ac 2 dc conversion

[mariush]

There's big differences between super capacitors and batteries.
For example, capacitors can discharge down to 0v while batteries will discharge down to around 2.8v and then you have to stop discharging them or you're gonna damage them.
Lithium batteries are also around 4.2v when fully charged, then quickly go down to around 3.7v where they sit around as they discharge and towards their end of charge they go down to around 3v.
So if you put 4 lithium batteries in series, you know you're gonna have 4x4.2v ... 4 x 3v = 16.8v ... 12v  while with super capacitors you're gonna have 4 x ~2.7..2.85v = 11.4v down to 0v.

You can probably try having 100 super capacitors in series to get the voltage of 285v, but you'll just blow up your fuse... like any capacitor when discharged the capacitor will "suck in" a lot of current, so you need to limit charging and that will cause an increase in charge time.

Here's a typical 3000F capacitor, check datasheet... https://www.eaton.com/content/dam/eaton/products/electronic-components/resources/data-sheet/eaton-xl60-supercapacitors-cylindrical-cells-data-sheet.pdf   
0.23 ohm esr ... it's gonna have  hell of a inrush current.
Keep in mind that unlike batteries these super capacitors are also only rated as cycles of discharge from full voltage to HALF voltage, not fully discharged... and keep in mind charging fast would cause the capacitors to heat up but you have to keep them below around 65c, probably even less..


Last but not least ... consider the total capacity ... a 3000F 2.7v has about 3Wh of charge in it... a laptop battery can have nearly 100 Wh ... and you can have multiple batteries totaling 100Wh charged in parallel in less than 1h.
 

[tooki]

You said it yourself "peak power".... peak power may not be important during discharge, but it may be very important during charge.

It arguably matters more during discharge than during charge. But again, sugar vs vinegar: you can’t compare things that serve fundamentally different purposes.

I hear on the internet you charge LIPOS on their peak discharge.   If you did that for a capacitor its actually infinity.

The maximum charge rate of a lipo battery depends on the specific battery. Some allow for very high currents, others do not, and the maximum charge and discharge rates can be the same or different. Gotta look at the datasheet for a particular cell.

Capacitor maximum charge current is theoretically infinite, but it’s not infinite in practice because a capacitor (like all electronic components) also has parasitic resistance and inductance that WILL limit the current. And depending on the capacitor, it could actually self-destruct. Just because a capacitor can theoretically charge at, say, 100,000 amps doesn’t mean its leads and plates wouldn’t vaporize if you actually tried to do it.

And the 2000 watts is no biggy,  this could easily be just the same as any other thing u pop in the wall,    But i'm going to utilize the whole lot of it at once and make a "battery charger" that full charges 3000farad supercapacitors in 10 seconds.

The amount of power available at your mains outlet is not infinite. That’s why, for example, charging a Tesla at home is very, very slow if you don’t have a special high-power EV charging system installed.

Not that any of this matters. The energy density of supercaps is so much lower than lipo that they’re simply not going to displace them. It’d take a quantum leap in energy density for them to become competitive.

Much nicer.  Just imagine all the $$$... all for me... all for me...

Trust me, I’m not even the slightest bit concerned about you out-earning me with this, since there’s literally zero chance your idea will work.

The other thing is it probably doubles as a car jump starter, if you can get a cable to inside your house.

They already make portable car jump starters, as well as ones that plug in. Nothing new there.

[cemelec]

A capacitor energy storage is 0.5 x C x V^2

Your 5F capacitor at 240V (if such a thing exists outside of a defence lab) stores 144 kilojoules.  At peak 240 x sqrt 2 (340V) it is 289 kilojoules.

A rifle bullet leaves the muzzle with typically about 7.5 - 10 kilojoules.
1 gram of TNT can release 4 kilojoules.

A capacitor can deliver its energy in microseconds.

I think your project might qualify for a Darwin award, and I would sincerely ask you to pursue some other ideas.

[Monkeh]

A rifle bullet leaves the muzzle with typically about 7.5 - 10 kilojoules.

Off the top of my head I can only think of a couple of a couple of cartridges used in elephant guns in that range.. most cartridges used today are in the 1.5-3.5kJ range, with a few magnums pushing 5kJ. Carry on..

[cemelec]

 

Off the top of my head I can only think of a couple of a couple of cartridges used in elephant guns in that range.. most cartridges used today are in the 1.5-3.5kJ range, with a few magnums pushing 5kJ. Carry on..

15 gram bullet at 1000m/s = 7500 Joules.  Very high end rifle bullet

You are right, maybe 2kJ more typical for say a Lee Enfield or something

Makes his project even more dire than I thought.

[Monkeh]

Off the top of my head I can only think of a couple of a couple of cartridges used in elephant guns in that range.. most cartridges used today are in the 1.5-3.5kJ range, with a few magnums pushing 5kJ. Carry on..

15 gram bullet at 1000m/s = 7500 Joules.  Very high end rifle bullet

You are right, maybe 2kJ more typical for say a Lee Enfield or something

Makes his project even more dire than I thought.

3-3.5kJ for .303, they're a little light. 8mm Mauser, .30-06, both edge about 4kJ. .308 sort of sits in the middle of those.

Yes, he's (trying to..) play with energy levels he doesn't quite grasp. Perhaps if we express this in terms of say a small car doing 40mph? About that sort of ballpark..

[Capernicus]

I wonder what charging a capacitor with a plugginable portable car jump starter would be like?   maybe it does charge the cap in 10 secs!  =)

(I just looked and they have dismal 12-16 amp performance,  what im doing is 88x the power of that.)

About killing yourself with super caps,  I think it only becomes a problem with too many in series,  otherwise ur ok.