ICE and capacitors

[HDi fun]

The fitment of large capacity electrolytic caps, paralleled with the 12v supply, in close proximity to speaker driving power amps is fairly common.

I have a question (two) for the chemists out there:

In what way does an electrolytic capacitor differ from a lead acid battery (accumulator)?
Apart from possible sealing issues and the emission of hydrogen gas, is there any difference in performance?

I am guessing that it's something to do with the boundary layer between electrolyte and electrodes. Does a capacitor for ICE usage have a faster current rise capability in response to current demand as compared to a typical 12 volt battery?

Anyone got information?

 

[herb]

Capacitors had there place in the 90's and before
They helped a lot with the inferior alternators

But thing's improved vastly from 2000 onwards with alternators that supplied enough current to supply the electrics + an amp or two without any adverse affects on the cars other electrics.

If you are building an ice vehicle Capacitors still aren't used high ampage alternators and high ampage batteries are used and it's all worked out mathematically before a single speaker/amp is fitted

 

[obi_waynne]

The supercapacitor offers a totally different storage mechanism because energy is stored electrostatically on the surface of the material, and unlike a battery will not be using chemical reaction. They can be charged very quickly, leading to a very high power density, and ability to store power doesn't fade over time.

They will not store as much power as a battery though and they tend to be more expensive but recent advances in creating new supercapacitor materials and improving material production methods may soon bridge the energy density gap for some commercial applications. Graphene is one development that could come into play here and help out.

Read more here http://berc.berkeley.edu/storage-wars-batteries-vs-supercapacitors/

 

[turbonutter69]

Herbs right. If you was to go the SPL route then Capacitors would probably be missed.
As herb says beefier alternators are used and banks of batteries. Although saying that, if space is an issue then capacitors would do the job.

But if you have a modest set up like I had in the Primera. The amps I used needed just that bit more when it was turned up.
So I installed a capacitor as a cheap way to solve the dimming of the lights when the bass hit hard.

Care is needed when installing and uninstalling capacitors, due to the amount of voltage they use.

 

[HDi fun]

What I was leaning at is whether a 12v battery connected in close proximity to the power amps would work similarly.

 

[turbonutter69]

Not a normal 12v battery no.
But you can get uprated 12v batteries specially for the job.

The problem with a normal car battery. Regardless of it's position in relation to the amp. Is it cannot deliver the juice required when a decent sized amp needs it.
A normal car battery is fine for stable use of it's juice. Amps fluctuate with how much power they need. That's what a standard car battery cannot deal with, the sudden need for current.

 

[HDi fun]

OK - so it's down to discharge characteristics then. Thanks guys.