Mike Johnson

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

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

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

I see what you meant now. Energy reduction was not my point, the relative efficiencies of balancing Li Po's in different ways to achive a ballanced pack was. Putting to much power into a cell and then taking it back out again can not be as efficient and as kind to the battery as charging to the correct value individually. This is a basic concept that should be easy to grasp and even easier for someone as educated as you tell us you are.  Mike

The problem with a subject like this, is the small amount of information that most club members have when discussing Health and Safety, they go one of two ways, the first and most popular is overboard, try to legislate for everything, the other way is to blame the nanny state for interfering with my fun, if only we could all be relied upon to use our common sense, starting up any engine is fraught with some danger, but to contemplate starting up an engine of 60 and over without some kind of restraint is irresponsible and a danger to the rest of your club members, be that restraint another club member or a stake into the ground, but don't rely on the other club member to do exactly what you want.  I regulary fly 60cc petrol planes and a stake in the ground is totally inadequate when checking full power, one club member per wing is the safest way.  So come on you guys who don't use a restraint or purport to have been lucky and not had an accident yet, give some thought to your fellow flyers who may not have as much common sense as you and show a good example to those who have been in the hobby for less time, use a restraint it make good sense. Mike

With due respect, it seems that there is no way of convincing you that dumping excess current as heat is inefficient?  During my formative years I was always told to keep an open mind to new and exciting posibilities and not be blinkered by old trusted technology, but to embrase change and evolution.  As to loosing the subject of the thread, discussing the different ballancing methods that chargers have is right on the money of the subject of this thread, so I don't understand your comments on loosing the subject matter.  Mike

Your best bet is BRC Hobbies, they have all the convertor leads in there range, what you need is a JST XH too your Kokam battery ballance lead, sorry I don't know what type of lead is on the Kokam.  At the moment BRC Hobbies advert is at the top of this page.  Mike  EDIT: the Kokam ballance lead is the same as Graupner and Robbe, other than that I can't find the spec, give BRC a ring they will be able to help.

How are we loosing direction and cohesion, we are talking about "LIpo Ballancing" which is the theme of the Thread.  Dumping excess voltage through heat and the ballancer is old technology and not the latest solution, the most effective way to ballance a pack of cells is to charge each cell individually with a cross link microprocessor controlling the power into each cell to ensure they are all charged equally, the only problem with this latest technology is the expence of making a charger capable of doing this with more than four cells.  If you are happy charging your cells through the power lead and dumping excess voltage through the ballancer then fine, carry on I have been doing it that way with my ten cell packs for a couple of years, because there is no alternative. The only reason for discussing the latest technology of charging through the ballance leads was to inform others of a more effective way of charging LiPo packs, if the manufacturers finally produce the right charger we will be able to charge each cell at up to 3amps each as the ballance lead is connected to each cell and the cables used are quite capable of taking that sort of load, so a three cell pack could be charged at 9amps if the battery is capable of taking that sort of charge rate, just think what this could mean for a ten cell pack at last we could get a charger that will charge at over 5 or 6 amps, mind you it would have to be a 1500 watt device, I wonder how much that would cost?  As to charging at a lower rate, talk to Ian at FlightPower due to the demands of the show circuit his ten cell packs are fast charged and only last approx 50 cycles, he recommends always chaging at a lower than optimum rate if possible, of course the disscharge rate has the greatest effect on the life of the battery and should be kept within the C value of the pack if you want it too last.  Mike

Perhaps a further explanation is in order:  On a charger that chages through the main leads and has a ballancer either attached or internal, the over charge that causes the inballance is already in the pack, the ballancer acts as a voltage dump to take excess voltage out of the overcharged cell to equalise with the other cells being charged, this is normally disipated as heat, in most cases the over charged cells are not receiving any charge during this process, hence a longer charge period waiting for the dump to finnish before re commencing charging. On a charger which charges each cell individually through the ballance lead only, each cell is monitored through an individual microprocessor for its voltage and if one or even two cells get in front of another cell in voltage terms those cells get a reduced charge rate untill the under voltage cell catches up, quicker and more efficient.  Mike

Ultymate Once you get above 5S the inballance of the cells after discharge needs to be addressed, even though the cells are all of the same C rating they can have slightly different discharge charicteristics, IMO on my 10S packs it is essential to ballance on each charge, if only for piece of mind because of the cost of replacement. Erfolg As you say most modern LiPo's will take a 1C charge rate, therefore it should only take a maximum of an hour to charge any pack with that capability, if the charge is going through the ballance leads the ballance is done automatically and therefore will not take as long as a charger that does it as an afterthought, that's why it took three to four hours to chage your 2000mah batteries. Most packs should not be discharged to thier fully flat state and so they will charge quicker than an hour at 1C, personally I only charge at 1C in the field, back in the hanger I charge at 0.5C, treating them with respect I still have a pair of 5000mah 3S2P from FlightPower that is gigantic, heavy and has a carbon cover, but still serviciable after 4.5years and 250 cycles, can't say the same for the cheaper branded ones though. Mike

Matt  It looks like they are for charging through the main leads and the ballancer is just a microprocessor to ballance whilst charging, its the same with all of the chargers over four cells at the moment, my Bantam 902 will charge 12S in any combination of packs and it links to the PC, you can check individual cell voltage either on the charger by scrolling through or on the PC screen, its as good as any of the others out there at the moment maybe a little bit better as it also charges A123's which I use as Rx packs in my bigger planes.  Will keep looking for a ballancing charger rather than a charger ballancer, strange how the description gets confused by lots of manufacturers.  Mike

The Cellpro charger on the above link has positive and negative connectors on the front case, why does it need these if it charges through the ballance leads?  Please do not think I am trying to be awkward I just want to know how many true ballance chargers are out there.  Mike  EDIT:  Sorry you have the 4S which does look like a true ballancing charger, so we now have the Tenergy, Cellpro and Orca, it seems more and more are becoming available, its a shame that they are all only capable of charging four cells.

