Amperage Draw

[XTRMEASURES 0]

Before installing a power amplifier in your system you should take into consideration the vehicle

[Tirefryr 1,742]

Don't forget to mention that when searching for alternators, you want to pay attention to the "hot" rating if there is one. If it's a good alt, there will be a "hot" rating.

[Jmac 24]

If you're playing nothing but sine waves, have all the options available for your car, and have them all operating at the same time, then you might be only limited to 32 amperes in your example. However, music is dynamic, most people don't have their A/C, heater, and lights on at the same time and most vehicles aren't fully loaded. Most headlights draw maybe 5 amperes each (10 total) and the taillights, dashboard, etc. draw very little (say 5 amperes total). The heater would be the biggest draw, around 20 amperes. Overall, you're looking at a good chunk of your alternator being free if you don't have everything on.

I don't quite understand your RMS/peak and fuse theory. Using the fuse may not be accurate because many manufacturers use slow-blow type fuses, so you see 1000+ watt amplifiers with 60 or 80 ampere fuses, but the fuses can actually handle twice their rated capacity for a few minutes of continuous draw.

A typical Class D amplifier is about 75% efficient at full output. A typical Class A/B amplifier is about 60% efficient at full output. Essentially, divide the power output at full capacity by the efficiency, then divide by the test voltage. For example, an amplifier is 75% efficient @ full capacity (1000 RMS with 14.4 volts). This means that current draw will be 92.6 amperes with a sine wave at full capacity and, obviously, less current draw at less than full capacity.

The type of music you listen to is also going to make a large difference. People who listen to bass-heavy music (rap, trance, techno, etc.) should leave a little more space while those who listen to "lighter" music may even be able to use an amplifier that can draw as much as their alternator can supply.

I forgot the rest of what I was going to say ... Damn drugs ...

[XTRMEASURES 0]

very good point...

[CBFryman 2]

Personal Experence:

If you are going to exceed you're alternators maximum capeability for extended periods of time, to the point you put a load on the battery, and you will do it in inconsistant dynamic peaks. Look into buying a new High Output alternator.

My stock 95a alternator just died. I've been informed by some of the asssociates at some of the alternator companies i have spoken with that that is often the cause of permature alternator failure. Usually it is the regulator and NOT the alternator itself, but if you are going to replace the regulator you may as well replace the whole alternator. Most are internally regulated anyway.