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Author Topic: BroMikey's Capacitor Dump Circuit  (Read 52734 times)

TinselKoala

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Re: BroMikey's Capacitor Dump Circuit
« Reply #15 on: March 13, 2014, 07:43:41 PM »
Ditch the mosfets and use a mechanical switch like a beefy double-throw relay or a solenoid-driven contactor. You can keep the contacts from welding shut by using the right capacitor across the contacts. Trigger the relay with a single mosfet driven by the Wiley Coyote control circuit. The relay's NC contacts can control the cap charging before the dump, then when you fire the relay the NO contacts close and dump the cap charge into the battery.

SeaMonkey

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Re: BroMikey's Capacitor Dump Circuit
« Reply #16 on: March 14, 2014, 04:25:47 AM »
Aye, the old fashioned approach with electro-mechanical
heavy duty relays is always good.  An automotive starter
relay or starter solenoid
relay may be able to handle the
job with ease.

Hoppy

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Re: BroMikey's Capacitor Dump Circuit
« Reply #17 on: March 14, 2014, 08:42:40 AM »
Ditch the mosfets and use a mechanical switch like a beefy double-throw relay or a solenoid-driven contactor. You can keep the contacts from welding shut by using the right capacitor across the contacts. Trigger the relay with a single mosfet driven by the Wiley Coyote control circuit. The relay's NC contacts can control the cap charging before the dump, then when you fire the relay the NO contacts close and dump the cap charge into the battery.

Agreed. I have in the past used an old multi-pole AC contactor and re-wound the coil for DC operation.

Farmhand

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Re: BroMikey's Capacitor Dump Circuit
« Reply #18 on: March 14, 2014, 01:53:02 PM »
I came to the conclusion that without some way to have the setup turn itself off I would need to keep checking it. So I went to a very simple picaxe setup which could sense the input and battery voltage. I also agree with others that say to recondition a battery they should be done separately. They can be better assessed individually as well. The circuit attached below is one I began with that I tested with a 17 volt input from a wall transformer and amateur code, I think I drew it correctly. I then used it with some different code and a solar input. I coded it to sense the battery voltage between pulses. I do realize I'm dumping through a diode but it's a good one and I needed it to sense the battery voltage. I modified it and built another circuit and wrote new code for a dual coil boost converter

The solar circuit is still on a solderless board  ;D but I'm not using it for a while anyway.

Anyway the basic switching setup with the mosfets is very sharp it makes the wires ping real good and I can pick up the ringing in the wires to the battery with another coil connected to my scope 4 meters away. I think the pinging affects me adversely, needs shielding I think, sounds nasty on the radio. Boost converter has paralleled smoothing caps so it doesn't have that issue. It's good to be able to plug it into the laptop and change the code to try different stuff. No need for the 12 volt regulator if a 12 volt battery is used for the supply. It can be coded to stop when the supply goes too low as well.

I don't think it necessary to use so much capacitance and voltage to dump to recondition a battery, it takes time though, a battery can't be desulfated overnight if it's sad to begin with. Slow and easy wins the race I think. I think proper discharging of the battery is important, placing a good load on a battery after it holds over 12 and a bit volts to discharge it with appropriate amp draw for the battery does wonders.

I also fear a battery explosion if too much voltage is used, especially if the battery is suspect in condition.

Cheers

totoalas

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Re: BroMikey's Capacitor Dump Circuit
« Reply #19 on: March 14, 2014, 02:07:31 PM »
Patrick's comparator  ckt  as discussed in energyscience forum  ultimate cap dump
And Peter lindermans interview by Aaron  talks about solartracker 5
Radiant or inductive charging was changed to capaci tive charger  with 15.2 v float charge
Using dc linear amplifier desi .gn

Opting to use scr   maybe the future 8)




MarkE

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Re: BroMikey's Capacitor Dump Circuit
« Reply #20 on: March 14, 2014, 03:49:43 PM »
I came to the conclusion that without some way to have the setup turn itself off I would need to keep checking it. So I went to a very simple picaxe setup which could sense the input and battery voltage. I also agree with others that say to recondition a battery they should be done separately. They can be better assessed individually as well. The circuit attached below is one I began with that I tested with a 17 volt input from a wall transformer and amateur code, I think I drew it correctly. I then used it with some different code and a solar input. I coded it to sense the battery voltage between pulses. I do realize I'm dumping through a diode but it's a good one and I needed it to sense the battery voltage. I modified it and built another circuit and wrote new code for a dual coil boost converter

The solar circuit is still on a solderless board  ;D but I'm not using it for a while anyway.

