Cap Dump Circuit

[BroMikey]

Fast turn off

yeah you got it, kinda, the coils inductance slows the flow of current from the
supply to the dump caps, I'm using smoothing caps because I 'm using a
transformer, I can't setup a large setup like yours but I can set up a smaller version.

So with the right coil between the supply and the dump caps and the right
"on" time and "off" time we should be able to get down to almost zero current
at switch off due to the coil storing the energy and causing the dump cap to
drop voltage without drawing directly from the supply during the dump time,
the dump caps fill when the switch is off because the coils "momentum"
causes it to discharge into the dump caps due to the switch turning off.

The intention isn't to heat up the coil or anything and a coil with less
resistance but a with the appropriate inductance is better.

I'm now using a microwave oven transformer primary, and with 30,000 uF I
can get the cap to fully discharge in around 70 mS or less which leads to an
almost no current situation at switch off. it takes about 350 mS to recharge
the cap and it goes to a slightly higher voltage due to the storage of energy
in the big coil. The peak current is the same if the voltage is the same and
the resistance of the current path on discharge is the same. This is a way to
isolate the supply from the load during the dump without using a second
switch "except for the diode".

I'll include some shots of the action of the voltage on the caps in that mode.
as well as a shot of the applied voltage and resulting current when the
discharge is short and the capacitor does not get fully discharged.

The coil and dump cap is a "resonant charging circuit" but it is very low "Q"
being so low a frequency. I can do from about 1 per second to about three
per second and keep a voltage rise on the dump caps.

Also if you put the capacitance and inductance in this calculator it will tell
you the resonant frequency of the two together which will tell how much
inductance is required for a given capacitance to get a certain frequency.

Resonant frequency calculator
Resonant Frequency Calculator

The first shot shows the supply capacitor voltage in blue and the dump cap
voltage in yellow, as the mosfet turns on the dump cap discharges but no
current flows directly from the supply to the load due to the coil causing a
delay and storing energy, which is released when the mosfet turns off.

Second shot shows the applied voltage and resultant current when the
mosfet is switched on and off before the cap can discharge, this requires a
fast turn off to do without excessive heating of the switch.
This shot shows the circuit working at 400 Hz and pulsing the battery with 10 Amp
rectangles of current for 260 uS, it's 400 Hz 10% duty, That really pumped up the battery.

Cheers

Hey Farmhand

Good run down on coil energy storing and inductance figures.

As you know I have been running coils in this location but no diode. Why didn't I think of that?

My coils are made of nickle chromium wire used in heating elements on clothes dryers. No real inductance, yet inductance should be part of this operation.

Glad you keep pointing these things out plus showing how this looks.

I am an oscilloscope quadriplegic. I can't show myself what's up yet. I have hooked a 1X probe across the collector and emitter on the MOSFET and I can get all kinds of things.

I can get the sawtooth dump.

I can dial it in to see nS and uS pulsing.

I will get better but in mean time YOU are there with the shots, good man.

I am thinking that my inductance coil is going to have to be 12awg wire and about 500 feet. Ball park. "Probably"? I should put taps along the coil to change input speeds or whatever you call that.

Yeah I am thinking a big coil now for sure .

Diode too.

Then this "CSR" current sensing resistor or some say "Load resistor or shunt resistor" I think this should be a coil also? If a coil is used a higher wattage low resistance value can be reached cheaply and energy is not wasted but stored.

Farmhand wrote:
This shot shows the circuit working at 400 Hz and pulsing the battery with 10 Amp rectangles of current for 260 uS, it's 400 Hz 10% duty, That really pumped up the battery.


Now you have my attention. I will be back to comment on this portion of your ability to pulse a battery with the drivers you show in the photograph.

I am getting excited now more than ever as I build my driver board.

It is so simple to make a board but knowing how to use these boards with diodes hooked to CSR and coil inductance's is way beyond.

I will have to repeat these ideas many times to the group as I remember them for myself.

You are leading the way Farmhand, great work.

Mike

[BroMikey]

Coils and shunt resistors

Farmhand wrote:

I'm now using a microwave oven transformer primary

A coil with less resistance but a with the appropriate inductance is better

Second shot shows the circuit working at 400 Hz and pulsing the battery with

10 Amp rectangles of current for 260 uS, it's 400 Hz 10% duty, That really

pumped up the battery.



