Why are Capacitors so Expensive?

That's $140 for a bank of 6....the price will probably come down some with increased demand and production...maybe you should design a cheaper alternative...?

..."About half the materials cost comes from the use of activated carbon to coat the electrodes, according to Materials Today. Supercapacitor-grade activated carbon can cost $15 per kilogram."...

https://www.sciencedaily.com/releases/2016/08/160818090645.htm#:~:text=However%2C%20supercapacitors%20are%20expensive.,can%20cost%20%2415%20per%20kilogram.&text=Biochar%20is%20a%20byproduct%20of,turns%20plant%20materials%20into%20biofuel.

I’ve been working with capacitors for the past 50 years, this is the first I’ve ever even heard of a capacitor rated in whole Farads. I assumed that you made an error in your post. My experience is with radios, power supplies, amplifiers, surge & power factor correction, motor starting. The market for this technology is pretty new, by comparison, so I suspect the cost is similar to the first $1000 VCRs on the market.

Here is a 2.5 Farad capacitor.

That’s amazing, I’ve never followed that branch of audio engineering, car sound systems.

The "large" capacity capacitors are electrolytic. It isn't easy to find something that big in an non-electrolytic capacitor.

But capacitors on a whole are more expensive than batteries for energy per dollar. And that's what I'm trying to understand.

I understand what you are questioning, I have no answer for you. My response was to the post where he had never seen a 1 Farad capacitor.

Still doesn't explain why it's expensive compared to batteries when you compare energy/$.

Expensive ? Not for about Half of the Power Supply for One of These...

https://www.sandia.gov/news/publications/labnews/articles/2018/08-06/Randy.html

"What happens when Z fires

The Z machine uses electricity to charge large capacitors — structures designed to store an electric charge and release it almost instantaneously. These capacitors discharge to produce radiation and high magnetic pressures, which are used to study everything from nuclear weapons to planetary formation to fusion energy. When Z fires, powerful electrical pulses strike a target made of hundreds of tungsten wires. It’s about the size of a spool of thread. The flow of energy through the wires dissolves them into plasma and creates a strong magnetic field that forces the exploded particles inward. The speed at which the particles move is equivalent to traveling from Los Angeles to New York — about 3,000 miles — in slightly less than one second. The particles then collide with one another along the z axis (hence the name Z machine), and the collisions produce intense radiation (2 million joules of X-ray energy) that heats the walls of the target to approximately 1.8 million degrees Celsius."

Your internal resistance and inductance are probably way high though. When you are ready to test I have a spool of fine tungsten wire.

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thewildotter

My comparison is with batteries based on energy/$. My question is, what actually makes it expensive because I can't point to anything in the material or the process that explains its expense compared to say batteries of the same energy value.

During my visit to a company manufacturing capacitors in France many years ago the most striking thing to me was the high-tech precision which was necessary to make these larger capacitors so I suppose the price is understandable

What do you use it for? The 128 Volts is probably the killer factor.

The question was to compare costs of capacitor with another energy storage like a battery. The scenario of 128 V was hypothetical, I am not using it for anything....yet

Neither is anyone else. That's why it's expensive.

Capacitors aren't used anywhere? That's not true at all.

That's not what he meant. You picked a high voltage for an extremely high capacitance. Capacitors WITH THOSE SPECS...

This hinges on the fact that a capacitor stores energy using completely different techniques. A capacitor stores electrical energy in the non-conductive space between two conductors. A battery stores energy chemically and thus works on an atomic scale to achieve higher energy densities.

That sounds plausible Refred. But consider this this particular case:

Case A

This 16V, 58F capacitor bank in my OP costs $140.

Stores 0.5*58*16^2 = 7424 Joules.

Joules/$ = 53.03

Case B

https://hobbyking.com/en_us/turnigy-2200mah-3s-25c-lipo-pack.html?countrycode=US&gclid=EAIaIQobChMIvYmY7bSK6wIVDvDACh2zLw97EAQYAiABEgLqRvD_BwE&gclsrc=aw.ds

LiPo battery: 11.1V, 2200 mAh capacity. Cost: $12.95

Energy stored : 11.1*2.2 = 24.42 Wh = 87912 Joules.

Joules/$ = 6788.57

Now I agree the battery chemistry is a great energy maker, but this is over 100 times! And I can't understand what is it about the material or manufacturing of Case A, that makes it so expensive, but in case B causes it to be just 12.95. Because if Case A was lesser, say $10, we would be looking at Joules/$ of 742.4 which is somewhat understandable.

Why is the rare earth metal, Yttrium, so much cheaper than Gold? The mining costs are probably similar. Yttrium is more abundant than Gold but not enough to account for the cost. Gold is one of the easiest elements to smelt and purify so the fabrication costs must be less, for it tends to not chemically bind with other elements.

The cost and function of everything are not related. They never have been and they never will be related.

To venture into the politically incorrect, a slave performs far more actual work than a slave owner but only the slave owner is considered wealthy.

Hmm..probably because gold has been an exchange standard since ages, while Yttrium was discovered just recently. It doesn't have many uses.

In any case, I'm still on this question.

I guess you've never heard of a YAG laser, aluminum alloys or how one gets a red color on a phosphor screen. Do you like white LED light?

Well at least you imply an understanding that the fabrication process doesn't set the price of everything.

Have you ever considered building a toaster from scratch?

Whoaaa! It's actually a lot worse than you think.

Two capacitors in series form a capacitor which is rated at twice the voltage, BUT, has only half the capacitance. _{(Series capacitor calculation is like resistor parallel calculation.)}

So you would actually need 14 x 8 to get to your 100 Farads.

Still seems cheap to us oldies who were always told that a 1 Farad capacitor would occupy more than a cubic metre and would cost a kings ransom. Even that was using increible technology. Try doing the calculations to see how many square miles of rolled up aluminium foil and cling film you would need to make a one Farad capacitor.

Yes, correct point. Connecting 8 in series would make the capacitance 58/8 = 7.25F, and 128V, and if I wanted 100F from 7.25F, would need 14. So 14 x 8.

Well that makes the cost $15,746

This is an Engineering forum.

The price of anything is only what two or more parties are prepared to pay for it.

Engineering requires making design choices on budget constraints as well, doesn't it? I'm trying to understand something deeper on why it's expensive, so I expected answers on manufacturing methods or materials used which I thought would be brought. I couldn't come across anything really as to why this 16V capacitor bank should be $140.