I think the Cellpro is a charger ballancer in other words it charges through the main negative and positive lead of the battery and ballances indipendantly, although microprocessor controled this is not true ballance charging.  As explained earlier a true ballance charger charges through the ballance leads without the main negative and positive leads connected too the charger, they are in effect seperate chargers for each cell, microprocesser controled to ensure each cell is ballanced as it is charged though its own lead, I hope that is clear.  Mike

Its more a question of trying to prolong the life of your very expensive packs, as they get further out of ballance they become more inefficient, as the cells will not discharge at the same rate as they have different capacities, therefore the out of ballance gets worse and the performance suffers more, untill eventually one cell will be so far out of ballance it will not recover to its full capacity when charged and that's the end of the efficiency of the pack.  Mike

I have the Bantam 902 with the interlink to ballance my 12S packs, but as the BC8 this is not a true ballance charger, as Edmond says it just discharges as it is charging to ballance the cells, with a ballance charger which charges through the ballance leads you are only charging one cell with the smaller cable, admittedly the interface cable between two cells is taking twice the charge of the single cable on the outside cell, but in any case the charge input is divided by the number of cells in the pack, so a 3S pack charging at 10amps is only taking 3.3amps per cable to the outside cells and a possible maximum of 6.6amps to the internal - + connection, the Tenergy ballance charger is only rated for 6amp charging so the current taken by the ballance lead is even less, I have not seen a ballance lead yet that would not be capable of taking that load.  Mike

I did say as far as I can make out, add one more to the list of real ballance chargers, we now have the ORCA and the Tenergy.  Anyone else? also does anyone know of one that does more than four cells, preferably 10 cells at 5 amps, this would have to be a 300watt charger the only ones available are below 200 watts at this amperage and voltage and are not true ballance chargers, anyone know any different?  Mike

I find the lack of correct spelling does not detract from the message in any way, if you can still understand the content then it is not an issue, and in any case I get an excemption error ever time I try to use it and it does not work.  Mike

Buy the Tenergy charger it is in fact four chargers built into the same case and microprosessor controlled to ballance each cell as they charge individually, as far as I can make out it is the only ballance charger available, the rest seem to be chargers with ballancers attached, you can tell them by the fact they charge through the main power lead from the battery and the ballance lead attached to ballance the unit, the Tenergy only has the ballance lead attached and charges each cell individually whilst monotoring the chage rate and voltage, its very clever the  way it reduces the charge rate on one cell to allow the others to catch up or visa versa.   Shame its only available for up too four cells, they have a bigger one on the way, but not available yet.  Mike

Dave  The transmission towers on either side of the Thames are broard band communication towers transmitting on all communication and information bands, the analogy with PPM was purly to point out that the area of transmission causes PPM interferance an is line with the communication towers it was not to allude to the fact that PPM is interfering with 2.4Ghz that was an assumption on your part.  If you require any scientific evidence that 2.4Ghz can be hit by outside sources please go to the dedicated thread on RC Groups titled "xps To hop or not to hop (moved from XPS site)" there you will find extensive evidence of 2.4Ghz interferance and the investigations into the non hopping of the XPS system.  XPS being Graupner IFS in Europe. Mike

Dave  I can't argue with PPM being for boats, but I was just interested if the area you flew the IFS in has any experience of PPM interferance, as it seems the IFS system does and goes into lock out when this occurs, my site is not PPM tolerant, I even went to the extreame of putting the Rx up inside the canopy of my plane to ensure that no servo or battery wires where anywhere near the antenna, but this did not seem to make any difference to the problem.  Mike

Dave  Did you fly the IFS system on a PPM interferance prone site? Mike

Thanks for the update, I saw this mod on the 6 channel system and thought the DSM2 system did not need the stepping reulator, however if you are getting 7 hrs from this mod, its got to be worthwhile.  Can you give us some more detail of the on light and sounders, they also look a worthwhile mod.  Mike

Absolutly, I also thought that with the Graupner name I was on a safe bet, I am now flying Spektrum exclusivly in my Futaba Zap without any problems, this was after getting the DX7 to test it out on my site.  Mike

I bought the Graupner IFS system which is the XPS system in the US, this was installed in my SebArt Angel, previously on a Spektrum DX7.  The site I fly from has known interferance on PPM from what we belive are transmission towers on either side of the Thames, these interferance areas are in four place's on our site and are well known, PPM generally glitches when passing through them. The IFS system locked out in these four areas with the associated brown trouser responce, I had done a full range test proir to flying and have since tested the system on the ground in the same areas with the same results, at no time did the system go into fail safe, it just locked out for a second or so each time the Rx was in the appropiate area.  In my opinion the IFS system is the same as flying on PPM, it locks out instead of glitching, from all of the US sites it seems this system does not hop to another frequency when experiencing interferance, Jim Drew who is XPS has been asked on many occasions to demonstrate the hopping of this system with no responce.  Graupner have now given my supplier a credit note for this system.  This is not meant to knock the system, but to inform all of its limitations on a highly interferance prone site.  Mike

What extra run time did you get using the switching regulator? I have some DE-SWO33's is this the one you used?  Mike