Is a Capacitor worth it?

[WHATJUSTHAPPENd 10+ year member]

I'm not an expert when it comes to alts, but I'm pretty sure that they are not fast enough to change their output for a "spike". Sure if it was a constant 200a then the alt would adjust, but I'm pretty sure the voltage regulator in the alt is designed to slowly change the output (if RPM's are kept constant) to keep the alt from getting damaged.

Bingo, you've just discovered the use of a capacitor. //content.invisioncic.com/y282845/emoticons/thumbsup.gif.3287b36ca96645a13a43aff531f37f02.gif

 

[smoka 10+ year member]

Bingo, you've just discovered the use of a capacitor. //content.invisioncic.com/y282845/emoticons/thumbsup.gif.3287b36ca96645a13a43aff531f37f02.gif

//content.invisioncic.com/y282845/emoticons/banghead.gif.8606515f668c74f6de0281deb475b6fd.gif

You mean battery....

 

[vellocet 10+ year member]

Yeah they are, I'll sell you one for 20 bucks. New and never used.

 

[WHATJUSTHAPPENd 10+ year member]

but a car batt will output down to a fraction of a voltby then ur alt has blown up and ur batt is about to explode

try it,

find the thickest metal bar u can,

start ur car,

put ur DMM across the batt

then place the metal bar carefully across the terminals of ur battery

Your Batt will only output to a fraction of a volt when there are no forces to recharge it.

The voltage regulator is the reason the above diagrams work. In the metaphor, it would be the determining factor in how high on the tank the faucet is located.

The electrical system of your car is designed to drop output from your battery at a certain point to avoid killing the alt. At this point you experience a voltage drop effectively allowing your battery to recharge enough to avoid damage.

This process does not happen when the alternator is not running because now the line between the battery and the amp is a simple circuit. Just like a light bulb attached to a battery. The flow of energy only goes one way instead of being balanced according to resistance 4 ways.

More poorly drawn examples:

Now bear with me, the resistance values are not to scale and will vary greatly, this is just to give you an idea of what I'm talking about, and the reason A healthy battery will not completely discharge while the alt. is running, but it will when it's not.

 

[WHATJUSTHAPPENd 10+ year member]

//content.invisioncic.com/y282845/emoticons/banghead.gif.8606515f668c74f6de0281deb475b6fd.gif
You mean battery....

While a battery adjusts quicker than an alt, A cap adjusts quicker than a batt. However too quickly to effectively prevent voltage spikes.

This is why just as I illustrated above A batt. and a Cap both can end up straining your elec. system more than strengthening it under the right conditions. Just as it can strengthen rather than strain under the right conditions.

You cannot simply expect to get the best performance out of you system by beefing up one mere component of it and leaving the rest.

A 900amp alt with a 50 amp batt. is crap.

5000 700amp Batts. on a 50 amp alt, is crap.

a 50 amp alt, a 500 amp batt, and a 938452037507235farad cap is still crap.

900 amps in alts, 20,000 amps in Batts, and 100 farads in caps is sexy no matter who you are.

 

[SomeGuyDude 10+ year member]

I motion to have those diagrams placed in a Sticky atop this forum.

 

[smoka 10+ year member]

The problem with your diagram is that nearly every single load in the car will have a higher resistance than the batt (with the amp being by far the highest load). Batts are purposely made to have a very low internal resistance for that very reason. I know the internal resistance goes up as you drain your batt, but its still very low compared to practically all other loads in your car. Your diagram makes it look like nothing gets power until the batt is full.

So any extra current from the alt would go to the batt last, after all the other loads in the car.

 

[smoka 10+ year member]

The electrical system of your car is designed to drop output from your battery at a certain point to avoid killing the alt. At this point you experience a voltage drop effectively allowing your battery to recharge enough to avoid damage.

There is nothing that controls the output from the batt. If your voltage goes too low your engine will probably stop running and your batt will continue to drop.

But I guess by "electrical system of your car" you might be talking about the "protect mode" of an amplifier. This mode will shut down the amp at low voltage but it does it to protect its own power supply, and not the alt.

