Former Member Posted May 10, 2008 Share Posted May 10, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 10, 2008 Share Posted May 10, 2008 Does your transformer not emitt heat?Is heat not a by product of the inefficiency of the voltage reduction process.Does the heat emitted from your microprocessor not indicate inefficiency of the device. Glad to see you have come arround to my way of thinking, that converting excess current into heat is inefficient.I do not know, but I suspect that the approach taken is, to Measure voltage across cell. If less than max value required charge cell at predetermined rate for a predetermined time. If equal to required range, do nothing If greater than required value then reduce voltage Set a flag to either true or false (full charged and overcharged or underchargedt) Go to next cell Repeat operations 1 to 5 When flags indicate all cells are charged (true) then stop procecessI think you are trying to be far to analitical about this.As I have said on many occasions the true ballance charger will charge all the cells at the same time individually and rest any overcharged cell, thus charging in a more efficient way, it will also charge much quicker than any other type of charger as each cell is receiving a optimised current i.e. if you are charging at 500mah each cell is receiving 500mah unless that cell has its current input reduced to allow one of the other cells to catch up, overall the battery is receiving 1.5Amps.In short I do not think the differences in charger types is worth dying in a ditch over. I certainly do not think the energy saved is worth worring about. I still need to be convinced that the maximum voltage achieved by either method is worth getting excited about.Please read this and take in, you don't seem to have read my post's, I have never said the energy saved is worth worring about, my whole concept has been the efficiency of charging and ballancing cells in a LiPo pack, just comming back to this thread with another diatribe completly ignoring what has been said and repeating yourself does not serve any usefull purpose, and just forces me to repeat myself, this is a complete waste of time if you do not read the posts correctly, and go off on a tangent on things that have nothing to do with the subject matter. Mike Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 10, 2008 Share Posted May 10, 2008 Eric Bray wrote (see)Occam's razor implies that the latest hypothesis is the correct one, until proven differently!My mother used to say "If you talk about something you no nothing about often enough, you will start to believe what you have said is correct" Mike Quote Link to comment Share on other sites More sharing options...
Erfolg Posted May 10, 2008 Share Posted May 10, 2008 I am truly sorry that you see this discussion as a diatribe.My problem is that, I think we do not agree on the definition of efficiency.It can be seen as energy used, against energy provided etc.It could in some circumstances be considered to be speed of reaction etc.It could be some measure that you have decided upon and measured.etc.In short, we neither seem to relate to ech other in objective. My background gives me a particular view of the physical world. It does not make me clever nor do i perport to be clever. But some very clever people over the centuries have provide a particular way of defining and measuring, that most engineers follow. If some one says to me this is the best, my immediate thoughts are, against what criteria, the next thought will be, do i need the best, does it really matter if it is the best. This is not unique to me, but is a trained responce of most engineers.Most of us have responces which are derived from our training and work. I guess yours is different to mine. No more or less valid in context, than my own.I hope that we can both agree that we have not on this occaison had a melding of minds, and then move on.Best RegardsErfolg Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 12, 2008 Share Posted May 12, 2008 Erfolg wrote (see)My problem is that, I think we do not agree on the definition of efficiency.It can be seen as energy used, against energy provided etc.In short, we neither seem to relate to ech other in objective. Erfolg I am sorry Erfolg, if you can not see that what I have been saying all along agrees with the above statement, putting excess power into a cell and then dumping it can not be efficient.Why you found it neccesary to mention your qualification I don't know, it had no bearing on the discussion in any way, it is a typical middle management statement of someone who is unsure of their gound and are trying to establish a view point that is dubious, any respect I had for your opinion was lost at that point. I will not be replying on this thread again so the last work is yours. Mike Quote Link to comment Share on other sites More sharing options...
Ultymate Posted May 12, 2008 Share Posted May 12, 2008 Methinks some of you guys like the sound of your own keyboards too much, and need to go flying more often Quote Link to comment Share on other sites More sharing options...
