Current Optimum "Simple" Desulfator

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Iwannabe2	Current Optimum "Simple" Desulfator	Lead	[-]
Posts: 3 (01/21/04 17:27:29) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Tags : None Hi board users, To make a long story short, I have built two of the original "AC" designs and have them working, getting results after a week. I have read through most of the original bulletin board set up by Alastair Couper and most of the one in use now and wanted to check my understanding of my review. My questions have to do with what is the current optimum simple desulfator circuit in use with results? I read about the Thomas Chapman circuit with a beefier C4 and parallel 220 uF L1(s). A 250% increase in pulse amplitude. Is this in use by anyone out there now? This seems like a relatively simple conversion. Are there others just as simple that give results (results relative to desulfating capability)? How about Andy Shiekh's circuit? I see where it is in testing, anyone showing results? ( I see this question posted and I will keep a look out there) Any other "simple" circuits or "simple" advices for a wannabe desulfator? Thanks and regards,
Anthony Doyle	Re: Current Optimum "Simple" Desulfator	#1	[-]
Posts: 177 (01/21/04 23:19:28) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi, 250% increase in voltage on AC's design; I don't think anyone has proved a conclusively an increase in desulfating rate because of this. Andy's circuit. Wait for someone to prove desulfation first. BA80 or "German". Maintenance only. I may be able to tell you in 5+ years if it works or not.
thomasasking	simple desulfator	#2	[-]
Posts: 519 (01/22/04 06:55:39) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi ! Welcome . Beefing up C4 came about as a result of reports of overheating of the original 100 uF by some folk . I think it depends on the choice of inductor for L1 .emails I have received suggests that some pulsers run at lower peak currents and the increase in C4 would not be noticed . I think it is one of those fit and forget ideas It does not change the AC design principle . However if you do run two 220 uH inductors in parallel you will need C4 to be at least 1000uF in my experience. Results? the only criteria I feel that is totally valid is a CCA test under controlled conditions .which is a bit beyond most folk.I do sometimes feel that all I have achieved is a full charging regime . It is a fraught subject but a very good hobby! A 12 volt battery is a string of six cells and I am sure we are equalising as much as desulfating ! Remember that Don with his thermistor controlled stamp circuit approach is actually putting a lot more energy in by running near to the margin of thermal runaway This is to speed things up I guess. AC suggested a rule of thumb approach .Deep discharge batteries needing higher peak currents pro rata to plate thickness. My results suggest a 2:1 improvement in desulfating time with the higher powered version.As they are all of a muchness I tend to build the higher powered versions.They are still very low power designs and nothing gets warm German thing as originally designed has not shown any results for me , and I think Anthony is right it is a simple device to stick on a battery that is not in use for a while. Best regards Thomas
Iwannabe2	Re: Current Optimum "Simple" Desulfator	#3	[-]
Posts: 3 (01/22/04 16:52:00) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi Anthony and Thomas, Thanks for your advices and comments. Thomas, I have the parts from Digi-Key right here beside me, I will give your modifications a try. Should I expect a louder "hum" ? All I have for diagnostics is a multimeter and a way to measure the specific gravity. The radio trick is nice... I know the my specific gravity started at 1.210 and I could not get any more charge into it after a day or so of high current charge (10 amps). After ~ a week on the desulfator and subsequent charge the specific gravity came up to 1.275. Still desulfating... Thanks for the comments on the resistive approach, I don't yet understand how the resistor in the output will "increase" the voltage. Thanks again and regards from a wannabe desulfator.
desulfator2	Re: Current Optimum "Simple" Desulfator	#4	[-]
Posts: 1001 (01/23/04 02:01:59) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Egadzooks! A 10 amp charge on a sicko batt for a day or two??? That may kill it for sure. You may find that a current regulated source (less than 0.5 amp) is a better companion for offline conditioning. Heavy charge currents are pretty much gauranteed to do damage (cell overheats, grid corrosion, etc....). Attempts to muscle a battery to better performance is sort of like taking a recent surgical patient down the gym for weight lifting and running on a treadmill to work out the kinks. Now I have jumped a batt with double the voltage for a fast (10 to 15 second) gassing period to mix the electrolyte at the tail end of recovery. This is followed by a 24 hour cool down period. But it's not a good idea to use a sustained high charge rate during the recovery period. My design for a Pulser/Charger uses a LM317 with two 1 ohm power resistors in the recommended constant current configuration (I like simple and low parts count). It results in less than 0.3 amps charge rate. One of the resistors can be shorted out with a front panel switch for a higher charge rate when being used to top a known good batt off. Works fairly well as you can connect and forget. The low charge rate does not seem to hurt anything and provides enough power to run the pulser and gently charge the batt. When the batt voltage fails to rise any further in a week or so, the batt can be gassed.
