Feedback on High Output alternator for car audio
#1
11-01-2013, 02:08 PM
Feedback on High Output alternator for car audio
Just getting some feedback on those who might of upgraded their alternator to a high output one for their car audio. The system I will have in my car will by far be the biggest system I will run to date. I already have a 2200 watt mono block amp hooked up running at 1ohm. I will be adding a 120.4 4 channel amp soon but figure I should get my electrical up to par to support it.
I've heard some people suggest just getting another battery and putting it in the trunk but I don't really want to do that. You all already know how small the G35 coupe trunk is already. I know the H/O alternator is pretty expensive and can run upwards of $700. I'd rather do things right though.
My questions are, are the H/O alternators simply a direct plug in replacement of the old alternator? What are the pros and cons of changing it? If I simply upgrade the alternator would that be all that needs to be changed and I'm good to go? I also heard I should upgrade the BIG 3 as well. Any feedback would be greatly appreciated!
I've heard some people suggest just getting another battery and putting it in the trunk but I don't really want to do that. You all already know how small the G35 coupe trunk is already. I know the H/O alternator is pretty expensive and can run upwards of $700. I'd rather do things right though.
My questions are, are the H/O alternators simply a direct plug in replacement of the old alternator? What are the pros and cons of changing it? If I simply upgrade the alternator would that be all that needs to be changed and I'm good to go? I also heard I should upgrade the BIG 3 as well. Any feedback would be greatly appreciated!
#2
11-01-2013, 02:46 PM
#4
06-06-2014, 05:51 PM
#7
06-06-2014, 09:06 PM
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Urbanengineer (06-06-2014)
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#8
06-07-2014, 01:44 PM
Here's real, scientific testing of a capacitor with proper load testing that eliminates a lot of the variables encountered in a car, so all you get is the truth of "do capacitors help provide power?" (spoiler: NO). If you don't believe in scientific testing, you might as well just rub holy water on your amp or sacrifice small animals to your subwoofer instead.
#9
06-09-2014, 10:19 AM
#11
06-09-2014, 05:03 PM
http://www.engineeringtoolbox.com/am...uge-d_730.html
again, I say BS
Besides, capacitors work best on a pulsing current such as an audio source signal or pulsing DC, such as the draw from an amplifier. They don't work well and direct DC applications.
again, I say BS
Besides, capacitors work best on a pulsing current such as an audio source signal or pulsing DC, such as the draw from an amplifier. They don't work well and direct DC applications.
Last edited by Texasscout; 06-09-2014 at 05:31 PM.
#12
06-09-2014, 07:50 PM
http://www.engineeringtoolbox.com/am...uge-d_730.html
again, I say BS
Besides, capacitors work best on a pulsing current such as an audio source signal or pulsing DC, such as the draw from an amplifier. They don't work well and direct DC applications.
again, I say BS
Besides, capacitors work best on a pulsing current such as an audio source signal or pulsing DC, such as the draw from an amplifier. They don't work well and direct DC applications.
The wire gauge is consistent across both tests, affecting with or without cap equally, so the poorer performance of the capacitor can't be blamed on the wiring.
The actual usable power from a cap before you're drawing from the battery is negligible. Once you've overloaded the the alternator and you're down to battery voltage, your capacitor is just something less efficient at transferring power than bare wire to the alternator.
Science:
Why caps don't do much good - the extremely short and basic version.
Let's imagine a car with a 12v battery and an alternator putting out 14v. This car also has a 1000watt amp powering some random sub.
We now add a 1 farad capacitor.
A 1 farad cap charged to 14v stores about 84 joules.
Since we have the battery sitting at 12v, the potential (usable power) of the cap is 2v or 12 joules.
We CANNOT use more than the 12 joules, since that would put the cap below the magical 12v where the battery kicks in.
In order to use the power stored in the cap, we would have to turn off the alternator, or the power it outputs would somehow have to drop - like if it's overloaded (BAD).
Note: 1 joule = 1 watt-second. 1000w for one second is 1000 joule.
Anyway, our 1 farad cap has 12 joules of power we can actually use. this translates into 12 watt-seconds. This can power our 1000w amp for 12/1000s of a second, or 0.012seconds.
This means that if we charge the cap to 14v, and turn off the alternator, we can play a single test tone of 83hz one single time before the cap becomes useless.
Since I'm not at all an expert on this, I have neglected to mention ESR and ESL, which would significantly reduce the benefit we get from the cap.
Because of ESR (ElectroStatic Resistance), an amount of power will be converted into heat in the cap. The more power you try to pull, the more heat and the less useful it is.
Additionally, the amp will convert some amount of power into heat - all depending on the amp.
In the end, the cap may give us as much as .005 seconds (single 200hz tone) of power at 1000w amp output, IF the alternator suddenly dies or for some magical reason (it's overloaded, duh) it drops it's output to 12v. If you only run 500W, it would be about 0.01 second or a single 100hz test tone.
Let's imagine a car with a 12v battery and an alternator putting out 14v. This car also has a 1000watt amp powering some random sub.
We now add a 1 farad capacitor.
A 1 farad cap charged to 14v stores about 84 joules.
Since we have the battery sitting at 12v, the potential (usable power) of the cap is 2v or 12 joules.
We CANNOT use more than the 12 joules, since that would put the cap below the magical 12v where the battery kicks in.
In order to use the power stored in the cap, we would have to turn off the alternator, or the power it outputs would somehow have to drop - like if it's overloaded (BAD).
