Crampster Posted April 20, 2009 Share Posted April 20, 2009 > I'm relatively new to electric flight so please bear with me.>> >> I run two packs of 25C 2100 3S1P in parallel (this provides perfect balance without having to add extra weight). I charge the packs with a Prolux Lipo balanced charger. I keep them connected in parallel when I charge the cells and up until now I charge each pack separately, however after charging just one pack and checking the other, I noticed that the ‘uncharged’ cell had achieved 80% charge rate. By charging the ‘uncharged’ pack the charge rate finished both packs went up to 95%. What’s going on? Should I disconnect the packs before charging? If it makes a difference I’m charging the cells at 500mA.>> > > Thanks in advance,>> > > Tony>> > Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 20, 2009 Share Posted April 20, 2009 I am confused. 1) I keep them connected in parallel when I charge the cells and up until now I charge each pack separately. Uh ?? 2) the ‘uncharged’ cell had achieved 80% charge rate. Cell ?? 3) they are 2100 mahr packs and I am charging them at 500m/a Why? Edited By Timbo - Moderator on 20/04/2009 22:46:46 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted April 21, 2009 Share Posted April 21, 2009 Hi Tony In you original post you refer to "cell" when I think you mean "battery". Each of your batteries contain 3 cells. I think I can explain what is going on. If you leave your batteries in parallel when charging then they will both get charged but remember only the one with the balancer plug connected will be properly balanced. You thus run the risk that you might damage one battery. For safety I would suggest that you charge your batteries completely independently. Charging at 500mA is well below the normal 1C rate (2.1A in your case) so it will take longer (and at lot longer if you leave the batteries in parallel!) I hope this helps Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 21, 2009 Share Posted April 21, 2009 In case you are still with us Tony, this might also help Quote Link to comment Share on other sites More sharing options...
Crampster Posted April 21, 2009 Author Share Posted April 21, 2009 Thanks guy's. >> Simon you were right. I did mean that I was charging the 'batteries' not the individual cells. Sorry - I did say I was new to this !>> >> I have read Tim's link and he seems to encourage charging the batteries whilst still connected together ? As long as its safe and doesnt effect the life of the batteries I would prefer to keep them linked together.>> Regarding charge rates, I assumed that the slower the charge the better it would be for the battery? It seems I'll have to do some more reading on this subject. > > Thanks again both of you.>> Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 21, 2009 Share Posted April 21, 2009 Well despite general opinion being that charging at slower rate is good for them, there seems no real proof or evidence that charging at less than 1C is particualarly beneficial - indeed some packs are now claiming charge rates as much as 2C or higher. Of course, one of the benefits of LiPo is the useful 1 hour charge time - in your case this would be 2.1A as Simon says ( per pack ) and in parallel it would be 4.2A. Please note that my piece about parallel charging does include the parallel connection in the correct sequence of the balance plugs also. Keeping the packs pretty much "permanently" connected in parallel with the balance plugs similarly wired is the best way to keep both packs and all cells well balanced. Edited By Timbo - Moderator on 21/04/2009 17:23:34 Quote Link to comment Share on other sites More sharing options...
Crampster Posted April 21, 2009 Author Share Posted April 21, 2009 Thanks Tim, my charger plugs into the balance battery plug only. If I keep both batteries connected will it pull too much of a load for the small balance wires and plugs? I have charged the batteries several times now and didnt notice anything getting hot. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 21, 2009 Share Posted April 21, 2009 I doubt your charger will charge at 4.2A through just the balance leads - these types of chargers are usually limited to slow charging or small capacity packs only....besides, unless you connect both sets of balance plug wires together ( in correct orientation ) only one pack will be balanced. Quote Link to comment Share on other sites More sharing options...
Ron van Sommeren Posted April 21, 2009 Share Posted April 21, 2009 Automatic wiring diagram 'generator': http://scriptasylum.com/rc_speed/_lipo.html http://scriptasylum.com/rc_speed/_wiring.html Vriendelijke groeten RonEdited By Ron van Sommeren on 21/04/2009 18:40:14 Quote Link to comment Share on other sites More sharing options...
Crampster Posted April 22, 2009 Author Share Posted April 22, 2009 Dat is erg handig, bedankt Ron Quote Link to comment Share on other sites More sharing options...
Ron van Sommeren Posted April 22, 2009 Share Posted April 22, 2009 Je bent welkom Quote Link to comment Share on other sites More sharing options...
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