At 400hz I don't think you need many caps do you? I mean at 400hz is almost a straight shot from the supply but it does solve some problems.

I thought of my 4 strand twisted 14awg coil I have. I could use that in generator mode or just the plain coil with no circuits.

Got me think

Mike

[BroMikey]

400hz Charging

Hey Farmhand

I should of asked you if charging a battery using 400hz is about as fast as a straight DC charger?

Also I think the caps are not being used so this would mean a direct flow from source to charge battery except for some ripple.

I did try that on my dump because I could go up to 20 or 30hz but the input will just lay right over, no fluctuation a steady flow of current but when I did it I wasn't sure what to expect of what was going on in the scope shot but the output side would lay over then pulse then lay over then pulse like a heart beat.

The current looked steady on but I know it was not. Like I said the output acted strange. The Fets cooled right off as they were not working very hard and the caps only pulses once every couple seconds. This would mean that the battery was being forced up by faster pulses and more current and I will assume much more heating of the battery plates along with a speedy charge.

Sometimes at the beginning of a charge cycle it might be nice to drive up the battery faster without the use of Direct Current because that temptation will arise when time runs out.

That 10 pulse is alot. 10 amp pulse? 400 times per second?

Mike

[BroMikey]

10 amp pulse@400hz

I heard the new bedini chargers for the small number ten something uses this idea to charge batteries of all kinds using 8 pulses per second. He said that on a video.

I heard Peter L talk about how a rest interval of some many microseconds was all that was needed to stop the super heating condition that conventional charge exhibit.

I know that heating of plates damage batteries and anytime an unattended charging unit is left a few seconds to long damage will occur.

I have some li-ion batteries in a cordless gun that I fried in 1 hour. The time before the pack charged fine but the next time it burned up because I guess I set it to high?

With so many functions to zap a battery up fast without heating a sensor of some kind would keep the battery safe. Maybe one cell can be fitted with a laser temp probe for giant batteries.

This way a tiny computer control could have a better feedback. Then a 400hz 10amp pulse could drive up the battery to 13vdc and drop back power levels to 3 pulses per second @30 amps instead of 100X more power of forced charging.

You see it is still a forced charge at 400X 10 amp pulses per second. I don't know how to explain this but it just seems like it to me that a battery would be charge in a few hours.

Mike

[BroMikey]

Thinking it through.

Really that was a stupid question on my part to ask Farmhand if the 400hz 10amp pulse was as fast of a charge as straight DC.

When I thought it through better I realized that the current is off 90 percent of the time so it can't really charge to fast.

Great post Farmhand you got me thinking beyond my 3 pulses per second.

The only thing I don't get is how do you get a 10 amp pulse from your caps?

But I will think about it more and come back.

I mean you can figure that the pulse is 10 amps 400 times per second but you can't see it on a meter.

Doing the calc's by math and not meters I am getting a 400,000 amp pulse

Not that the big one is better. Got to try it both ways now.

Mike

[BroMikey]

Coil Suppression

Here is my latest addition to my dump. It ran much cooler I must say.

I still need to get away from the slow switching speeds but for now it

is best to lower heat other ways first.

BroMikey's Science Projects

Thanks Farmhand

Mike

Here is the link to the video I just did tonight.

CapDump 12devices 4coils Bromikey Alum Batteries - YouTube

Today I did 60 amp pulses per second charging a 24vdc battery set.

This video shows 12 fets and 4 balancing coils of 12 turns each, 1" dia when wound on 1/2" cpvc hot water pipe. The energy stored in both coils (Or all 4 coils 2 for each bank) creates pressure on both sides of the waterfall so avalanche occurs in more of an evenly distributed non sparetic rather uniform action.

I looked at the Bedini energy pump circuit and saw John was using a high wattage very low ohm (.005) resistance and thought to myself only a coil could do that. It seems I was right after using 8awg (45 amp) wire to make the coils and testing I find that this solves most if not all of my mosfet heating issues without the use of higher accuracy driver.

I have noticed posts that show experimenter doing everything right using high quality driving circuits and the heating issue will still be a problem.

Use coils for low induction short term energy storing and balancing.

They work beauty like.

Mike

[BroMikey]

Coils of Emitter and Colloector

I ran all day and adjusted my timing circuit around to see if there is a change.

