Alternating Battery Switching Implementation Idea's

[Farmhand]

Hi All, I was thinking about how would be the best way to use switches to
recover magnetic field collapse energy in motors and stuff, and remembered
the Gray Patent with the two battery switch setup. I am trying to think of the
best way to implement it into a design.

I can't find the patent drawing at the moment but I'll try to find it and post it
if someone else has it please post it.

So anyway I made this sketch.


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EDIT: here's the patent drawing.


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I think it's viable and would like to experiment with it somehow, but I am a bit
ignorant of what is available to do the switching, and I don't want to start
trying things that are not ideal if there is a better way.

The only thing I can think of to do the switching in a robust way is relays.
And I'm not good with relays, plus that would limit the switching frequency.

My thoughts are that if the correct switching frequency was used for the
batteries or battery type the best result could be gotten. Switching
frequency would also be related to loading for best effect I think as well.
However it could be done at a fixed frequency for simplicity in implementation,
but for testing and experimentation things need to be adjustable.

I'm starting to work through some overall switching solutions with a load
device in mind.

Any idea's for ways to do the actual switching are welcome, meaning
hardware and control circuitry. Also using two sets of two batteries and
switching from series for recovery and to parallel for loading would be good
but more complicated, it could help to keep things cool though.

Cheers.

[skaght]

Switching...

I've been working with mosfets for switching batteries. They can switch very quickly with a good driver. They are more complicated than a relay. If you are switching an inductive load, you typically need a protection diode across the FET and across the inductor, which may change the dynamics of your circuit by channeling the emf spike through the diodes. You basically need to build a timing circuit and feed that to low and high side drivers depending on whether or not the FET's source is grounded. I'd be happy to walk you through more if you like, although the FETs blow up pretty easily with inductive spikes even with the protection circuitry.

[citfta]

Hi Farmhand,

Look through the last 20 or so pages of the "Use for a Tesla Switch" thread. There you will find several ideas for switching batteries. I am currently using mosfets in parallel and have been having no problems switching all kinds of loads. You just need to protect the gate driver chip so that no spikes are fed into the gate driver chip and on to the gate which will destroy the gate. Feed the gate driver chip through a resistor like a 100 down to a 5 ohm or so depending on how many mosfets you want to drive. Then put a .1 uf cap and a 47 uf cap from pin 8 to pin 5. Also put a 12 volt or so zener from pin 8 to pin 5. The gate driver chip I like is the FOD 3180. It will give you very quick switching times and allow you to go pretty high in frequency for your switching.

Carroll

[Farmhand]

Thanks for the tips guys, I have a feeling mosfets will work well but could get quite
complicated. I need to switch the four poles of the two batteries, but each of
the four supply/recovery wires needs to be switched between two batteries,
not just on and off. I think to use mosfets I'll need to either use a micro and
suffer a lot of headaches learning them or suffer a lot of headaches designing
IC circuitry to do it, maybe it won't be as complicated for the two battery
way. I don't have time or parts to start yet, so I'll make a few drawings as I
get time to break down what I need to do to make it happen. I realize I just
need to use two mosfets for each supply/recovery wire and switch one on
and the other off, first thing I will buy and setup is the fuses to prevent a fire.

I'll look for that Gray patent too it'll be in a thread somewhere. I'm terrible at
searching patents.

Thanks guys, i'll check the Use for a Tesla Switch thread and will be sure to
ask for some help if I need it.

I've got a 16F PIC and a 08M2 PIC but I don't have a data cable for the 16F
yet the 08M2 I do, I also have some 89 amp/55 volt logic level mosfets, and
50 amp/60 volt regular mosfets, I have got enough for a few spares.

I will definitely take advantage of the experience gained by you guys in the
Tesla Switch thread, thanks to Matt for reviving that thread.

Cheers

[soundiceuk]

I have been thinking something quite similar, however using a 5 pin 12 volt relay, two 12 volt batteries, 2 car ignition coils, a spark gap and two high voltage capacitors to make a Tesla 'Stout Bars' circuit (Lechers Lines).

It was the only simple way I could think to replicate AC using DC.

I figure its much safer to push the boundaries of this circuit using 12v as the source.

PaulTheAngel's Channel - YouTube

[Farmhand]

I have been thinking something quite similar, however using a 5 pin 12 volt relay, two 12 volt batteries, 2 car ignition coils, a spark gap and two high voltage capacitors to make a Tesla 'Stout Bars' circuit (Lechers Lines).

It was the only simple way I could think to replicate AC using DC.

I figure its much safer to push the boundaries of this circuit using 12v as the source.

PaulTheAngel's Channel - YouTube

Hi soundiceuk, yes I like to use batteries as much a possible, one because I
have them and two because they get charged by sunshine.

Is that you're video ? I ask because I'm interested how the spark gap is driven
What the power source is, I found the gap in the bottle is much better as well
they are very noisy in open air, especially when they are wide.

Interesting demonstration.

Cheers

[mbrownn]

Farmhand, now I think you are getting it the secret is the switching, it hidden in plane sight.

It might be possible with a commutator but it will have to have many segments to get the switching rate up and the brushes will have to be narrowed to one segment width. Then we will have one live segment followed by two dead ones, does this sound familiar? I think Gray built his own motors so that he got enough inductance and the switching he desired, OK he used high voltage too but remember the secret is never fully revealed in the patents.

Because of the low inductance of modern motors we still may not be able to get a high enough frequency so MOSFET's is what I am looking at now.

Skaght, you don't want the protective diodes across the motor, we channel the inductive kickback to a capacitor across the source.

[Farmhand]

Hi mbrownn, Yes the magnetic field collapse from the motor goes to the other
battery, the batteries have a capacitor across them then they get switched
so rather than overcharge batteries or swap them they both remain about the
same in relation to each other but just drain slower.

Maybe if the switching is done slowly or fast it might not matter. Maybe the
batteries could be switched at every cycle but with the field collapse coming
slightly after the input pulse some dead-time would be needed. So it might go something
like; input pulse 1/2 cycle - field collapse recovery 1/4 cycle - dead-time 1/4 cycle - switch - repeat.

Or the switching could be done governed by two parameters, ie, if charge
battery exceeds 14.8 volts then switch and/or if source battery gets to 11.8
volts then switch.

However I think the parameter switching with lead acid batteries might be
hard on the batteries because of no rest time, other battery types probably
don't have that issue.

It would be good to only need two batteries to extend run times. My
objective is not to charge the batteries but get the most from energy used
from them to power a motor or something with a recovery system.

Also like soundiceuk said it may be possible to run an AC motor using two
batteries so maybe 50-50 switching with very small dead time, which is a another good
reason to learn how to use the Micro's so there can be full control over the
way the switching is done just by reprogramming the chip.

Here's EV Gray's Patent drawing, looks simpler than i remembered.


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Here's the patent link, I cannot believe it, he refers to the collapsing magnetic
field as Back EMF. Seems kinda strange I would have thought EV Gray at
least would have known it is Forward EMF which causes it's own Back EMF,
that patent should not have been approved like that in my opinion, Wow.
http://www.free-energy.ws/pdf/gray4595975.pdf


Cheers

[nueview]

there was a paper by Rex research done some thirty years ago about this and it is very promissing for charging battery banks.
i think the mans name was Franks i will try to look it up and get a post for you.
he used six batteries and and switched three in series and three paralell using bipolar transistors he also gave the frequencies and relaxation cycles as well.
Martin