super cap instant charge station

Ian0

Joined Aug 7, 2020
9,679
The loss to resistively charge a capacitor is independent of the time to do the charge, or the value of resistance in series with the capacitor.
The loss is always equal to the energy stored on the capacitor (1/2 CV²).

The only way to reduce that loss is to resonantly charge the capacitor through an inductor (for a perfect inductor, there would be no loss).
I thought that this thread was mainly about constant current charging, and I was referring to the losses in the ESR
 

Papabravo

Joined Feb 24, 2006
21,159
Don't know where I heard it before but when I did - I thought it was some sort of blond reference.
Because Disney World is known in some circles as the "Magic Kingdom" it seems logical that the actors want you to have a certain kind of day, regardless of their actual feelings.
 

Jon Chandler

Joined Jun 12, 2008
1,029
If I'm following this correctly, or at least as stated, you're talking about using 1pF caps. Supercaps are measured in the several Farad range. 1pF is 10^–12 Farad.

*Sniff* Nope.
 

MisterBill2

Joined Jan 23, 2018
18,179
My advice is to be sure to put on your safety goggles or at least your safety glasses before you apply the power. Flaming capacitor fragments are a hazard, and can do serious eye damage.
AND, the classic ladder voltage multiplier uses diodes, not resistors.
 

BobTPH

Joined Jun 5, 2013
8,814
@Capernicus, you really need to learn some basic physics (conservation of energy) and some basic electronics. Everything you post is absolute nonsense. You gave a like to my post #14, but, apparently, did not learn anything from it.

A calculation like I gave you can determine the absolute minimum charging time of any capacitor to any voltage based only on the power the power supply can output.

You cannot charge a 3000F capacitor to 30V with a 30V 3A power supply faster than the 15000 seconds I calculated without violating the laws of physics. Using only passive components, you cannot charge it in less than than twice that time.

If you are claiming otherwise, you are making a free energy claim, and this thread will have to be closed.
 

Ya’akov

Joined Jan 27, 2019
9,078
I guess the point is, if your supply has enough capacity to charge the cap quickly there is a
You cannot charge a 3000F capacitor to 30V with a 30V 3A power supply faster than the 15000 seconds I calculated without violating the laws of physics. Using only passive components, you cannot charge it in less than than twice that time.
Just a clarification. It‘s a 2.7V capacitor he wan’t to charge at 30V to do it faster. How he will know when the cap is at 2.7V is not at all clear.
 

BobTPH

Joined Jun 5, 2013
8,814
So, you can charge it at 3A in only 2700 seconds. Still a long way from the 10 seconds he thinks he can get.

And the minimum with a 100% efficient constant power charger at 90W it is 121.5 seconds.
 

MisterBill2

Joined Jan 23, 2018
18,179
This looks a lot like a manifestation of the "Jim Moore syndrome", thinking that if you really want something to be true, it is true.
J.M. was a person I worked with years ago, and he was able to specify things that could not exist. He was also able to improve instrumentation systems by designing in multiple ground loops into 4-20Ma circuits, which was an amazing achievement.
 

Thread Starter

Capernicus

Joined Jun 24, 2022
87
If I'm following this correctly, or at least as stated, you're talking about using 1pF caps. Supercaps are measured in the several Farad range. 1pF is 10^–12 Farad.

*Sniff* Nope.
the 1pf caps are for charging the super cap, they dont have to be super caps themselves, they can just be mini ceramics.

Well when it doesn't work, I'll have to hide in a little hole for a while, and feel a little hurt, but I'll be back, cause a man that doesn't make mistakes, doesn't make anything.
 

Ya’akov

Joined Jan 27, 2019
9,078
the 1pf caps are for charging the super cap, they dont have to be super caps themselves, they can just be mini ceramics.

Well when it doesn't work, I'll have to hide in a little hole for a while, and feel a little hurt, but I'll be back, cause a man that doesn't make mistakes, doesn't make anything.
Have you tried simulating your circuit?
 

MisterBill2

Joined Jan 23, 2018
18,179
The quantity of charge a capacitor can accept is a direct function of it's capacitance, in fact, the definition of it's capacitance. AND a capacitor can not deliver more charge than it can accept. That reality is independent of how rapidly the charge/discharge cycle is repeated. It is not affected by what anybody wishes were true.
 

k1ng 1337

Joined Sep 11, 2020
940
This looks a lot like a manifestation of the "Jim Moore syndrome", thinking that if you really want something to be true, it is true.
J.M. was a person I worked with years ago, and he was able to specify things that could not exist. He was also able to improve instrumentation systems by designing in multiple ground loops into 4-20Ma circuits, which was an amazing achievement.
What did he accomplish that was impossible?
 

Ya’akov

Joined Jan 27, 2019
9,078
here secrets out..
Heatsinks? I mean, how do you do something like that without knowing you are going to be heating things up dramatically?

Also, no current measurement? That's an odd omission.

He was using higher voltage than the capacitor rating but he was also monitoring it manually and could shut it off when it reached full charge. But think for a moment how much energy was being pushed into those caps. I wouldn't trust leaving them sitting open on a bench while doing that.

A catastrophic failure would require more safety equipment than just eye protection.
 
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