Tom Foreman Posted May 12, 2008 Share Posted May 12, 2008 Mike you probably want the new FMA Cellpro 10S , although I don't know if its landed in this country yet. Its available from aurorra.co.uk and does 10 cells at 8 amps split into two groups of 5 cells, it can charge up to 8 cell packs at 10A. I personally use the smaller cellpro 4s charger which will charge up to 3C (if you dare) but as it only does 4A max on 3s & 2s and 3A max on 4s you struggle to charge packs of more than 1200mAh at higher C ratesI've ended up charging my 3s1p 2200 packs at 4A (1.8C) to speed up the charging. It also has a useful Fuel Percentage feature, when the pack gets to 95% it can be used saving charging time as the last 5% generally takes the longest! Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 12, 2008 Share Posted May 12, 2008 Tom I already have the Bantam 902 which can charge 12S, unfortuantly it is only a 300watt charger so on 10S (42volts) it can only charge at 7amps, I will have a look at the Cellpro and see what it can achive, thanks for the heads up. Mike EDIT: The Cellpro is also only a 300watt charger so the same 7amps is only achivable on 10 cells, most of the manufacturers will quote a 10amp charge rate, but they are talking about a lower than 10 cell count, still it was worth a check, thanks again. Mike Quote Link to comment Share on other sites More sharing options...
JohnP25 Posted May 13, 2008 Share Posted May 13, 2008 Good grief - all I was going to ask is has anyone used a Pro Peak EQ-5 and are they any good.I have some old 3S packs I was thinking of balancing. John Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 13, 2008 Share Posted May 13, 2008 John Sorry the thread lost some direction in there, afraid I can't help on the Pro Peak as I don't have one, so it would only be supposition on my part to comment, I will have a look at one and give you my opinion, but in my experience the Tenergy or DN power are two of the best with I think its the ORCA for balance charging anything up too four cells. Tom I have just read through the spec of the new Graupner Duo Charger it has the ability to charge through both outlets separately at 180watts, so as I have my 10S packs as two 5S I could charge each 5S pack at 8amps each pack at the same time, or more sensibly at the 1C rate of 4amps each pack, that is the optimum rate of charge and will give the quickest turn around of the discharged packs, now all I have to do is make up a cooling cell to put the batteries into when the come out of the plane so that I can charge them as soon as they cool down. Mike Quote Link to comment Share on other sites More sharing options...
Tom Foreman Posted May 13, 2008 Share Posted May 13, 2008 I think I'll stick with the Cellpro for now but good luck with the Graupner. By the way, the cellpro doesn't mind charging warm packs, if you believe the destructions! Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 13, 2008 Share Posted May 13, 2008 Tom Its on advice from FlightPower that you should wait for the pack to cool down before charging, The Bantam 902 has a heat sensor lead that you can put on the pack and it will cut the charge off or never start it if the pack is over 80deg C, this seems to agree with FlightPower's recommendations. Mike Quote Link to comment Share on other sites More sharing options...
Tom Foreman Posted May 13, 2008 Share Posted May 13, 2008 Wow 80 Deg C is pretty hot, I don't let my packs get that hot. Normally they come out at about 40 Deg C after a good thrashing! I just want a bigger charger in the future when I get some bigger packs (4s1p 3700) for a nice 40 size Extra! Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 13, 2008 Share Posted May 13, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Don McQuillen-Wright Posted May 13, 2008 Share Posted May 13, 2008 I use a Cellpro4 charger , adapted for A123 technology, for charging Lipos.I have purchased some A123 batteries and am having difficulties obtaining the correct adapter for the charging plug. . Neither BRC or FMA have been much help. Don Quote Link to comment Share on other sites More sharing options...
Tom Foreman Posted May 13, 2008 Share Posted May 13, 2008 Don, I use a TP/PQ daughter board from FMA and a TP to JXT adaptor from BRC to connect my 4s lipos to my cell pro charger as the JXT daughterboard only goes up to 3s. Alternatively you can buy Cellpro pigtails that plug directly into the charger and solder to your A123 balance lead. Perhaps you could cobble somthing together , what balance plugs are on the A123s? Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 13, 2008 Share Posted May 13, 2008 Don What do you need? I may be able to help, I use Deans plugs and sockets on my A123 and XHjst ballance leads, these are on two and four cell packs I have made up from DeWalt 36volt batteries. Mike Quote Link to comment Share on other sites More sharing options...
Mike Johnson Posted May 13, 2008 Share Posted May 13, 2008 Eric I have one of those fans inside the plane to keep the lipo's cool, I only switch it on once I have landed by a Tx switch, mainly because the max temp I have seen is once I have landed, due to no airflow over the batteries. Mike Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 13, 2008 Share Posted May 13, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 14, 2008 Share Posted May 14, 2008 Quote Link to comment Share on other sites More sharing options...
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