The Spike

[minoly]

"The critical thing is the spike, it's been the spike all along, the exact replica basically of a nerve impulse." – who said this...

1.    How can we create it...
https://youtu.be/KKUbVAMFZqw
There are many methods to create it I'm hoping to get the basic basics please share 1 or 2 of the best methods you use or have heard of.

2.     How can we harvest the spike..
I don't have a quick video reference for this but I basically want to talk about methods to get it from the inductor to a "storage" device which "later" allows us to use it in some way. The above video for example uses a single diode and a full wave bridge rectifier to get it to a CAP.

3.   What can we do with it...

NilreHob gives us some math. Look in description for the pdf's:
https://www.youtube.com/watch?v=xZcvOWSXcbU
Woopy:
https://www.youtube.com/watch?v=tag5OlvPi54
me:
https://www.youtube.com/watch?v=7tFTyYsB1QY
there are many things people have done over the years. Lights batteries drive motors, on and on. First I want to get into creating it.

I see here on this forum topics can get off hand quickly and into a different universe entirely. Let's hope this one can stay on topic and yet allow for ideas to thrive at the same time. No gestapo here...

I will continue to post as the subject remains close to topic and as I have time.

[minoly]

Here I attempt to remove as much human error as I care to at this point.
I keep saying the energy rushes into the cap when I mean to say coil...
https://youtu.be/822yyCWyYXw


Notice the wave form, notice that it captures the inrush of energy as well as the discharge. My cap does not have enough joules to fill that coil does it...
The battery does however and allows us to see more of how a coil takes in and discharges.
cheers

[minoly]

Laurent creates the spike using a "universal motor" and melts tungsten!
https://www.youtube.com/watch?v=TAx7Y0UIyHA
Nice work!

[MileHigh]

Minoly,

I assume that you have been following the discussions on the other threads.  By now you should know that the spike is simply the coil discharging its stored energy in the form of a pulse of current into a load.  If the load is zero ohms, then the pulse of current manifests no voltage spike at all.  If the load is 10,000 ohms, then you can expect to see a short high-voltage spike.

How does that apply to the charging of a battery in a JB pulse motor?

One thing that is never discussed is how many amps of current can the battery reasonably be expected to sustain when you are pulse charging it?  Imagine a small battery.  If the initial pulse of current is 50 amps, that might floor the battery with way too much current.  Then the battery will simply act like a big fat resistor and one can assume that most of the spike energy will be lost as heat instead of actually recharging the battery.  It might even ruin the battery.  On the other hand, if the initial pulse of current is 20 miliamps, the battery may barely be charged by that feeble pulse and it will take days to noticeably charge the battery.  Who knows, perhaps the battery has a minimum current threshold to get charging going in the battery chemistry, and 20 milliamp current pulses will just be lost and mainly heat the battery also.

What this implies, is that for different physical battery sizes, and for different battery chemistries, there is some kind of "sweet spot range" for optimum battery charging with current pulses.  That "sweet spot range" may also be a function of the ongoing state of charge of the battery through time also.

Here is one thing that is absolutely certain:  No current pulse going into a battery, no matter how optimized it is, will be 100% efficient in charging the battery.  There will always be some waste heat generated for each pulse of current going into the battery.

Here is another thing that is absolutely certain:  If the battery is 100% charged, then all pulses of current going into the battery will become 100% waste heat.

Here is another thing that is presumably a certainty:  Every battery will have a pulse current charging threshold where above that current threshold you are more like frying the battery as opposed to charging the battery.  Frying the battery means that the majority of the energy in the current pulse becomes waste heat.  Presumably, there is a good chance that the battery will become damaged by excessively large currents in the current pulses.

Therefore, if you want to design a good pulsing battery charger, you need to have a handle on what current pulse the battery "likes" and then you have to tune your current pulse characteristics and associated pulse frequency to make everything amenable to charging the battery as efficiently as possible.  Presumably you also have to know when to stop charging so you don't whack your battery needlessly with current pulses that go nowhere and just become waste heat.

[MileHigh]

So how do we characterize the current pulse coming from the drive coil that goes into the charging battery?

It's has an initial current value that can easily be measured with a scope and a one-ohm CVR.

It has a fixed amount of energy in it that is proportional to the initial amount of current in the pulse.  E = 1/2 L i-squared.

It will have a discharge curve that decreases down to zero that is a function of the load.  The voltage that you see manifesting from the current pulse is a function of the load.

In summary, when you are pulse charging a battery the two main properties of the current pulse are the initial number of amperes in the current pulse, and the total amount of energy in the pulse.

The total amount of energy in the pulse is a function of the size and number of turns in the drive coil.  If you are going to pulse charge a battery you should measure the amount of energy in the pulse.  The more energy in the pulse, the longer the discharge curve will take to decrease to zero.

What is the current discharging curve like when it goes into a target battery?  Just take a look at the waveform across the one-ohm CVR for yourself and find out.  It will look somewhat similar to the exponential discharge curve that you see when a coil discharges across a fixed resistor.

How come you see almost no voltage spike when the current pulse goes into a charging battery that is in good condition?  If the current level is one amp and the battery is 12.6 volts, then R = V/I so the battery looks like a 12.6-ohm resistor.  However, the differential resistance of the battery is very low, say mlilliohms, so you only will see a small bump in the battery voltage above 12.6 volts.  It's the battery that is determining the voltage output by the coil.

So we know that you see a big voltage spike when the battery is old and dead and sulfated.  In this case the battery is acting like a high-value resistor, so it's natural that the coil will manifest a high voltage.  Note that the coil will force its current into any load, no matter what.  It's like a charging bull of current, and if it has to turn the air into conductive plasma in order to discharge it will.  It's just the way it works.  That's why inductive current pulse charging can rejuvenate a dead battery when applying a voltage source to the battery won't recharge it.  The voltage source will not force energy into the dead battery but a discharging inductor will literally force its energy into the dead battery.

So that's the deal.  If you take your favourite JB pulse motor you should hook it up to a charging battery and put a one-ohm CVR in line with the charging battery and scope the CVR.  All of the information about the battery charging characteristics will be in the CVR waveform.  Whatever pulsing you see in the charging battery voltage is secondary, more of a sideshow.

The other thing you want to do is measure the average charging power that goes into the charging battery.  That gives you a handle on how much energy you may be putting into the charging battery.