Anyway the basic switching setup with the mosfets is very sharp it makes the wires ping real good and I can pick up the ringing in the wires to the battery with another coil connected to my scope 4 meters away. I think the pinging affects me adversely, needs shielding I think, sounds nasty on the radio. Boost converter has paralleled smoothing caps so it doesn't have that issue. It's good to be able to plug it into the laptop and change the code to try different stuff. No need for the 12 volt regulator if a 12 volt battery is used for the supply. It can be coded to stop when the supply goes too low as well.

I don't think it necessary to use so much capacitance and voltage to dump to recondition a battery, it takes time though, a battery can't be desulfated overnight if it's sad to begin with. Slow and easy wins the race I think. I think proper discharging of the battery is important, placing a good load on a battery after it holds over 12 and a bit volts to discharge it with appropriate amp draw for the battery does wonders.

I also fear a battery explosion if too much voltage is used, especially if the battery is suspect in condition.

Cheers
The input side negative rail should be tied to your circuit common.  Maybe that's just an oversight in the schematic. 

When playing with batteries:  Always have a failsafe that can cut off supply current.  Don't apply voltages way above the current cell voltage.  If you want to knock the sulfur off use current pulses of moderate value.  Lead acid batteries also respond better if you charge, let them rest or even discharge slightly, and then charge some more.  Finally, temperature monitoring and enclosing in an explosion proof vessel are both good ideas.  Take a hint from Boeing with their Li-ion battery problems on the 787.  A case that can safely vent gas pressure without spilling toxic material into places where people are is a very prudent idea.

TinselKoala

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Re: BroMikey's Capacitor Dump Circuit
« Reply #21 on: March 14, 2014, 06:41:41 PM »
The MJL21194 has a peak collector current of only 30 amps. Good luck with that, switching a big cap into a low-impedance load.

This would be a good place to put a cheap high-current mosfet instead of the big expensive BJT.

Farmhand

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Re: BroMikey's Capacitor Dump Circuit
« Reply #22 on: March 14, 2014, 08:10:16 PM »
I used a pair of IRL3705 mosfets @ 89 cents each, but IRF1010 would be better maybe for the solar setup same price, the switchboard is on a PCB all soldered up, it's just the electronics not permanent yet. I used what I had on hand for the boost converter IRFZ48 @ 74 cents each.

From here. Takes a while to arrive, but cheap.
http://www.futurlec.com.au/test13.jsp?category=TRANSMOSFET&category_title=Mosfet%20Transistors&main_menu=TRANSISTOR&sub_menu=TRANSMOSFET

Cheers

SeaMonkey

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Re: BroMikey's Capacitor Dump Circuit
« Reply #23 on: March 16, 2014, 12:58:21 AM »
BroMikey has made a video showing how he intends
to use his Capacitor Dump Circuit as well as the
experimentation he's done with pulsing and
lead-acid batteries.

He's made considerable progress in his understanding
of certain basics but probably isn't yet ready for
in-depth technical discussion regarding MOSFETs and
how to best drive them as efficient switching devices.

Ammonium Alum as an additive to battery electrolyte
should show some benefit, similar to what the addition
of Magnesium Sulfate does;  but the best technique for
enhancing the longevity of the lead-acid battery is well
controlled pulsing to both charge and desulfate.  The
pulse width for the charging phase can be quite long.
Once the battery is nearly fully charged then the pulse
width should be made very narrow (not more than 50
microSeconds) to top it off and complete the desulfation.

