Tim Mackey Posted December 13, 2008 Share Posted December 13, 2008 Most peeps know that I am a fan of charging same cell count Lipo packs in parallel to speed up things when recharging, especially at the field. Connecting the balance taps in parallel ( IN THE EXACT CORRECT CONFIGURATION OF COURSE ) also, means that all cells will get balanced also, and if using lowish currents ( up to around 1A ) there is only need to connect the main charger leads to one of the packs...... charge current wil flow into the others through the balance leads. I have made up a small multi way board which I call a "Parallel balance board" using perforated veroboard and a few connecting links underneath. All that is required is to connect each socket's negative pins together, and subsequent cell connectors in order. I have fitted 2 x 5 way, 2 x 4 way, 4 x 2 way and 6 x 3 way balance sockets as this suits my likely needs. It means that I can now charge up to 6 3s packs all together, and they all balance each other out during the process.... other combos as well of course as per the layout of the board above. ONLY charge multiple packs of the same cell count, and at roughly the same charge state together, and all will be well. It works a treat, and heres a few pictures to illustrate things. Any more info ? just shout! Quote Link to comment Share on other sites More sharing options...
Ben Mullins Posted December 13, 2008 Share Posted December 13, 2008 Cleverness and cunningness to the highest degree! I wont ever try something like that, I dont trust myself with one Lipo pack let alone however many u've got going at one time! but it sure does look good. How did you work this out, or did you get the idea from somewhere else? (or am i being a complete numpty?!) Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 14, 2008 Author Share Posted December 14, 2008 Pretty simple actually Ben. The connection layout of the veroboard just ensures that each little balance socket is connected in parallel to one another, and the main lead to the chargers balance unit is connected to the largest of these sockets ( in this version the top 5 pin one ). Heres a crude sketch of what I mean. It should be legible if clicked to full size. When each battery is plugged into the respective balance socket on the board, this also then configures each cell to "pair up" with the same cell in each additional battery plugged in. This pairing off via the balance plugs very effectively ensures each cell balances its partner. 2 x 3s batteries for instance would then be paralled up, but each of the 3 cells in each battery will also pair up ( again in parallel ) with its partner cell in the other battery. What you end up with is one larger 3s2P battery. Maybe this second picture will help. The individual cell taps are connected together by the sockets as mentioned above - this is represented by the semicircular dotted pencil lines in sketch two. By virtue of the fact that the two end taps are connected to the battery main terminals also, ensures the two batteries ( as a whole ) are also connected together in parallel, so therefore connecting the main charger output leads to ANY of the batteries main terminals will suffice. Charge current is fed to each battery via these balance tap leads, and as long as it does not exceed around 1 A or so, then all will be well. Higher charge currents just means connecting the battery main leads together also with a suitable parallel harness. The actual balancing currents passed by the balance wires is usually only a few hundrerd millivolts at max, so these wires ( and the veroboard strips ) would not normally carry large currents. I hope this makes sense Quote Link to comment Share on other sites More sharing options...
John Cole Posted December 16, 2008 Share Posted December 16, 2008 Where did you buy the "sockets"? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 16, 2008 Author Share Posted December 16, 2008 I didnt as such, they were desoldered from an old balance board that I already had. You could always buy such a board and do the same.Try TJD models, or motors and rotors to name but a few.here Quote Link to comment Share on other sites More sharing options...
John Cole Posted December 16, 2008 Share Posted December 16, 2008 Thanks. Quote Link to comment Share on other sites More sharing options...
Stephen Stokes Posted December 17, 2008 Share Posted December 17, 2008 Hi TimboFor the 6x3s packs pictured do you charge at 1C ie 1.25A and dose this still take an hour to balance all 6 packs? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 17, 2008 Author Share Posted December 17, 2008 Hi Stephen - no the correct 1C charge rate is whatever the sum of the packs under charge equals. So, for 3 X 1250 maH packs thats 3 x 1250 = 3750..or the closest to it - lower NOT higher. So in this case 3.5A.Assuming the packs did not realy need much balancing, then it will take 1 hour approximately - however how long it takes depends on 3 things....none of which I know in your particular case .1) The state of unbalance of the packs under charge 2) At what stage of the CCCV stage the balancer kicks in3) The bleed current of the balancer.My particualr balancer can be set to only start working when the packs are nearly full ( CV stage ) as this speeds things up alot. Balancing when the packs are empty / near empty is pretty futile. Quote Link to comment Share on other sites More sharing options...
philfly Posted January 14, 2009 Share Posted January 14, 2009 Timbo i dont seem to be able to see the pictures in your post? Quote Link to comment Share on other sites More sharing options...
