Capacitor Charger/Coilgun V2.0

Ok. I know that there is already an instructable on how to build a capacitor bank charger, but for those of you who are either looking for more inspiration, or just want to see a different way to make it, check here. This version made is more of a ~much~ more deluxe version. Why did I make this? Well, I was going to use it for a coilgun, until I realized that the idea of being able to shoot something at at least 300fps is not plausible, unless you have a more powerful circuit (and therefore more powerful cap. bank). I am a bit new to this electronics stuff, so if any of you out there have some know-how to contradict this, and if it really IS plausible, please, prove me wrong! Please note, though, that this device has a very high output voltage, and it (might?) kill the weak of heart if an arc occurs across their heart (not to mention, it HURTS), so be careful when handling any capacitors and/or the circuit connected to them. Lastly, Please excuse me for any errors there may be in this instructable; it is my first. Enjoy!

6-21-07 UPDATE: Added an SCR into the circuit (new button; the old one short-circuited). Details on the SCR on step 3.

Step 1 Enter at your own risk!

EDIT: Make a more robust coilgun! Use this guide as a supplemental reference, but you probably don't want to use it as a standalone walkthrough. This is a wonderful starting point but some things have been misengineered (made up my own word...).

Looking back on this instructable, I realize there are numerous fatal flaws in the design. Some recommendations:

-A more stable (and much faster and effective) CHARGER

-At the current time, I'm pretty sure the SCR in this design will, *ahem*, explode the way it is implemented. One with higher voltage/current abs. max ratings is necessary, or you can use a technique called "Paralleling, Anode to Anode, Gate to Gate, and Cathode to Cathode" (I'm quoting an excellent site for coilgun reference HERE ). Pardon my engineering but I think it was about 15 when I did this instructable.

Good luck and have fun!

Comments

[liddleLOL]

I need help:

I am making a charging circuit for a coilgun, but i accidentally bought non polar caps. I was wondering if i could still use these with some sort of circuit adjustment, or if i need to purchase all new polarized caps? Can you help?

[lilpesh]

parallel=voltage series=capacitance

[MadScientist101]

how much did your caps cost cause i got one for £26 rated at 400V@3900uf and i was wondering if this was a bit expensive?

[Raydoom]

do i need to have the circuit board from the camera to charge the compasiters , i have many large compassiters but no board , can i just hook the compasiters to a battery and it will charge ?
or do i need the circiut board from the camera to get the power from the battery into the compasiters at a higher volatge or somthing

[moza]

what are the red and black things stinging out of the box (there are 2 pairs of each)

[freerunnin1]

they are plugs for external power connections, there instead of alligator clips

[carrierpilot1357]

binding posts (no offense, but that was sort of a stupid question.) :/

[tehpwnz0r]

The only stupid question is the one that isn't asked

[newtons_eple]

Very true.

[student.mckinney]

I disagree. Some questions are honestly just stupid, like asking a postman what he is doing while putting mail in mailboxes, or other such questions. The only questions worth asking are the ones that will benefit the inquirer, audience, venue, or person asked.

[penguin27388]

i disagree, not all people know what a mailman is. ex(if someone comes from a smaLL TOWN and there is no mail, they would not know what a mail man was

[student.mckinney]

Um... what? Mail comes to literally every city in the U.S., and pretty much anywhere anyone with access to a computer has access to a mailman, so...

[penguin27388]

yes because fedex will drive 50 miles into the corado mountains to deliver mail. good try but fail

[theexpert]

or it may be a small town where people still drive to the post office to get there mail PO boxes guys get with it

[PaulMakesThings]

There are no stupid questions, but thinking everyplace in the country gets mail directly delivered is a stupid assumption.

Also, maybe the poster just hasn't worked with electronics and thought the binding post might be some functional part they've never seen, have some understanding for people who's pool of knowledge is different than yours. And asking questions about things you don't know is smart.

[OXI2vasyl]

red spaghetti? lol

[skuitarman]

are the capacitors in series or parallel

[OXI2vasyl]

it easy... parallel = POWER but spent batteries FAST series = LESS POWER but spent battery SLOW it also has explanations more informative, but this is just an example ^^

[seabeepirate]

Parallel. If you try to wire them in series they will do nothing. I can't quite explain how they work, but wikipedia sure can :) Even if you don't really care how they work, for safety's sake, and future experiments, it's probably a good idea to read about them anyway.

