Robert Alexander 1 Posted May 16, 2014 Share Posted May 16, 2014 Dear friends, I have bought a few Turnigy 3 Cell nano-tech 1800 mAh 25-50C discharge for my quadcopter back in February. Have not flown a lot with them since "real life" get in the way too often Maybe 10-15 cycles ? This is the batt: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11908 I have it hooked up to one of those inexpensive beepers set to sound if any cell drops <= 3.5 volts. In the last two flights I promptly landed upon the ear-piercing shriek began and after landing gave it time to show the voltages and I glimpsed the first one being 3.6 but the second one with a wildly flashing 2.7 or something similarly abismally low, third 3.6 again. Immediately disconnected even the measuring thingy. Now at home I have an old but trusted analog meter and on the first two leads I measure something around 3.6 and when I move to the second positive lead on the balancing connector get around 6.9, the third positive sends the dial off the 10V range. As I said before this is the second flight with this behaviour. This flight seemed of a normal length (approx 10-12 mins) of light beginner style almost hovering only flight in various directions (I'm in the phase in which I'm trying to learn one direction at a time now that the "aligned with my head" phase has been decently conquered). Should I worry or is it only a "bug" in the small buzzer ? Thanks ! Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 16, 2014 Share Posted May 16, 2014 I only have experience of one of these but it died very quickly - loss of capacity and voltage drop on load - after being subjected to exactly the same charging and flying regime as my Hobbystores supplied Dynamic packs which cost less with (I have to assume) legitimate taxes and duties having been paid at source. I have seen it claimed that there are different quality Nano-Tech packs available. Quote Link to comment Share on other sites More sharing options...
malcolm woodcock 1 Posted May 16, 2014 Share Posted May 16, 2014 I have a battery checker, a watt meter (with battery checker incorporated) and three different chargers, they all give different reading for the battery. I think it's the price we must pay, poorly calibrated instruments, for cheaply made equipment. Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 16, 2014 Author Share Posted May 16, 2014 Sigh ! Can anyone suggest better 3S 1800-2200 25-50C LiPos with XT60 connectors possibly that I can buy online here in Europe ? Thank you Quote Link to comment Share on other sites More sharing options...
ben goodfellow 1 Posted May 16, 2014 Share Posted May 16, 2014 ive had a few of the nano techs go bad and not seem to hold there charge to well. the normal turnigys though seem to be quite good as do zippys . giant sharks gens ace and loong maxs are quite good too... fly low Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted May 16, 2014 Share Posted May 16, 2014 I also do NOT rate the nano techs. Had some puff and overheat during a mere 30C discharge, so I will not be buying anymore. The "A" grade versions are apparantly good, but these days, I am using, happily, Zippy Quote Link to comment Share on other sites More sharing options...
Barryorbik Posted May 16, 2014 Share Posted May 16, 2014 Haiyin Lipo's (from Electriflyer) are fast becoming the favorites at our club as they perform well above their claimed C ratings and last well. The individual cells are selected for ESR and capacity etc before being assembled into packs, so the costs are a little higher than nano techs but you only buy them once, so though life costs are much lower. Barry Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 17, 2014 Author Share Posted May 17, 2014 Aaaargh, Electriflyer cannot ship the LiPos out of the UK Sigh sob. Probably will try Zippy's then (need to find them shippable here to Italy). Thanks a lot Quote Link to comment Share on other sites More sharing options...
Steve Colman Posted May 17, 2014 Share Posted May 17, 2014 A couple of guys at the club used to use these but no more for the reasons described earlier. I think they are way overrated. I've generally used standard Turnigy packs which have performed adequately for my needs over the past couple of seasons. I recently bought a couple of Zippy compact lipos which have been excellent so far. So pleased am I with them, I'm going to order some more. Quote Link to comment Share on other sites More sharing options...
FlyinBrian Posted May 17, 2014 Share Posted May 17, 2014 Posted by Barryorbik on 16/05/2014 22:00:20: Haiyin Lipo's (from Electriflyer) are fast becoming the favorites at our club as they perform well above their claimed C ratings and last well. The individual cells are selected for ESR and capacity etc before being assembled into packs, so the costs are a little higher than nano techs but you only buy them once, so though life costs are much lower. Barry Ditto from me on the Haylin packs, I bought two a couple of months ago and after about fifty flights they are excellent especially for the price. Brian Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 18, 2014 Author Share Posted May 18, 2014 Thanks. Found some Haiyin on Ebay from Germany. Will try a couple of 3S 2200's. Cross fingers Advice for a decent charger/balancer that would not break my bank ? Quote Link to comment Share on other sites More sharing options...
Robert Putley 1 Posted May 18, 2014 Share Posted May 18, 2014 Hello Robert, As I live in Germany these days. I am very interested in Haiyin Lipos, because I also have mixed results with nano tech batteries. Would you have the Email address for this ebay website please? Many thanks. Robert. Quote Link to comment Share on other sites More sharing options...
