Pulsing a coil with a cap pulser

[John_Koorn]

Hi JK,
If it is BJT (Bipolar Junction transistor) MJE15024 should be ok...hmmmm..
one transistor and Ringing it twice...ok !
Rgds,
Faraday88.

Faraday,

I have absolutely no idea what "ring the bell twice" means. If you want to paraphrase that quote to suit this set up, knock yourself out. I'd rather use "really efficient battery charger".

John K.

[John_Koorn]

I appreciate your knowledgeable comments here, John.

Would you be so kind as to make a quickie schematic of such circuit including battery voltage and amp hours and also coil number of turns, wire gauge and type of core, air or iron, nothing exact, just off the top of your head approximate numbers?
A 12 volt 100 amp hour battery would be a good example but I can scale up or down from whatever you choose.
555 timer circuits are plentiful so if you can just "black box" diagram that part and show the frequency.

Thanks.

Hi Richard,

Here's a simple schematic. I'm not going to list component details, that's up to you guys to experiment with. The batteries you're planning on using will determine the size of the coil, the transistor, etc., etc.

Simple 3 Batt Switch.pdf

This is about as easy as I can make it.

[Faraday88]

Faraday, you don't have to do it exactly the way I am. Think about it - in it's simplest form it's a 3 battery switch that pulses a coil and then captures the spike into the third battery.

You could do the switching easily with 1 transistor and a 555 timer. Would cost about 50 cents in parts to do that.

John K.

Hi JK,
If it is BJT (Bipolar Junction transistor) MJE15024 should be ok...hmmmm..
one transistor and Ringing it twice...ok !
Rgds,
Faraday88.

[John_Koorn]

JK,
Thanks for that little help! however, your schematic earlier shows the primary coil in series with the charge battery while the secondary is 'kind of parallel' via the conversion in FWBR.
Since i do not have the Large Comparator... I would in essence have the Capacitor Discharge through a SCR or a MOSFET,(Transistors will not survive for sure) the SCR would Self commutate due to Series Resonance action but with this startegy you cannot make the 'bell ring twice' so Dual MOSFET is the best bet. BTW this is true even with Battery based primary switching..a cousin of the SSG.
just my way of tinkering...
thank s again... lets experiment..
Rgds,
Faraday88.

Faraday, you don't have to do it exactly the way I am. Think about it - in it's simplest form it's a 3 battery switch that pulses a coil and then captures the spike into the third battery.

You could do the switching easily with 1 transistor and a 555 timer. Would cost about 50 cents in parts to do that.

John K.

[Faraday88]

Faraday, no the coil was not specifically designed for this experiment. It's the same coil I was using on my SS SG.

Don't over-think this, it's not that difficult. You can pulse the coil any way you like. I already explained how it works. Now there's even a proper schematic. Anyone who's been around for a while should be able to build something in about 20 minutes to prove the concept.

John K.

JK,
Thanks for that little help! however, your schematic earlier shows the primary coil in series with the charge battery while the secondary is 'kind of parallel' via the conversion in FWBR.
Since i do not have the Large Comparator... I would in essence have the Capacitor Discharge through a SCR or a MOSFET,(Transistors will not survive for sure) the SCR would Self commutate due to Series Resonance action but with this startegy you cannot make the 'bell ring twice' so Dual MOSFET is the best bet. BTW this is true even with Battery based primary switching..a cousin of the SSG.
just my way of tinkering...
thank s again... lets experiment..
Rgds,
Faraday88.

[John_Koorn]

Faraday, no the coil was not specifically designed for this experiment. It's the same coil I was using on my SS SG.

Don't over-think this, it's not that difficult. You can pulse the coil any way you like. I already explained how it works. Now there's even a proper schematic. Anyone who's been around for a while should be able to build something in about 20 minutes to prove the concept.

John K.

[Faraday88]

Hi Gary,

The load coil is 81 strands of #23 (0.5mm), 64 strands are being used for the "power" winding and 16 strands are used as the "output" winding.

1 strand is not connected (it was previously used as a trigger winding on another experiment)

John K.

Hi JK,
Is the coil specifically designed for this experiment and why 81 strand in that ratio? 64 Primary and 16 secondary (and 1 'not in use')kind of Coupling ratio.. Faraday's equation would have said it be Turns ratio for a conventional transformer for Voltage.. Wow! This is Teslian coupling ratio for Current amplification right?? look i answered my own question !!!
how about a Capacitor alone in place of the Comparator unit..since not all have access to it now??
ofcourse it still needs to be 'rung twice'
Rgds,
Faraday88.

[John_Koorn]

Hi Gary,

The load coil is 81 strands of #23 (0.5mm), 64 strands are being used for the "power" winding and 16 strands are used as the "output" winding.

1 strand is not connected (it was previously used as a trigger winding on another experiment)

John K.

