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Model Forum / Radio Controlled / Air Models / February 2007Ya out there Red?
Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps bouncing. I could use a little help. If you see this would you e-mail me at mikegordon10takethispartout@iveracity.com. Thanks > Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps > bouncing. I could use a little help. If you see this would you e-mail > me at mikegordon10takethispartout@iveracity.com. Thanks Here is his web page. http://www.rcbatteryclinic.com/ Also his email. redscho@bellsouth.net ka8jvx | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | bouncing. I could use a little help. To be fair, the people on this group generally know a fair amount about batteries, and generally aren't unwilling to help ...  SignatureDoug McLaren, dougmc@frenzied.us He was as lame as a duck. Not the metaphorical lame duck either, but real duck that was actually lame. Maybe from stepping on a land mine or something. > | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps > | bouncing. I could use a little help. > > To be fair, the people on this group generally know a fair amount > about batteries, and generally aren't unwilling to help ... and if its a LiPo question I dont think Red is an expert in this field judging by some of his replies on chargers IE "Most Lipo chargers employ a tapering current as they approach cut off, what we would term as a soft cut off" as that just plain old physics nothing to do with the charger OK, just hook your constant current charger Ni-Cd to your LiPo pack and see what physics does for you. :-( Say Hi to the firemen when they arrive. SignatureRed S. Red's R/C Battery Clinic http://www.rcbatteryclinic.com Check us out for "revolting" information. >> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | >> bouncing. I could use a little help. [quoted text clipped - 7 lines] > current as they approach cut off, what we would term as a soft cut off" > as that just plain old physics nothing to do with the charger > OK, just hook your constant current charger Ni-Cd to your LiPo pack and see > what physics does for you. :-( > > Say Hi to the firemen when they arrive. who said constant current I never did? a constant voltage but current limited charger as in all Lipo chargers the current has to reduce to approx zero by simple physics, it has nothing to do with the charger its all to do with the cells voltage rising to the charge voltage >> OK, just hook your constant current charger Ni-Cd to your LiPo pack >> and see what physics does for you. :-( [quoted text clipped - 5 lines] > nothing to do with the charger its all to do with the cells voltage > rising to the charge voltage You forgot the most important law of physics, which is that Red Scholefield is always smarter than you. Just ask him. >>> OK, just hook your constant current charger Ni-Cd to your LiPo pack >>> and see what physics does for you. :-( [quoted text clipped - 8 lines] > You forgot the most important law of physics, which is that Red > Scholefield is always smarter than you. Just ask him. No, he forgot the all imnportant law of Usenet, it's wise to not open your mouth if all you can manage to do is put your foot in it. "A man would better remain silent and be thought a fool, than speak and remove all doubt" Hey Zeus Christ, I didn't want to stir up the sh.t. I just wanted Red's e-mail address. DH er I mean NP why don't you go off in a corner and F*#k yerself. >> OK, just hook your constant current charger Ni-Cd to your LiPo pack >> and see what physics does for you. :-( [quoted text clipped - 5 lines] > nothing to do with the charger its all to do with the cells voltage > rising to the charge voltage Well it cam be anything from a taper from full to nothing gradually decreasing, or full current charge until the moment it exceeds the 4.2v per cell, at which point it switches off. Or like the Astro, continue to put 1 second bursts of full current in, until the voltage stays at 4.2v for 30 seconds, and THEN switch off.. I guess physics is a tad more complicated than you think... >>> OK, just hook your constant current charger Ni-Cd to your LiPo pack >>> and see what physics does for you. :-( [quoted text clipped - 10 lines] > per cell, at which point it switches off. Or like the Astro, continue to > put 1 second bursts of full current in full voltage maybe but not full current as the cell voltage would go above 4.2v , until the voltage stays at 4.2v > for 30 seconds, and THEN switch off.. > > I guess physics is a tad more complicated than you think... er no its not not unless you have rewritten ohms law the decreasing current has nothing to do with the charger per say The charge current cannot and will not stay at max until it reaches 4.2v a cell, it has to decrease by simple physics, you can charge a lipo pack with nothing more than a work bench supply that has variable current and variable voltage, at the beginning of the charge the current limiter is the primary control as the cell voltage will be below 4.2v volts and at maximum set current as the cell voltage rises and the current will decreases and the voltage will be the primary control and the current will continue to decrease gradually to zero until the cell is charged and the bench charger wont not even know it charging a LiPo and it will happily follow the graph below even your Astro will current graph for a simple voltage charger below http://www.flyelectric.ukgateway.net/li-chart.htm and have a look at this graph of a charge on a capacitor http://www.kpsec.freeuk.com/capacit.htm its the same, voltage increases current decreases its not rocket science the trick with charging Lipos is doing it safely by correctly sensing the number of cells the max current and the max voltage ETC >>>> OK, just hook your constant current charger Ni-Cd to your LiPo pack >>>> and see what physics does for you. :-( [quoted text clipped - 20 lines] > > the decreasing current has nothing to do with the charger per say *Per se*, actually, and yes, it has EVERYTHING to do with the charger, which is responsible for controlling it. > The charge current cannot and will not stay at max until it reaches 4.2v > a cell, It can. And in many cases does. >it has to decrease by simple physics, A charger is not simple. >you can charge a lipo pack > with nothing more than a work bench supply that has variable current and [quoted text clipped - 8 lines] > current graph for a simple voltage charger below > http://www.flyelectric.ukgateway.net/li-chart.htm Chargers - commercial chargers - are not simple voltage chargers. > and have a look at this graph of a charge on a capacitor > http://www.kpsec.freeuk.com/capacit.htm LIPOS are not capacitors either. > its the same, voltage increases current decreases its not rocket science > > the trick with charging Lipos is doing it safely by correctly sensing > the number of cells the max current and the max voltage ETC First bit you actually got right.... Well that would all be true if the output impedance of the charger were some finite positive constant value. Electronics however can be used to make it whatever you wish. Non linear, very non linear, even negative and so on. Perhaps a very very simple explanation will serve. Consider a very high voltage source, and a variable resistor controlled be a computer that senses the output voltage. For every output voltage the computer looks in its memory and sets the variable resistor to a particular value, or even switches it off altogether, needing a manual rest button to start it again. With such an arrangement you can have a COMPLETELY arbitrary arrangement of current with respect to voltage. It is not controlled by the load at all, or 'simple phyiscs'. It is controlled entirely by software and the circuitry. It can have as many completely arbitrary values as the computers ability to sense voltages, and store (or calculate) an appropriate current. The only interesting possibilty is if you had two of hem back to back, fighting each other..;-) It is perfectly possible to have a totally constant current, or even and INCREASING current, with voltage. Then all you need us a voltage detector that trips the thing off at a point, and you have a current which steadily increases till the voltage reaches a preset value, and then stops completely. For example. Not that such a circuit is desirable for charging LIPOS. I am not responsible for bad information on other peoples web sites. I am well aware that the behaviour you describe is characteristic of a bench power supply. And those can be used to charge LIPOS. It is not the only characteristic possible however, and is most definitely NOT the behaviour of the Astro 109, which is computer controlled to maintain full charge current right up to cutoff, and then pulses full charge current - and I mean FULL - until the *resting* voltage reaches the maximum. Other commercial LIPO charge chips do similar, or just cut off when the voltage reaches full, or taper down to full voltage. The problem with constant current to cutoff, is that the resting voltage of the cell will be somewhat below the allowed maximum. That is why a taper is normally used..but the taper is a very slow process..the charger approaches full voltage asymptotically, and in fact never reaches *full* charge, The Astro shortens that process by taking the LIPO OVER full voltage under charge, then disconnecting the charge to see what the resting voltage is. This allows the voltage to be brought up to maximum relatively quickly, and still safely. >>>>> OK, just hook your constant current charger Ni-Cd to your LiPo pack >>>>> and see what physics does for you. :-( [quoted text clipped - 23 lines] > *Per