thomasasking	current optimum simple desulfator	#5	[-]
Posts: 519 (02/01/04 06:26:37) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi ! Don is right 10 amps not dropping suggests a very sick battery ,shorted cell maybe? The mod I suggested to parallel two 220 uH inductors and beef up C4 does not change the design concept at all but seems to give better results on larger AH starting batteries as the pulse current is about doubled. A good example recently during a very cold snap in England here, we were having trouble starting our old winter run about car . Symptoms were that we could not turn the engine over, and charging from an external 3 amp charger always terminated fairly quickly ( a good sign of a high resistance battery fooling the charger) I am normally reluctant to pulse in situ but the battery could not be removed because of corroded holding bolts and it was bloody cold ! The pulser was left singing away over night and much too our surprise the battery turned over easily next day (24 hours later) without recharging. Very unscientific but rewarding ! And still OK They do not all recover like that especially when they are made by Lucas and are five years old ! blissful pulsing Thomas
Iwannabe2	Re: 220 in parallel	#6	[-]
Posts: 3 (02/04/04 18:49:54) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi Thomas Thanks for the advices. For some reason, I did not realize you were in the UK. I spent 3 years in Southern Spain and got to meet some really nice folks from UK who were living there and working in Gibraltar. Cheers I was also fortunate enough to visit some places there, London, Hartlepool, my wife and family visited north UK with some friends we met in Spain. Anyway, my battery has been on the AC circuit for about 3 weeks, with a discharge and recharge mixed in with some low current charging. Specific gravity is up to spec and I hooked it up to a 3 A draw (an old car fuel pump I pulled out few years ago) that I put in my garage sink and let run for about 18 hours. Recharged, battery appears to be in good shape to me. Well, I did build the 220 parallel circuit with the beefier capacitor..... well.... I cooked it... not sure what happened. I also cooked my first AC. The mosfet and 1000 uH inductor got very very hot... I could have had a short circuit, ha ha. I did all the resistance checks that Don recommends that I got somewhere on this board before I put in the 555 and thought everything was okay.... oh well. When I get the urge, I will probably try the 220 parallel again, any checks I can do on my "dead" board, I am sure the mosfet and 1000 uH are cooked. Regards from Tennessee
G4HDS	Re: 220 in parallel	#7	[-]
Posts: 14 (02/05/04 10:19:26) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi Tennessee , Just couldnt resist a reply when i saw you had visited Hartlepool, THE MONKEY HANGING CAPITOL OF THE WORLD.. Anyway its only 5 mins down the road from my home into Hartlepool Where they have just Built what are claimed to be the biggest three windturbines in the U.K. Cheers From just outside Hartlepool..... Paul
Anthony Doyle	Re: 220 in parallel	#8	[-]
Posts: 177 (02/06/04 00:33:46) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi Tennessee, Before you try anything again, you need need a peak meter build from a signal diode and a 10nF cap to measure the output (and therefore meltdown potential quickly) on a digital multimeter. Also you need to be able to vary the FET on time with a pot as any variation in high power components will likely change required FET on time. Lastly, if your going to up the power, get a bigger L2 (1000uH) or change it for a 220uH etc. I had a few L2 meltdowns before I started to have any success...
