How Many capacitors for How many Watts?

[Paradise_Ice]

What would you say the rule if for adding capacitors to a car audio system is?
I think its 1 farad per 40 amps of current draw or is there something more mathimatical?I am looking at a Soundstream 3 joined capacitor thingy! is that any good? i know soundstream is no longer sound stream and Acoustik Power is the one pulling the strings, I bloody hate acoustik power!

 

[Immo_G]

Dunno who designed that rule, i'd say one of the car rice companies that produce caps. The high end competition cars don't use caps, and most people i know don't use them. If you are getting lights dimming on the beat, your battery and charging system can't cope, a capacitor doesn't hold enough charge to help that.

 

[Matttcattt]

Dunno who designed that rule, i'd say one of the car rice companies that produce caps. The high end competition cars don't use caps, and most people i know don't use them. If you are getting lights dimming on the beat, your battery and charging system can't cope, a capacitor doesn't hold enough charge to help that.

Is there any point using capacitors, or should you just have a huge battery and alternator?

 

[baggystevo82]

I would have thought just a bit of light dimming on the beat might be fixed with big caps, so long as there's enough charging to get it all back up in between. Maybe if the lights dim constantly and never recover, or engine running problems etc it may need a different approach
Steve
edit: maybe even a completely seperate alternator/battery system just for audio as Matt suggested

 

[Paradise_Ice]

Dunno who designed that rule, i'd say one of the car rice companies that produce caps. The high end competition cars don't use caps, and most people i know don't use them. If you are getting lights dimming on the beat, your battery and charging system can't cope, a capacitor doesn't hold enough charge to help that.

Is there any point using capacitors, or should you just have a huge battery and alternator?

I didnt know that! people in the know, dont use caps? ok.
So i need to get a trackor battery? space in my engine is not that free, i have a stock altenator also, its good for around 90 amps, but a seperate battery needs a seperate regulator right? i cant just parallel 2 batterys together?
I cant add a bigger altenator or even add another one, to many pullys and pumps on my engine bay as it is, The Ampilifir in question has 100 amp current draw that is giving me the disco lights! i think its embarresting

 

[sss]

normally the battery voltage is 12V , when the engine is running its 13.8V .
when u are using high power amps that need high current the battery voltage drops to 10V or even less , to 8-7 volts ! this causing the lights to dim , it can cause your HU to work un properly - that way distortion can be added to the audio signal .
using big cap near the amp will prevent this , the high current peaks will be drown from the cap and not from the battery .

dont buy those fancy 100$ or more caps , u can use "simple" big caps for that porpuse

 

[richie00boy]

A cap will only help with an non-frequent, burst load. If you are running an amp that needs 100A the only solution is to upgrade the alternator to a higher current one. A cap cannot allow more continuous current to be drawn than is available from the alternator, the cap has to be recharged and often this puts massive demands on the alt. There is no such thing as perpetual motion

IMO a cap is the worst value-for-money item you can buy for car audio and you are better spending the extortionate amount they cost on buying better headunit/amp/battery/power cable/alt in the first place.

 

[Paradise_Ice]

A cap will only help with an non-frequent, burst load. If you are running an amp that needs 100A the only solution is to upgrade the alternator to a higher current one. A cap cannot allow more continuous current to be drawn than is available from the alternator, the cap has to be recharged and often this puts massive demands on the alt. There is no such thing as perpetual motion

IMO a cap is the worst value-for-money item you can buy for car audio and you are better spending the extortionate amount they cost on buying better headunit/amp/battery/power cable/alt in the first place.

There is peretual motion if you have a super conducting liquid or Gravity! with no friction , Your right caps cost alot of money but its a good gimmic! My problem is i have more then 1 amp, i have two old good old school JBL GTs 300 as i love the sound quality from them. They need 40 amps each, and this new one from Visonik is a greedy ******, its draining my system big time, i have 4 runs of 4 gauge cable from my battery that is to a 110 amp marine boat battery, its pretty big! The only thing is i dont need that much power, who does bloody hell! its just to show people how much power i can get out of one of my Goliath infrawoofer, I dont want to have a battery in the car but its starting to look like i will have to, I wont spend silly money on a optima yellow top, there expensive in Scotland! I know i will damge my cars electrical system if i keep on pushing it! thats not what i want to do to an old Saab 900 thats 5 years old! Is there something i can buy to add another battery on have it on the same charging system?