 

[smoka 10+ year member]

900 amps in alts, 20,000 amps in Batts, and 100 farads in caps is sexy no matter who you are.

Sexy, till you realize your fuel economy dropped to 5 mpg. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[audiolife 5,000+ posts]

I like how flow charts are used but the process is ignored. Just because a cap is 1 farad does not mean it is actually 1 farad of support either. What dies faster a cap or a battery? How is a cap going to recharge to a higher voltage when after its nutted and the electrical system is still at 13v or under?

 

[haloweenhamster 10+ year member]

The problem with your diagram is that nearly every single load in the car will have a higher resistance than the batt (with the amp being by far the highest load). Batts are purposely made to have a very low internal resistance for that very reason. I know the internal resistance goes up as you drain your batt, but its still very low compared to practically all other loads in your car. Your diagram makes it look like nothing gets power until the batt is full.
So any extra current from the alt would go to the batt last, after all the other loads in the car.

what the hell

r u backwards?

if ur amp was the highest resistance in the car then u would strugle to drive headphones

the LOWER the resistance the HIGHER the current flow

car batts have a souce impeadance of 5-10Mohm

a headlight is about 3ohms

a 1KW amp is 144mohm (0.144ohms for people that dont know what a small m is)

 

[haloweenhamster 10+ year member]

The problem with your diagram is that nearly every single load in the car will have a higher resistance than the batt (with the amp being by far the highest load). Batts are purposely made to have a very low internal resistance for that very reason. I know the internal resistance goes up as you drain your batt, but its still very low compared to practically all other loads in your car. Your diagram makes it look like nothing gets power until the batt is full.
So any extra current from the alt would go to the batt last, after all the other loads in the car.

what the hell

r u backwards?

if ur amp was the highest resistance in the car then u would strugle to drive headphones

the LOWER the resistance the HIGHER the current flow

car batts have a souce impeadance of 5-10Mohm

a headlight is about 3ohms

a 1KW amp is 144mohm (0.144ohms for people that dont know what a small m is) on full wack

 

[smoka 10+ year member]

what the hellr u backwards?

if ur amp was the highest resistance in the car then u would strugle to drive headphones

the LOWER the resistance the HIGHER the current flow

car batts have a souce impeadance of 5-10Mohm

a headlight is about 3ohms

a 1KW amp is 144mohm (0.144ohms for people that dont know what a small m is) on full wack

Ah, ya I got turned around by those diagrams that were posted. He has the internal resistance decreasing as the batt is drained, when in reality its the opposite. Somehow I got reversed too lol. Thanks for correcting that.

But the arguement is still the same. His diagram, is wrong.

1. The batt resistances are backwords.

2. The first diagram assumes the alt can power a dynamic load which is not true.

 

[AlterEgo99 5,000+ posts]

I've read this entire thread like three times. I feel like I am spinning in circles. //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

OK, so, here's my question:

I've got a 145amp OEM alternator. I've got a Kinetik HC2000 102Ah battery. I've got a 1,000W RMS max audio system (see my sig for details). I've done the "Big 3". (again, see my sig)

If my lights are dimming (slightly) at "high" volume (high for me is like 21-23 volume on an Alpine CDA-9887 that has a max. volume setting of 35), where is the problem and what would be the solution? Another battery? An HO alternator? A cap?

Please, please, PLEASE don't start getting all pissy and upset. I'm just asking a question. There may be more than one way to get to the answer, and I know you guys are simply trying to help and provide us your knowledge. Don't get personal, just help a dude out. K? //content.invisioncic.com/y282845/emoticons/thumbsup.gif.3287b36ca96645a13a43aff531f37f02.gif

 

[alexregalgs 10+ year member]

your problem could b as simple as a ground near the amplifier but also could b the voltage regulator on the alt since your vehicle is new what i would try is a small second battery near the amp just to see if it solves a ground issue or if you just needed that little bit of extra storage to solve the problem