10 farad cap.

[lion_g]

hey all i got a 99 vt commodore running a 500 watt mono block option audio amp, with 2 12" rampage subs possibly going to change the subs to option audio subs soon.

my car is having a bit of trouble rolling over when the head unit is connect up possibly because of the amp?
also the lights dim at night..i was thinking of buying a cap i can get 1 farad ones in town for about 95$ but then again on ebay i can buy a 10 farad boss audio ones for $115..
will there be any downs sides to having such a big cap?
im thinking of adding another any for some speakers in the future.

[acarmody]

You car has serious electrical issues if you are getting light dimming with 500w of bass. A cap will not fix this or do anything for that matter.

[SuperSixty6]

You car has serious electrical issues if you are getting light dimming with 500w of bass. A cap will not fix this or do anything for that matter.

You are usually on the money champ, But this is a bit misleading...

There is obviously a problem with your Electrical, When you find the problem there will be a solution. Caps aren't that great, The only reason i have them is too look pretty. I could only imagine how useless Boss ones would be.

What condition is your battery in ? Alternator ?

[Coast_Calais]

look at your battery, chances are it's on it's way out... next suspect would be connections to battery and/quality of earth to chassis from battery.
Failing that, i'd be looking at connections to the starter motor itself.
A cap would not fix or help your starting issue...
Cap will only aid in quick and large fluctuations in supply PAST the cap in a more regulated manner, thus it would reduce the 'dimming' of your lights..

[Zarconia]

Apologies for hijacking the thread but ive got a 1000w mono running 3 subs and a 400w running all the speakers. All sounds good just when it gets fairly loud the lights start to dim a little. Thats not an electrical problem is it? Will a cap help with that?

[calais_cruzin]

Apologies for hijacking the thread but ive got a 1000w mono running 3 subs and a 400w running all the speakers. All sounds good just when it gets fairly loud the lights start to dim a little. Thats not an electrical problem is it? Will a cap help with that?

Elec problem, first step upgrade the grounds off ur battery to thicker cable, 2guage is more than enough for 1000w
Cap wont help

[StoneX]

Cap won't help? That's exactly what they do, reduce voltage fluctuations which the visible symptom is dimming.

It is best to ensure your whole power supply uses sufficient sized wire, meaning power from alternator to battery, battery to amplifier, ground from battery to chassis, battery to engine block, chassis to amplifier. If that is all done and you still have dimming, a capacitor is cheapest option after that. Don't even try to say a battery as the dimming is the supply dropping from alternator charge voltage down to battery voltage, so a battery cannot fix that. A good battery can stop it from dropping below 12-12.5v, but by then your lights have already dimmed.

[edit] This is not in reply to the original poster. He clearly has an electrical issue. My information is for someone with a healthy electrical system.

[Coast_Calais]

Cap won't help? That's exactly what they do, reduce voltage fluctuations which the visible symptom is dimming.

It is best to ensure your whole power supply uses sufficient sized wire, meaning power from alternator to battery, battery to amplifier, ground from battery to chassis, battery to engine block, chassis to amplifier. If that is all done and you still have dimming, a capacitor is cheapest option after that. Don't even try to say a battery as the dimming is the supply dropping from alternator charge voltage down to battery voltage, so a battery cannot fix that. A good battery can stop it from dropping below 12-12.5v, but by then your lights have already dimmed.

[edit] This is not in reply to the original poster. He clearly has an electrical issue. My information is for someone with a healthy electrical system.

We all acknowledge the function of a cap, as previously stated, however it (a cap) will in no way ever ever fix a car having trouble turning over...

[acarmody]

I still want to know whats wrong with the OPs car if he has dimming with a max of 50amps being pulled. Probably a lot less since its a 500 watt amp, more likely 100-200wrms. Especially since the OP has a VT which has the 100amp Bosch unit.

[Coast_Calais]

I was replying to the post directly above mine, which generally doesn't require you to quote their post for normal people to understand what my post is about... But I did add the disclaimer at the end for retards who don't understand that concept.

So glad you cleared that point up..

[Pickle']

Apologies for hijacking the thread but ive got a 1000w mono running 3 subs and a 400w running all the speakers. All sounds good just when it gets fairly loud the lights start to dim a little. Thats not an electrical problem is it? Will a cap help with that?

i had a 1000w mono running 2 12s and 2 4 channels running 4 6x9s and a set of splits the lights used to dim massively... i had a volt gauge in the old car without the cap with high bass used to drop from 14 to about 8.. i bought a 2 farad cap and the thing never moved again lights stopped dimming it fixed me perfect.. i really dont know why everyone here is saying caps do nothing... worked fine for me

[Coast_Calais]

i had a 1000w mono running 2 12s and 2 4 channels running 4 6x9s and a set of splits the lights used to dim massively... i had a volt gauge in the old car without the cap with high bass used to drop from 14 to about 8.. i bought a 2 farad cap and the thing never moved again lights stopped dimming it fixed me perfect.. i really dont know why everyone here is saying caps do nothing... worked fine for me

let me try to clarify this properly, and for those of you getting worked up about it, don't read this like i'm having a go and don't get all defensive when you reply...