se*, actually, and yes, it has EVERYTHING to do with the charger, > which is responsible for controlling it. the only thing the charger limits is the voltage it has no idea during the charge process when its going to end its not some ultra smart algorithm ,the cell limits the current by pure physics LiPo chargers are exactly the same as a CV lead acid battery charger (but not the crap you buy at your local car shop)put 14.6v across a lead acid battery and the current will fall as the cells charge >> The charge current cannot and will not stay at max until it reaches >> 4.2v a cell, > > It can. And in many cases does. crap again, prove it show me any website/document where any LiPo charger can charge a cell at 4.2v at max current for the whole charge sequence >> it has to decrease by simple physics, > > A charger is not simple. it can be read up on it >> you can charge a lipo pack with nothing more than a work bench supply >> that has variable current and variable voltage, at the beginning of [quoted text clipped - 10 lines] > > Chargers - commercial chargers - are not simple voltage chargers. they are all based on cc/cv (constant current start/constant voltage finish) >> and have a look at this graph of a charge on a capacitor >> http://www.kpsec.freeuk.com/capacit.htm > > LIPOS are not capacitors either. No but the physics are the same >> its the same, voltage increases current decreases its not rocket science >> [quoted text clipped - 5 lines] > Well that would all be true if the output impedance of the charger were > some finite positive constant value. > Electronics however can be used to make it whatever you wish. Non > linear, very non linear, even negative and so on. Perhaps a very very [quoted text clipped - 5 lines] > particular value, or even switches it off altogether, needing a manual > rest button to start it again. but that is not got anything to do with a LiPo charger its a bit like saying the more I put my foot on a brake the quicker I stop which is true but totally Irrelevant > With such an arrangement you can have a COMPLETELY arbitrary arrangement > of current with respect to voltage. It is not controlled by the load at [quoted text clipped - 12 lines] > then stops completely. For example. Not that such a circuit is desirable > for charging LIPOS. but not on a LiPo cell its not, its not physically possible > I am not responsible for bad information on other peoples web sites. but you are for the crap you type > I am well aware that the behaviour you describe is characteristic of a > bench power supply. And those can be used to charge LIPOS. It is not the [quoted text clipped - 3 lines] > current - and I mean FULL - until the *resting* voltage reaches the > maximum. it cannot give a full current pulse as it limits the voltage to just over 4.2v a cell RTFM I have "the charger goes into mode three and the charge current is turned on and off and the charge cycle is slowly reduced until the cell voltage approaches 4.2v > Other commercial LIPO charge chips do similar, or just cut off when the > voltage reaches full, or taper down to full voltage. possibly but not constant current charge the current has to taper it cannot do anything else > The problem with constant current to cutoff, you do type some crap you cannot charge a Lipo to full charge with a constant current it cannot and will not happen is that the resting voltage > of the cell will be somewhat below the allowed maximum. That is why a > taper is normally used. its not "used" its fact it cannot be any thing else .but the taper is a very slow process..the > charger approaches full voltage asymptotically, and in fact never > reaches *full* charge, The Astro shortens that process by taking the > LIPO OVER full voltage under charge it goes over 4.2v a cell very slightly in pulses next time you put a battery on charge have a look at the charge current it falls towards the end it has to , then disconnecting the charge to > see what the resting voltage is. This allows the voltage to be brought > up to maximum relatively quickly, and still safely. I can only say that just about every statement you made is false in this post. nfly3 wrote: >>>>>> OK, just hook your constant current charger Ni-Cd to your LiPo >>>>>> pack and see what physics does for you. :-( [quoted text clipped - 146 lines] >> see what the resting voltage is. This allows the voltage to be brought >> up to maximum relatively quickly, and still safely. >> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | >> bouncing. I could use a little help. [quoted text clipped - 7 lines] > current as they approach cut off, what we would term as a soft cut off" > as that just plain old physics nothing to do with the charger Much as I agree that Red is not the greatest Guru on LIPOS, his statement in this context is correct, and yours is wrong. How the current falls as the charger approaches full LIPO voltage is entirely a function of its design. > >> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | > >> bouncing. I could use a little help. [quoted text clipped - 13 lines] > How the current falls as the charger approaches full LIPO voltage is > entirely a function of its design. A LiPo charger is nothing more than a CC to CV system. That is why the guys that were early adopters of the technology used big lab supplies to charge them. They just set the max charge current on the CC control and the max voltage on the CV control. There is a natural taper when the unit is in the CV mode because the pack is filling up, but the "charger" is not allowed to ramp up the voltage. The taper is just a natural extension of the CV part of the cycle. Now the charger may have a time limit on how long it says in the CV top off mode, but the taper is just plain 'ol physics. Jim >>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | >>>> bouncing. I could use a little help. [quoted text clipped - 24 lines] > > Jim Thanks but he wont believe you > >>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | > >>>> bouncing. I could use a little help. [quoted text clipped - 25 lines] > > Jim > Thanks but he wont believe you The facts are the facts. All you gotta' do is look at the datasheets for the cells. Classic CC/CV charge cycle. Sure, you can add some nice touches with an MCU, like pre-CC conditioning/testing, usually done to attempt to guess the cell count, but you still have to go by the rules. I have designed many of them. Jim >>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | >>>>>> bouncing. I could use a little help. [quoted text clipped - 35 lines] > > Jim is it true you can leave a LiPo battery permanently connected to a charger without any damage? > >>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | > >>>>>> bouncing. I could use a little help. [quoted text clipped - 37 lines] > is it true you can leave a LiPo battery permanently connected to a > charger without any damage? The quick and safe answer is NO. UltraLife Battery says : "Float Charge A charge at a low rate of current to compensate for self-discharge of a cell or battery. Not recommended for lithium ion or lithium polymer batteries." Portable Design says : "In order to obtain maximum charge in the battery, the Li-Ion cell must be provided a constant current source to charge the battery up to the 4.2-V level. Once at this point, the battery is only 70 to 80% charged. A voltage termination is necessary in order to ensure maximum charge. When the voltage reaches its maximum level and the voltage termination portion of the charging circuit takes over, the current to the battery begins to decay. At some point, the charge must be terminated; Li-Ion cells have a very low self-discharge rate, and keeping a float voltage applied to the battery will result in overcharge and damage the battery. The termination point cannot be set by the voltage level. As stated earlier, when the voltage reaches the maximum battery level, the battery is only partially charged. When the charging current drops off to a minimum level, the battery can be determined to be fully charged. During constant voltage mode, the current decays down to a minimum level where charging can then be terminated. " I would imagine if the charger is designed right, there should be a shut down point and not just a float. Jim >>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps >>>>>>> | bouncing. I could use a little help. [quoted text clipped - 30 lines] >> All you gotta' do is look at the datasheets for the cells. >> Classic CC/CV charge cycle. Thats but one way to skin the cat, and you know it. Or - horrifying thought, pehaps you really DON'T know it? >> Sure, you can add some nice touches with an MCU, like pre-CC >> conditioning/testing, usually done to attempt to guess the cell count, >> but you still have to go by the rules. >> I have designed many of them. Remind me never ever to buy one then. >> Jim > is it true you can leave a LiPo battery permanently connected to a > charger without any damage? > >>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps > >>>>>>> | bouncing. I could use a little help. [quoted text clipped - 33 lines] > Thats but one way to skin the cat, and you know it. > Or - horrifying thought, pehaps you really DON'T know it? I ask you again, What other method is there? Even "pulse" charging is just CC/CV when it is averaged. You got the big brain on today. Wow us with your electronics wisdom. > >> Sure, you can add some nice touches with an MCU, like pre-CC > >> conditioning/testing, usually done to attempt to guess the cell count, > >> but you still have to go by the rules. > >> I have designed many of them. > > Remind me never ever to buy one then. I have literally millions of my products all around the