The added coils do lower heat on the sink is noticeable. Coils used this way are sometimes referred to as "ARC SUPPRESSION" coils.

I am seeing comments from others who compare my cap bank to theirs.

Let me stress that the way my bank is made is way more powerful than the average bank of capacitors. I know I have many cap banks.

For instance I have 2 banks that I compared one against the other.

Both banks were charged to 50vdc or 65,000uf. The physical size comparison is bank two is the size of a softball and bank one is size of a beach ball.

Same voltage and same microfarad size. Bank one seems to be 5X more powerful. Don't ask me why but I think rating vary with physical size.

At any rate, the pop coming from the physically smaller bank is far far weaker.

This is puzzling and unless an experimenter has build a bank of this using 250vdc caps they have nothing to compare it with.

It is 4-5 times more powerful than my 65,000 uF bank.

Now having laid the ground work for this next statement, I conclude by saying that a larger cap bank requires more Mosfet's to handle the power, so when the average JOE EXPERIMENTER flies by this forum and sees my uF value he is thinking how he has done that many times no problem.

Also I reread the Patent on the John Bedini energy pump and it say a cap bank of 132,000uF is chosen to operate the unit. Therefore I recommend that experimenters not automatically assume that the uF value on their caps are equivalent to all other capacitor Banks. That would be a gross misconception.

If we all look back at various web data surrounding John Bedini's capacitor discharge circuits we find that for charging a 12vdc battery a 75-80vdc cap is selected. The next most common capacitor voltage available for a 36vdc or 24vdc would be 200-vdc or 250vdc following that pattern.

However what I see is experimenter using the same 80-100vdc capacitors to dump 70vdc. Using low voltage caps to dump 75-85vdc throws the rated values off by double and triple what the cap bank should be.

Like I said I know I have multiple cap banks and they all have a job.

Mike

[BroMikey]

Heat reduction method

PS update

Been finishing up now, 12 fets are running also changed the 30 amp meter out to read pulses because it was heating the shunt. I have been burying the needle so got a 200 amp meter in it's place. The pulses are as high as 50 amps but I didn't know that til I switched meters.

I will be showing the added coils in video after I am sure of success but so far with 12 brand new FET's running for the first time today giving 40-50 amp pulses, these suppression coils help to balance out electrical pressures thus helping to even out heating issues.

Of course next on the list is to finish the new control board for further reduction of heating due to incorrectly steering the FET's.

Mike

[BroMikey]

Coils Solve heat troubles

Here is the link to the video I just did tonight.

CapDump 12devices 4coils Bromikey Alum Batteries - YouTube

Today I did 60 amp pulses per second charging a 24vdc battery set.

This video shows 12 fets and 4 balancing coils of 12 turns each, 1" dia when wound on 1/2" cpvc hot water pipe. The energy stored in both coils (Or all 4 coils 2 for each bank) creates pressure on both sides of the waterfall so avalanche occurs in more of an evenly distributed non sparetic rather uniform action.

I looked at the Bedini energy pump circuit and saw John was using a high wattage very low ohm (.005) resistance and thought to myself only a coil could do that. It seems I was right after using 8awg (45 amp) wire to make the coils and testing I find that this solves most if not all of my mosfet heating issues without the use of higher accuracy driver.

I have noticed posts that show experimenter doing everything right using high quality driving circuits and the heating issue will still be a problem.

Use coils for low induction short term energy storing and balancing.

They work beauty like.

Mike

[Dupe]

Cap dump

@BroMikey

Following your posts here day by day. At what point do you terminate your charge? I have two solar panels (max 10 amp) on a small set up using four 12 volt auto batteries. My own design controller uses a PIC micro and allows a full charge to 15v after which switches to pulse mode_ discharging the full panel voltage (approx 20v) via caps twice per second/charge discharge. Keeps the batteries topped at 13/14v. Controller reverts back to charge mode when battery level drops below 12v (during daylight hours)
Based on your own experiments I may look again at cap discharge techniques especially at low light levels compared with conventional charging if it proves to be more efficient and faster. Kind Regards Dupe

[BroMikey]

