Cap Dump Circuit

[thx1138]

A few notes

If you know this already just disregard but I thought it might be helpful.

The MOSFET's used at the cap-dump are voltage controlled devices. The voltage applied to the gate determines when and how fast they turn on.

We'll call the resistor connected to the gate R1 and the resistor connected between the gate and the drain R2.

R1 acts as a current limiting device between the power from Wiley and the MOSFET.

I = R / V

So raising the resistance decreases the current which isn't important to the MOSFET since it is voltage driven but does affect how much power will be drawn from the driving circuit.

The two resistors that you show at each MOSFET (R1 and R2) results in a voltage divider. These will affect the MOSFET switching since they affect the voltage. Vout will be the voltage between R1 and the gate. Vin is the volatage from Wiley to R1.

Vout = Vin * (R2 / ( R1 + R2))

The transistor you show in the 555 circuit is a BJT (Bipolar Junction Transistor) and it is driven by current rather than voltage. So the current limiting resistor in this circuit does affect the turn-on time of the transistor. It affects how much current is available to turn the circuit on and how fast that current accumulates in the transistor.

This may help you do some calculations to determine the switching you need. You compare the values calculated to the device datasheets to attain the results you want. If the device you are using won't give the results you desire just look for another device.

[totoalas]

Great totoalas

This new Oscillator is a darlington?

Keep at it.

Mike

http://www.energeticforum.com/renewable-energy/15966-zpdms-oscillator-new-oscillator.html#post246907

[BroMikey]

New Oscillator

Thanks Bro Mikey
you give me some insight on my future set up
Im using Cool joules SSG monster charger with my alum batteries
planning to migrate to cap dump and your design is easy to follow

Im current ly using zpdm oscillator with induction from a wall adaptor and earth ( no batteries) to charge a 470 uf 450 v dc cap up to 338 v in 9 hours.....
will use this as a source beside my solar and sg motor/gen to go to the cap dump circuit
thanks

Great totoalas

This new Oscillator is a darlington?

Keep at it.

Mike

[BroMikey]

30 mili-seconds

Hi Mario

I am down to as low as 30 mS using 560 ohms dumping 80vdc from 80,000uF.

I burned up my small dump driving to the max on the big yard battery, then I burned up my SSSG Osc transistors over driving them so I am going to bring in a slight evolution for the Solid State Version Oscillator.

Plus I am putting together two toroidals, one hand wound 115v down to 55v and the other is a 30 amp 400hz toroidal variac with bridge and caps.

It was almost done last night. This unit gives me 0-70vdc and then also last night I got out my one foot long 1 ohm resistors and charged and discharged my cap bank watching the delay. Perfect.

This resistor will let me run 10-50 amp surges with slightly delayed charge times.

This will be easier from this pulsating arrangement.

The room is a total disaster.

I will get it all done ASAP.

Mike

[totoalas]

Hi Totoalas

If you run the solar panel to the lights in the house and pulse charge the battery AT THE SAME TIME you will trash your inverter.

If you shorten the pulse time and lower the current dumped you will extend the life of your inverter.

Mike

Thanks Bro Mikey
you give me some insight on my future set up
Im using Cool joules SSG monster charger with my alum batteries
planning to migrate to cap dump and your design is easy to follow

Im current ly using zpdm oscillator with induction from a wall adaptor and earth ( no batteries) to charge a 470 uf 450 v dc cap up to 338 v in 9 hours.....
will use this as a source beside my solar and sg motor/gen to go to the cap dump circuit
thanks

[Mario]

[BroMikey]

Solar

Hi all
can ur ckt be used in solar charged primary with sg oscillator also

Hi Totoalas

If you run the solar panel to the lights in the house and pulse charge the battery AT THE SAME TIME you will trash your inverter.

If you shorten the pulse time and lower the current dumped you will extend the life of your inverter.

Mike

[totoalas]

Hi all
can ur ckt be used in solar charged primary with sg oscillator also

[BroMikey]

Rise and Fall

Hi Mike, it means that if you have a square wave the rise time is the time it takes to go from off to on (low to high) and the fall time is the opposite, meaning the time it takes to turn off.
Is that millisecs or microsecs?

regards,
Mario

Hi Mario

Yes I realize that it means what you just said but what I should have said was I do not know how 107 ms relates to a possible 1% figure that you mentioned as a target.

Okay the div/ms on a scope humm....... not sure........ all I know is that a 107 ms flash on my led is faster than the blink of my eye.

Eyes blink at 150 ms miliseconds. I think.

Are we looking for micro-seconds?

As I dial up and down the LED will get lazy looking at 900 ms humm.........

I better research this as it really was a question of mine when I read that value.

Well at least I am getting my head on straight a little

Maybe these pulses are in mili-seconds and if so that is very slow.

Is it possible that a 560 ohm base resistor would slow the rise time down that much?

I see data showing Mosfet's switching much faster. I just don't know what a 1% switching means in relation to seconds.

I thought that mili-seconds = (mS) microseconds=(uS) and nano-seconds =(uS)

I better stop being afraid to lower base resistance, it looks like huh?

Of course I am switching at low level voltages 20-25vdc and amp pulses are

at 1-2 amps so I will go up to 90vdc at 20 amp pulses first to see if

switching time is effected dramatically or no.

This was in my mind from the beginning and so far I am studying the function

of the scope and now can see some point of reference.