world. What do you have? Jim >>>>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps >>>>>>>>> | bouncing. I could use a little help. [quoted text clipped - 47 lines] > > Jim apart from delusions of grandeur that is you're fighting a loosing battle he wont admit he's wrong and he will swear black is blue until the cows come home but he wont be able to back up any claims on this one > >>>>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps > >>>>>>>>> | bouncing. I could use a little help. [quoted text clipped - 51 lines] > swear black is blue until the cows come home but he wont be able to back > up any claims on this one The funny thing is, he has probably been flying my products for years and doesn't even know it. Jim >>>>>>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps >>>>>>>>>>> | bouncing. I could use a little help. [quoted text clipped - 54 lines] > The funny thing is, he has probably been flying my products for years > and doesn't even know it. I doubt it. > Jim Jim > apart from delusions of grandeur that is > you're fighting a loosing battle he wont admit he's wrong and he will > swear black is blue until the cows come home but he wont be able to back > up any claims on this one Been staring into the mirror and projecting your won fanatasies on the rest of the world again? Wake up. The real world is more complicated than you can ever imagine. > Jim >> apart from delusions of grandeur that is [quoted text clipped - 5 lines] > rest of the world again? > Wake up. The real world is more complicated than you can ever imagine. just put a scope on your astro as its charging and see what it does voltage wise then shut up you are renowned for making the simple things sound complicated >> Jim >>> apart from delusions of grandeur that is [quoted text clipped - 9 lines] > then shut up > you are renowned for making the simple things sound complicated Actually I have mail that says exactly the opposite, time and time again. >>> Jim >>>> apart from delusions of grandeur that is [quoted text clipped - 11 lines] > > Actually I have mail that says exactly the opposite, time and time again. do this once or admit your wrong 1,prove by posting a link to a website that any Lipo charger puts exactly the same current at the end of the charge that it put in at the start of the charge proving your CC only method 2,post a link to any non cc/cv charger for Lipo's or any makers website that states its not CC/CV >>>> Jim >>>>> apart from delusions of grandeur that is [quoted text clipped - 15 lines] > exactly the same current at the end of the charge that it put in at the > start of the charge proving your CC only method Why? obviously at the end of the charge it puts out zero current! how else do you define 'end of charge' I think you need a few lessons in logic first. > 2,post a link to any non cc/cv charger for Lipo's or any makers website > that states its not CC/CV www.astroflight.com for the last. You can argue all you like, but you assertion that that is the ONLY way things CAN happen according to thwe laws of physics, is the problem. Its not the only way. You can have any V/i/t curve you want provided it doesn't violate the max current/max voltage limits of the cells by enough to damage them. There are an *infinite* number of curves that fit those boundary conditions. In essence the problem resolves to fitting a piece of string in a box. As long as it doesn't go outside the box and goes from one corner to the other, it can take any path it wants. > >>>> Jim > >>>>> apart from delusions of grandeur that is [quoted text clipped - 25 lines] > > www.astroflight.com for the last. Yes, I looked at the link and their charging pulses. It is CC/CV. It is PWM at the end. Once again, the pulses integrated over time make a CC/CV cycle. All you have to do is look at page 5 ov the manual and see. Jim >>>>>> Jim >>>>>>> apart from delusions of grandeur that is [quoted text clipped - 28 lines] > > Jim but page 5 does not have any scales so it could be a pulsed voltage or a pulsed current which nether backs up his claim or disproves it > >>>>>> Jim > >>>>>>> apart from delusions of grandeur that is [quoted text clipped - 30 lines] > but page 5 does not have any scales so it could be a pulsed voltage or a > pulsed current which nether backs up his claim or disproves it That's true. No X or Y legend. I just assumed...... I read the datasheet. I see no claim of a revolutionary new way to charge LiPo's or anything. The charge cycle is the same 'ol, same 'ol. Phase 1 (That somehow changes name to Mode 1 in the next paragraph) is just the standard preconditioning/cell guessing we talked about earlier in the thread. Mode 2 is just plain 'ol CC with a pause to more accurately measure the cell/pack voltage. Mode 3 is just a PWM taper to full charge. Which is just CV in pulsed form. Nothing new and revolutionary here. I like how this is being heralded as the one big example of how we are wrong, and yet it is just the same 'ol crap as everyone else. Jim >>>>>>>> Jim >>>>>>>>> apart from delusions of grandeur that is [quoted text clipped - 50 lines] > > Jim he cannot back up his claim but there are hundreds of sites to back up the CC/CV charge cycle, mind you do a google for "Astro 109" fires and see what this charger is capable of :-) > >>>>>>>> Jim > >>>>>>>>> apart from delusions of grandeur that is [quoted text clipped - 53 lines] > the CC/CV charge cycle, mind you do a google for "Astro 109" fires and > see what this charger is capable of :-) Not to deliberately throw my detracters a bone or anything, but there is one advantage to the pulsed charging method. You get more useable power from the battery. I know of some tests done with an ECar that had to use a PWM charger because a linear one would dissipate enough heat/power to damn near offset any savings from not burning gasoline. When they switched to a PWM charger the efficiency of the charger went WAYYYY up and one noted side effect was more useable power from the battery. I don't know why, I never followed up on it. Jim >>>>>>>>>> Jim >>>>>>>>>>> apart from delusions of grandeur that is [quoted text clipped - 62 lines] > and one noted side effect was more useable power from the battery. I > don't know why, I never followed up on it. Th astro algorithm allows 100% charging..a CC/CV charger dare not go to 100%..except by tapering over an extremely long time..you might say it approaches 100% charge after an infinite time.. The astro gets you 100% charge in about 1 hour and 15 minutes from almost flat. No other charger I am aware of does that. The simple ones that 'stop' when they get they 4.2v/cell will generally show 10-15% more charge can be taken when stuck on an astro,. The CC/CV stuff will take about 5 hours estimated to get to 95% charge. A SMPS will always be more efficient than a linear regulated power supply anyway..and you have to use SMPS to charge more than a 12v battery from a 12v DC supply. > Jim > >>>>>>>>>> Jim > >>>>>>>>>>> apart from delusions of grandeur that is [quoted text clipped - 78 lines] > supply anyway..and you have to use SMPS to charge more than a 12v > battery from a 12v DC supply. I built a test bed to play with the pulsed taper after the bulk charge. I will let you know how it works out if you want. To know for sure I will have to calculate the area under the curve for a CV cycle compared to the area of the pulses for a CC pulsed system, BUT I'll bet they come close. With the pulsed system you get a make an easier power control system. You just stick with a CC power input and then you use pulse width to taper. In fact, Maxim offers 2 basic IC's to do that very same thing, but you have to supply the constant current wall wart, and I don't recall seeing too many of those. Jim >>>>> Jim >>>>>> apart from delusions of grandeur that is [quoted text clipped - 19 lines] > Why? obviously at the end of the charge it puts out zero current! how > else do you define 'end of charge' crap statement as all charges do that that proves nothing > I think you need a few lessons in logic first. > >> 2,post a link to any non cc/cv charger for Lipo's or any makers >> website that states its not CC/CV > > www.astroflight.com for the last. so you have failed where on the site does it state its a CC only charger then?????? and its not a pulsed cc start and pulsed cv finish as I said you cannot back up your claim one bit I can find hundreds of hits for CC/CV but not one for a CC only liPo charger as they don't exist as you cannot hit a charged cell at full current and it not go over voltage > You can argue all you like, but you assertion that that is the ONLY way > things CAN happen according to thwe laws of physics, is the problem. and physics are different for you and Astro then > Its not the only way. You can have any V/i/t curve you want provided it > doesn't violate the max current/max voltage limits of the cells by > enough to damage them. There are an *infinite* number of curves that fit > those boundary conditions. and thats bollocks you cannot have any curve you want and if you think you can you are utterly and totally, wrong the battery determines the curve not the charger show me any LiPo charge curve that does not have the voltage climbing and the current decreasing, or the current increasing and the voltage decreasing > In essence the problem resolves to fitting a piece of string in a box. > As long as it doesn't go outside the box and goes from one corner to the > other, it can take any path it wants. another crap statement that has nothing to do with the thread I can walk three ways to my local shop so what? >>>>>> Jim >>>>>>> apart from delusions of grandeur that is [quoted text clipped - 56 lines] > another crap statement