15.2vdc full Charge

@BroMikey

Following your posts here day by day. At what point do you terminate your charge? I have two solar panels (max 10 amp) on a small set up using four 12 volt auto batteries. My own design controller uses a PIC micro and allows a full charge to 15v after which switches to pulse mode_ discharging the full panel voltage (approx 20v) via caps twice per second/charge discharge. Keeps the batteries topped at 13/14v. Controller reverts back to charge mode when battery level drops below 12v (during daylight hours)
Based on your own experiments I may look again at cap discharge techniques especially at low light levels compared with conventional charging if it proves to be more efficient and faster. Kind Regards Dupe

Hi Dupe

I determine that the batteries are fully charged in various ways. In a practical light the beginning phases of recharging are fast and hard and ever tapering off. If the power needs to be used from a battery while it is being charged then charging can not be done with large pulses.

However I see circuits that produce a faster charging capability for 1/10th the size of other units using hundreds of pulses per second, instead of 3 pulses per second.

I guess it all depends on what you need or what you want?

To answer your question. A battery must be given some time to charge without running it down and when this stage of charging is reached any battery needs to top out at 15 plus vdc. If it will not go over 14vdc or 14.5vdc you have a battery that is losing it's capacity.

It will take seemingly forever to charge a sulfated battery up from 14.5vdc -15.5vdc and made never reach it's peak unless battery plate heating is eliminated.

Pulsing will stop the heat if done right. So if you have a pulse circuit charging a battery and you can't get above 13/14vdc it may not be able to cold boil a battery.

For instance all of the big laptop producers pulse charge all of their batteries but the heat produced for these circuits is not what we want.

We want to cold boil a battery or in other words, we want to charge the battery up in pulses with a sufficient rest period and not over drive with current.

This way a battery can actual go to 15.2-15.8vdc in the end and never have any heating, in fact the only way these voltages can be obtained is with reduced current inputs so heating for all practical purposes is non existent.

If you are stopping at 13/14vdc it's because the batteries are not going higher so it seems like time to stop. Heating will keep you from a 15 plus vdc charge. So if you slow down at the end the battery can cold off so lower inputs at higher pulses can bring up the voltage.

I have found that once the batteries warm up it takes hours to cool them down again so I only pulse charge. This requires that I have at least 2 batteries to work with, one to run my lights on while the other is charging.

Any pulse charger that produces so much heat on a battery plate that it stops at 14vdc should be considered to be the same as any conventional charger. It may be lighter because it does not use a block transformer but the theory of forced currents are exactly identical.

Mike

[Dupe]

Cap charging

@BroMikey
Thanks for your response Mike. What about thermal compensation for increased ambient temperatures during hot weather! should charge levels be reduced as with conventional charging methods?

[BroMikey]

Outside Ambient Temp

@BroMikey
Thanks for your response Mike. What about thermal compensation for increased ambient temperatures during hot weather! should charge levels be reduced as with conventional charging methods?

Hi Dupe

My batteries are in the basement where average temps are 70 degrees year round. However I do have an 800ah collection of batteries that were in a hot upstairs room where they were 'COLD BOILED" at 100 degrees in the summer.

"Cold Boiling" is when a battery receives an abundance of electrical energy "WITHOUT" the heat generally associated with high current flows.

It is the direct current current flow or even pulsating over currents that force a battery up faster than it should. Heat will evolve every second of every minute and is called forced current mode. Battery temps climb to 150 plus degrees.

If the outside temp is 100 degrees and a forced charge is initiated the temp of that battery under slow charging direct current will start at 120 degrees with in minutes.

On the other hand I am sending 50amp pulses to my batteries for 24 hours without any heat "AT ALL" no heat can be felt whatsoever from the top of the battery case.

My charging equipment is upstairs at 50 feet away where the room temps are 95 degrees. My 12 Mosfets are 98 degrees with the fan blowing the heat off all day long but no heat whatsoever is generated from the batteries after hours of operation.

I was sending 60 amp pulses for a while but most of the time I send 45 amp pulses. 900 - 1000 watts are flowing into my pulse hammer and being sent to the batteries yet no heat is generated.

Mike

[Dave45]

Hey Matt you still around.
Do you mind if I post your circuit on another forum?

[BroMikey]

I am Here

Hey Matt you still around.
Do you mind if I post your circuit on another forum?

Go for it man it is open source free fun.

You never did answer my question about why you like certain inverter circuits.

Maybe I could build one if you found one that is somehow special.

Mike