Bedini Comparator Cap Dump

[adys15]

Hy guys i finished building both circuits posted here,Ron Chase one,and RS's.First i did Ron's circuit and seems to work well,the''problem'' being that when i tuned the 25k pot the voltage on the cap varied just a little,15v-15.40v.I used a ss bedini coil and a when i turned the coil pot the cap charged way past 15v(35v cap).Now i wanna ask you..how the dump led should blink?my ss coil stays in the khz range so the led is mostly on but turns of when i decrease the 25k pot res.

The RS circuit worked too,alowed the dump voltage to be adjusted,,charges the batt,but the main issue is that the bd transistor gets hot in minutes because the colector conects strait to the bridge output,when i conect it after the 2.2k it doesnt get hot and the coil buzz turned into pulses as i adjust the 100k pot,and i think the 12v zenner should be 15v because i want to charge the batt past 12v....so both are good in a way,and i cannot decide which to each...)

[adys15]

Can anyone tell me how the comparator led should blink(dump)? if i adjust the 25k pot the lowest dump freq is 2 dumps/sec...and the highest is led always on..if i go higher the led turns off....I saw a video of a user that shows led dump every 2 secounds but he used a wheel,i used a solid state ssg,Jon B's comparator also dumped slow..what i'm doing wrong???(the skematic is from Ron Chase)
Anyway today i charged one scooter battery(12v-9A) with only spikes from the ss ssg coil, i charge it to 13.50v and after i stoped the circuit the batt balanced at 12.50v.I put it on a scooter and when i cranced it,it barelly turned the engine and then died...so fluffy charge...the voltage was there but no real amp power...
cheers!

[RS_]

the BD243C should not get hot when hooked to the cap and battery pos rail, check the wiring..... you want the 12V zener so that the 741 circuit can be active down to that voltage in a 12V system... the gates of the MOSFETs need to be pulled up to 15V to fully turn on, and to do that, the opto and the BD243C collectors have to be at a much higher voltage than the 12V that the zener is powering the 741 with.....The 15V zener on the emitter of the BD243C keeps the gates from getting over voltaged.......

how fast it pulses/LED flashes, depends on how much energy is coming off the source, what size capture cap you have, and the kind and size of the charging battery......

watch the voltage on the charging battery, and adjust it to where the voltage rises fastest........ each kind or size of charging battery will act differently. and "LIKE" different settings.......

[Tom C]

Adys,

13.5 is not even half way charged needs to go 14.5 to 15.3 depending upon the battery, and if its an old crappy battery it wont have any capacity.

Tom C

[adys15]

Thanks very much guys.RS,i'v noticed the pulsing is depending on the input power(rectified coil bridge)and the 25kpot but in the 2videos i'v seen the wheel was spining much faster and the dump led flashes very slow.I have not tried caps biger than 4700mf,i will have to find more...Rs i want to keep the leds on the schematic but with your mods its that ok?
Tom i'v conditioned that batery for 4days with the coil spikes ãnd cap dumping,but in the end the spikes seemed to take it to 13.50v the cap dump is week...at 13.50v the batt was ''boiling'' and it cannot pass that voltage no meter what i did.Yes it was a crapy batt that would not hold a charge well and was keept outside in the winter.We have to carge it conventionaly to see what happens
cheers

[aln]

Adys,
Conditioning a bad battery will take many many cycles, try out your system on your car or lawn mower battery or a different good battery and you will see a difference much sooner. If this one is bulged, it may not ever come to life. Al

[RS_]

New, Flooded acid battery's will work better for you....

some times on these old battery's that will not hold a charge, they hit a voltage plateau, while bubbling like crazy, and will not charge farther...... if you discharge them really hard at high amps, with a big power resistor, or a auto head lamp or 2 or 3, for 1 or 2 minuets, then put them back on the charger, they will get past that plateau, and come on up in voltage. some times it takes several cycles of this treatment, to bust past that thick layer of sulfate on the plates.....

So, you do this cycle 5 or 6 times, and you dont see the high A load lasting longer each cycle, you prob have a bad battery..


So, if you discharge it at hi A once, and the battery go's on up to 14V+ and then plateau again do it again, and then you may see 15V and then go to a C20 discharge rate from then on....