John Cole Posted January 14, 2009 Share Posted January 14, 2009 I can see them OK. In My Forum, Forum Settings, for Forum Images I have Render Images selected (not Render as Link). Does that help? Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted February 4, 2009 Share Posted February 4, 2009 Ok Tim cracking Idea I currently charge my packs using an oldish Jammara "LIcharge 3" which limits me to 3s bty's. and a dual sky standalone balancer. so I can keep a track of how much a bty is taking I've wired an MPI dc watt meter between them. not a clear pic but I'm guessing you get the picture Now my question this charger / balncer combination charges through the balance leads only would your system work ok in this situation? the charger can only charge at a max of 2amps so I realise this would limit me to a couple of 1000mah bty's or things would take some time however all my air craft at present use either 620mah2s1p. or 1300mah3s1p or 1800mah3s1p btys the 1800's also get used in paralell to give me a 3600 bty and at 2amps this would take close to 2 hrs but I'm guessing quicker than charging each bty at 1.5amps individually Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted February 20, 2009 Share Posted February 20, 2009 A more simple question, can I charge two identical batteries using a 'Y' lead?, I use an Accucel 6 and usually buy my batteries in pairs, regards, Terry Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 20, 2009 Author Share Posted February 20, 2009 Hi Phil - sorry I missed this post until now Are you certain that the charger charges through the balance tap leads ? The reason I ask is that even 2A is a quite high current for the weedy leads and connector, and although I dont know this particular model, I can only see in the picture two main lead output sockets?? Anyway, the answer is still yes - you can parallel them up and charge together. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 20, 2009 Author Share Posted February 20, 2009 Terence. Lithium type? Yes. As with any parallel connecting of batteries, try to get them at roughly the same state of charge / discharge before coupling them. Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted February 21, 2009 Share Posted February 21, 2009 That was my thought also Tim but yes it only connects through the balance taps and seems to do a perfectly good job on the bty's I've got however have only used it up to 1.5 amps so far as my biggest bty at pres is only 1800mah Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 21, 2009 Author Share Posted February 21, 2009 I still dont get it - there appears to be only two main output jacks on the charger panel - where is the balance connector? Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted February 21, 2009 Share Posted February 21, 2009 the output jacks of the charger are connected to a "watt meter" (so I can record tot imput to keep an eye on bty performance) this is connected directly to an "inline balancer" the output terminal off which is the jst-xh port. suprisingly this unit never gets warm and it works fine with smaller btys (up to 2000mah) at <1c I must point out that wjhen I bought these Items they cost a good bit less than they doo now and the only leccy model I had was a twister bell 47 running 620/800mah 2s1p LiPo's now I'm totally leccy I really am looking for a more capable setup and your advice is being acted upon as we speak Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 21, 2009 Author Share Posted February 21, 2009 Ah ...so its the balancer that solely connects to the balance plug on the battery not the actual charger - sorry I was being thick In this case, to benefit form true cell equalising parallel charging then obviously you must connect all balance plugs together in paralle and in the correct sequence IYSWIM. Quote Link to comment Share on other sites More sharing options...
Guest Posted February 21, 2009 Share Posted February 21, 2009 ""ONLY charge multiple packs of the same cell count, and at roughly the same charge state together, and all will be well"" Timbo how close do you define "roughly the same charge state" ?? I am not familiar enough with lipos being connected in parallel but I would anticipate that with low internal resistance of these batteries, that connecting them together like this could result in heavy current flows as they balance between one another. Do you have a guideline to follow such as connect together when no more than 0.X volts apart thanks John Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 21, 2009 Author Share Posted February 21, 2009 Well the jury is still out on that one - some peeps dont worry up to around .5V difference, but the more cautious amongst us like to get 'em down to say 200 mv or so +/- Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted February 24, 2009 Share Posted February 24, 2009 Hi Tim, making up an actual charge lead for two 2S1P is no problem but how do I connect the two balance plugs? I will also be using two 2200 3S1P and charging them in parallel but have the same problem, I need an idiot proof lead for each that cant be short circuited, regards, Terry Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 24, 2009 Author Share Posted February 24, 2009 Well if you feel confident about soldering etc, then you couldmake one up, with either short patch leads with sockets on the one end, and a single plug on 'tother. I use old sockets of old balance boards., and bits of veroboard to hold em. Otherwise, check around for suitable leads from BRC and the like. If all else fails, let me know, and I will make one up for ya. Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted February 24, 2009 Share Posted February 24, 2009 Hi Tim, I have some replacement leads for two cell but these are plugs so doubt they are of use, I gather I need three cell plug and two cell sockets? may find some on eBay or mebe the great demi-god Maplin.. many thanks, Terry Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 24, 2009 Author Share Posted February 24, 2009 I doubt that Mpalins will have any - ebay more likely. Yes...2 x sockets and 1 x plug of the correct pin count for each pair of batteries you will be charging IYSWIM Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted February 25, 2009 Share Posted February 25, 2009 Hi Timbo, had a good hunt around but no joy, nothing at Maplins and nowt on eBay at present, what I want to do is charge my 7.4v packs in pairs and my 11.1v ditto. I have loads of Deans plugs and sockets and plenty of red JST(?) plugs and sockets to make charging leads but nothing for the balance side of things, quite willing to pay for the bits if you have any spares, regards, Terry Quote Link to comment Share on other sites More sharing options...
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