Rep Power: 313

thanks to this thread (http://www.7thgencivic.com/forums/sh...d.php?t=271646)

I have some conserns about my alternator.

I have a Audiobahn 1200 RMS (2400 MAX) Sub with a 2000 watt max amp & a cheap 2 farad capacitor...

my question is IS MY ALTERNATOR GOING TO DIE SOON???

All I know is my stock alternator can handle 70 amps.

I have no idea how many amps Im pulling with my system!

Audio Guru’s HELP!

Thanks!

 
Rep Power: 337

dont even worry. youll be just fine.

 
Rep Power: 313

For sure!!!

So my alt will not be affected by the 2000 watts???

Because of the cap??

or because the stock changing system can handle it???

Elaborate on this for me please

Reped ya too!

 
Rep Power: 337

youll be fine because of the transient nature of music. For fractions of a second, the current draw will be WAY more than your who car can handle. (guess what? same thing happens when you turn your power windows or AC or fan on!)

but for the rest of the time, making up the vast majority of drive time, draw is less than the alternator can provide for. So little, in fact, that the car automatically shuts the alternator off.

dont take my word for it, though, see for yourself:

you can hook up a multimeter or even a voltage gauge in your car in the dash, easily visible while driving. You'll notice that while driving around, voltage will be in the 12 volt neighborhood.

at times, the voltage will seemingly randomly bump up to 14-ish. after a time at 14, itll randomly drop down to 12 again.

as far as I can tell in my car, the alternator is always running above 3500 rpm whether it needs to or not.
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anyways, doesnt really matter. the amplifier is easily capable of drawing enough current to kill the battery fast. never does though, because between low draw and high draw times, the alternator keeps the battery charged well enough.

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exceptions to this rule are folks who have the gains cranked to max, the bass boosts cranked everywhere they can find one, and then play bassheavy synthesized electronica designed to do nothing but play straight bass from the time they turn the key to the time they shut the car off.

and even they would be okay if they shut the stereo completely off a few minutes before reaching their destinations. (not a bad habit, either. keeps thieves in the dark.)

 
Rep Power: 337

youll be fine because of the transient nature of music. For fractions of a second, the current draw will be WAY more than your who car can handle. (guess what? same thing happens when you turn your power windows or AC or fan on!)

but for the rest of the time, making up the vast majority of drive time, draw is less than the alternator can provide for. So little, in fact, that the car automatically shuts the alternator off.

dont take my word for it, though, see for yourself:

you can hook up a multimeter or even a voltage gauge in your car in the dash, easily visible while driving. You'll notice that while driving around, voltage will be in the 12 volt neighborhood.

at times, the voltage will seemingly randomly bump up to 14-ish. after a time at 14, itll randomly drop down to 12 again.

as far as I can tell in my car, the alternator is always running above 3500 rpm whether it needs to or not.
------------------------------------------------

anyways, doesnt really matter. the amplifier is easily capable of drawing enough current to kill the battery fast. never does though, because between low draw and high draw times, the alternator keeps the battery charged well enough.

--------------------------------------

exceptions to this rule are folks who have the gains cranked to max, the bass boosts cranked everywhere they can find one, and then play bassheavy synthesized electronica designed to do nothing but play straight bass from the time they turn the key to the time they shut the car off.

and even they would be okay if they shut the stereo completely off a few minutes before reaching their destinations. (not a bad habit, either. keeps thieves in the dark.)

 
Rep Power: 0

02BLKCIVIC, I think this is an awsome thread. Finally we can get to the bottom of this situation about how a cap really prevents an alt to blow. Ok, so what everyone has been told up to this moment about the miracle "capacitor" from preventing an alt from failing is like saying that it can produce the same amount of power from less amperage. Wow, I think I'm going to install capacitors in my fuse panal of my house first thing tomorrow after work. Thats going to save me a **** load of $. You know what, I'm also going to get rid of all my power bars that protect my PC and home theater because capacitors from what we've been told also prevents power surges.
02BLKCIVIC I think we are going to be rich from this idea, I don't think we should be posting this subject publicly. LOL big time.


night time lights-15amps
ac-15amps
wiper motor-15amps
rear defrost-20amps (cause its raining out and the rear window is fogging up)

So what your saying is that in this situation listed above is that it would still be ok to run a stereo system and not worry? This situation can easily happen.

 
Rep Power: 337

cannon, the issue isnt current draw while running, its the instantaneous current flow when you flip the switch.

once again, please dont take my word for it, experiment.

find yourself a 1F cap, and totally drain it. just dead, to V=0.

now hook it up directly to your battery. Youll notice a very large spark. sometimes, the capacitor explodes. in this case, the instantaneous current draw at time=0 is actually infinity. yet during normal operation, the cap draws zero from the charging system.

other electronics are much the same way. many car electronics have small capacitors inside their electronics. a couple thousand microfarad, usually around 16 volts. the idea is to prevent powercycling when instantaneous drops from things like the AC fan turning on occur. they usually last for milliseconds or less, but have the potential to cause electronics to shut off and turn back on.




but ultimately, I didnt answer your question. do you drive in florida at night? thats the only scenario I can think of where you would be running rear defrost, your wipers, AC, and headlights all at once. then add the draw of a multikillowatt stereo on top of all that. Have you tried it? If you are capable, I suggest you try it.

because yes, unless you duplicate the conditions I've gone into above, you'll be fine!

 
Rep Power: 313

WOW!!! WOW.

Thank you sir!!!

Your the man WhiteRabbit!!!

Thanks agian!

 
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Whiterabbit, last night I followed your instructions about charging my capacitor directly from the battery and poof it exploded in my face. I had to be rushed to the emergency room for third degree burns. Joking, lol.

So what your saying is that my system draws close to 0 amps from my alt besides my headunit, if I connect a cap?

Why don't I just connect a capacitor between my altenator and my battery, wouldn't that be like running all my electronics from practicly 0 amps?

 
Rep Power: 285

i have 1600 watts rms running on my system with the stock alt.. i have two 1000 watts mono blocks with an optima yellow top under the hood and my alt can't take it... my deck cuts out and when the system is pounding it drops below 12 volts.. so should i get a cap to help with this cause i was also thinking of getting a 200 amp H.O alt this winter..

 
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the cap should help from what WhiteRabbit said^^^

 
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well... my Yel. Opt. blew on the interstate the other day, form a 162 amp peak alt from Ohio Gen. i had to send if back due to the battery light being on, maybe its the wiring it needs but idq. i know for a fact adding a ground wire from the engine to the frame and also adding another 4 ga. from the alt. to the batery + side should help. since a alt twice its size can fry your fuse box

 
Rep Power: 313

I already have a custom ground kit.^

It helps a lot.