Im really nervous


New member
Username: Doylee

Post Number: 6
Registered: Mar-06
i need to know anything that anyone knows about pierce audio pretty sure that im one of the first to buy their new line of speakers!its 1000 watts max i think!!im gonna run my hifonics tx1505d which is 1500 watts max!im hoping i dont kill my 80 amp alternator!im putting it in a 4 cube box!!do u think it will still sound good!!the sight and stats on my 15" wmd is!i was gonna go put a backorder on the new havoc but i went outta my way to try somethin new!!i hope i didnt waste my money!i will be posting pics of sub when it comes inn!

Gold Member
Username: Theelfkeeper

Stockbridge, GA USA

Post Number: 1488
Registered: Feb-05
don't know about pierce audio, but 1500 watts or even 1000 watts will kill your 80 amp alternator.

also, don't use MAX ratings for anything, pretty useless stuff.

New member
Username: Doylee

Post Number: 7
Registered: Mar-06
u think it will kill my alt?i heard u can get away with running stock alt up to 1000 watts???where do u suggest i get a moded alt from???

Silver Member
Username: Lewass

Boomfield Hills, MI USA

Post Number: 425
Registered: Jan-06
I have a 105 amp alt, and ~1000 wrms, it's not even CLOSE to keeping up...

Platinum Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 11396
Registered: Dec-03
Alternators and Charging Systems

Upon reading and answering many questions about car audio, one question always pops up:
"Do I need a high output alternator or just a capacitor?"

If you want a killer system, you may think that all you need are big amplifiers and huge speakers. Not so! Adding a bunch of car audio components to your vehicle without the proper charging system may lead you to disappointment, distortion and damaged equipment.

Let's say you install a 1,200 watt amplifier in your ride. Your rides charging system must produce enough electrical current to run the amplifier and still power the rest of the car's electrical requirements. Now how do you know how much current is needed? Simple:
step 1: Find out how much RMS wattage your amplifier will produce based on the load presented by your speakers.
step 2: Divide this number by 12 (volts)
step 3: Take the resulting number and multiply by the factor below, based on the amplifier type:
Class AB: *1.4
Class T or D: *1.2
step 4: Add the totals together if there is more than one amplifier in the system
step 5: add your stock alternator's HOT current rating to this figure.
The total you get is the amount of current your car and audio system will draw at peak output.

Most vehicle electrical systems are 12.5VDC at idle, and between 13.8 and 14.4VDC above about 900rpm but we use 12 volts as the standard for these calculations because most amplifiers today use a regulated power supply, so they get 12VDC regardless of input voltage, so...
1,200 watts divided by 12 volts equals 100 Amperes of current.
If this is a class D amplifier, it'll be ~80% efficiend, so we'll add 20% of 100A to the total, and we get about 120A of current demand continuously at peak output.
This means that the electrical system of the vehicle will need to produce an extra 120 Amperes of electrical current to power your amplifier and subwoofer at peak levels. Keep in mind that the factory electrical system is designed to produce enough charging power (alternator and battery) for the vehicle's stock equipment, and was not designed to accomodate high-powered audio systems.

The biggest mistake made by consumers (and many installers) is failing to beef up the charging system to handle the extra load of the audio system. First, you need to understand how the electrical system operates. This must be one of the most mis-understood systems of the entire vehicle, so here's a brief summary:

Turning the ignition key begins the process of cranking the motor. The battery supplies the power to get things started. Once the engine is running, the electrical burden is shifted over to the alternator, and the battery then goes into a charging state, and only functions to filter and stablize the DC voltage from the alternator. The alternator uses the engine's mechanical power to produce electrical (AC) current. The AC current is passed through a rectifier and changed to DC current by the DC voltage regulator to smooth out and set the voltage rails for the car . The alternator also has the duty of recharging the battery after starting the vehicle by providing a forward bias voltage higher than that of the battery.

Everything works perfectly so long as the power requirements of the vehicle do not exceed the capabilities of the alternator. If the peak output is surpassed due to excessive load, then power will be pulled from the battery. If the alternator and battery combined cannot meet the demand, then the vehicle's voltage rails, and subsequently the electrical devices are diminished (dimming lights, spark plug misfires, audio distortion and amplifier clipping, or even the car stalling.)

The first place to look to determine if your charging system is up to the task is the alternator itself. If possible, look for the HOT RATING on the alternator. IF you can't see it easily, call a local auto-parts store or car dealership and ask them to look up the stock alternator size, or rating for your vehicle. The hot rating will tell you the amount of power the alternator will produce once the engine reaches it's operating temperature (this is a lower rating than the cold rating). I suggest using your stock alternator unless you experience problems. That's how you know if you need to upgrade, since there is no concrete way to tell if a stock alternator has enough reserve to handle your additional burdens. Now, if you do need a new and larger alternator, after finding the stock rating, then allow your alternator about 10 Amperes credit or buffer area.
For more information on charging systems and alternators, see here:

Silver Member
Username: Dustin3

Tigard, Or U.S.

Post Number: 648
Registered: Oct-05
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