BroMikey's Capacitor Dump Circuit

[totoalas]

Another quote from Bro Mickey
I charged up my 120,000 uF bank just for fun to 65-70vdc and pulsed that through one big mosfet to a battery and that thing only worked once.

Maybe I will end up will 12 instead of 6 AAA?

But 1 or two? it's little legs just can't carry it.

My cap bank is set to deliver massive amounts of inrush to the battery.

By the way I did go down to 10,000 ohms of resistance on the base to get a full On so as to dump the entire load but that fet gave up the Ghost.

Just had to see. That pulse also burnt a tooth off of my gator clip so maybe the shorting out added resistance smoked the fet I do not know these things.

But one thing is sure the Wiley will always be my friend forever after that stunt.  Yes big big inrush amps enough to blow the sulfation right of a huge battery plate.

I am going to pick up some 500 ah 4vdc cells in a few hours.

So I need this thing working come hell or high water.

Yeah 10k on the base gave me a "FULL ON" condition and it smoked that fet in a New York mil second.

Mike

[MarkE]

quote from Bro Mickey
I failed to include other info such as 80,000 uf 250vdc caps charging up to 90vdc.

Also the circuit that controls dump down voltage needed more resistance in the bases at 16K each. Just finished testing this. What happened was this is my first time using mosfet's for a dump so large and I trusted others who told me 200 ohms.

When I decided that the diagram I had was wrong my fets were toast so I started with 20k and nothing got through then 10k and 6k worked and 16k worked the best so my other pot control works with it well.

Another aspect of the dump is............ when i first hook the batteries to the dump they charge up the cap bank backwards through the fets I think, maybe this is smoking my junctions.

Again when I hook the 36vdc charge bank up to the dump with empty caps the power some how back tracks and I think to fast and this maybe damaging things.

So I thought like car audio caps maybe I better have those caps charged up first or think up some other protection. Who knows maybe I had 1 or 2 trashed fet's by then. I am in a whirlwind of study. Gotta think back and keep trying.

These are my first conclusions and will grow in the process of failures.

What does he hope to get from this combination MOSFET and battery eradicator?  Depending on how many pulses his MOSFETs survive, he is going to drive big pits into his battery plates.  He may also induce a hydrogen explosion in the batteries.  Lead acid batteries make a big mess when they explode.  Flying H₂SO₄ and burning metal are not the kind of stuff that you want to find yourself dodging.  I hope he is keeping all of this inside an explosion proof enclosure.

Charging a big capacitor bank to two or more times the battery voltage means that he is going to through a lot of energy away in the wiring and the MOSFETs.  A little work with Ohm's Law will determine a more appropriate voltage for the capacitors.  I don't care what he does with his MOSFET drive, the combination of a fat capacitor bank charged to 30V or more above his batteries is going to smoke the transistors.  That's about his only protection against dumping enough energy into the battery to create an explosion hazard.

There are lots of good pulse circuit based battery chargers that desulfanate out there.  He really should take a step back and reconsider the wisdom of the fire that he is literally playing with.

[Hoppy]

There are lots of good pulse circuit based battery chargers that desulfanate out there.  He really should take a step back and reconsider the wisdom of the fire that he is literally playing with.

Looks like he's doing a an ultra Berdini cap dump!! 

[wattsup]

@totoalas

hehehehehehehehehehehehehe. Man you iz a crazy bugger.

I think you will have to invent a new mosfet called Samurai Battery Pulsing Mosfets. You have to take a course in Harakiri first to get the full impact of a one shot pulse. hehehe

Pulsing is a bitch.

wattsup

[SeaMonkey]

I did post an invite at Energetic!

thx
Chet

Thanks for doing that!

Totoalas,

Thanks for posting the diagrams - they're
very helpful.

In order to charge/desulfate a 36 Volt battery
bank as BroMikey hopes he'll need to add some
additional devices to his circuitry.  Gate Driver
Chips will be needed as well as a precise Pulse
Generator circuit (a 555 may do the job) which
produces a driving pulse of not more than 100
microSeconds.  Applying very short pulses to
the battery bank may result in a low enough
average power to avoid destroying the MOSFET
switches.

Caution is certainly necessary as a capacitor bank
charged to 90 or more volts is lethal.