Robert Parker Posted January 2 Share Posted January 2 Hi All, I have 5 "ZIPPY" LiFe RX batteries which do not want to charge, 2 of which have puffed up Due to life and events outside my control I was unable to build or fly at all last year and hopefully I will manage to get some flying done this year. I last put all of my batteries into storage mode last March, with the intension of repeating in September but this did not happen. I'm now going through all of my batteries and have managed to ressurect all but two of my NiMh batteries, LiPo's are good but all 5 of my LiFe RX batteries will not charge/ or increase their, their voltage is as follows:- Batt 1 6.556v c1 3.2v c2 3.2 puffed 2% Batt2 6.764v c1 3.4v c2 3.3v good 3% Batt3 6.606v c1 3.2v c2 3.3v lightly puffed 2% Batt4 6.714v c1 3.3v c2 3.3v good 3% Batt5 6.771v c1 3.3v c2 3.4 good 3% I have 3 good quality chargers and tried the batteries on all 3 chargers Any ideas are please, I just don't want to loose a plane for the sake of a faulty battery or just simply dispose of these at the local recycling centre and buy new. Regards Robert Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted January 2 Share Posted January 2 I accidentally flattened a couple of 3-cell LiFe packs that I use in transmitters. I got interrupted while I was working on a project and hadn't switched them off! D'oh! Both were somewhat puffed. One stayed that way, and one cell appeared to have completely died. After a few days, the other one seemed to revert to normal. The puffing subsided, and it took a full charge. Capacity checks have proven good, but at the moment I've restricted it to a "bench test" Tx rather than risk it in anything critical. To date, I've not had a LiFe fail due to lack of use. The two damaged above were as the result of my own carelessness. My experience indicates that they can recover. BUT: My advice would be to leave them a week or so, and then try again. They may magically recover, like one of mine appears to have done. However, I would advise against using them in anything critical. Perhaps keep them for bench testing and setting up. -- Pete 1 Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 2 Share Posted January 2 Have you tried a controlled discharge to see what their actual capacity is? I would discharge one fully and try several charge/discharge cycles to establish its condition. Quote Link to comment Share on other sites More sharing options...
Bruce Collinson Posted January 2 Share Posted January 2 Can you "fool" them by using an unregulated charge just to get some charge into them, to get them over the threshold where the LiFe charge programme thinks they are too low to be charged at all? I recall seeing some Yourtube videos using this to resuscitate NiMhs, but I wouldn't take my eyes off them. BTC Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 2 Share Posted January 2 They appear to have a reasonable charge level - discharge cut off is 2.5v for these and the nominal voltage is 3.3v - their full charge voltage is 3.6v which declines rapidly to near the nominal voltage, gradually reducing fairly linearly over the discharge to around 5-10% capacity where the voltage drops off rapidly. Quote Link to comment Share on other sites More sharing options...
Philip Lewis 3 Posted January 2 Share Posted January 2 Those voltages are pretty much fully charged voltages fot a LiFe pack, if you want to test them discharge them on a charger and see what comes out then charge them up again and check agoin what goes back in. Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted January 2 Author Share Posted January 2 Thanks for the replies. I'll try out your suggestions tomorrow, wife is getting fed up of hearing the "Bleeps" Regards Robert Quote Link to comment Share on other sites More sharing options...
Don Fry Posted January 2 Share Posted January 2 1 hour ago, Martin Harris - Moderator said: Have you tried a controlled discharge to see what their actual capacity is? I would discharge one fully and try several charge/discharge cycles to establish its condition. And give it a discharge of at least twice what you expect the plane to drain, and repeat thrice. The puffed stuff gets the bin. Plane, battery, what do you value. Quote Link to comment Share on other sites More sharing options...
MattyB Posted January 2 Share Posted January 2 The short answer to this is no - you can’t recover damage to an over discharged lithium pack (Lipo or LiFe). However, it may still be usable in a lower current draw usage afterwards for a reduced number of cycles. Personally speaking though I don’t like to take any chances with a pack that could fail n charge or discharge as a result of previous mistreatment, so I tend to just discharge em to <1V/cell, cut off the leads, twist em together and dispose at the recycling centre. Life’s too short for endangering your family and house with sketchy packs! 1 Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted January 3 Share Posted January 3 Not worth taking a chance with suspect batteries. They are often one of the least expensive components of a model, usually represent a single point of failure, yet many choose to take a punt on an iffy unit. Annoying when one has to throw out a seemingly good item or keep it for bench use only, but I personally would never take a chance for the sake of a few quid over the potential much greater loss of a model or worse. Bad enough with Nimh technology but lithium needs to be treated with far more caution. We spend a lot of time checking over our models for faults, testing radios and ages getting trimming and set up 'just so' - but the temptation to rely on an ages old battery or one showing signs of distress is still too much to resist for some flyers. 3 Quote Link to comment Share on other sites More sharing options...
Phil Green Posted January 3 Share Posted January 3 I've a huge collection of A123 LiFePo4 cells from a race bike project some 12 years ago, from experience once a cell has gone, its gone. It may appear to charge ok (though rather quickly) but will have a high ESR and much reduced capacity. There seems to be no recovery from this state, believe me I've tried 🙂 1 Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted January 3 Author Share Posted January 3 Thanks once again for your replies. I have tried discharging/charging and although the batteries are showing around the 1100mAh mark the % is still 3% on the three I tried, and as has been quite rightly pointed out above what do you value most, the house/planes always come first. Thanks for all of your advice Regards Robert Quote Link to comment Share on other sites More sharing options...