[Gary Hammond]

Hi John,

With your 81 strand coil, how many strands are used as the primary (pulsed by the Large Comparator) and how many are used as the secondary to collect the radiant spikes?

[John_Koorn]

Here's a better schematic...



John K.

[John_Koorn]

Hi Faraday, bad guess. RF had nothing to do with that charger (thank goodness).

John K.

[Faraday88]

Ah, the RC-20A. I re-wrote the software for that. Is your's still working? Looks like you had issues with the LCD at least... If by chance you don't want it anymore I'll make an offer on it

As for the "charge module" in it I'm not sure if it's a comparitor or not. I certainly don't have any details on it. It does appear to be a "cap pulser" though.

JK,
My guess...its the Small comaprator version by Rick friedrich..or his version what ever..
Teslagenx does not have the small comparator in their list of product nay more..

Rgds,
Faraday88.

[John_Koorn]

Hi John,

I was looking through an old battery charger, I was wondering if you could tell me if this is one of John's comparitors?
I suppose I would be dreaming if anyone had any details on it?

Ah, the RC-20A. I re-wrote the software for that. Is your's still working? Looks like you had issues with the LCD at least... If by chance you don't want it anymore I'll make an offer on it

As for the "charge module" in it I'm not sure if it's a comparitor or not. I certainly don't have any details on it. It does appear to be a "cap pulser" though.

[Deuis]

Hi John,

I was looking through an old battery charger, I was wondering if you could tell me if this is one of John's comparitors?
I suppose I would be dreaming if anyone had any details on it?

[Faraday88]

Hey JD, as far as results go I'm still doing test runs. But compared to either straight DC current charging, standard SSG charging, or just pulsed DC charging with a cap dump this setup would appear to be the most efficient method. You don't need a big coil to prove the concept. Just about anyone on this forum should be able to replicate without too much difficulty.

The second picture will probably throw you off because what I'm running is a lot simpler. That diagram was just a bunch of ideas I was scribbling down.

What I was after is more like the first picture in a block diagram. Like I said and Faraday rightly picked up is the circuit is basically the "3 battery switch" that PL showed - but not like the one most people have built. What I wanted was a setup that can squeeze everything out of a solar panel and efficiently charge a battery with it. Note that at this point while I'm testing I've been using a lab power supply to simulate the solar panel.

Here's how it works:

The Large Comparator is connected to the output of a solar panel, which in this case will be a 24V 200W panel. It will put out an Voc of around 45v in direct sunlight with a maximum of 5A. The Ctv (capacitor trigger voltage) on the comparator is set to ~25V.
The load coil is 81 strands of #23 (0.5mm), 64 strands are being used for the "power" winding and 16 strands are used as the "output" winding. The output winding is connected to the AC side of a FWBR as in the schematic I scribbled. The DC output of the FWBR is connected to the charge battery. The coil has an "air" core. (Please ignore the transistor at the bottom of the power winding and also the output diode. they are NOT in this circuit. I will scribble a better schematic some time in the future)
The battery is a 12V deep cycle LAB.

As per a "3 battery switch" the Comparator output is the "2 series batteries" for 25VDC. The coil is obviously the load and the battery is the "3rd battery".

But unlike a "3 battery switch" I', not using a constant DC current to charge the battery - I'm using the output of the comparator to "pulse charge" the coil and in turn the battery. When the comparator discharges its caps a very high current 25v pulse is placed over the charge battery and the coil which are in series.

During the comparator discharge pulse two things happen at the same time. Firstly, the coil is charged and secondly the battery gets a high current pulse charge.

Now, as soon as the pulse from the comparator is completed the coil discharges (a very high potential "radiant" spike) through the FWBR and then to the charge battery.

Effectively the charge battery is getting two massive charge pulses for every discharge pulse from the comparator.

What I really like about this setup is it's simplicity and it's efficiency. The comparator is the only device that is doing all of the switching. Aside from some switching losses in the comparator, everything else is being captured by the battery. There is no heat in the coil and no heating of the battery. I also like that it uses a lot of the concepts that JB has taught us.

But to replicate this you'll need something to regulate the current into the comparator. Do not use a couple of 12v batteries in series or a 24v battery as the comparator/cap pulser input.
My setup on a lab power supply running at 3A input will have the Large Comparator dumping at around 4Hz. You probably want to start with something smaller. Just grab a standard coil like an 8 strand and take 2 strands for the output winding. Any cap pulser will probably work, as long as you can set the dump voltage to about 2 times the charge battery voltage. Go slow at first with little current charging your caps, so you can visualise what's happening.

On the weekend I'll do a short video of my setup in operation and I'll show you the scope shot you're looking for. With a bit of luck I'll have it hooked up to a solar panel as well.

John K.

Effectively the charge battery is getting two massive charge pulses for every discharge pulse from the comparator.
'Ring the bell twice'
Rgds,
Faraday88.