that has nothing to do with the thread > I can walk three ways to my local shop so what? The fact that you don't see the point, proves the point, to those who can. Ignorance is bliss. >>>>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps >>>>>>>>> | bouncing. I could use a little help. [quoted text clipped - 35 lines] > What other method is there? > Even "pulse" charging is just CC/CV when it is averaged. I am sure the world is really flat, when averaged. So you don't need low gears at all do you? Get real And stop weaseling. > You got the big brain on today. > Wow us with your electronics wisdom. You wouldn't believe it if I told you. > >>>>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps > >>>>>>>>> | bouncing. I could use a little help. [quoted text clipped - 48 lines] > > > You wouldn't believe it if I told you. Yes, I would, because then I would research it. That answer is just a non-answer because YOU DON'T KNOW. If you show me, I will even publically admit that I am wrong, right here. Jim | > >> Sure, you can add some nice touches with an MCU, like pre-CC | > >> conditioning/testing, usually done to attempt to guess the cell count, [quoted text clipped - 3 lines] | > Remind me never ever to buy one then. | I have literally millions of my products all around the world. Which products out there have you designed? (Specifically battery chargers, but if there's anything else you think is relevant, feel free to mention them.) Please be specific. Give models and names, and any specific circumstances. (Something along the level of completeness as `I designed about 50% of the Astroflight 109 charger, which has sold 69 units so far!' would be ideal.) As for claims that LiPos can only be charged with a CC/CV system, the fact that there *are* chargers out there that specifically don't do this would suggest that this isn't the case, but so be it ... SignatureDoug McLaren, dougmc@frenzied.us We've got a blind date with Destiny -- and it looks like she's ordered the lobster. --The Shoveler > | > >> Sure, you can add some nice touches with an MCU, like pre-CC > | > >> conditioning/testing, usually done to attempt to guess the cell count, [quoted text clipped - 16 lines] > fact that there *are* chargers out there that specifically don't do > this would suggest that this isn't the case, but so be it ... 1, name one 2, name a cell manufacturer that does not specify cc cv pulsed or other wise method >> | > >> Sure, you can add some nice touches with an MCU, like pre-CC >> | > >> conditioning/testing, usually done to attempt to guess the cell count, [quoted text clipped - 20 lines] > 2, name a cell manufacturer that does not specify cc cv pulsed or other > wise method I've been reading this thread a little reluctantly, sort of the way one feels one ought NOT to stare at the auto accident by the roadside, but can't help looking. Seems to me we have: 1. Doug: cites specific evidence of non-constant current and non-constant voltage regimes in at least one charger. Tends to bait the person he's arguing with. 2. Jim: claims that all chargers are CV/CC, and must be by the nature of physics. Includes "pulsed" as an example of "constant". Needs to use the comma key more often. Makes claims without substantiation. I don't know much about chargers -- only what I've read in The Art of Electronics, and little I've picked up here and there -- but I *do* know enough mathematics to be pretty certain that a square wave, except for duty-cycles of 0% and 100%, isn't a constant. Perhaps you can treat it as constant at certain time-scales (maybe 1/10th of the pulse- or gap-width?) for the sake of some analyses, but even then, you'd also want to look closely at the transition points for part of the analysis. Anyhow, carry on. I'll keep rubbernecking and feeling slightly queasy from it... --John > >> | > >> Sure, you can add some nice touches with an MCU, like pre-CC > >> | > >> conditioning/testing, usually done to attempt to guess the cell count, [quoted text clipped - 34 lines] > of physics. Includes "pulsed" as an example of "constant". Needs to use > the comma key more often. Makes claims without substantiation. It is really easy to check my claims. Just google "Lithium Polymer Charging Cycle". You will find nothing about any other type of charging method. With the pulse system, it is just basic math, (like the commas?) 1 amp for 100 ms is that same amount of power delivered as 100mA for the full second. It has been used by SLA chargers for years claiming some sort of cleansing of the plates. It is, however, an easy way to put energy into a battery and then let it sit while you measure the voltage of the cell instead of the voltage you are using to jam electrons into it. I wouldn't doubt that is exactly what the charger he keeps harping on is doing. Send a charge pulse, rest for XmS, read the pack voltage, average the value, repeat for as many cycles as needed. It is just CC/CV when the values are integrated. Jim > With the pulse system, it is just basic math, (like the commas?) > 1 amp for 100 ms is that same amount of power delivered as 100mA for the > full second. Perhaps you can define the word "constant" for me. My Ph.D. in mathematics clearly left me unprepared for some usages. I would say that a function f from the reals to the reals is constant if its image has a single element. In simpler terms, f is constant if f(x) = f(y) for all x,y in the reals. Apparently some folks would like to believe that the function x \mapsto round(sin (x) + 0.5) is "constant", but you'd have a hard time convincing ME of it. It'd be reasonable to say that a function f: [a,b] -> R was "constant, at scale A, within tolerance e," if |f(x) - f(y) | < e whenever |x - y| < A, except on a set of small measure. Even with this rather liberal definition, from what I can see, the pulsing chargers are not "constant at any timescale" that's even close to, say, 5 seconds. Even if you take "constant" to mean "2-valued" (i.e., the value is 0 some times, and some number C at other times), it's certainly possible to build a charger that doesn't use a 2-valued current or 2-valued voltage scheme over time. And you keep telling me to integrate stuff. Well, take any electronic device you can name. Integrate its current use over the entire time it's used. You'll get a number. Divide by the time used, and you get a number, C. You COULD say that the device used a "constant current C", because "you just integrate." I hope no one would take you seriously. So: tell me what interval to integrate over, and why; then tell me what "constant" means. Without knowing these things, I can't say whether I agree with you or not. (If "constant" for you means "blue with orange spots," for instance, then we don't have an argument -- just a difference in terms.) --John > It has been used by SLA chargers for years claiming some > sort of cleansing of the plates. It is, however, an easy way to put [quoted text clipped - 6 lines] > > Jim >So: tell me what interval to integrate over, and why; then tell me >what "constant" means. Without knowing these things, I can't say >whether I agree with you or not. (If "constant" for you means "blue >with orange spots," for instance, then we don't have an argument -- >just a difference in terms.) In electronics, constant current means two entirely different things when seen from the perspective of the source and the perspective of the load. A power supply can be capable of delivering a constant current to a load but a load may be presented with a varying load by pulsing the source output either internally or by external components. A load can present a constant current draw to a power supply the has no current regulation at all. A constant current supply presents a specific amperage to a load (the device being powered) but there is no requirement for the load to use all that amperage. Batteries, TV sets, radios, CD players and all manner of other equipment present an active load to a power supply which can only offer the maximum amount of current as it was designed to offer. The device draws what it can draw or needs to draw. A constant current source is not an irresistible force of nature. It's governed by a variety of factors as noted above. What a constant current supply actually does for batteries is to allow the topping off of the electrons stored in the battery. When a battery nears full charge, the tendency is to stop drawing (needing) current and the number of electrons entering the device drop, almost trickling in, which can become either an exponentially longer charge time or result in the battery never actually reaching full charge. The constant current supply is like a compressor adding air to a tire until the maximum pressure of the compressor is reached. If that's set to 60psi, that's how much air is in the tire when the maximum pressure is reached. If you pulse that air, it will still reach the maximum pressure but the average pressure in the hose drops until equilibrium is reached on the entire system. As you can visualize, the air is still at a constant pressure based on the maximum that the compressor can supply but now but the air is no longer flowing having no place to go. As the compressor fills the tire, the pressure in the entire system is now at the maximum. The same is true of a constant current supply. When there's no place for the current to go, it has to stop flowing but the potential to flow (pressure) is still there. It's still able to provide a constant current which won't vary according to the needs of a varying load. Difficult concept, yes. -- Ray > A constant current source is not an irresistible force of nature. > It's governed by a variety of factors as noted above. What a [quoted text clipped - 14 lines] > longer flowing having no place to go. As the compressor fills the > tire, the pressure in the entire system is now at the maximum. I believe that the paragraph above describes a "current-limited source" rather than a "constant current source." In general, a constant-current source really DOES supply constant current, over some specified range of loads. These used to be used in the old Model 33 teletypes, for instance, in their "20 mA current loop" transmission lines. For sufficiently-low-frequency to DC circuits, this means that when the load resistance rises, the applied voltage has to rise to keep the current the same. Given that there's usually some maximum voltage that the source can provide, you end up with something that provides constant current over a certain range of resistive loads. (All this ignores non-resistive loads and complex impedances, which would just muddy the issue.) The "compressor" is much more closely analogous to a constant-voltage source. Or at least, that's what Horowitz and Hill would lead me to believe. The interesting thing about a constant-current source is that (within the specified load range), the current coming from it tends to be constant over time, in the mathematical sense of "constant" that I described before, at least over the interval of time when it's operating, rather than on the whole real line (i.e., for all time). So that's a notion of "constant" that I've got a pretty good grip on. What I can't see is how something that looks like a pulse-train can be considered "constant." Probably just a problem with my narrow world-view. -John >> A constant current source is not an irresistible force of nature. >> It's governed by a variety of factors as noted above. What a [quoted text clipped - 32 lines] > >Or at least, that's what Horowitz and Hill would lead me to believe. Voltage is a potential, in electronics and current is a pressure. The electrons are presented in a maximum level limited by the voltage. The electrons are presented in a maximum number or quantity by the current. An ordinary, run of the mill, power supply with a voltage rating of 12 volts and a current of 500 milliamps will have the capability of developing that much pressure whereas a constant current supply with the same ratings WILL develop that much pressure. Both present to a load the maximum as required but the constant current device will not waver with load. The current will be there but not always used. In the case of LiPo batteries, they will continue to absorb the electrons even when the devices are absolutely full to capacity. This tends to destroy the innards (I'm using baby talk here for those who are following what has become a very deep thread) and the battery can be damaged and even catch fire if a constant current (pressure) is presented to the battery. There are constant current power supplies that will safely charge LiPo batteries. The Maxim company makes integrated circuits that monitor the level of charge (they call it the gas gauge) on a cell. Some even 'remember' the batteries under charge so that subsequent charging of those batteries can be done safer each time. They present that constant pressure of electrons until about 70% of the charge is met and then they begin to taper the actual time that the current is presented by pulsing the output eventually cutting it off completely when the battery is charged. The constant current supply still presents the same pressure to the circuit but only in dribs and drabs. It's the fastest way to charge LiPo batteries without causing too much damage to them. Unlike other types of batteries, they do degrade when fast charging is done. >The interesting thing about a constant-current source is that (within >the specified load range), the current coming from it tends to be >constant over time, in the mathematical sense of "constant" that I >described before, at least over the interval of time when it's >operating, rather than on the whole real line (i.e., for all time). Sometimes I think that those who debate the issue are rubbing their hands in glee with a word such as constant can present many meanings to the discussion allowing for others to interpret them as they will. The word does imply some sort of permanence and stability in most usages but in electronics, due to active loads versus constant loads, the meaning is very clouded. >So that's a notion of "constant" that I've got a pretty good grip on. >What I can't see is how something that looks like a pulse-train can >be considered "constant." Probably just a problem with my narrow >world-view. It's common, John, to those who don't live in the world of electronics or physics. Remember, we've had to deal with hole flow and electron flow to explain what you probably know as quantum physics or quantum mechanics. The limited world view concept applies there. Why learn all the complicated theory behind the workings of a transistor when the analogous holes/electron theory fits exactly. -- Ray > Voltage is a potential, in electronics and current is a pressure. If you're trying to make the standard analogy with fluids, Ray, it goes like this: (a) Voltage represents electrical potential. (a') For a fluid, the height of the water-tower represents the potential energy stored in the tower; a higher tower gets you higher water pressure at the tap. That water PRESSURE corresponds to voltage. (b) Electric current is the net flow of electrons along a conductor. (b') Fluid current is the net flow of the fluid in a pipe. Fluid FLOW is the analog of electric current. (c) Electrical resistance is the resistance to the flow of electrons through a conductor (or not-so-good conductor, which is called a 'resistor'). (c') Fluid resistance is the resistance to the flow of fluid through a pipe, typically the result of viscosity and a bunch of other stuff. Narrow pipes correspond to large-value resistors; fat pipes correspond to small-value resistors. So (at least in the usual analogies) current isn't a pressure. It's a flow. (Funny...it means that when you talk about the ocean, too. Current is the FLOW of water, while TIDE describes the water LEVEL, although those two terms are often misused/swapped as well). Indeed, if you replace the word "pressure" with "flow" everywhere in the paragraph you wrote below, you'll get something that's more or less correct. Of course, I could be completely wrong; maybe Ray's really an expert. But I think I feel safe in suggesting that anyone who doubts me or Ray should take a look at Horowitz and Hill, "The Art of Electronics". They're pretty clear and pretty authoritative. Used in a bunch of courses at MIT, for instance. So you can probably trust them... > The electrons are presented in a maximum level limited by the > voltage. The electrons are presented in a maximum number or quantity [quoted text clipped - 10 lines] > very deep thread) and the battery can be damaged and even catch fire > if a constant current (pressure) is presented to the battery. --John >> Voltage is a potential, in electronics and current is a pressure. > >If you're trying to make the standard analogy with fluids, Ray, it >goes like this: > >(a) Voltage represents electrical potential. Correct. >(a') For a fluid, the height of the water-tower represents the >potential energy stored in the tower; a higher tower gets you higher >water pressure at the tap. Not exactly. The total water regardless of height is the voltage analogy. Height would be directly responsible for pressure since we have gravity in play. >That water PRESSURE corresponds to voltage. Pressure is the amount of force applied by the water at end of the pipe which would correspond to the electrical load. Look, I'm trying to make this work for CONSTANT CURRENT, not for all conditions, OK? Remember, this isn't about something that everyone here can understand. I could go into FFTs and a variety of other instantaeous current calculations and blow smoke all over the place but we are dealing with a variety of people here, some of whom are ignorant of the math involved. Thus, I use analogy that explains things. The pressure represents the CONSTANT current, not relating to the total current which is analagous to the flow itself. Understand? Actually, I am sure YOU do but not everyone else. Stop trying to help other readers here unless you truly aren't getting the concept yourself. Fair enough? >(b) Electric current is the net flow of electrons along a conductor. > >(b') Fluid current is the net flow of the fluid in a pipe. Fluid FLOW >is the analog of electric current. Did I state otherwise? I gave my analogy to represent what happens with a CONSTANT CURRENT power source. >(c) Electrical resistance is the resistance to the flow of electrons >through a conductor (or not-so-good conductor, which is called a >'resistor'). Duh. Has this moved into the realm of complete Ohm's Law? >(c') Fluid resistance is the resistance to the flow of fluid through a >pipe, typically the result of viscosity and a bunch of other >stuff. Narrow pipes correspond to large-value resistors; fat pipes >correspond to small-value resistors. Double duh. >So (at least in the usual analogies) current isn't a pressure. It's a >flow. (Funny...it means that when you talk about the ocean, [quoted text clipped - 4 lines] >that's more or less correct. Of course, I could be completely wrong; >maybe Ray's really an expert. I am an expert. Thanks for asking. Retired from Electronics Engineering in 1999. Taught it for a while, too. Still teach it part time at local colleges here. >But I think I feel safe in suggesting that anyone who doubts me or Ray >should take a look at Horowitz and Hill, "The Art of >Electronics". They're pretty