Power caps

[turbonutter69]

Hi all just wanting some info on removing my power cap? Do I need to de-energize it? If so how is this done? Many thanks

[HDi fun]

Join the terminals with a 1KOhm resistor. Don't apply a dead short - this will damage the electrolyte boundaries

[turbonutter69]

Originally Posted by HDi fun

Join the terminals with a 1KOhm resistor. Don't apply a dead short - this will damage the electrolyte boundaries

I've got a bulb that came with the power cap. Do I disconnect the cap from the battery then put the light bulb between the terminals on the power cap?

[waynne]

How do you test a capacitor is working properly?

[turbonutter69]

Originally Posted by waynne

How do you test a capacitor is working properly?

Usually they either work or they won't work at all. When you first switch your stereo on without a power cap you get good pounding bass for only a couple of seconds then it drops slightly. With a power cap you should be getting as much bass as when you first switched the head unit on. If that makes sense. But anyways if it's wired correctly it's workin. And if it's been wired wrong it just won't work... Hope this helps you mate.

[turbonutter69]

Oh an i'm sure Hdi will put it in technical words for me and maybe he'll explain it so you can understand lol

[waynne]

I have a broken DVD player and I'm pretty sure that one of the capacitors has died. If I can work out which one then I'm sure I can fix it for less than 50p. It seems a shame to throw it away.

[turbonutter69]

Originally Posted by waynne

I have a broken DVD player and I'm pretty sure that one of the capacitors has died. If I can work out which one then I'm sure I can fix it for less than 50p. It seems a shame to throw it away.

Oh ok sorry thought you meant a power cap. I think you'd need to find a circuit diagram. Or use a multimeter but i'm not sure what setting you would use?

[HDi fun]

Capacitors store electrical charge. Large ones, such as these were discussing, are connected in parallel with the 0-12 volt rail that supplies the audio equipment. The purpose is to smooth out inconsistencies in the supply voltage and current. They also serve the purpose of making large gobs of current available when the power amps and music source demands it.

Bass is the thing that demands lots of current. You need to move lots of air with the bass drivers.

The improvement in sound quality is astounding as making this extra juice available prevents the bass end's demands from compromising the mids and highs as well.

To put this in perspective, try regarding your car's battery as a large 12 volt capacitor. That's all it is. It uses lead and copper plates immersed in sulphic acid to store electrical charge and to supply it again on demand.

Electrolytic capacitors are just the same. *

Capacitors can fail open or short. if they fail open then the effect is the same as it not being there. If it fails short then there's usually signs of damage to the casing, which may rupture. Be careful, the gel electrolyte can be harmful on skin contact. Quite often in this situation other damage will occur to other parts of the electrical system asn a result of the short circuit.

Don't connect a bulb (correct term is actually a lamp) across the terminals of a large cacpacitor if it's charged - this is close enough to a short circuit to cause damage.

* WHy not consider using a couple of Yuasa 6 volt lead acid or NiMH batteries (series connected) in place of a power cap> It's a bloody sight cheaper and will have exactly the same result! Just mount them as close to the power amps as possible and use heavy gauge OFC copper to make the connections. If you can connect a separate pair for each power amplifier then even better.

[turbonutter69]

Cheers mate I hoped you'd explain it in proper terms. I've disconnected the cap but i've not moved it yet. It's a 2 Farad does it really matter because when I bought it the guy at the shop said it didn't really matter as it isn't a massive cap? He did seem a bit of a plum though.

[HDi fun]

2 whole farads is large

[turbonutter69]

Originally Posted by HDi fun

2 whole farads is large

I thought the same but the shop said they'd installed hundreds with no problems. I haven't got a 12v light anywhere i've looked. I haven't got a resistor either. I have took the fuse out but not done anything with the cap yet......

[HDi fun]

wrap a wet tea towel round the terminals

[turbonutter69]

Originally Posted by HDi fun

wrap a wet tea towel round the terminals

Won't that short it? What will it do?

[HDi fun]

discharge it slowly

[turbonutter69]

Originally Posted by HDi fun

discharge it slowly

Ok I may try this later if I go to my mums.

[prevtec]

Originally Posted by turbonutter69

Hi all just wanting some info on removing my power cap? Do I need to de-energize it? If so how is this done? Many thanks

hi mate, hows things??

whats a power car, its wrecking my head

[gendox]

its a power cap and it gives your sound system juice if your sub requires large amounts of power it uses the stored power rather than the batterys power also smooths the sound out. Not an expert though

[prevtec]

Originally Posted by gendox

its a power cap and it gives your sound system juice if your sub requires large amounts of power it uses the stored power rather than the batterys power also smooths the sound out. Not an expert though

thanks for the info

[turbonutter69]

Originally Posted by gendox

its a power cap and it gives your sound system juice if your sub requires large amounts of power it uses the stored power rather than the batterys power also smooths the sound out. Not an expert though

Thats exactly right mate. an amplifier most of the time requires more power than the battery can deliver. A Power Capacitor stores electricity and supplies the amp as and when needed. Because I have 2300 watts of amps in the boot the battery cannot cope when the bass hits hard. Also a power cap will stop the sub distorting because it can feed it power when the battery can't.... Hows prevtec anyways?

[HDi fun]

So do lead acid batteries.