FarmHands's micro controlled solar system would be
capable of handling that sort of charging algorithm.




SeaMonkey

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Re: BroMikey's Capacitor Dump Circuit
« Reply #24 on: May 08, 2014, 09:16:20 AM »
BroMikey continues to work with and improve
his CapDump Circuit.  He's asked a question but
hasn't yet received a response.

Rapid rise times and short time durations of
pulses applied to the lead acid battery are
most effective for desulfation.  The very sharp
and short pulses reach the lead sulfate crystals
with maximum effect and cause them to be
converted chemically back into active plate materials
and renewed sulfuric acid in the electrolyte solution

Longer pulses with not so sharp rise times are most
effective for charging the battery and less effective
for desulfating and restoring batteries.

The very short and sharp pulses get the desulfation done
with such low average power that the battery isn't
dangerously overheated or caused to gas excessively
as the desulfation nears completion.

Longer pulses would result in higher average power into
the battery and can cause overheating as the battery
being charged transitions from bulk charge into finishing
charge.  Even a good battery can be overheated if the
finishing charge rate is too great.  It is during the finishing
charge segment of the charging regimen that gassing will
occur and if it is too violent because of excessive charging
current the battery can be damaged.

Batteries which are in very good condition can be charged
with long pulses for the entire bulk charge process, then
the pulses should be shortened or reduced in frequency
in order to accomplish the finishing charge.

Sulfated batteries which are not in good condition should
be desulfated with very short pulses which are very sharp
to limit the power put into the battery during this process.
Desulfation releases considerable heat as the lead sulfate
crystals are chemically converted back into active plate
materials and sulfuric acid, and it is essential that the battery
not be overheated to avoid permanent damage.

Farmhand

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Re: BroMikey's Capacitor Dump Circuit
« Reply #25 on: May 08, 2014, 10:16:51 PM »
SeaMonkey, I quoted your posting over to EF and rambled on a bit myself to try to help a bit.

..

Oh I worked out there is a function to copy the code to a forum,  :-[ I had trouble trying to post code before.

Anyway just to show how dodgy my code writing ability is here is the code I developed to run the solar setup I posted above.

There is likely a lot of stuff that is redundant and others may not be able to understand it together with the drawing because there are no labels ect. in the code. To understand the code people would need to know the pinout and stuff for the 08M2 picaxe. Or look it up.  :D

..

main:
pause 1
readadc C.1,b1
if b1 => 152 then goto char
if b1 > 20 then goto boost
if b1 < 20 then goto humm
wait 1
goto main

humm:
do
low 2
pause 100
readadc C.1,b1
if b1 > 125 then low 2 goto boost endif
readadc C.4,b4
if b4 > 173 then pulsout 0,5 endif
if b4 > 173 then pulsout 0,5 endif
pause 100
loop

boost:
do
readadc C.1,b1
if b1 < 95 then low 2 pwmout 2, off goto humm endif
if b1 => 139 then low 2 pwmout 2, off goto char endif
if b1 < 130 then pwmout 2, 49, 50 endif
if b1 => 130 then pwmout 2, 49, 60 endif
readadc C.4,b4
if b4 => 149 then low 2 pulsout 0,3 pauseus 1 endif
if b4 => 150 then low 2 pulsout 0,3 pauseus 1 endif
if b4 => 151 then low 2 pulsout 0,4 pauseus 1 endif
if b4 => 152 then low 2 pulsout 0,4 pauseus 1 endif
if b4 => 153 then low 2 pulsout 0,4 pauseus 1 endif
if b4 => 154 then low 2 pulsout 0,4 pauseus 1 endif
inc b9
if b9 = 250 and b4 => 162 then low 2 high 0 readadc C.4,b5 low 0 let b9 = 0
elseif b9 = 250 and b4 < 162 then let b9 = 0 goto boost endif
if b5 => 143 then low 2 pwmout 2, off low 0 goto float endif
loop

