alternator overdrive pully on zzperformance

[loud95sse]

I have 1 alpine type R 15, and a Alpine mrd-m1005 amp running it. It is hooked up at 2 ohms pushing 1000 watts RMS. I have quite the voltage drop as expected, so I am trying to find ways to fix the problem.

Of course there is upgradeing the alternator, but I'm trying to hold off on that. I am currently getting ready to do the Big three with 4 ga wire, I know that will help.

I am wondering if the overdrive alternator pully will work on my 1995 bonneville sse, with a series II 3800. It has a 125 amp alternator in it. Here is the link to the pully. Says it can increase alt. output by %10.

http://www.zzperformance.com/grand_prix ... php?id=206

[99ssei]

I may be mistaken, but over driving your alternator pulley, makes the alternator spin faster, thus producing more current.
HOWEVER, the downside to this is you are pushing your alternator harder than originally designed, which will most likely shorten the life expectancy.

The audio amps usually draw off of the battery. Your battery can only hold X amount of a charge (i.e. 12 - 14 volts). When you pull too much current from the battery, the rest of the system suffers. Your best bet is to get a large capacitor. A capacitor helps your electrical system maintain consistent voltage, supplying a reservoir of power that your amp can draw from during peak demand. If you're running 1000w @ 2 ohms, you should consider getting a 1 farad capacitor (depending on your draw). Take an meter to your battery and crank the music to see the draw your amps have and that should help tell you which one to get (always round up). Here's a list of capacitors on crutchfield:
http://www.crutchfield.com/g_725/Capaci ... rs&tp=2614

Here's an article on capacitors:
http://ezinearticles.com/?Understanding ... &id=374955

[bonnevillain]

capacitors are controversial. if you're already taxing your system frequently, a cap will only add more load to the alternator, and kill it even sooner.
I say upgrade the big 3 like you mentioned, and if that doesn't help i would invest in a bigger alternator (or have it rebuilt. not that expensive)

[loud95sse]

The big three didn't help to much. Didn't see much of a differance. I would like a cap eventually. But I think it would only add more draw on the weak alternator. I think I am just going to have to look into a ssei 140 amp alt that will fit my car.

I am looking also at a Xstatic 800 watt batcap for sale on craigslist. I still need to add an amp for my highs so i will be looking at even more voltage drop.

1st things first, alternator, then cap or batcap, then new amp for highs and mids. I was just hopeing I could avoid the new alternator with that overdrive pully. But you are right it would only cause my alt. to go quickly, then I would still need an alt.

[99ssei]

capacitors are controversial. if you're already taxing your system frequently, a cap will only add more load to the alternator, and kill it even sooner.
I say upgrade the big 3 like you mentioned, and if that doesn't help i would invest in a bigger alternator (or have it rebuilt. not that expensive)

Your car amplifier requires a lot of power to play loud music, especially when there's lots of heavy bass. Without a capacitor your amplifier will be robbed of power by parts like your lights, engine, and air conditioner.

Audio capacitors store that necessary power your amplifier will need to punch those big bass notes while limiting clipping. A capacitor is a bit similar to your car battery; it stores electrical energy. But unlike a battery it doesn't produce its own power. They store power during intervals when it is not required, which is most of the time, and release it when momentary peak demand exceeds what is available from the car's power system. Along with an adequate basic power supply, a stiffening capacitor for your amp is the simplest way to be sure your system always gets every bit of current it needs. Your amplifier is simply trying to use more energy than the electrical system can supply. Mount them as close to the amplifier as possible, and choose at least .5 farad (500,000 microfarads) per 500 watts RMS of power output. You can use as many farads as you wish, but just the number indicated by the formula above is all that is necessary.

If you're drawing more than what a capacitor can handle, you should consider going with a 2nd battery just for the audio system ($$$). Audio System Batteries are car batteries specifically designed to handle the power needs of car audio systems under extreme power demand. A capacitor will not substitute for an electrical system that does not provide sufficient current to equal the reserve indicated by the fuse on the amplifier's power supply connection.

[loud95sse]

Ya, I was thinking a batcap which is a battery with the same ability as a capacitor. The thing is I think my alternator is to weak to add a cap just yet, especially since I still want to add another amp.

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... gory=50547

Anyone know how much a 140 amp alt. will run me? It can be used.

[99ssei]

Your battery will only hold so much of a charge (i.e. 12-14 volts). The audio amps are connected directly to the battery (not the alternator). The alternator charges the battery, the battery charges the capacitor, and when using a capacitor, the amps draw on the capacitor FIRST before drawing on the battery. Audio amps pull power in peaks (as needed). Increasing the alternator is good for adding electrical components to your electrical system that require constant power (not spikes in voltage like car amps). I really don't think increasing the output of your alternator will solve your problem.

[grandprix104]

your amp connects directly to the battery which is directly connected to the alt. There is no separation between the two. When there is a high draw on the electrical system the alt supplies the power. When the alt can no longer supply the power the battery is then drawn upon. The same holds true when you start the car. Since the alt isnt producing power the starter draws from the only part of the system that has it. The battery. Now when you add a cap you are essentially adding another source of stored power. It will immediately release that power when requested but then the cap will add a high load to the entire system while it recharges. This will once again dim your headlights if your system isnt up to the challenge. The only benefit is that instead of your amp being starved for power in that instant of hitting that loud note, your entire electrical system will have that load placed on it for a longer amount of time. This way you get that awesome burst of sound but there is no energy created by the cap. The alt still has to produce it.

