Garry Pollard Posted May 23, 2009 Share Posted May 23, 2009 Hi Lads Can I ask for a bit of help?. I have two identical lipos Dualsky 3300 mah 14.8 v 22c. Used them both today but when I recharge the firdt one it shows charger recognises it is a 4 cell lipo and all is well. The second one the charger reads it as a 3 cell battery when it knows it should be a 4. I have a small tester and when plugged into the balance plug it shows the following No 1 3.16 No 2 3.09 No 3 3 39 No 4 3.37 All 13.0 There seems an large variation between 1 and 2 and 3 and 4. I obviously will not charge it until it registers 4 cell. Anybody help please Garry Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 23, 2009 Share Posted May 23, 2009 Garry Buy an engine ! You dont have to keep buying the latest "whatever"to so-called get best performance for this months charger /discharger/ loads of props/ things that match perfectly for a super efficient 8 minute flight . ic's have been around for years & are reliable but you must enjoy the smell of fuel ! Better than those horrid electric type smells you used to get with transformers etc in my day Grumpy(Probably off thread )But you can tell I'm not biased Hope polypropermod is not reading Quote Link to comment Share on other sites More sharing options...
Garry Pollard Posted May 23, 2009 Author Share Posted May 23, 2009 Myron Been there done that a long time ago, had a lay off for 15 yrs came back two years ago and am sorry you can have the ic engines ill stick to nice clean electric, they dont drip on the carpet in my warm safe spare wardrobe, now who is sad Garry Quote Link to comment Share on other sites More sharing options...
birdy Posted May 23, 2009 Share Posted May 23, 2009 Have you tried wiggling the balence plug about? Usually works when my charger is fanticising about 11.1volt 1cell lipos! Quote Link to comment Share on other sites More sharing options...
Doug Ireland Posted May 23, 2009 Share Posted May 23, 2009 Bin it! Sure as hell it will bite you when you try to charge it and burn your house down! Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted May 23, 2009 Share Posted May 23, 2009 Garry, beware of the small testers, I've got a cheap one and while it's a good indicator of the overall battery voltage mine is not accurate enough to give an accurate reading of each cell, when I've checked with a Digital Volt meter the individual cell voltages have been a lot closer than the simple battery checker showed. Having said that if the above are the offload voltages, you have allowed the battery to discharge to a very low level and maybe your charger does not like the low battery volts so thinks it's a 3 cell battery. To get the charger to recognise it you need to get the pack voltage up a bit, you could trying to charge it as a 3 cell and this might get some charge back into it which would then allow you to switch the charger off and then back on and the charger then might recognise it as a 4 cell battery. If your charger has a LiFe setting you could try this as LiFe batteries are a slightly lower voltage, the charger will then charge the battery upto a higher voltage (it will be like partially charging the pack), once there the charger will then recognise it as a 4s lipo and you can go back to the normal setting. If you don't have a LIfe setting the other alternative would be to change the charger to a Nimh or Nicd type battery, set a low current say 0.3A and put a bit of charge into it for a few mins (watching it closely to make sure the overall pack voltage does not go above say 15v), this will get some charge back into the battery you can then switch back to Lipo setting and it should recognise it as a 4 cell battery. It happened once to me with a 3s I let the battery run right the way down to the LVC on the ESC and the charger refused to put it on charge I ran it for 5-10 mins as a Nicd at 1/10c and then put it back as a Lipo and the charger then worked OK. DO NOT LEAVE THE BATTERY UNATTENDED IF YOU TRY THIS and next time set your timer for a few mins less so you don't run the battery this low again. Edited By Frank Skilbeck on 23/05/2009 22:30:29 Quote Link to comment Share on other sites More sharing options...
260 Flyer Posted May 23, 2009 Share Posted May 23, 2009 Gary Cell detection problems are common in over-discharged packs such as yours. At 3.09V you are only a gnat’s appendage away from cell death! Do a manual charge to about 15V at 0.5C without using the balance function and then balance charge from there. Quote Link to comment Share on other sites More sharing options...
Garry Pollard Posted May 23, 2009 Author Share Posted May 23, 2009 Thanks Birdy Unfortunatly have done that Thanks Garry Quote Link to comment Share on other sites More sharing options...
Garry Pollard Posted May 23, 2009 Author Share Posted May 23, 2009 Thanks Frank and Rob Stuck it on at 15 v 0.5 amp for 5 mins watching it then went to balance charge and it recognised it as a 4 cell. All cells are showing 3.53 now. Will take a slapped wrist for this one as I always use the timer but had been doing more full throttle than normal and she went dead stick. Will certainly watch out for this in future Thanks again lads Garry Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted May 24, 2009 Share Posted May 24, 2009 hello garry-that bat sound's dodgy-put it in a box and send it up here asap-that'll save you the worrry.......................s ken anderson...bat doc anon................ Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted May 24, 2009 Share Posted May 24, 2009 It all depends on the ESC Low Voltage Cut off point and the battery charger being used, I accidentally ran one of my 4s 3200 mah (Zippy) cells to the LVC yesterday but fortunately the charger (Turnigy) didn't object and I charged it OK, put back in 3150 mah Quote Link to comment Share on other sites More sharing options...
Garry Pollard Posted May 24, 2009 Author Share Posted May 24, 2009 Thanks for all the help lads, glad to say all cells are back to 4.20. Should I still send it to you Ken as I dont want to cause myself un nessary worry, perhaps you can advise lol Another point has come to mind, when I am charging sometimes the charger flashes "Full" other times it never does . On these occasions the voltage shown is 16.80 and all cells show 4.19. They have never been cycled as the charger does not have the facility. It is a 1sthobby H1300 power charger 5 Thanks Garry Quote Link to comment Share on other sites More sharing options...
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