Dickw Posted January 3 Share Posted January 3 What are you measuring the "3%" with? Dick Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted January 3 Author Share Posted January 3 Hi Dick, I'm measuring with a battery capacity meter made by overlander Regards Robert Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted January 3 Share Posted January 3 What is the voltage per cell reading? That's the most important measurement. Quote Link to comment Share on other sites More sharing options...
RottenRow Posted January 3 Share Posted January 3 1 hour ago, Dickw said: What are you measuring the "3%" with? I was wondering the same thing when I read this yesterday. The 3% doesn't seem to tie in with the voltage readings. It looks like whatever is providing the 3% figure is perhaps assuming that the batteries are LiPos not LiFe. If it's one of those horrible little black 'battery capacity controllers' (as they are labelled) then they are meant for LiPos. And the cheapo ones are very inaccurate even then. Sadly that includes the ones sold by Overlander at the Nationals a few years back for example, where they had a bin full priced at a few £ each. All will be revealed no doubt. Brian. Quote Link to comment Share on other sites More sharing options...
Brian Cooper Posted January 3 Share Posted January 3 By all means play around with a dud battery to give it the "kiss of life" but don't rely on it afterwards. A replacement battery is going to cost considerably less than replacing a model. Have fun. 1 Quote Link to comment Share on other sites More sharing options...
RottenRow Posted January 3 Share Posted January 3 28 minutes ago, RottenRow said: If it's one of those horrible little black 'battery capacity controllers' (as they are labelled) then they are meant for LiPos. I forgot that these checkers have a button marked 'type'. After connecting to the battery to be tested, the 'type' button must be pressed once to change from LiPo to LiFe. This doesn't affect the voltage readings but changes the range of the percentage calculation to suit the lower voltage of LiFe cells. The left hand side of the display shows the battery type selected. If the button isn't pressed, the checker defaults to the LiPo range, which is probably what is happening here. Brian. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 3 Share Posted January 3 Absolutely consistent with the checker assuming LiPo - they are virtually flat at 3.3v If you’re repeatedly getting 1100mAh from an 1100 mAh pack then in all probability they’re OK - LiFe cells are pretty resilient. What discharge rate are you using? Quote Link to comment Share on other sites More sharing options...
Robert Parker Posted January 3 Author Share Posted January 3 Hi All, The charge rate was set at 0.7. Having finally checked over the batteries now that they have all completed the same cycle/discharging process there is only one battery has given me confidence to use in flight and with thanks to you Rotten Row for pointing out about the button, You tend to overlook these things especially when you have been away from the hobby for just over a year. I was indeed using the LiPo mode when recording the %ages. The battery I'm keeping in LiFe mode comes in at 98% whilst the others are below 50% Now, it's time to clear the building board and finish off a half built Ruhig Tiger 72 with IC motor. Regards Robert Quote Link to comment Share on other sites More sharing options...
Dickw Posted January 4 Share Posted January 4 16 hours ago, Robert Parker said: Hi Dick, I'm measuring with a battery capacity meter made by overlander Regards Robert Hi Robert I had to go out last night, so sorry about not following up on this. However, I think all the other follow on replies showed why I asked the question and have helped you move forward. Dick Quote Link to comment Share on other sites More sharing options...
Phil Green Posted January 4 Share Posted January 4 (edited) 17 hours ago, Martin Harris - Moderator said: If you’re repeatedly getting 1100mAh from an 1100 mAh pack then in all probability they’re OK This is key - no voltage tester will tell you if a cell has lost capacity, you really need to do a few measured discharge runs. Edit: Re my A123 cells, I just checked and it was 2007 - almost 17 years ago and most are still going strong! Edited January 4 by Phil Green Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted January 9 Share Posted January 9 Whatever your charger may tell you, you cannot put LiFe packs on a storage charge since the voltage will always be 3.3V/cell. I try to leave mine fully charged and have several Zippy packs which have seen no action for a few years. They now take 10mA/hr at the most and are good to go. I have managed to kill several by forgetting to disconnect them from Failover switches until it was too late. Once these are discharged to zero the only place is the bin. Quote Link to comment Share on other sites More sharing options...
Phil Green Posted January 10 Share Posted January 10 (edited) 23 hours ago, Martin McIntosh said: Whatever your charger may tell you, you cannot put LiFe packs on a storage charge since the voltage will always be 3.3V/cell. Your charger may not support it but of course you can and should long-term store LiFePo4s at their storage SoC (about 50-60%), an easy way is to do a measured discharge from 'full' with a 40% of capacity cut-off if your charger can do that, otherwise just do the sums and set a timer on your phone... :) Edited January 10 by Phil Green Quote Link to comment Share on other sites More sharing options...
Don Fry Posted January 10 Share Posted January 10 (edited) On 09/01/2024 at 16:05, Martin McIntosh said: Whatever your charger may tell you, you cannot put LiFe packs on a storage charge since the voltage will always be 3.3V/cell. I try to leave mine fully charged and have several Zippy packs which have seen no action for a few years. They now take 10mA/hr at the most and are good to go. I have managed to kill several by forgetting to disconnect them from Failover switches until it was too late. Once these are discharged to zero the only place is the bin. Martin, why can’t a charger put a life cell to storage. The cell voltage does drop across the normal discharge range of the cell, about 0.2 Volts across a cell between the start and end of the flat bidder bit of the curve, and that’s not an unmeasurable voltage. I’m curious rather than stating your wrong. I’ve also killed a few forgetting Failover switches are not on/off switches. Edited January 10 by Don Fry Quote Link to comment Share on other sites More sharing options...
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