mightypeesh Posted June 30, 2016 Share Posted June 30, 2016 Hi folks. I managed to very succesfully park a model at the top of a tree for a couple of weeks before it eventually came down thanks to the help of some club mates with very little damage - thanks chaps. It has an enloop rx pack that was obviously switched on this whole time so was rather on the dead side by the time I got it back. Just out of curiosity I popped it on a very low charge and to my suprise it is taking it no problems at all. My questions are, A; can I trust this pack now, and B; Is there an easy way of testing it with a small load? Cheers, Simon Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted June 30, 2016 Share Posted June 30, 2016 Has anyone at your club got a load tester Simon, to borrow, as they are quite common to put the 4.8v pack under test. You may well have got away without any damage, and cycling the pack can only help it. From the tree, it would have been helpful to see how much the pack took back in. Remember next time Quote Link to comment Share on other sites More sharing options...
John F Posted June 30, 2016 Share Posted June 30, 2016 Panasonic, the folk who make these batteries, simply state that you charge them up but cycle them to get them back up to capacity : **LINK** No mention of anything other than just to cycle them. Quote Link to comment Share on other sites More sharing options...
PatMc Posted June 30, 2016 Share Posted June 30, 2016 Cycle it 2 or 3 times with the discharge rate set at 200 - 300mA and a low cut off at 4v. Note what the discharge mAH is each time & decide whether it's worth using based on the results Quote Link to comment Share on other sites More sharing options...
Jon H Posted June 30, 2016 Share Posted June 30, 2016 I agree with Pat although i would do the first charge at the lowest current your charger can handle. You might even be able to use one of those old 70ma chargers that used to come with futaba radios back in the day. After a few hours with that proceed as Pat suggests but leave the battery a week or so before your final test cycle to see if it looses the plot during the week at full charge. Quote Link to comment Share on other sites More sharing options...
mightypeesh Posted June 30, 2016 Author Share Posted June 30, 2016 Hi folks, thanks for the info. I will cycle it a few times and use a club mates load tester to check it out. Cheers again, Simon Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted June 30, 2016 Share Posted June 30, 2016 I just made up a pack of these from Overlander bought at Wings and Wheels. Did my usual trick of discharging at 500mA then recharging at 100mA with an Overlander RC-6S. The initial discharge was as expected but the recharge refused to cut off even after 2900 mA/hr had been pumped in. The pack got quite warm. Subsequent cycling at 300 discharge and 400 charge produced not much better than a 1700 mA/hr recharge. This was a new one built for a buddy so I put another recently built for myself and known to be good through the same cycle. It produced similar results. Tried my other RC-6S charger on the original pack and it charged normally. I think that I shall have to give him my pack since I would not now trust his. Must be a suspect charger. Considering the cost of a new battery versus the rest of the model, the best thing to do with this is that if you are not completely satisfied after leaving the pack for a week or so then re checking the capacity is to junk it. Generally, LiFe packs will withstand being completely flattened but not NiMh`s. Quote Link to comment Share on other sites More sharing options...
ChrisB Posted June 30, 2016 Share Posted June 30, 2016 Futaba do a variable load tester which is very good! Quote Link to comment Share on other sites More sharing options...
cymaz Posted June 30, 2016 Share Posted June 30, 2016 For the cost of a pack, get a new one. Better safe than crash the model because the old battery died a death all of a sudden. Keep it though, very useful for a bench test etc. Quote Link to comment Share on other sites More sharing options...
MaxG Posted July 1, 2016 Share Posted July 1, 2016 I seem to remember that trying to charge these packs at very low currents means that the delta peak gets ignored. To get a more reliable delta peak detection you need to be charging at about 1C or more. If that is the case then that could be why it never finished charging in Martin's case. Perhaps the more knowledgeable would care to comment upon this? Maxg Quote Link to comment Share on other sites More sharing options...
Artto Ilmanen Posted July 1, 2016 Share Posted July 1, 2016 BePosted by Martin McIntosh on 30/06/2016 19:13:52: I just made up a pack of these from Overlander bought at Wings and Wheels. Did my usual trick of discharging at 500mA then recharging at 100mA with an Overlander RC-6S. The initial discharge was as expected but the recharge refused to cut off even after 2900 mA/hr had been pumped in. The pack got quite warm. Subsequent cycling at 300 discharge and 400 charge produced not much better than a 1700 mA/hr recharge. This was a new one built for a buddy so I put another recently built for myself and known to be good through the same cycle. It produced similar results. Tried my other RC-6S charger on the original pack and it charged normally. I think that I shall have to give him my pack since I would not now trust his. Must be a suspect charger. Considering the cost of a new battery versus the rest of the model, the best thing to do with this is that if you are not completely satisfied after leaving the pack for a week or so then re checking the capacity is to junk it. Generally, LiFe packs will withstand being completely flattened but not NiMh`s. In case NiMh (eneloop) pack is completely discharged you may need to start with very low charging current such as 0,1-0,2C. Once the pack is 1/2 capacity charged you can stop slow charging. At this point charge at 0,5-0,7 C to ensure the delta peak cut-off works properly. Once you complete the first charging from flat to full count how many Mah you were able to charge in total. Then let the pack wait maybe 15min or so and do a couple of discharging-charging cycles to see how the battery behaves. Discharge to about 0,9v per cell at min. 1Ah current to see wether the battery is able to maintain voltage above 1 volt per cell when loaded. If the battery maintains the voltage at 1+ volt when loaded then you can use the battery safely. Before going flying charge the battey by first discharging the battery to avoid being confused by faulty delta peak cut-off. Or, alternatively, pay attention on how much you typically charge to the pack after each flying session, typically somewhat 400-700Mah if your model is a 60 -size sport model. This trend should be consistent and if it changes, then, you probably should check or replace your battery. Rgds Artto Edited By Artto Ilmanen on 01/07/2016 13:26:31 Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted July 1, 2016 Share Posted July 1, 2016 I wandered a little off thread but some good points raised there, particularly regarding the non detection of a delta peak at low charge rates. Maybe the slightly different chemistry of the Eneloop 1900 Mignon cells has affected this as I have not had the problem with the 2000 ones. I suppose that the initial 2900 charge would not really have been much different to using a wall charger overnight which probably most i/c flyers would use. Incidentally, my own pack took a further 130 mA/hr using my other RC-6S. Quote Link to comment Share on other sites More sharing options...
Derek Stevenson Posted July 1, 2016 Share Posted July 1, 2016 I completely discharged an eneloop 4.8v pack, left the plane turned on in the shed by mistake. I recharged it at and it took a complete charge (think it was a 2400mA) and it performed as usual. Don't charge too low or ir won't read the peak, I normally charge at 0.4v. Hope it works for you. Quote Link to comment Share on other sites More sharing options...
Derek Stevenson Posted July 1, 2016 Share Posted July 1, 2016 I completely discharged an eneloop 4.8v pack, left the plane turned on in the shed by mistake. I recharged it at and it took a complete charge (think it was a 2400mA) and it performed as usual. Don't charge too low or ir won't read the peak, I normally charge at 0.4v. Hope it works for you. Quote Link to comment Share on other sites More sharing options...
Glyn R Posted July 1, 2016 Share Posted July 1, 2016 You are obviously in doubt or the question would not be asked. How will you feel next time you fly using this battery? Is it worth all the hassle for one Rx pack? Quote Link to comment Share on other sites More sharing options...
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