Note: 1 joule = 1 watt-second. 1000w for one second is 1000 joule.
Anyway, our 1 farad cap has 12 joules of power we can actually use. this translates into 12 watt-seconds. This can power our 1000w amp for 12/1000s of a second, or 0.012seconds.
This means that if we charge the cap to 14v, and turn off the alternator, we can play a single test tone of 83hz one single time before the cap becomes useless.
Since I'm not at all an expert on this, I have neglected to mention ESR and ESL, which would significantly reduce the benefit we get from the cap.
Because of ESR (ElectroStatic Resistance), an amount of power will be converted into heat in the cap. The more power you try to pull, the more heat and the less useful it is.
Additionally, the amp will convert some amount of power into heat - all depending on the amp.
In the end, the cap may give us as much as .005 seconds (single 200hz tone) of power at 1000w amp output, IF the alternator suddenly dies or for some magical reason (it's overloaded, duh) it drops it's output to 12v. If you only run 500W, it would be about 0.01 second or a single 100hz test tone.
#13
06-09-2014, 08:29 PM
No caps don't supply any reserve voltage...
Look, I agree that if you don't have the amperage from your alternator it won't run your sound system. However, a capacitor will add a little fill-in if you're just at the borderline. If you have a sound system that is drawing 150 A average, and you have a alternator that only puts out 85 A, a capacitor will not help you. but if you have a system that only draws 90 A and you have an 85 amp alternator a capacitor will probably help you.
I use a 3 F capacitor on my amateur radio gear in my truck it keeps the waveform from getting distorted when I transmit.
Look, I agree that if you don't have the amperage from your alternator it won't run your sound system. However, a capacitor will add a little fill-in if you're just at the borderline. If you have a sound system that is drawing 150 A average, and you have a alternator that only puts out 85 A, a capacitor will not help you. but if you have a system that only draws 90 A and you have an 85 amp alternator a capacitor will probably help you.
I use a 3 F capacitor on my amateur radio gear in my truck it keeps the waveform from getting distorted when I transmit.
Last edited by Texasscout; 06-09-2014 at 08:45 PM.
#14
06-09-2014, 11:22 PM
No caps don't supply any reserve voltage...
Replacing My Car Battery with Capacitors! 12V BoostPack Update - YouTube
Look, I agree that if you don't have the amperage from your alternator it won't run your sound system. However, a capacitor will add a little fill-in if you're just at the borderline. If you have a sound system that is drawing 150 A average, and you have a alternator that only puts out 85 A, a capacitor will not help you. but if you have a system that only draws 90 A and you have an 85 amp alternator a capacitor will probably help you.
I use a 3 F capacitor on my amateur radio gear in my truck it keeps the waveform from getting distorted when I transmit.
Replacing My Car Battery with Capacitors! 12V BoostPack Update - YouTube
Look, I agree that if you don't have the amperage from your alternator it won't run your sound system. However, a capacitor will add a little fill-in if you're just at the borderline. If you have a sound system that is drawing 150 A average, and you have a alternator that only puts out 85 A, a capacitor will not help you. but if you have a system that only draws 90 A and you have an 85 amp alternator a capacitor will probably help you.
I use a 3 F capacitor on my amateur radio gear in my truck it keeps the waveform from getting distorted when I transmit.
Re-read the math in the previous post. The "Fill-in if you're at the borderline" is .01 seconds of available power when your system taking more load than the alternator is supplying (the only times when the capacitor would be providing a benefit, if any) with a fairly typically-sized capacitor. There's no magical way of making the capacitor provide more power than that. After the capacitor has given up that small burst, its voltage is equal to the charging system, so it's not discharging, it's just mildly throttling the power that the amp can draw from the charging system by trying to constantly charge and discharge - that leaves more power available for the other electrical components in a car, like headlights, so they don't visibly dim.
#15
06-10-2014, 08:55 AM
There's a huge difference between using all 14v of a capacitor vs. the drop of 14v to the 12v "baseline" of the battery. If the car hadn't started first try, I doubt he'd get a second chance, as it would be generous to guess the car would crank for a good 2-3 seconds with those. Energy density of lead-acid batteries is about 5-10x that of capacitors.
Re-read the math in the previous post. The "Fill-in if you're at the borderline" is .01 seconds of available power when your system taking more load than the alternator is supplying (the only times when the capacitor would be providing a benefit, if any) with a fairly typically-sized capacitor. There's no magical way of making the capacitor provide more power than that. After the capacitor has given up that small burst, its voltage is equal to the charging system, so it's not discharging, it's just mildly throttling the power that the amp can draw from the charging system by trying to constantly charge and discharge - that leaves more power available for the other electrical components in a car, like headlights, so they don't visibly dim.
Re-read the math in the previous post. The "Fill-in if you're at the borderline" is .01 seconds of available power when your system taking more load than the alternator is supplying (the only times when the capacitor would be providing a benefit, if any) with a fairly typically-sized capacitor. There's no magical way of making the capacitor provide more power than that. After the capacitor has given up that small burst, its voltage is equal to the charging system, so it's not discharging, it's just mildly throttling the power that the amp can draw from the charging system by trying to constantly charge and discharge - that leaves more power available for the other electrical components in a car, like headlights, so they don't visibly dim.
That's exactly what the caps I have on my radio gear does, it just fills in any low amperage that is not delivered by the batt/alt. It will not "power" anything.