[Wargasm]

Actually, wiring capacitors in series increases their voltage rating, but halves total capacitance.

[brianpucci]

It will not necessarily half the capacitance 1/Ct = 1/C_1+ 1/C_2+1/C_3 ....

[seabeepirate]

I'll have to read up on that, I was under the impression that you could not directly wire them in series, but I think I've got a great use for higher voltage. Thanks for the correction.

[JTreehorn]

Just completed a slightly modified version of this project and thought I would post a very important issue.... .....On my cameras chip (all 4 of them), the positive and negative are in reverse from your drawing. Found this out the hard way. I blame myself for not taking note of the batteries position before removal. So again, on the cameras that I have (Kodak HD Power Flash) the negative is by the flash which would be the bottom right on your drawing. Thanks for taking the time to post this instructable and aside from the issue with the drawing (which could be a design change by Kodak) it was very helpful.

[iloveairsoftstuff]

i am noticing some contradiction between diffirent coil gun ibles. some say to use a charger bank, while others just use one charger and it seems to work fine. wat are the advantages and disadvantages to useing a bank as opposed to a single charger?

[Wargasm]

The little flash circuits are not really designed for high current charging. And they make really crappy coil gun units. If you're looking for something powerful that will charge the capacitor bank radiply, check out this intructable. http://www.instructables.com/id/DC-DC-HV-Boost-Converter/ I used this one for a small (but powerful) coilgun project. You don't really have to stick to the parts list but if you're a novice, go ahead and stick to it.

[bombmaker2]

it charges faster with a bank

[philgenius]

i still do not get how u wire the capacitors. do you wire them (-+) (-+) with a wire making a U on top of those, turning around at the bottom or (+-) (-+) et cetera with the wire.

[Wargasm]

In this project, they are wired in parallel. All the + are wired together, as well as -. If you are wanting to double the working voltage, you could wire pairs of 2 in series (I'm assuming these are 330V caps) and you will end up with a voltage rating of 660V (a recipe for instant death) and half the capacitance. So if they are 180uF, 2 of them wired in series would result in 660V @ 90uF. So If you had 8 and wired four of them in series, and then wired the pairs in parallel, you would have a bank of  660V @ 360uF. Pretty dangerous. I don't recommend anyone with a lack of experience in HV attempt to build anything on this page. I've seen capacitor banks so powerful, that they have actually blown off fingers! This one, while it may not blow of any body parts, can still stop your heart if you get bitten by it in the right location and at the right timing.

[mortaldoom780]

You wire them all in parallel. That is + to + and - to -. Imagine it as railroad tracks. You take a capacitor, and line it up with the + leads and all the - leads of the ones behind and in front of it, and then place them on the tracks. At the end of the tracks, you do not make a 'U' or anything (that would short it out, anyways). Visualize it like this: + + + + + + + + + + + + - - - - - - - - - - - -

[philgenius]

btw, is it okay to wire capacitors with the same voltage but different uF together?

[mortaldoom780]

Yes, but the voltage rating as well as capacitance (uf) has to be the same or higher. ESPECIALLY the capacitance; otherwise if you use one that has a lower capacitance compared to the others, it may rupture and even explode!

[Gjdj3]

Wait... so you do need them to all have the same capacitance?

[mortaldoom780]

Yes

[alex-sharetskiy]

but why? capacitors charge until they're full, i've never heard of over charging capacitors

[flamesking]

Its possible that they could explode due to the full dump of the charge... for thats how capacitors work... and if it went into a smaller capacitor and overload it..... boom..... so i could see it exploding out... nothing really super dramatic with music or anything.

[philgenius]

Nah, I don't think so. If a smaller capacitor was fully charged, the extra energy goes to the larger one, not contribute to explosivity.

[alex-sharetskiy]

well ya, if that capacitor a had RIDICULES internal resistance, and you charged it with a large amount of current

[philgenius]

That's what I was thinking....I think you meant voltage in the "rupture and explode" statement. It's like using different-charged alkaline batteries in a toy. It still works, though there is the increased chance of leaking (though it never happens...).

[mortaldoom780]

Excuse me. NO I mean. Sorry to sound confusing. Look at my other post again.

[philgenius]

thank you.