts than 12 has a lot to do with the design of the amp. There are two types of regulation in an amps power supply. There is output regulation and input regulation. If an amp is not tightly regulated with regard to the power input of it's supply it can make quite a difference. In our test lab we have seen differences of as much as 20%. As far as the fuse is concerned just because you have a 60 amp fuse that in no way means that the limit is 60 amps. All fuses have a thermal time constant that determines how fast they will blow. A 60 amp fuse will never blow at 60 amps. It may take several seconds at 80 amps and it can probably pass 200 amps long enough for a large music peak to blast. A typical 60 amp fuse can pass several thousand amps for a few milliseconds! The interesting thing to remember is that the battery can only supply a maximum voltage of 12.8 volts and that is if it is fully charged. Your alternator can probably supply 14 or even 15 volts but at a lower current capacity than the battery. The battery is actually a load on the alternator and supplies no power to the system until the alternators output capability is exceeded by the current demands of the system and it's output voltage drops.

Thanx you very much for your replies, I have learnt something new from this forum again. Sorry I tend to ask more questions than contribute to answers, that is cos I dont have a broad understanding on car audio, I'm quite new to this. So I hope everyone can be patient with me, I apreciate all replies. Having said that, there another problem I'd like help on if I may:
I use a 60A fuse on an 8G cable running to two amps, 1 4X50watt and 1 2X150. But my fuses keep blowing up, driving on a hot day especialy. Here in Australia, temperatures hit around 35 degrees celcius all the time, is that a cause for the blow up? I have the fuse near the battery, which is next to the often hot engine. How can I fix this cos I dont want to replace a new fuse every 15mins or so. I have checked all wiring, there is no short circuit anywhere, nor faulty installation. I am at a real lost to why this is so, will it be better if I use a stinger 125amp fuse? Please help me if you can...thank you!

I find when a car has a problem with blowing fuses that they are often running too small of a power wire. In your particular situation my recomendation is to run the small amp its own dedication power wire and leave the 8 ga to the 2x150 amp.

what does everyone else think.

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(Art S.)

Why you trippin?

[Richard Clark]

Not exactly. Your solution is a good one but your diagnosis is wrong. If you find a car that is blowing fuses it is because the fuses are too small (assuming there are no equipment faults or wiring errors). The wire may also be too small but that is not why the fuse is blowing. Don't forget a fuse is really a small piece of wire that is designed to blow (melt) before the load (amp) or the wire. They are designed in glass or other protective covers so that when they blow they do no damage and start no fires. If the wire is too small it will either melt or prevent the amp from drawing enough current to blow the fuse. Since a 60 amp fuse is about right for an 8 gauge wire I would suggest that you run another 8 gauge wire for the other amp and put it on it's own fuse. That should solve things easily and with the least cash outlay.

Based on your advice, I have got rid of the small fuse and did as follows. Replace 8 with 4G power cable,with stinger 150Amp fuse in line, to power block, then distribute power to 2 amps. The total minimum fuse size required based on PPI recommendation was 120A for the two amps (pc450 & pc2600). So far so good, there has been no problems and the system is not as hot as it used to be. Thank you Richard, and other members for your help on this once again.