char:
do
inc b9
readadc C.1,b1
if b1 < 138 then low 0 goto boost endif
if b9 = 252 and b1 => 140 then high 0 pauseus 1 readadc C.4,b5 low 0 let b9 = 0
elseif b9 = 252 and b1 < 140 then let b9 = 0 endif
if b5 => 140 then low 2 low 0 goto float endif
if b1 => 144 then high 0 pauseus 160 low 0 pauseus 100 goto char endif
if b1 => 143 then high 0 pauseus 140 low 0 pauseus 120 goto char endif
if b1 => 142 then high 0 pauseus 100 low 0 pauseus 180 goto char endif
if b1 => 141 then high 0 pauseus 60 low 0 pauseus 220 goto char endif
if b1 => 140 then high 0 pauseus 15 low 0 pauseus 285 goto char endif
if b1 => 139 then high 0 pauseus 4 low 0 pauseus 298 endif
loop
 
float:
do
pause 50
high 0 pauseus 1 readadc C.4,b5 low 0
pause 50
if b1 > 148 and b5 < 142 then pulsout 0,3 pauseus 2 endif
if b1 > 148 and b5 < 142 then pulsout 0,3 pauseus 2 endif
if b1 > 148 and b5 < 142 then pulsout 0,3 pauseus 2 endif
if b1 > 148 and b5 < 142 then pulsout 0,3 pauseus 2 endif
readadc C.1,b1
if b1 < 115 then goto humm
if b5 < 138 then goto char
loop

..

SeaMonkey

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Re: BroMikey's Capacitor Dump Circuit
« Reply #26 on: May 09, 2014, 04:14:55 AM »
Writing "Code" for a microprocessor or a
microcontroller is indeed a learned skill
and it can be daunting in the beginning.

If the Code fits into the available system
memory and does what it is intended to
to then it is Good Code.

If the initial effort is tightened up a bit
by modifying the algorithm and using
instructions which are more economical
of code space then it becomes Elegant
Code.

In the old days it was often necessary to
reduce the Code in a program to the
barest minimum because of ROM and RAM
limitations so some programmers got really
good at finding the most economical way to
accomplish almost any task.  They were
the ones who got the Big Bux.

Your Code is an excellent example of how
a fairly complex job is done;  the thought
processes which enter into the solution and
the sequence of events necessary to make
things happen when they should.

Any Code that does what it is supposed to do
is Good Code...

MileHigh

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Re: BroMikey's Capacitor Dump Circuit
« Reply #27 on: May 09, 2014, 05:15:47 AM »
I can do 8086 and 6502 assembler!  lol

I _hate_ the 80X86 instruction set.  The 680X0 lost out, it's a shame.

So Farmhand, is it you that wrote the nasty script that's crashing on OU recently?  lol

Farmhand

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Re: BroMikey's Capacitor Dump Circuit
« Reply #28 on: May 09, 2014, 05:37:22 AM »
 ??? Hilarious, it would take me years to even entertain the thought of being able to do such things. If anything I am a victim there as well. I must check for any developments over there. Might be something interesting.

To write the code above I had to refer to the picaxe pdf every time I needed to do something different and look for a way to do it. I just made the circuit with a pretty good idea of what the chip could do and then worked out the code later. Took a while, no interrupts used, still haven't worked that out yet. I've got Arduino now too but haven't even used it yet.

The 08M2 chip is good for beginners, it's small, cheap and can do basic stuff with simple code.
..

SeaMonkey

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Re: BroMikey's Capacitor Dump Circuit
« Reply #29 on: May 09, 2014, 07:04:57 AM »
Quote from: MilesHigher
The 680X0 lost out, it's a shame.

Aye, it did and I thought so too.

The Commodore Amiga and the Atari ST series
did mighty fine with it and were quite advanced
for their time.  Ah, those were the days!

Quote from: FarmHand
I quoted your posting over to EF and rambled on a bit myself to try to help a bit.

Your "ramblings" added a great deal to the discussion.
You did well.