clear and pretty authoritative. Used in a >bunch of courses at MIT, for instance. So you can probably trust >them... I believe. I really do. Am I saved now? >> The electrons are presented in a maximum level limited by the >> voltage. The electrons are presented in a maximum number or quantity [quoted text clipped - 10 lines] >> very deep thread) and the battery can be damaged and even catch fire >> if a constant current (pressure) is presented to the battery. John, I think we're actually on the same page. The constant current power supply is a strange beast since it is absolutely non responsive to varying loads. An ordinary power supply is not able to provide a current source when the load demand drops. The constant current source can but doesn't absolutely have to do so. It's a distinction worthy of note when your goal is to gather as many electrons as you can into a battery. Our goal is to make the battery so full it nearly, but not quite, overflows with electrons. -- Ray >>So (at least in the usual analogies) current isn't a pressure. It's a >>flow. (Funny...it means that when you talk about the ocean, [quoted text clipped - 8 lines] > Engineering in 1999. Taught it for a while, too. Still teach it part > time at local colleges here. Ain't the world strange? I get to teach mathematics and computer science at an Ivy League school. And yet we disagree. Guess that's what makes a horse race. >>But I think I feel safe in suggesting that anyone who doubts me or Ray >>should take a look at Horowitz and Hill, "The Art of [quoted text clipped - 3 lines] > > I believe. I really do. Am I saved now? Sure. Since you believe, why not write down the equations so that we can see the analogy between water flow and electricity? Equations are comparatively precise, and we won't have to weasel too much what the words mean, I'll bet. [stuff snipped] > John, I think we're actually on the same page. Ray, I think we're not even looking at the same *book*. Back to the water tower. I've got a large tank, atop a 10 meter tower. And a BIG pipe from the tank to the ground level at which I'll be working. There's 1,000 kg of water in the tank. The potential energy stored in the tank is one million g (where g ~ 9.8 m/s^2), which (rounding off a bit) gets me 98,000 joules. At the bottom of the BIG pipe, the water pressure will be rho g h, where rho = 1000 kg/m^3 is the density of water g ~ 10 m/s^2 is gravitational acceleration h = 10m is height. That comes out to a pressure P1 = 1000*10*10 Pascals, or 100 kiloPascals. If we plumb a 1 meter piece of (idealized) PVC pipe into the bottom of the BIG pipe, and leave the other end open to the air, the pressure on the open end will be pretty nearly zero (air pressure really is negligible at this scale). So the pressure at the other end of the pipe will be P2 = 0 Pascals. What rate will water flow through the PVC pipe? Well, it all depends on the diameter. The flow rate (I admit it...the flow rate in an idealized model of a pipe!) is proportional to the pressure difference between the ends; the constant of proportionality is the "resistance to flow" of the pipe. So the equation looks like this: flowrate = flowResistance * (P1 - P2) OK. Hold that thought. For an electrical circuit, consisting of a single resistor, with voltages V1 and V2 at its ends, we have current = resistance * (V1 - V2) Do we still agree? Great. Those two equations are REALLY, REALLY, analogous. And the analogies are (1) electron flow (current) <--> water flow; (2) electrical resistance <--> resistance to flow in the pipe (3) voltage <---> pressure Two things you'll note here: * current is NOT analogous to pressure, but to flow. * voltage is analogous to pressure. Because the pipe happens to have constant resistance, that means that voltage, which is analogous to pressure, is also a constant multiple of the current. But that particular coincidence is a consequence of the simple situation, which the more general analogy (voltage analogous to water pressure) works even in more interesting cases, where the resistance varies. Just to hammer the point home: go back and double the tank's size on the water tower. Put 2000kg into that tank that's 10m high. Observe that the equations for pressure and flowrate, and the associated computation, don't change at all. Pause to look at what you said earlier: "The total water regardless of height is the voltage analogy." Now explain to me where "the total water" has anything to do with the flow-and-current analogy. I just doubled the total amount of water, and nothing in the relevant equations changed. Ray says: "The pressure represents the CONSTANT current, not relating to the total current which is analagous to the flow itself." If I read this last statement correctly, your analogy would be Mass (or volume) of water in the tank <---> Voltage Pressure at bottom of feed pipe <----> "the constant current" Flow <----> "the total current" Let's look at that circuit again. V1 ---/\/\/\/----- V0 with resistance R ohms. Let's call the current through the resistor "i". I *think* that you're saying "i" corresponds to pressure in the feed pipe. which I have called P1. As for "the total current", I'm not really certain what you mean. You might mean the total charge transport over some period (integral i(t) dt, taken over a fixed interval [a,b], which, because i is constant, just turns out to be i*(b-a) ); that'd be measured in amp-hours rather than amps, though, so it wouldn't be a current. I can't believe an EE would mean that. But I can't figure out what else it COULD mean. Now...what equation involving voltage, current, and resistance, corresponds to WHAT equation involving "total water", "pressure, and flow"? I guess I'm stumped. I've got an analogy that's good down to the level of equations. It happens to agree with the analogies presented by lots of other people (Google "voltage corresponds to pressure"), whereas yours seems to agree with no one else's (Googling "voltage corresponds to total water" leads to a bunch of pointers that say...voltage is analogous to pressure!). But hey, if it works for you, you should go with it. As for others ... I'll just say that I find Ray's explanation (a) unusual, (b) not as helpful as other explanations in letting me predict circuit behavior. Even though he's an EE and a teacher, I'm sure he'll agree that there are many fine textbooks whose explanations you can rely on, even if they differ with his explanations in some particulars. I commend them to you as you seek to determine which explanation to believe. --John >Ray, I think we're not even looking at the same *book*. Now we're both wasting time. You asked how a constant in electronics could be different than a constant in physics and I explained the differences and why. I used analogy to avoid confusing the casual reader. I really didn't believe you'd need any lessons beyond the analogy. As of now, you may continue this debate with only yourself. The answer you sought was given. Now you're just finding points to contend. Have fun. You win. I give up. -- Ray > > With the pulse system, it is just basic math, (like the commas?) > > 1 amp for 100 ms is that same amount of power delivered as 100mA for the > > full second. > > Perhaps you can define the word "constant" for me. My Ph.D. in mathematics > clearly left me unprepared for some usages. Ray did a very good job at explaining the terminology. In this case constant current means that the average current is kept at a certain value over a certain time frame. Constant voltage means the same thing. The average voltage is maintained over a certain time period. Peak voltage and peak current can be vastly different, but you get the idea. I didn't invent the terminolgy, but it is what we are stuck with in this case. Jim > So: tell me what interval to integrate over, and why; then tell me > what "constant" means. Without knowing these things, I can't say > whether I agree with you or not. (If "constant" for you means "blue > with orange spots," for instance, then we don't have an argument -- > just a difference in terms.) This sounds like the old bit where a guy is sitting with one foot in a bucket of ice water and the other foot in a bucket of water at 150 degrees. On average, his feet are comfortable! <g> SignatureJim in NC | 1. Doug: cites specific evidence of non-constant current and | non-constant voltage regimes in at least one charger. Tends to bait | the person he's arguing with. Just for the case of accuracy here, I've only posted once in this thread (well, this is post #2) so you don't really have enough information to come up with any sort of tendency, at least not in regards to this thread. Perhaps you're attributing somebody else's posts to me? I'm really more of a spectator in this thread, but since James Beck has pointed out that his designs are used in millions of chargers (?) out there, I think that's worth expanding on. If you think that's baiting him (or arguing with him), then so be it. | Anyhow, carry on. I'll keep rubbernecking and feeling slightly | queasy from it... Oh, it's too late for that now. You're now a part of the train wreck (as I would also appear to be) ... SignatureDoug McLaren, dougmc@frenzied.us Maybe, just once, someone will call me "sir" without adding, "you're making a scene." --Homer Simpson > | 1. Doug: cites specific evidence of non-constant current and > | non-constant voltage regimes in at least one charger. Tends to bait [quoted text clipped - 11 lines] > out there, I think that's worth expanding on. If you think that's > baiting him (or arguing with him), then so be it. NEVER said millions of charger. Better work on that reading comprehension. I said millions of PRODUCTS, big