[adys15]

Thanks for the tips guys,I know about discharge\charge cycles but only done it 2times on that batt.I will ''torture'' it more..
RS I would like to thank you again for your help on the circuit,i replaced that bd with tip120transistor and conect the colector to the +terminal before the diodes,and now the led is flasing properly and the caps are charged\disch corectly,and tr. stais cool.I also not used the1.2k res between pin 6 of the opamp because i tried with it and no diference,it has the 2.2k with the led already so no need for it.From Ron circuit i kept only the 2.2k and led on pin 1 of opto and power on led,and now its working very nice,and boiled the batt in 3minutes from 10v.... but i want to discharge the caps a bit longer, because they discarge very rapidly only 5v of 35v,so i want the ''on time'‘ to be longer..how do i do that?i use 3-4700mf,2-3300mf,2-2200mf 40v caps.
Cheers

[aujawindur]

Hey. Great to finally find a good cap dump circuit. I'm trying to build it for my bifiliar SSG now, but I am wondering, is the bridge rectifier necessary?
And is a 4,7mF cap too big when it is just a simple 1 transistor SSG?

[adys15]

aujawindur i tried with fbr and with 1diode,i did not noticed a difference,right now i have a batt charging on the comparator without the fbr.

[NeonBlue84]

Thank all you guys for the great info and tips on the illusive comparator cap dump riddle.

"i want to discharge the caps a bit longer, because they discharge very rapidly only 5v of 35v, so i want the ''on time'‘ to be longer..how do i do that?"

adys15 , I have seen a few videos now where the builders are finding the right capacitor value placed between pins 2 and 3 of the Op amp. Apparently this holds the on-time on for just that little bit longer you need for all the cap bank to dump through the Mosfets.

https://www.youtube.com/watch?v=D87E9lSNDEI

Although I'm not sure about some of the schematic.....

[alfinip2000]

the BD243C should not get hot when hooked to the cap and battery pos rail, check the wiring..... you want the 12V zener so that the 741 circuit can be active down to that voltage in a 12V system... the gates of the MOSFETs need to be pulled up to 15V to fully turn on, and to do that, the opto and the BD243C collectors have to be at a much higher voltage than the 12V that the zener is powering the 741 with.....The 15V zener on the emitter of the BD243C keeps the gates from getting over voltaged.......

how fast it pulses/LED flashes, depends on how much energy is coming off the source, what size capture cap you have, and the kind and size of the charging battery......

watch the voltage on the charging battery, and adjust it to where the voltage rises fastest........ each kind or size of charging battery will act differently. and "LIKE" different settings.......

RS,if my source is 12v solar panel which part that i have to change..so it can dump even at lower voltage,say 5v and is it ok if the source voltage is 18v...TIA
Alfin

[RS_]

alf,

what voltage battery are you trying to charge.....?
if you are charging 6V battery's or less, than you can use a 5V zener in place of the 12V zener for power, and a 3V or 3.3V zener in place of the 5V reference zener, or use 3.3V zener for the power and 2.7V zener for the refrence
For these lower V battery's, 18V open circuit is good......

I have been using 3 harbor fright solar panels in series at 70V open circuit and charging motor cycle size battery's with 25V pulses, and charging good....

this weekend, just for fun, I hooked 2 of the 295W 24V 8.5A solar panels from my new solar installation in series, at 80V open circuit, and it will pull a discharged motor cycle battery up to 16 to 17V, and make the battery boil like crazy within 2 minutes, and I have to stop it, and let it rest for 15 to 20 minute's while the voltage settles down to below 13V before doing it again.......

will move this this cap pulser setup to some golf cart battery's to test on some time this week....

[alfinip2000]

RS,
Am trying to charge 12v batt...with my 100wp (18v open v) with SS SSG cap mod .. so this schematic will be ok without any changing right?TIA
Alfin

[RS_]

Ah, I see, you are powering the SS SSG with the solar panel and feeding the cap pulser..... I was not thinking about it like that, as lately i have been using the solar panels directly.. Yes, the 12V version Sch should work just fine as is...... you might want to also try the MAX931 micro power version posted in this thread.......