This is my first day. Today is the first day in years that I wanted to get

myself in the know concerning switching times.

Thank you so much for your continued patience helping me crawl in slow

motion. Patience is a virtue I am told and is probably quite true.

I have heard your instruction on using a pot from 1000 ohms down to 47

ohms till you get what you want.

Now that I can read the scope in a small way I will complete my test at the elevated power levels as mentioned above and them go back to a single FET to test again.

Last night was the first time in my life that I sat down in front of my scope

and the reading was exactly the same as it was the day before.


Just so you know Mario 2 days ago I had the wrong high frequency probes

hooked up and I had power supply hum and you know the drill, I mess of

signals entering my view even from my own hand touching things, so I am

not totally scope illiterate.

I know very little, this is my first day to see that with the high frequency

probes I better use my 2 regulated supplies for a clean view of switching

times.


I have dozens of tiny 12vdc batteries so I hooked them up to get my cap at

24vdc and dumped the power to another battery of 12vdc using a separate

12vdc battery to run the timer/trigger circuit.


All clean voltage, no hum.

Now that I see this difference it has become quite clear that my bench

battery chargers will not work here.


I recently learned how to fool a tl594 chip found in PC switch mode power supplies and have an extra 0-24vdc regulated supply.

I also have a 0-15vdc +- 5vdc+- variable 1 amp dc supply.

My bench needs cleaning and the shelves are going in now.


It is an exciting time for me.

Mike

[Mario]

Hi Mario

I am finding my head with both hands learning this scope functions.

I had the wrong probes out of 4 probes I own. Now when I sit down it pops right on to the place where I left off.

I can go down to 107ms rise and fall is 33ms

Don't know what that means.

Mike

Hi Mike, it means that if you have a square wave the rise time is the time it takes to go from off to on (low to high) and the fall time is the opposite, meaning the time it takes to turn off.
Is that millisecs or microsecs?

regards,
Mario

[BroMikey]

Measuring the switch

http://www.free-energy-info.co.uk/Chapter12.pdf

regards,
Mario

Hi Mario

I am finding my head with both hands learning this scope functions.

I had the wrong probes out of 4 probes I own. Now when I sit down it pops right on to the place where I left off.

I can go down to 107ms rise and fall is 33ms

Don't know what that means.

Mike

[BroMikey]

Great Help

I found this one helpful
https://www.youtube.com/watch?v=10R0Mrqwjuo

I liked the little pnp for draining the gate fast.

Thanks for the help.
I rebuilt my fet bank and this time I used 560ohm on the bases but will need more at 90vdc dumping.

Sg Oscillator to dump to industrial AGM ALUM converted batteries - YouTube

You guys are all helpful and so i will get up to speed.

I spent 4hrs on my scope and can see waveforms now.

Mike Ps the book on this scope is hundreds of pages long

[lotec]

I found this one helpful
https://www.youtube.com/watch?v=10R0Mrqwjuo

I liked the little pnp for draining the gate fast.

[BroMikey]

1% On Time

http://www.free-energy-info.co.uk/Chapter12.pdf

regards,
Mario

Hey Mario

This is a great doc for guys to freshen up with, somehow I missed this one.

Dc to dc conversion and shutdown the supply WOW all great proposals and I was thinking of some way to throw a (HUGE) resistor in between the bank and supply to slow the bank charge time alittle but better to let it charge fast and shut her down.

Yes I need brushing up that is for sure. My circuit with the 555 timer I showed you has both the standard 555 timer 50% duty and the extra knob is for cutting off dump time.

This means that my LED will flash like the blinker on a cars turn signal and is adjustable all the way down to an ever hastening (faster) cutoff time than can be seen with the naked eye.

I must have read the scale wrong but I was varying my timer circuit up and down and the scope was showing 5 ms to 50ms or whatever the division.

Okay I know this the button I push is "RISE TIME" "FALL TIME" well all of it can easily be read I just need more time. Last night I was out of it.

Yes all of the things you are saying, right down to the nicer controlling drivers and smooth supplies have lodged in my thinking.

I have not missed anything you have pointed out or I would come right out and ask you about it.

Keep talking

Here is that circuit



Many people miss the fact that a standard timer circuit can easily be altered to control the duty cycle without going the the 556 dual timer with separate sections one for timing and one for duty cycle.

This circuit is working on 2 of my other cap dumps that are in use now and allow me to dump caps down to any voltage I like.

For instance this circuit was running lat night and I charged the caps up to 45 volts and cut off the dump time to 35 volts showing on the meter.

I can dump at 60 and start recharging at 55volts or I can dump at 30v and stop at 25volts if I want to.

I have more to learn about the difference in using a LM741 or a NAND gate but I could start if needed.

Let me play with this scope some more and I will tell you for sure what I am getting.

I have been controlling dump down voltage and charging batteries this way for 1 year as I said with the smaller units.

In fact I am about to take my small bank of 60,000uF out to the trailer so I can get it charged up more, it is just that I wanted to use Mosfet's on a bigger system.

The one I use now has 4 deflection transistors in it and they never blink.

They run cool and are very stable.

Thank Mario for helping me use Mosfet's. Among other things of interest.

It is not like mosfets are the only way of doing this.

Mike

[Mario]

http://www.free-energy-info.co.uk/Chapter12.pdf

regards,
Mario