A Capacitor will not help your car if it is having trouble starting, this is what were are telling the OP, so maybe try to re-read the thread from beggining and you'll see why were are saying 'a cap won't work'....

A capacitor WILL help with headlight fade and load spikes. I have said this and this has been covered. Please read all the posts and to whom responses were directed before you assume everyone in this thread is wrong and you are the only person with the right answer..

Cheers....

/flame suit...

[Pickle']

let me try to clarify this properly, and for those of you getting worked up about it, don't read this like i'm having a go and don't get all defensive when you reply...

A Capacitor will not help your car if it is having trouble starting, this is what were are telling the OP, so maybe try to re-read the thread from beggining and you'll see why were are saying 'a cap won't work'....

A capacitor WILL help with headlight fade and load spikes. I have said this and this has been covered. Please read all the posts and to whom responses were directed before you assume everyone in this thread is wrong and you are the only person with the right answer..

Cheers....

/flame suit...

lol yeah sorry wasnt aimed at you.. there is deffinately other issues if the car isnt starting..

[acarmody]

i had a 1000w mono running 2 12s and 2 4 channels running 4 6x9s and a set of splits the lights used to dim massively... i had a volt gauge in the old car without the cap with high bass used to drop from 14 to about 8.. i bought a 2 farad cap and the thing never moved again lights stopped dimming it fixed me perfect.. i really dont know why everyone here is saying caps do nothing... worked fine for me

I'm sorry but I find it hard to believe that your voltage got down to 8 volts. I'm not saying your lying or anything but I just can't see it happening without your battery being on its last legs.

When a your car is puttering down the road it should have about 13.5-14.4v, because that is what the alternator puts out, anything less and you should get it checked. When a bass note hits the alternator will supply the juice first, up to its rated amperage, which for a VE I believe is 100amps. If that is not enough than the voltage will drop to about 12 volts, this is the battery voltage, the battery is now picking up the slack that the alternator can't put out. The battery is capable of throwing hundreds of amps out, think of your starter motor which requires a few hundred amps. If the combined output of the battery and the alternator than you will experience further voltage drops. But as the voltage gets lower so does the power output of the amp since it creates less output power with less voltage. For example an amp may make 100wrms at 4-ohms at 14.4v, but will only make 70wrms at 4-ohms at 13v. So as the voltage drops in the overall car so does the draw by the amps. Anyway I'm getting off track.

Basically if you were actually getting 8v readings than your battery was buggered or depending where you wired up the gauge, the amp wiring was too small. Especailly since your system if fairly small. The alternator should of handled it fine.

[Coast_Calais]

I'm sorry but I find it hard to believe that your voltage got down to 8 volts. I'm not saying your lying or anything but I just can't see it happening without your battery being on its last legs.

When a your car is puttering down the road it should have about 13.5-14.4v, because that is what the alternator puts out, anything less and you should get it checked. When a bass note hits the alternator will supply the juice first, up to its rated amperage, which for a VE I believe is 100amps. If that is not enough than the voltage will drop to about 12 volts, this is the battery voltage, the battery is now picking up the slack that the alternator can't put out. The battery is capable of throwing hundreds of amps out, think of your starter motor which requires a few hundred amps. If the combined output of the battery and the alternator than you will experience further voltage drops. But as the voltage gets lower so does the power output of the amp since it creates less output power with less voltage. For example an amp may make 100wrms at 4-ohms at 14.4v, but will only make 70wrms at 4-ohms at 13v. So as the voltage drops in the overall car so does the draw by the amps. Anyway I'm getting off track.

Basically if you were actually getting 8v readings than your battery was buggered or depending where you wired up the gauge, the amp wiring was too small. Especailly since your system if fairly small. The alternator should of handled it fine.

Your alternator can't regulate at that speed. 90 amp load for less than 0.5 sec, you'll get a voltage drop no matter what, even with a new battery.

[Pickle']

I'm sorry but I find it hard to believe that your voltage got down to 8 volts. I'm not saying your lying or anything but I just can't see it happening without your battery being on its last legs.

When a your car is puttering down the road it should have about 13.5-14.4v, because that is what the alternator puts out, anything less and you should get it checked. When a bass note hits the alternator will supply the juice first, up to its rated amperage, which for a VE I believe is 100amps. If that is not enough than the voltage will drop to about 12 volts, this is the battery voltage, the battery is now picking up the slack that the alternator can't put out. The battery is capable of throwing hundreds of amps out, think of your starter motor which requires a few hundred amps. If the combined output of the battery and the alternator than you will experience further voltage drops. But as the voltage gets lower so does the power output of the amp since it creates less output power with less voltage. For example an amp may make 100wrms at 4-ohms at 14.4v, but will only make 70wrms at 4-ohms at 13v. So as the voltage drops in the overall car so does the draw by the amps. Anyway I'm getting off track.

Basically if you were actually getting 8v readings than your battery was buggered or depending where you wired up the gauge, the amp wiring was too small. Especailly since your system if fairly small. The alternator should of handled it fine.

this was in a vr, i reallyhave no idea for all of what you said.. all i know is what i seen. maybe my battery was ####ed.. if so it was like this for around 18 months, and it had a reco alternator so i dunno..