 

[Paradise_Ice]

A cap will only help with an non-frequent, burst load. If you are running an amp that needs 100A the only solution is to upgrade the alternator to a higher current one. A cap cannot allow more continuous current to be drawn than is available from the alternator, the cap has to be recharged and often this puts massive demands on the alt. There is no such thing as perpetual motion

IMO a cap is the worst value-for-money item you can buy for car audio and you are better spending the extortionate amount they cost on buying better headunit/amp/battery/power cable/alt in the first place.

There is peretual motion if you have a super conducting liquid or Gravity! with no friction , Your right caps cost alot of money but its a good gimmic! My problem is i have more then 1 amp, i have two old good old school JBL GTs 300 as i love the sound quality from them. They need 40 amps each, and this new one from Visonik is a greedy ******, its draining my system big time, i have 4 runs of 4 gauge cable from my battery that is to a 110 amp marine boat battery, its pretty big! The only thing is i dont need that much power, who does bloody hell! its just to show people how much power i can get out of one of my Goliath infrawoofer, I dont want to have a battery in the car but its starting to look like i will have to, I wont spend silly money on a optima yellow top, there expensive in Scotland! I know i will damge my cars electrical system if i keep on pushing it! thats not what i want to do to an old Saab 900 thats 5 years old! Is there something i can buy to add another battery on have it on the same charging system?

 

[Immo_G]

I know people who have used a larger car battery (95 RC 440CCA) battery, with 1200wrms setups, and had little dimming. The main difference, he had the battery with the amps.

4 runs of 4ga shouldn't be causing any voltage drop with that sort of load, i'd be wondering about your battery condition.

Serious question, what is your battery ground cable like? If its the stock usual 8ga wire, i'd expect that to be your main problem. Also if its badly mounted or rusted (never had a Saab myself), this will cause a major voltage drop on everything.

I guess check your amp grounds as well, but the main one i'd check is the battery ground.

 

[richie00boy]

If I was running that sort of power I would be connecting dedicated earth wires to the battery for the amps.

 

[Paradise_Ice]

i made a mistake my car is 15 years old! i missed the one,
I have 4 gauge earth wires, i think your right about my battery, its a bit of an old dog now i suspect, I did'nt think running dedicated earth wires was a good idea? Funny thing is the car has Zero rust and its in Sunny Scotland! so the earthing points are solid, I am glad i have not thrown money away with caps, but some in this thread said there good if there close to the amp?
I am not sure is that makes a difference?

 

[imix500]

Why not add an additional battery that sits next to the amps as previously suggested? It would provide the extra current reserve and not be limited by the resistance and length of the power cables. If it was fully charged from the get go, a charging system shouldn't see any difference between two slightly discharged batteries and one more than slightly discharged battery. Just a thought.

 

[imix500]

Btw, I heard some time ago 200,000uf per 100watts. But I have no idea if this is accurate.

 

[clayton]

If you install another battery make sure both battery are identical in cca. Otherwise you will shorten the life span of the batteries. Also use no less than 2awg. wire for your second battery running it to your main. This will enable it to get the full amount of charge from your alternator.

 

[NB23]

If you add a second battery, would it cause the alternator to work harder? To charge up both batteries. Or maybe it does not matter because, even with two batteries you are still pulling the same amount of current as with a single battery. If you put the second battery in the trunk with your amps, don't you need a sealed battery, because normal unsealed batteries release hydrogen when current is drawn from it, thats not good if its close to your amps.

 

[baggystevo82]

If you're worried about gas emmission and leakage then take a look in a racecar catalogue (most car accessory catalogues now too to be honest) and look for batteries. FIA race spec batteries will have a gel inside (instead of a liquid) and are fully sealed, so no gas emissions and no leakage. Leakage is definitely a concern if you keep the battery under a seat or something...definitely wouldn't want to be in there if you rolled with a normal battery there! Those same catalogues normally have some huge alternators too, all gets a bit pricy though
Steve

 

[xplod1236]

capacitors do help. I was running my amp, and it was dimming the lights. Then I added a cap, and no more dimming. I was surprised because I was playing continuous bass music, and the lights didn't even dim.

 

[baggystevo82]

maybe theyre continuosely a little bit dim so you don't notice?
Steve

 

[xplod1236]

they might be, but without the cap, the dimming was noticable. So caps do help.