POWER!!! need more power!!

[semi]

10 bucks says it was a copy paste job. DEPHILILE

 

[Tasmaniak]

ahem??????

 

[phree]

10 bucks says it was a copy paste job. DEPHILILE

Nope.

Actually typed it for once!

:wave:

 

[phree]

what constitutes a good earth though? I feel another article coming on!

Theres this one:

http://www.caraudioaustralia.com/forums/index.php?showtopic=47755

 

[semi]

good work phree, you are the first person to spell my name right :thumbsup:

what about this then??

http://forums.justcommodores.com.au/showthread.php?t=21609&highlight=dephilile

 

[dephilile]

LOL, I can’t believe you wasted time looking for that. I stand corrected.

 

[shaggerz]

Actually there is a good solution for this. Most places that sell car audio will also have 1 farad capacitors. This will smooth out the lumpy voltage hehe. They cost about $100 on average I think. Jaycar have one for that much, and JB HiFi stock them too. All you do is stick it in the engine bay in parallel with the battery, connected by very fat cable lol.

Oh and by the way, don't ever over-voltage one (don't worry... the 1 farad ones for cars are rated to 20 volts) and DON'T connect it around the wrong way.

Capacitors literally explode of you do either of these things. I blew up a one microfarad capacitor one day (deliberately) and it left my ears ringing. It was only about half a cm across and 1cm long.

Imagine the bang your 30cm long 8cm diameter capacitor would make!

EDIT: 1 farad is 1,000,000 microfarads.

 

[dephilile]

1F and 2F capacitors are a solution but they are not a good solution. They are a bandaid solution to a much larger underlying problem. If you were to try and fix your voltage drop problems with capacitors by the time you buy say 5 or 6 of them, it would have probably worked out cheaper just to get a larger alternator.

Also, if you do use a 1F capacitor it’s best to put it as close to the amp as possible, not right next to the battery which is just about as far away as you could get.

I have a 1F cap and still have voltage drop problems.

If you do get more than one cap connect them in parallel to add their capacitance together.

My friend had a 1F cap and the electronics in the top (all the blue led’s and voltage display) used to keep blowing up. He got it replaced three times (it was a jaycar cap, the guys at jaycar said they had never seen one do what it was doing). In the end they only reason they could come up with as to why all the pretty lights were dieing is because he was overloading his system so much. I’m not sure how big his alternator is but it’s only a 4 cylinder car so it wouldn’t be all that big.

LOL, I remember in physics I connected an electrolytic capacitor in reverse. Within a couple of seconds boiling fluid was spraying out one of the sides. LOL, good times

 

[shaggerz]

I woud have thought that all other things checked (all wiring good, good earth, etc) it shouldn't matter where you put the cap.

Haven't got one myself, but from what I understand, they are fairly effective. There is a limit of course, but unless you are building an SPL comp vehicle, I doubt you'll need to go that far.

Check out http://electrochem.cwru.edu/ed/encycl/art-c04-electr-cap.htm for a crapload of information on capacitors if you are curious, in particular I draw attention to a section quoted below:

Car audio (bus stiffening): One ideal application is for large, multi-kilowatt car audio amplifier bus stiffening applications, where the 13 V dc rail may have hundreds of amps peak drawn with every bass drum kick or every bass guitar slap or pop. This can cause the car battery voltage to drop by several volts, dimming the headlights in rhythm to the music and lessening the life of the alternator and battery, not to mention to degrading the audio distortion and output levels. The solution is to use electrolytic capacitors near the amplifiers. These special-purpose capacitors have ratings from 0.5 to 2.0 farads at 15 V dc. These capacitors usually have a series resistance near one milliohm, so are quite effective at stiffening the car's battery voltage, when used at a level of about 1 farad per kilowatt. Future capacitors will probably be rated 0.2-0.5 F at 60 V dc for the higher battery voltages.

So there u go... about 1 farad per kilowatt of power. Just remember, car audio amps are only about 50% efficient, so you'll really want about one farad per 500 watts. (RMS watts not BOSS watts lol)

 

[StoneX]

Caps doesn't help SPL cars. Caps are used to limit voltage variation... In SPL it is a constant draw and the alternator is not running to recharge it, so the cap would drain instantly and not be recharged.