[99ssei]

A capacitor is an electrical/electronic device that can store energy in the electric field between a pair of conductors (called "plates"). The process of storing energy in the capacitor is known as "charging", and involves electric charges of equal magnitude, but opposite polarity, building up on each plate. If your battery has stored power, AND your capacitor has stored power, I don't understand the logic of how the entire system would be strained for longer amounts of time while it recharges. A capacitor is only good so far as the audio system isn't trying to pull too much from the electrical system. A capacitor doesn't provide more power, it's designed to 'stiffen' the voltage to the amp, nothing else. If the current isn't there, a cap won't help. The alternator must have at least 20% more amperage power than the entire vehicle and sound system combined for a capacitor to be of benefit which is ironically the same requirements for an amp to be efficient. A rule of thumb is that 0.5 farad of capacitance is needed for every 500 watts of power in your audio system. A capacitor does not affect sound in any way. It is strictly for power conditioning.

I was looking at the Tsunami 1.2 farad cap and found an additional benefit. They are claiming to "also filter AC voltage induced in the system by the amplifier's power supply which could cause objectionable noise." Now, If the voltage drops below 10 volts or rises above 17.5 volts the capacitor emits an audible alarm. If you're consistently getting a 10V drop, then upgrade the alternator.

http://www.crutchfield.com/App/Product/ ... ailed_info

Perhaps we should find out how much voltage loss loud95sse is having First. Put it on a meter and let us know the drop in voltage. This will determine which one you'll need.

[phoenix_flame220]

Although the battery and alternator are all connected together, its the alternator that does the work when you have the engine running.
The battery serves a dual purpose. Its provides power to start the vehicle and run the power accessories when the engine is off, AND it is used to reduce the AC ripple created by the alternator. The battery is actually THE BIGGEST CAPACITOR in an audio system, but most people overlook this. When the engine is running the battery is effectively just another load on the the alternator.

Ideally when you drive you car, the battery should have very little load on it because the alternator is producing enough current to run all of the devices, plus keep the battery in a fully charged state.

Keep in mind that the current draw of a stock electrical system is generally pretty constant with spikes only when you turn on heaters and power accessories. When you add a big audio system, you are introducing large spikes in current draw, not a constant draw. When your system is cranked and the bass hits, there is an almost instant current draw, which is provided by the battery because the alternator will not be able to increase its output quickly enough. The battery discharges a bit to produce the current, creating a voltage drop in the system. The alternator detects this lower voltage and ramps up its output to bring the voltage back up.

When you keep the system cranked the process happens repeatedly and the electrical system starts to get bogged down by the pulsing current load. (this is assuming that the audio system is drawing enough current to overtax the electrical system) Your lights dim, and your alternator is working nice and hard to keep the voltage up.

Another way to think about it is this: your battery has a maximum charge of 12.66 volts. Your alternator has a maximum output of typically 13.6-14.4 volts. When you draw power from a circuit like this, the higher voltage source (the alternator) will be the one powering the circuit. That is until the load is so great that the alternator voltage drops to 12.66 volts, in which the alternator and battery are working together because they are producing the same voltage.

When you add a capacitor you are adding a reserve of power, as mentioned above. The capacitor will be charged to the highest voltage available to it. Which is 13.6-14.4 volts when running. The following is why caps are good and bad. Its all about timing. A Cap, and Alt, and a batt, have differant discharge characteristics. The alternator is the slowest at providing power. The battery is faster than the alternator. The capacitor is the fastest of all. A cap can drop a lot of its charge in milliseconds. The catch is that it takes 5 times longer to charge a cap than to discharge it.

BENEFIT OF A CAP: Your amps require instantaneous current when they have to play a big bass note. The capacitor is the only component that can provide power this quickly (with the battery being second in speed). In a sufficient, well matched system, a capacitor can absolutely give you better sound because it helps create a smooth, fast, consistant power supply which is exactly what your amps need to sound theyre best. Its an important part of a balanced breakfast so to speak.

So you have a cap in your system. You have the stereo cranked. The bass hits. The cap drops its charge almost instantly to keep the voltage up. Then the cap runs out of juice. The voltage drops down to 12.66 volts and the battery provides the current to drive the amps. The alternator detects the drop and tries to bring the voltage back up, but now it has the task of running the amps, charging the battery, and chargng the cap. If you only 'burped' the system and the current draw from the amps went back down, the alternator would have no problem charging everythign back up. The problem is that music doesnt do that. It keeps the bass coming, pounding the system over and over. By now the alternator should be providing constant high current to keep the voltage up, but the voltage is still dropping when the bass hits, sometimes as low as 9 volts.

The alternator cant handle the load all by itself. It keeps borrowing power from the cap and battery, while trying to charge them back up. It cant do it all so the voltage drops more and more as the battery (main source of power at this point) keeps losing its charge. You now have a failing system that wont recover until you turn the bass down and let the alternator recharge the system back up.

Im not saying that theres a 100% chance that youll blow something, but that kind of strain cant be good for it.

The bottom line is that a capacitor is a good thing, but it is NOT to be used as a band-aid solution for an outmatched electrical system.

Your best option would be to get a larger alternator that can provide more power, AND get a cap because a higher output alternator creates MORE AC RIPPLE therefore needs more capacitance to absorb it.

Also, Make sure all your ground and power contaces are clean because even .01 ohms in resistance can cause a .5 voltage loss under high current conditions.

[loud95sse]

I will check my voltage drop here in the next day or so. I'm going to work on an alternator first. Then a Batcap, later down the line.

I was really hopeing the overdrive pully would do the job on the alternator output. I was asking before I went to spend the money on an alternator, $16.99 would have been a lot cheaper than $150

6 months down the road this will be a custom SPL system all the way. need to build a floor and wall along back seat(accept for the fold down trunck entry) and maybe even add another 1000 watt RMS alpine amp to the 15" alpine. That will be 2000 watts RMS to one 15". Only for comp use only of course.