Blue Max Posted July 13, 2011 Share Posted July 13, 2011 First of all, my apologies for what seems to be a basic question but I have two Overlander Lipos, a 2700 Extreme and a 2500 Sport, I used these earlier in the year and used a Elysium Charger to charge them, using a 2700 charge for the 2700 Extreme and a 2500 charge setting for the 2500 Sport. Having not used the Lipos for a few months I charged them and flew both batteries, taking them out of the model after the flight I noticed that the 2700 was swollen, later I noticed that the 2500 was also swollen. I was told by a club member that I should not use them anymore and to safely dispose of them. My question is why did they swell ? I am new to electric and my knowledge of Lipos is very limited. Do I hve to dis charge the Lipos, if so what frequency ? Is there any special charge / dis charge requirements for storage of the Lipos ? Any assistance in this issue would be appreciated Thank you Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 13, 2011 Share Posted July 13, 2011 Well forstly, there is a ton of info on the use of lipos HERE, and plenty of other threads too.It depends on how badly they are swollen TBH - if its only slight puffing of the outer pouch, I wouldnt worry too much, and wpould continue using them.Why have they puffed? Probably got a bit hot, either through over discharging them, excessive current draw, or ambient high temp...maybe all three?I had a previyuosly fine almost new pack swell abit on me the other day after heavy use in an EDF Edited By Tim Mackey - Administrator on 13/07/2011 16:43:59 Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 13, 2011 Share Posted July 13, 2011 Hi Blue.....they swell because gas has been discharged within the foil pouch..... This happened to me recently when a LiPo I hadn't used over winter went onto the charger to be topped up (from a storage charge of 11.4volts) & puffed up. It was a pretty new pack too... Good practice suggests storing your LiPos at 11.4volts or about 1/2 charged...most decent chargers have a "Storage" program. It is not generally thought necessary to cycle Lipos like we ued to with Nicd/NiMH batteries.... I don't have any evidence to support this but I think it pays to be doubly careful when charging a LiPo that has been unused for some time....a balance charge at 1/2C might be the correct way but I'm not sure.... I think Tim is on duty today so I'm sure he'll be along with words of wisdom & vast experience soon.... There is info on disposing of LiPos on the BMFA website here I would get a second opinion before disposing of them though.... Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 13, 2011 Share Posted July 13, 2011 Curses Tim got there first... Quote Link to comment Share on other sites More sharing options...
Blue Max Posted July 13, 2011 Author Share Posted July 13, 2011 Thank you for your advise, it is appreciated and I am looking to learn Very positive Blue Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted July 13, 2011 Share Posted July 13, 2011 Just a word of caution - Steve has reasonably assumed a 3 cell pack but the storage voltage should be specified per cell - so the figure might be better quotes as 3.8 V PER CELL i.e. the pack voltage for a 2 celll pack would be 7.6V based on that figure but it's best to do it on a balance charger that will discharge each cell to the set voltage. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 13, 2011 Share Posted July 13, 2011 Good point Martin.......I'm very much a 3S man & this clouds my thinking.... Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 13, 2011 Share Posted July 13, 2011 Posted by Tim Mackey - Administrator on 13/07/2011 15:41:51: Well forstly, there is a ton of info on the use of lipos HERE, and plenty of other threads too. It depends on how badly they are swollen TBH - if its only slight puffing of the outer pouch, I wouldnt worry too much, and wpould continue using them. Why have they puffed? Probably got a bit hot, either through over discharging them, excessive current draw, or ambient high temp...maybe all three? I had a previyuosly fine almost new pack swell abit on me the other day after heavy use in an EDF Edited By Tim Mackey - Administrator on 13/07/2011 16:43:59 What's "forstly"???? PS Blue Max; love the name PPS Loved the film too PPPS Ursula Andress; now you're talking..... Quote Link to comment Share on other sites More sharing options...
Brian Lambert Posted July 13, 2011 Share Posted July 13, 2011 Hi spicy one, that Tim gave rc mad Tom such a hard time about his use of English too.And now in one post we have wpould, abit, and its to add to your catch of forstly.Ah well perhaps we should keep quiet, he is a mod' you know. Quote Link to comment Share on other sites More sharing options...
Brian Lambert Posted July 13, 2011 Share Posted July 13, 2011 I am not sure how but I missed previyuosly.Must go to Specsavers. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 13, 2011 Share Posted July 13, 2011 If I was the devious sort ( oy! ), I could have simply used my unlimited superpowers and edited them all.... I'm on your case now Lambert Quote Link to comment Share on other sites More sharing options...
Brian Lambert Posted July 13, 2011 Share Posted July 13, 2011 Tim, where is the knees shaking smiley when you need it? And thats Mr Lambert to you! Quote Link to comment Share on other sites More sharing options...
Doug Ireland Posted July 13, 2011 Share Posted July 13, 2011 Throw those nasty, dangerous, non-environmentally-friendly Lithium things in the bin and buy an ENGINE! Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 13, 2011 Share Posted July 13, 2011 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 14, 2011 Share Posted July 14, 2011 Posted by Brian Lambert on 13/07/2011 22:38:08:Tim, where is the knees shaking smiley when you need it? And thats Mr Lambert to you! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 14, 2011 Share Posted July 14, 2011 Posted by Doug Ireland on 13/07/2011 22:44:30:Throw those nasty, dangerous, non-environmentally-friendly Lithium things in the bin and buy an ENGINE! Actually Doug, they ARE environmentally friendly Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 16, 2011 Share Posted July 16, 2011 Posted by Brian Lambert on 13/07/2011 21:31:44: Hi spicy one, that Tim gave rc mad Tom such a hard time about his use of English too. And now in one post we have wpould, abit, and its to add to your catch of forstly. Ah well perhaps we should keep quiet, he is a mod' you know. Not so much the 'mod' bit I'm concerned about. I think he may know where I live.... Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted July 17, 2011 Share Posted July 17, 2011 Blue MaxDid all the cells in the pack puff up?If so then somewhere along the line the whole pack was over stressed.If only one cell puffed then you may not have done anything wrong, its just that one cell was a bit weaker in some way than the others. The cheap packs appear to be a bit more prone to this fault than the 'quality' ones. If you do continue to use the pack there is a danger that the weak cell will continue to deteriorate, loose capacity, get over discharged in use and that's when LiPos can get nasty. Whilst it is technically possible to rebuild a pack from the good cells out of identical failed packs it can be a rather dangerous operation (an accidental short circuit can cause a LiPo fire and you don't want that!) and is certainly not recommended.Edited By Simon Chaddock on 17/07/2011 17:04:57 Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 17, 2011 Share Posted July 17, 2011 For my own info, if they are puffed, are they U/S??? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 17, 2011 Share Posted July 17, 2011 Maybe- maybe not ....depends how puffed. Quote Link to comment Share on other sites More sharing options...
Roger in Dubai Posted July 19, 2011 Share Posted July 19, 2011 I have a reasonably new 3S pack that I unfortunately left in the sun (it wasn't in the sun when I put it in the boot of the car but the sun has a habit of moving around !!). When I returned the pack was "blown". Still works OK but always aware that when the flight is finished I now put any pack in a cool bag complete with ice blocks that normally keeps the water cool in there. Of course with ambient temps of 45 or thereabouts in the shade and direct sun temps well into the 50's it was a mistake that I now curse each time I see the pack. Live and learn as they say !! Quote Link to comment Share on other sites More sharing options...
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