desulfator2	Re: 220 in parallel	#9	[-]
Posts: 1001 (02/06/04 21:07:22) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Dead board? Smoked components? Why does that sound sooooooooooo familiar. Without the assistance of scopes, etc... there are a few things to try after you have exhausted the troubleshooting tips. 1. Connect a 2K gate bleed resistor from gate to POS (PFET) or NEG (NFET). 2. Pull the 555 out of the circuit. If it is soldered in, short the LOAD end of the 330 coupling resistor to POS (PFET) or NEG (NFET). OR short out any gate bleed resistor. With the 555 gate signal effectively killed either by removal or shunting the gate signal, your output stage should be able to be connected to a battery with no ill results. I do this BRIEFLY in stages, 1sec, 5sec rest, 2sec, 5sec rest, 5sec, 5sec rest, 10sec, etc.... If you have a shorted FET, Q1, L1 and L2 will get toasty warm fairly quickly. Be sure you have a finger or two on L1 and L2 when you go for these brief connects. Cool as a cucumber after a 30sec connect??? Now bring your 555 up and running. If the output stage remains cool when statically connected, hot components with the 555 driving the circuit can be caused by any of the following, 1. C2 is defective or possibly has a cold solder joint. This results in either a PRF that is too high with a large current draw OR an extended pulse width trigger to the gate. All output stage components will heat up (overdriving the FET). 2. A short or partial short anywhere on the load side of Q1. ----Only Q1 heats up if the short is at the Q1/L1 junction or a diode is defective or installed in reverse. ----Q1 and L1 only heat up if L2 is shorted or there is a short/partial short at the L1/L2 junction. 3. Pulse width trigger is too long of a duration. Check for cold solder joints/correct value of R2 (overdriving the FET). 4. Your floating ground is not good (PFET pulser) or C1 is defective. This causes pulses to sneak through the 555 and give you oscillations on the gate shut off signal. All output stage components will heat up. 5. Cold solder joints on the floating ground components will lower the voltage to the 555 and possibly result in an insufficient gate signal (underdriving the FET or running Class A operation).
thomasasking	re 220 uH in parallel	#10	[-]
Posts: 519 (02/10/04 03:15:50) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi ! reminds me of the old joke about Hartlepool First prize one weeks holiday in Hartlepool Second prize you guessed it ,two weeks holiday Only joking! Those dreadful wind turbines ! you can bet who ever is financing them lives a good 100 miles away from their noise and hideous appearance. As a small island with very high tides we could get most of our energy from the sea (there was a plan to dam Morecombe Bay ) Components overheating always puzzles me as the circuit is such a low energy device Even with 110 uH for L1 everything runs cool. I would hazard a guess from the emails I receive that the pulse width /frequency is out on most occasions . This is why I suggest buying an oscilloscope before almost anything else and checking the pulse width etc before making that final connection to the FET gate. Plenty of them on Ebay and you can learn to drive them very quickly ( easier than coping with windows in fact ) You can always mail a waveform for analysis if in doubt. It does open up a lot more possibilities Blisful pulsing Thomas
Anthony Doyle	Re: re 220 uH in parallel	#11	[-]
Posts: 177 (02/10/04 19:41:44) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hi all, I took some measurements today. I thought I would compare 220uH (5A continuous rated) with 110uH (2 * 220uH in parallel). Both were peaked using my trusty peak meter. [For some reason I can see the peak and then a drop before it rises again to cook the FET. I never could see such pronounced peaks in my earlier version pulser. The dip is about 5V and the drop sharp.] Results: 110uH - 38V@battery - 120mA DC current draw. 220uH - 37V@battery - 145mA DC current draw. Done on a good 310CCA battery. Results obtained using a charger which regulates the voltage to a fixed 13.2V. Obviously FET on times were different but not recorded. I also noticed that the diode ran cooler with 110uH. I think the 45mOhm FET also ran cooler too. Other testing: Replaced 2200uF low ESR cap with garden variety 4700uF cap to find no significant difference. Changed L2 from 220uH (5A) to 470uH (5A) to find DC voltage drop by 17mV, and the peak output (even after re-peaked) was 1.5V down at 35.5V on the peak meter. I was surprised the difference was so geat in peak voltage. I thought it would be insignificant.
hydeout22	optimum simple desulphator	#12	[-]
Posts: 5 (06/10/07 05:27:06) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Hey guys, Am so far having good luck with the standard AC circuit. Peak voltages seem to be lower than everyone else but after checking part numbers, seems that all I can find is the recommended diode is 200ns recovery time. I am running a 35ns recovery time diode. Anyone else notice a lower voltage or using fast diodes? I am interested in your mods for the higher amp circuit, Thomasasking. So just to clairify, I run two 220uH in parallel for L1 and one 220uH for L2. Use a 4600uF for C4? That is it? The timer circuit does not have to be adjusted? I can use the same P Fet as the original circuit? Same diode? Does the diode have to be rated for more amps, 10, 12? You mentioned that this is for larger Ah batteries. What is larger? I have a couple 8D batteries. I think they are around 250aH. Currently using the standard AC pulser on a couple of 90 aH deepcycle batteries and they are slowly coming around. It does seem to take from a month to two for that size battery. Thanks.

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