our Alternator output?

[sammy21c]

I am using 400W 4ch and 500W for sub. I never had problem, it's been 1yr now.
Some people told me that I can fry my alternator. What is our alternator output?
Do I need capacitor? Thx.

[asaf]

Nah, no way do you need a cap. I'm actually doubful as to whether a capacitor has any REAL benefits to a sound system. From what I remember we have an 80AMP alternator. Which should be able to push more than 1100W, and remember that your amps are listed using their MAX power, so most of the time you'd be at 60%.

There are many articles on the net from many people discussing the lack of convincing evidence that a CAP is neccessary.

[Atomic]

Here's what I've found:

Type
Battery voltage sensing
Rated output
13.5V 75A, 90A (I guess it can be either 75A/90A, maybe depends on model/yr., not sure)
Voltage regulator type
Electronic built-in type
Regulator setting voltage
14.4 ± 0.3V
Temperature compensation
-10 ± 3mV/°C

As far as using a cap., do you want the most performance out of your amp? At most you would need a .5 farad cap. which aren't that expensive on eBay.

I can tell you from personal experience, every car I've had, that had a system in it, adding a capacitor made a HUGE difference.

Some improvements I've noticed:

1. No dimming of any lighting at night when I'm running around town with my A/C full blast, windows down and system blaring. (AZ peeps know what I'm saying about A/C on full blast at night with windows down)

2. I can push my system harder for longer, sound output doesn't slowly fade as the amps & speaker coils heat-up.

3. My main (+)power wire that feeds my caps. and amps. doesn't get as hot.

I use a 1 farad capacitor on my Fosgate amps mainly because those amps like a 13.5v-14.5v input, instead of your standard 12v input, for best performance. Also because I'm pushing 1275 digital watts @ 2 ohms, 77% efficient output. I plan to add another cap which should bump my amp's wattage output up another 105-140 watts plus minor improvements in efficiency % output. I'm also adding a yellow top optima 34/78 battery.

[southpawboston]

if you have an 03 chances are you have the 90A alternator. they upped it from 75A mid-02 model year.

[YBKewl]

My guess is that the 90A alternator is for all xd with A/C or car sold in "cold" contries like Canada

[cclngthr]

From the info I have, the Elantra has a 90 amp alternator even without the A/C (if it does come without it).

[Hyundia_90250]

How much is it to up grade to the 90amp?

[southpawboston]

let's just say that if your current alternator mysteriously stopped working, and your car is still under warranty, hyundai will probably upgrade it to the 90A unit. a hyundai service tech told me that himself.

[sammy21c]

Thx, I got 90A on my car.

[Sledge]

He is draining about 65 amps with that set up I know that you divide the wattage by the voltage and you get you're amp draw. not sure how to put them in but a cap might work.

[mtvslick]

my lights still flash no matter how many caps I put on I have 3 now and my lights still flash I even have 2 batteries, WTF! can this be an alternator issue???

Mark,

[Atomic]

my lights still flash no matter how many caps I put on I have 3 now and my lights still flash I even have 2 batteries, WTF! can this be an alternator issue???

Mark,

It's possible. Not knowing your setup, it's hard to say. Do you have a local autoparts store, like AutoZone/Checker, that'll check your charging system for free? They can tell you if its your battery, alternator or something else, I believe.

[johnblaze94]

If you are constantly drawing 100 amps, no 90 amp alternator will keep up, no matter how many caps you have.

[Soron]

A capacitor compensates for power drains by charging in the times that the amp/sub isnt drawing as much power, it acts as a quick discharge battery in the times that the battery/ alternator cant provide the output needed. I agree with Johnblaze94 in that if you dont have a high enough output it does not matter how many caps you have. Btw dont forget to hook them up in parallel to the power input of the amp/sub to see any benefit as hooking up more than 1 cap in parallel increases capacitance while in series (with each other) it decreases/devides capacitance also if you hook up the cap in series with the power input it will cut off the input when it is fully charged. The larger the cap that you use, the more it will smooth out power fluctuations, 1 farad caps or above are normal for sub/amp setups.

With his 900W power setup he is drawing approxamitly 75 amps according to ohms law (watts/volts=amps = 900/12 = 75) so no, an 80 amp alternator (stock setup according to tech sheets I have for a 03 elantra) is not going to cut it at all, even a 90 amp alt is pushing it. You need to upgrade the alt to handle the extra load AND get a 1 farad or larger cap. If you want, you can get a 1 farad cap now and then several more 1 farad caps and hook them up later in parellel to increase capacitance ((2) 1 farad caps = 2 farads) but only after you get a new alt first.

[2loud2k2xd]

listen, i have the stock alt and in pushing 3300 watts rms and i compete. yes i have 2 batteries abd a 3 farad cap. so far 65,000 miles and the same aly. i will not pay 700.00 for a 180 amp alt. just buy another stock alt if it burns up.

