Thread: Does my car have enough "power"?

Moved out of the FAQ Emporium.
Don't post there unless you have an infomrational post to share.

Opus doesnt make a 180w PSU.


Since your lights brighten when you hit the gas, it indicates the battery may be flat, since the alternator kicking in provides more power.

If you take the battery to AutoZone or O'Reilley or any other major auto parts chain, they'll test it for free.

my 01 civic powers a 200 watt opus, a 1600 watt (max) audiobahn amp, a 50 watt 3 way crossover, and a 400 watt alpine amp.

I can't say how well your battery will take it, because i upgraded mine to a optima yellow top, but i can say that my alternator takes the strain fine.

I would also advise against a capacitor, you could try the "big three" upgrade. Search the forums for it.

Why would you suggest against getting a capacitor? Aren't they supposed to help maintain a level voltage and provide protection against suddens surges or dips.

Yes, I would recommend against purchasing a capacitor. Many people see them to be "band-aids" myself included. What makes you think you need one?

heres a link to the "big three" upgrade: http://forum.sounddomain.com/forum/u...=5;t=007801;p=

For me I dont really see the need although I have thought about it. But then I've also put a higher output altenator in my car and keep contemplating doing a dual battery setup with a capacitor tossed in for line conditioning. But I know I tend to overkill the power side but I also always look at what I might use in the future and try to prevent having to upgrade something I just installed a month ago. And I have also done the top-three that you mentioned.

Edit: Personally I wouldn't be using the capacitor as a band-aid so much as an insurance policy against a sudden surge.

well... i expect Shadow to weigh in any day on this, but I'll give my thoughts on the matter... capacitors I think people look at with too narrow a scope. All anyone really sees is the issue of "can it support my massive subwoofer when my alternator/battery can't?". The answer to that is invariably no. You have to remember that for every watt you get out of that cap, you have to put another watt, plus efficiency losses back in. So if your power supply is insufficient to begin with, a capacitor just delays the inevitable.

So what the heck good IS a capacitor then? Think in terms of the system-wide effects. Amplifiers generally perform best and coolest when supplied with ample voltage. Usually manufacturers bench test and rate their amps with a 14.4v regulated power supply. Compared to our cars, this power is awfully clean and devoid of any of the fluctuations in voltage imposed by other devices like defrosters, headlights, wiper motors, fuel pumps... A capacitor can help smooth out or eliminate these fluctuations PROVIDED that your alternator is supplying adequate current for all your devices.

So do the math, if your amplifiers are 50 percent efficient, and you go somewhat conservative on RMS power and get 50x4+500x1. 200+500 watts at 50% efficiency means you could conceivably be drawing 1400w which at 13.8V (assuming your alternator maintained that voltage), is over 100 amps. I am reasonably certain that your average import passenger car is not going to supply you with much more than 80 amps... and remember, that's gotta run the car and all it's accessories too.

So how do you get around the power problem? You've got at least two possibilities:

1. You muscle through it. You buy a 170 amp alternator for $600+ and then start spending $1+ per foot of 0-gauge wiring which you have to somehow run under your car or cram under your carpet, not to mention all the wiring under the hood you'll have to replace so that the new alternator can deliver that kind of current without burning wires... plus the cost of whatever amplifiers you get.

2. You plan for efficiency. First thing to check out is whom you would like to buy a full-range class-D amplifier from. Traditionally, class-D amplifiers have been unable to cleanly reproduce high-frequency sound, but there are a few companies, including Bang & Olufsen who produce high-end, high efficiency full range class-D amplifiers. These are typically 85-95 percent efficient. So, we'll take mine for example since i know it's specs off the top of my head: 50x5+300x1. That's 500w for 4 speakers and a sub. At 95% efficiency i'm going to be drawing about 38 amps at full tilt. My alternator produces a maximum of 80 amps, and the car takes about 40 of that. Cutting it close for sure but then the music isn't cranked to 11 on every dial either. At the levels i'm comfortable listening to, i'm only drawing about 6 amps. That sort of thing won't even phase your stock alternator.

The next thing if you're adding a subwoofer is to pay attention to it's sensitivity rating. Manufacturers have various methods of arriving at this number, so don't take it as gospel, but it can help in determining which speakers can produce the most volume for the power you are giving it. Again, the louder your system sounds at a particular volume level, the easier you're likely to go on the amps.

So back to capacitors, what good are they? Well again, maintaining voltage is key. Lets assume for a moment that your alternator can handle the complete electrical needs of your audio and vehicular systems. The mere act of turning on a device will create a voltage drop, drawing sometimes twice as much current as it's rated for for an instant. An appropriately rated capacitor can temporarily supply your entire electrical system with additional power to maintain that constant voltage, rather than succumb to a voltage drop. Voltage drops do two things, and the extent of which depend on the severity of the drop, but your lights may dim, and your sound quality may suffer. This is what capacitors are good for.

So to sum up that longwinded rant: capacitors are NOT a power generating device. if your alternator can't keep up with your amps, a capacitor, no matter how big, will not help. Think efficiency before just strapping on bigger batteries and alternators. Because if your alternator CAN supply the power you need, then a capacitor will do just the trick to help you get the most out of your amps.

power distribution blocks are definitely convenient. brand doesn't really matter. all you're buying is a fancy gold or chrome plated chunk of metal... maybe fuses come with it, maybe not. Just make sure that it is rated to handle all the various wire gauges you will be using, that it has enough terminals, and that it comes with some sort of cover (and why wouldn't it?!) to protect it from whatever might land on it and cause it to short.