difference. Besides, that's still not the point. Let's assume that I know NOTHING about battery charges and you are going to enlighten me. Show me the datasheets that would substantiate your claims. My claims are easily googled. Jim | > I'm really more of a spectator in this thread, but since James Beck | > has pointed out that his designs are used in millions of chargers (?) | > out there, I think that's worth expanding on. If you think that's | > baiting him (or arguing with him), then so be it. | | NEVER said millions of charger. OK, you said millions of products. I did follow chargers with a (?) to indicate that I wasn't sure that they were chargers. I assume you're familiar with the convention of following something with a (?) to indicate that you're not certain of it? | Better work on that reading comprehension. Uh-huh. | I said millions of PRODUCTS, big difference. OK, then tell us about the products. Since they're apparantly relevant to the discussion, let's be specific about what they are. | Besides, that's still not the point. If you don't want to tell what your products are, that's fine too. | Let's assume that I know NOTHING about battery charges and you are | going to enlighten me. Show me the datasheets that would | substantiate your claims. I really haven't made any claims in this thread, except that chargers do exist that don't do CC/CV for LiPos. Perhaps you're thinking of somebody else's posts? However, if you're looking for an example, you only need to look at any of the adapters that are put on a NiCd/NiMH charger to allow it to charge LiPo batteries. Generally they just cut the circuit when it hits 4.2 volts/cell -- so the current is constant (during the entire charge period, anyways -- of course the current is zero before and after.) There is no CV phase at all. Personally, I wouldn't bother with any of those adapters, but they do exist. Here's an example for you -- http://www.slkelectronics.com/lipodapter/index.htm . Of course, the downside is that your battery will not be completely charged. How close you get depends on your charge rate -- if it's high, your battery may be far from fully charged, and if it's low it will be close. But it's certainly possible to design a charger that gets your battery up to 99% charged using only a CC charge regime (you just charge at a low rate.) Or you could design a charger that does multiple CC regimes (i.e. do 1C until voltage hits 4.2 volts, then 0.5C until voltage hits 4.2 volts, then 0.25C until voltage hits 4.2 volts, then 0.1C until it hits 4.2 volts again) then you could charge your battery almost completely and yet never have a true CV regime at all. Or with a little smarts, your charger could calculate the internal resistance of the cell and actually charge up to higher than 4.2 volts (because the voltage would drop back to 4.2 volts once the current was off) but you'd better not make any mistakes or you'll damage the pack! Or you could take your basic cell phone charger -- a 4.2 voltage source, run through a resistor to limit the current, into the battery. The only time the current or voltage (at the battery) is constant is at the end -- when current = 0 and voltage = 4.2 volts. (Though you might want to label that as a CV charger, as the input voltage (input to the resistor+battery, anyways) is a constant.) Either way, I think CC/CV is so popular because 1) it works, and 2) it's easy to implement, especially to companies who have already made NiCd/NiMH chargers. But it's hardly the *only* possibility. SignatureDoug McLaren, dougmc@frenzied.us Is there anything that beer can't do? --Homer > | > I'm really more of a spectator in this thread, but since James Beck > | > has pointed out that his designs are used in millions of chargers (?) [quoted text clipped - 7 lines] > you're familiar with the convention of following something with a (?) > to indicate that you're not certain of it? Why does it matter. That still doesn't change the thread. > | Better work on that reading comprehension. > [quoted text clipped - 25 lines] > of course the current is zero before and after.) There is no CV phase > at all. Oh, I see you got a Popeil Pocket Hair Splitter for Christmas this year. Just because an adapter cuts out one portion of the charge cycle (the CV part) doesn't mean it isn't using the classic charge cycle, it is just deleting one part of it. Not much of a "charger" if the battery isn't charged. > Personally, I wouldn't bother with any of those adapters, but they do > exist. Here's an example for you -- [quoted text clipped - 12 lines] > hits 4.2 volts again) then you could charge your battery almost > completely and yet never have a true CV regime at all. Still, if you do the integration, you are just doing the CV portion by pulse width or cycle timing. > Or with a little smarts, your charger could calculate the internal > resistance of the cell and actually charge up to higher than 4.2 volts > (because the voltage would drop back to 4.2 volts once the current was > off) but you'd better not make any mistakes or you'll damage the pack! That's what is usually done in the deadtime. Still, old tech. > Or you could take your basic cell phone charger -- a 4.2 voltage > source, run through a resistor to limit the current, into the battery. > The only time the current or voltage (at the battery) is constant is > at the end -- when current = 0 and voltage = 4.2 volts. (Though you > might want to label that as a CV charger, as the input voltage (input > to the resistor+battery, anyways) is a constant.) Still nothing new, see FLOAT CHARGER. > Either way, I think CC/CV is so popular because 1) it works, and 2) > it's easy to implement, especially to companies who have already made > NiCd/NiMH chargers. But it's hardly the *only* possibility. What other possibility? You said "hardly", so that must mean there are a myriad of choices. Throw a few at me. I read all the trade magazines, I see no big changes on the horizon. Battery Power Magazine, Electronic Products, Electronic Times, Electronics Component News (ECN), and the list goes on. Part of my job is to keep abreast of the situation. You going to be at the Battery Power Expo (Actually called Battery Power 2007) in Denver this spring? I am. See ya' there. Jim > | > I'm really more of a spectator in this thread, but since James Beck > | > has pointed out that his designs are used in millions of chargers (?) [quoted text clipped - 37 lines] > of course the current is zero before and after.) There is no CV phase > at all. and they dont actually finish the charge big deal > Personally, I wouldn't bother with any of those adapters, but they do > exist. Here's an example for you -- [quoted text clipped - 12 lines] > hits 4.2 volts again) then you could charge your battery almost > completely and yet never have a true CV regime at all. how novel a "non constant" constant current charger if you measure a small enough time all cc/cv chargers fall into this as the current will be a constant for n milliseconds > Or with a little smarts, your charger could calculate the internal > resistance of the cell and actually charge up to higher than 4.2 volts > (because the voltage would drop back to 4.2 volts once the current was > off) but you'd better not make any mistakes or you'll damage the pack! thats one of the most daftest ideas and the way to kill a cell > Or you could take your basic cell phone charger -- a 4.2 voltage > source, run through a resistor to limit the current, into the battery. > The only time the current or voltage (at the battery) is constant is > at the end -- when current = 0 and voltage = 4.2 volts. (Though you > might want to label that as a CV charger, as the input voltage (input > to the resistor+battery, anyways) is a constant.) DOH which is a current limited constant voltage charger which is perfectly normal cc/cv charge cycle > Either way, I think CC/CV is so popular because 1) it works, and 2) > it's easy to implement, especially to companies who have already made > NiCd/NiMH chargers. But it's hardly the *only* possibility. | DOH which is a current limited constant voltage charger which is | perfectly normal cc/cv charge cycle You two have convinced me of the error of my ways! I see it now! It's so simple ... { spoilers follow } All chargers of all sorts are CC/CV chargers! (Since a CC charger is just a CC/CV charger that spends no time in CV mode, and a CV charger is just a CC/CV charger that spends no time in CC mode. And you don't really need a constant voltage output to be a CV charger, and a CC charger is still a CC charger, even if the current changes.) Why didn't I see it before? It's so simple in retrospect! (Really, I should have just known better than to get involved in the first place. `Don't feed them', they say. I'll try to do better next time.) SignatureDoug McLaren, dougmc@frenzied.us Aah, change is good. -- Rafiki Yeah, but it ain't easy. -- Simba > | DOH which is a current limited constant voltage charger which is > | perfectly normal cc/cv charge cycle [quoted text clipped - 16 lines] > first place. `Don't feed them', they say. I'll try to do better next > time.) > | DOH which is a current limited constant voltage charger which is > | perfectly normal cc/cv charge cycle [quoted text clipped - 10 lines] > CV charger, and a CC charger is still a CC charger, even if the > current changes.) how the hell did you get to that idea are you on drugs? a cc charger that changes the current and a cv charger that changes the voltage do read it back as its crap its either constant or its not > Why didn't I see it before? It's so simple in retrospect! > > (Really, I should have just known better than to get involved in the > first place. `Don't feed them', they