[southpawboston]

With his 900W power setup he is drawing approxamitly 75 amps according to ohms law (watts/volts=amps = 900/12 = 75) so no, an 80 amp alternator (stock setup according to tech sheets I have for a 03 elantra) is not going to cut it at all, even a 90 amp alt is pushing it. You need to upgrade the alt to handle the extra load AND get a 1 farad or larger cap. If you want, you can get a 1 farad cap now and then several more 1 farad caps and hook them up later in parellel to increase capacitance ((2) 1 farad caps = 2 farads) but only after you get a new alt first.

you are correct about ohm's law, but it's not that clean and simple. if the 900W setup is 900W RMS, and he has class A/B amps, then the amps are no more than 50% efficient, meaning that the current they draw is about DOUBLE your estimate (900/12 = 75, but x2 for heat dissipation = 150A). BUT, if the setup is 900W PEAK, then he is really pushing more like 300W RMS (which equals about 25A x 2 for heat dissipation = 50A). then if he pushes 900W PEAK for short moments, the current draw will exceed the capacity of his alternator, but only for short bursts. in that scenario, a cap will definitely help.

when talking about whether a battery and alternator setup is robust enough for a given system, it's less reliable to base it on the claimed wattage output of the amps than to base it on the fuse rating of the amps. if the amps have a combined fuse rating of 50A, then you KNOW the system will never draw more than 50A, except for perhaps extremely short bursts, which fuses can withstand. wattage ratings are notoriously unreliable for determining battery/alt demands.

[Soron]

I am not a system specialist (more of an oil freak) but as I understand it / recall from my circuit design classes at college an a/b amp is only 50% efficiant but does not draw 2x the power, only 50% of the power drawn is actually used and the rest wasted as heat.

2loud geez, 3300W rms!? are you sure the batteries and the caps arent compensating for the alt? They would get charged when the amp isnt using max power.

[2loud2k2xd]

yeah, my system only battery is rated at 1125cca. :) and the cap also helps.
my sub amp alone has 6-40 amp fuses and the component amp has 4-40 amp fuses.
140slp for daily and the same 80 amp stock alt. but my alt is on its way out. i know it. i dont drive around at full volume but i do listen to it at about 3/4 volume.
when i compete i keep the rpm's up in the 2k range to power up the batteries for when i "burp" (30 seconds of heart stopping bass)

[southpawboston]

I am not a system specialist (more of an oil freak) but as I understand it / recall from my circuit design classes at college an a/b amp is only 50% efficiant but does not draw 2x the power, only 50% of the power drawn is actually used and the rest wasted as heat.

where do you think the heat comes from? it has to come from an energy source. that source is electrical current. so while 50% of the power that is drawn to power the speakers, the other 50% of the power that is drawn is wasted as heat.

[Soron]

I just asked an audio systems specialist I work with about this question, apparently he says you need to upgrade to an optima battery and a cap as the alt is NOT providing enough power to power your systems alone.

2loud He wants to know what systems/setup you have (he requests pics too) as he says there are only 2 manufactuerers in the usa the can produce a 3300W rms system and can tell if your being ripped off and that your 2 batteries and caps really are compensating for the alternator.

southpaw an example of what I understand/recall from classes 100W input, 50W power is amplified and the other 50W is wasted as heat, from what you said earlier it sounded like it was drawing 200W of power, amplifying the same 50W of it and the rest is waste heat.

if the 900W setup is 900W RMS, and he has class A/B amps, then the amps are no more than 50% efficient, meaning that the current they draw is about DOUBLE your estimate (900/12 = 75, but x2 for heat dissipation = 150A).


like I said im not an audio systems specialist (my coworker is) so I am not really going to argue with you on this as I know more about oil than amplifiers.

[2loud2k2xd]

i have tons of pics on this forum. also try this site. tons of more pics. and i know for sure i have 3300 watts rms or i would not be able to hit 140+spl in comps :D thanks
heres a quick link: scroll thru all the pics. you can see my set-up.
http://photobucket.com/albums/v287/2loud2k2xd/?

by the way, i have an adjustable voltage setting on my 3 farad cap. i have it set to 14.6 volts. ive had it drop to 12.4 during deep loud bass hits. almost too loud to be inside the car.

[Soron]

I think I got the pics I need but I still dont know the setup

[2loud2k2xd]

go to my member profile. i have every mod and aftermarket part listed in there.
or click on my sound domain link in my sig.

[Soron]

Just talked to my audio specialist guy last night, he was impressed with your setup/pics (actually he said he was getting a hard on looking at the pics) but does have some advice, he says "get 2 or 3 kicker kx2400 amps and then you wou'll have amps worthy of your X" I really don't know what hes talking about just passing the message on.

[2loud2k2xd]

Just talked to my audio specialist guy last night, he was impressed with your setup/pics (actually he said he was getting a hard on looking at the pics) but does have some advice, he says "get 2 or 3 kicker kx2400 amps and then you wou'll have amps worthy of your X" I really don't know what hes talking about just passing the message on.

no thanks, the 1 2400 rms sub amp is plenty. i will need a bigger box if i want to put more power to it. the sub will actually handle up to 5000 watts rms. the soloX 18" will handle up to 10,000 watts rms. im happy with my setup. hitting a 140-145spl and doing it daily and not setup for spl is cool with me. i may not be the loudest at comps, but at least im the only one that can actually listen to the sub daily and not sound like **** like everyone elses set-up because theirs is setup for spl only :D