The Ultimate Cap Dump

[min2oly]

I am starting this thread in search of the ultimate simplified CAP dump for dummies :-) [that's me not you]

The idea is that you all are much smarter than I am and will come up with something even more brilliant than the lame ckt I am using, or that we will come to a better understanding about how JB is using his Comparator, or both, or something else entirely.

I am of the mind that simpler is mostly always better. And, mostly because Necessity is the mother of invention, and since I am not as adept w/ circuits, I have had to invent my own. I had hoped to find an SSR that I could make break down the way JB did on his Ferris Wheel, sadly I have not yet found it.

In this case we also need to use the least amount of energy possible to dump our Cap across our charge batteries.

I plan to, in the end, show my little ckt, which is no big deal. I hope this first video will take us in a positive direction:



Maybe we can post and share video responses???

Kind Regards,
Patrick

[Floris]

Patrick, what is that device that you are showing? A (SS) relay?

[min2oly]

Patrick, what is that device that you are showing? A (SS) relay?

Hi Floris,
yes, that is a Douglas Randall SSR model K08A.
There were a few of us who purchased various models and were not able to get them to reverse breakdown. Maybe we just aren't hitting it w/ enough amps. That Ferris Wheel packs a big punch.
JB revealed it here
and discuses it here

Patrick

[Catrinisin]

Patrick,

Is this device you are showing from the Ferris wheel, supposed to break down by itself and discharge the cap? I noticed in the video JB had only two leads connected like you were showing in your video.

-Chris

[BobZilla]

Patrick,
Thanks for starting this thread. I will be watching it very closely but unfortunately I don't think I have much to contribute concerning cap dumping so I am looking forward to learning from you guys.

On a side note I have a question about moving a back battery to the front.

If a capacitor can re-gauge and make that possible then the question is what if we put a cap on the primary side of the machine to re-gauge? What I mean is supposing we charge a battery straight from a ssg with no cap, straight to the battery. We could call this "negative" charge or whatever. Now that battery could be used to do other work with no problem but NOT used as a primary to charge another. If we put a cap on the input of the machine would it solve that issue? I am just wondering if that would work?

I'm assuming the answer to this question is no because it is just to simple and I would think that it would be common knowledge if it did work but I thought I would ask so that I could hear some thoughts from others.

I am only talking about creating the conditions to take a back battery and run it on the front. I know that cap dumps can be used for many other functions like back popping or charging a 3rd battery etc. I very much want to learn to make a cap dump for those types of applications but I am curious if putting a cap on the input would sort of filter a negative battery for use as a primary.

[min2oly]

Hi Mike,
The SCR solution is a fun little project. I was only ever able to get it to work under very specific situations w/ good batteries and small builds. The SCR will IMHO never handle large amperage the way we need it to w/ the larger builds here.

Regarding the CPD mod, have you had a chance to watch this:

If you're having troubles, start small at first. Try a joule thief 1.5 volt front and back, use a 1mg pot, get the LED's to blink... Some can jump right off a cliff and fly, most of us need to learn how to crawl before we can walk etc...
-KR
Patrick

[RS_]

Bob...

"I am curious if putting a cap on the input would sort of filter a negative battery for use as a primary."

No.......

the only thing that putting a cap on the input of a SSG or SG will do is change the circuits input impedance..... with some circuits adding a cap on the input helps, but one must test several values to get it to be most helpful (higher v spikes), and not hinder the circuit...... ( lower V spikes)

[min2oly]

Patrick,
Thanks for starting this thread. I will be watching it very closely but unfortunately I don't think I have much to contribute concerning cap dumping so I am looking forward to learning from you guys.

On a side note I have a question about moving a back battery to the front.

If a capacitor can re-gauge and make that possible then the question is what if we put a cap on the primary side of the machine to re-gauge? What I mean is supposing we charge a battery straight from a ssg with no cap, straight to the battery. We could call this "negative" charge or whatever. Now that battery could be used to do other work with no problem but NOT used as a primary to charge another. If we put a cap on the input of the machine would it solve that issue? I am just wondering if that would work?

I'm assuming the answer to this question is no because it is just to simple and I would think that it would be common knowledge if it did work but I thought I would ask so that I could hear some thoughts from others.

I am only talking about creating the conditions to take a back battery and run it on the front. I know that cap dumps can be used for many other functions like back popping or charging a 3rd battery etc. I very much want to learn to make a cap dump for those types of applications but I am curious if putting a cap on the input would sort of filter a negative battery for use as a primary.

Hi Bob,
I like your idea, so what happens when we place the cap on the front in parallel w/ the primary battery... is the energizer only getting the joules from the cap, and then the battery refills the cap...

What if we place a couple of large resistors between the cap and the battery? Then the battery should have a resistive load, might waste heat though... I'm just thinking out loud-ish.

JB has always said we can place an inverter between the primary battery and cap. However, which is more efficient, either of the methods above, or a cap dump?

speculation is fun, how about we try some experiments and report back :-)
-KR
Patrick

[min2oly]

Slider suggested a zener and MOSFET, any ideas how to hook those up?

What about a Sidac?

All we need to do is supply a small pulse across the input. It has to be a pulse, any constant current will keep it turned on...

I hope everyone is finding their weekend well and in good health.
-KR
Patrick

[ZPDM]

Min2oly,

I'll throw out three ideas for you and Ibpointless who seems to be thinking along the same lines. Disclaimer, I have no formal electronics education or work experience in this idea, I have only tried the first of these ideas.

1) Use a 555 chip to trigger a relay. This works but is a bit complicated.

2) This is what I read about "avalanche breakdown" on wikipedia "once avalanche breakdown has occurred, the material will continue to conduct if the voltage across it drops below the breakdown voltage. So, take a one megaohm potentiometer run it to an avalanche diode and from there to the base of a transistor, or possibly a relay, hooked up across your cap. You could then adjust the pot to trigger the diode breakdown at a specific cap voltage. As the diode would "continue to conduct" below the breakdown voltage you should get a full discharge of the cap. I would be curious if this would work and it is simple.

3) This would be a variant of a circuit published by Forrest Mims. It is online here http://www.radioshack.com/graphics/u...7_P1_PM_EN.pdf on pages 56-57. It is called a two transistor oscillator and at some point I may try and see how it might compare to something like a JT circuit in oscillating a coil. The timing cap is dumped to ground but you might be able to use a large cap there and dump it to something other than ground. Again it is complicated but might be fun to try.

I think number two is the most promising but from my lack of background don't know if there is an obvious flaw. Of course simplest of all would just be a physical commutator with brush contacts.