say. I'll try to do better next > time.) do grow up 1, you cannot have a pure CV charger for LiPo's as the initial current for a discharged cell would exceed the charge rate and shorten the life of the cell 2 you cannot fully charge a LiPo with a purely cc charger as it will never reach full charge with out going over the max voltage of the cell 3, and if you dont or cannot see 1 and 2 are correct then dont get involved as this is what the argument is over > | 1. Doug: cites specific evidence of non-constant current and > | non-constant voltage regimes in at least one charger. Tends to bait [quoted text clipped - 10 lines] > has pointed out that his designs are used in millions of chargers (?) > out there, I think that's worth expanding on. no he did not he said and I quote " "The funny thing is, he has probably been flying my products for years and doesn't even know it." how is that "millions of chargers" I for one have never flown a charger If you think that's > baiting him (or arguing with him), then so be it. > [quoted text clipped - 3 lines] > Oh, it's too late for that now. You're now a part of the train wreck > (as I would also appear to be) ... >| 1. Doug: cites specific evidence of non-constant current and >| non-constant voltage regimes in at least one charger. Tends to bait [quoted text clipped - 4 lines] > information to come up with any sort of tendency, at least not in > regards to this thread. Apologies, Doug. I'd failed to properly notice that we have two others posting and you just making a quick comment. Your name was the one that stuck in my mind as I did a followup. My comment about baiting comes from reading your posts on other topics (which I usually find pretty informative...but sometimes provocative as well!). --John > | > >> Sure, you can add some nice touches with an MCU, like pre-CC > | > >> conditioning/testing, usually done to attempt to guess the cell count, [quoted text clipped - 16 lines] > fact that there *are* chargers out there that specifically don't do > this would suggest that this isn't the case, but so be it ... Which ones? What charging algorithim do they use? I would LOVE to use a better way. Jim -On Tue, 30 Jan 2007 14:24:25 -0500, James Beck <jim@reallykillersystems.com> wrote: >> >>>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps >> >>>>>>> | bouncing. I could use a little help. [quoted text clipped - 49 lines] > > Jim As a matter of curiousity , what are some of those products ? Thanks Ken > -On Tue, 30 Jan 2007 14:24:25 -0500, James Beck > <jim@reallykillersystems.com> wrote: [quoted text clipped - 58 lines] > > Ken I don't know what the kind of NDAs we have, so I'll stick with generics, but if you have bought an aftermarket BEC, glow driver, or servo mixer/reverser, it might be one of mine. I doubt you have one of my battery chargers unless you are in the gaming industry, automotive, or work with "real" UAVs. We are currently doing a VERY small power conversion project for one of the automakers. We do so much gaming stuff, there is no way you can go into an arcade or casino and not be surrounded by my stuff. There are so many players in the hobby market for things like chargers and speed controls, it is just not worth the money to get involved unless you really come up with something new and unusual or really have a big end buyer. I can say that a couple of the guys in my club have and use some of the prototype chargers that I gave them. Jim >>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | >>>>> bouncing. I could use a little help. [quoted text clipped - 25 lines] >> Jim > Thanks but he wont believe you Of course not. I have one, it has a current meter on it, it behaves nothing like that. I have also spent a large party of my life designing non linear and linear electronic equipment and programming digital equipment. Ther is no point however in citing my academic background, qualifications and experience in electrical and electronic engineering, because people who think they are right don't listen. Hey, the earth is round, ever hear that? Nah. YOU KNOW its flat or we would all fall off. Stands to reason dunnit? >>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps >>>>>> | bouncing. I could use a little help. [quoted text clipped - 39 lines] > Hey, the earth is round, ever hear that? Nah. YOU KNOW its flat or we > would all fall off. Stands to reason dunnit? you do spout some crap so the astro pulses the current but it the same CC then CV > you do spout some crap > so the astro pulses the current but it the same CC then CV No CV at all. Only CC. When it detects the correct voltage, it just stops. As do many other chargers. Ive seen it go up to around 12.9v on a 3s pack.. Will you people please change the Subject on these posts. The original was for an e-mail address. Red S. > Will you people please change the Subject on these posts. The original was > for an e-mail address. > > Red S. er pot kettle black Ah yes -- another anonymous self-proclaimed expert with a phony E-mail address -- PLOINK! Signature"funfly3" <dontemailme@ntlworld.com> wrote in message news:SD5wh.57896 > er pot kettle black > Will you people please change the Subject on these posts. The original was > for an e-mail address. > > Red S. Why don't you weigh in on the subject? I'm sure you have seen how the current array of chargers handle the charge cycle. I'm pretty much done with this thread, but I would like to know your take on things. Jim It has been covered very well by those with at least a basic knowledge of electronics, not much I can add. The charge profile is essentially a function of the charger's design as many have stated. Red S. >> Will you people please change the Subject on these posts. The original >> was [quoted text clipped - 8 lines] > > Jim > It has been covered very well by those with at least a basic knowledge of > electronics, not much I can add. The charge profile is essentially a > function of the charger's design as many have stated. > > Red S. thats the trouble its not? stick a cell across a fixed 4.2 volt source and the current at the start will be high and it will decrease as the cell charges, the decrease in current is not a function of the charger its physics try it if you like and prove me wrong the only thing the charger does to this curve is limit the current at the start to prevent damage to the cell >> It has been covered very well by those with at least a basic knowledge >> of electronics, not much I can add. The charge profile is essentially [quoted text clipped - 3 lines] >> > thats the trouble its not? stick a cell across a fixed 4.2 volt source Which is "a function of the chargers design".... Oh dear. I bet he still thinks Bush is an intelligent man.. > and the current at the start will be high and it will decrease as the > cell charges, the decrease in current is not a function of the charger > its physics > try it if you like and prove me wrong > the only thing the charger does to this curve is limit the current at > the start to prevent damage to the cell Holy crap Red. I have not seen your name so much since the good ole days of the "AMA", "Kevin Kline", "Hugo", "Six", etc... threads! (I am sure I left out a few names) > Will you people please change the Subject on these posts. The original was > for an e-mail address. > > Red S. >>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | >>>> bouncing. I could use a little help. [quoted text clipped - 14 lines] >> > A LiPo charger is nothing more than a CC to CV system. Not necessarily. They can be radically different. > >>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | > >>>> bouncing. I could use a little help. [quoted text clipped - 16 lines] > > Not necessarily. They can be radically different. No, they can't. They have to obey the CC/CV charging rules. They may do other things above and beyond that, but the simple fact is, that's how they charge. What other methods have you used? What other methods do the cell manufacturers recommend? Jim >>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | >>>>>> bouncing. I could use a little help. [quoted text clipped - 17 lines] >> > No, they can't. Wrong. > They have to obey the CC/CV charging rules. They don't. All they have to do is never exceed a safe current, or a final safe resting voltage. CC/CV is but one way to achieve that. > They may do other things above and beyond that, but the simple fact is, > that's how they charge. No it isn't. Not all of them. > What other methods have you used? The Astro for one, and a simple CC and stop at a given voltage. > What other methods do the cell manufacturers recommend? All of the above are fine, and recommended. > Jim > >>>>>> | Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps | > >>>>>> bouncing. I could use a little help. [quoted text clipped - 37 lines] > > All of the above are fine, and recommended. Wow, what a massive list. I'll bet if you integrate the pulses they are just CC/CV. Show me a cell makers link that shows ANYTHING other than CC/CV for their cells. Jim You must have found the right combination red@rcbatteryclinic.com since I got your message regarding the charger question. Red > Been trying to contact Red S @ Battery Clinic. Yer e-mail keeps > bouncing. I could use a little help. If you see this would you e-mail > me at mikegordon10takethispartout@iveracity.com. Thanks Unbelievable ;-)) > You must have found the right combination red@rcbatteryclinic.com since I > got your message regarding the charger question. [quoted text clipped - 3 lines] >> bouncing. I could use a little help. If you see this would you e-mail >> me at mikegordon10takethispartout@iveracity.com. Thanks |
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