David... Posted May 18, 2014 Share Posted May 18, 2014 I use the HK a Turnigy batteries and have not experienced any issues. An observation is the lowest cell voltage for a LiPo before damage occurs is 3.6 volts, so if you have your voltage monitor set below this value expect very short life from your battery. Plus when they reach 3.5 volts they are all but empty and your flight duration post this voltage will be a few seconds, so not good practice. I suggest you check your meter against another to see if it's relative accuracy is OK. Are the batteries puffed? Edited By David... on 18/05/2014 08:10:18 Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 18, 2014 Author Share Posted May 18, 2014 Hi Robert (yourself), you're welcome. Here's the ebay page on which I've ordered them. Cannot vouch for transit time / goods quality since it's the first time I order from them but their feedbacks are good. http://www.ebay.it/itm/151126740862?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 Take care Robert (myself) Posted by Robert Putley 1 on 18/05/2014 07:35:38: Hello Robert, As I live in Germany these days. I am very interested in Haiyin Lipos, because I also have mixed results with nano tech batteries. Would you have the Email address for this ebay website please? Many thanks. Robert. Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 18, 2014 Author Share Posted May 18, 2014 Hi David, thanks for your post. No the batteries are not puffed. I was under the impression that the "damage threshold" was around 3.3, not 3.6. So you suggest setting the alarm at 3.6 right ? (hoping the meter is decently accurate). Ciao Posted by David... on 18/05/2014 08:07:30: I use the HK a Turnigy batteries and have not experienced any issues. An observation is the lowest cell voltage for a LiPo before damage occurs is 3.6 volts, so if you have your voltage monitor set below this value expect very short life from your battery. Plus when they reach 3.5 volts they are all but empty and your flight duration post this voltage will be a few seconds, so not good practice. I suggest you check your meter against another to see if it's relative accuracy is OK. Are the batteries puffed? Edited By David... on 18/05/2014 08:10:18 Quote Link to comment Share on other sites More sharing options...
Robert Putley 1 Posted May 18, 2014 Share Posted May 18, 2014 Hi again Robert, Thank you so much for that. Very much appreciated. The other Robert ! Quote Link to comment Share on other sites More sharing options...
David... Posted May 19, 2014 Share Posted May 19, 2014 Yes, minimum for a 3S pack is about 10.6 volts (3.6 per cell), at which point there is generally about 10-20% capacity left, flight wise that is bad news with about 30-secs of flight left for most craft. Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 19, 2014 Author Share Posted May 19, 2014 Thanks David, there's something I don't understand. If 10% of the capacity equals 30 seconds, wouldn't 100% give 300 seconds (5 minutes) ? Empirically I know my quad flies without visible problems almost 15 mins. Is this because of the capacity drain not being linear ? Take care PS Robert you are very welcome Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 19, 2014 Share Posted May 19, 2014 The problem is that the cells in a battery may not degrade uniformly. As a cell degrades its internal resistance rises. This means that when passing 'flight' current although the battery voltage may still be 10.6V in fact one cell is below 3.6 whilst the others are still above. I monitor the individual cell voltages particularly during the first few seconds of the charge to check for any difference. Ideally there should be no more than 1/100 of a volt between them. If the difference is say 0.5V at this point then its a sure sign one cell is weak. Do remember this difference will only really show at the start of the charge. By the end of a balance charge the voltages will be equal (this is what a balance charge is supposed to do) but a weak cell will still drop its voltage faster during discharge and if it is worked as hard as the 'good' cells in the battery it will degrade still further. Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted May 19, 2014 Share Posted May 19, 2014 Posted by Robert Alexander 1 on 18/05/2014 06:56:27: Thanks. Found some Haiyin on Ebay from Germany. Will try a couple of 3S 2200's. Cross fingers Advice for a decent charger/balancer that would not break my bank ? Regarding the turnigy nano tech cells I too have had low usage cells puff while in storage those Haiyin cels I replaced them with are out performing even my Gens ace ones so far. Regarding a recomendation for a charger I've had one of these GT-A-6-19, 200W for some years now and for the price they're a good piece of kit, just one word of warning don't expect to get the full 10A charge rate when charging 5 and 6s LiPo's you will just get a temp warning after a few seconds as the charger hates having to work that hard to boost the 12v input volts to match the requirements of an 18 to 22v LiPo, otherwise they're a great piece of kit. Yes GC have them as special order which in "my time media" speak seems to mean not getting any more but other suppliers should have them and any similar spec'd unit should perform the same always go for the highest powered unit you can afford as it will mean less chance of needing an upgrade in the future Phil Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 19, 2014 Author Share Posted May 19, 2014 Thanks everyone. As usual I'm learning a lot by reading your comments. Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted May 20, 2014 Share Posted May 20, 2014 Hi -- Today I have been flying with my 2200 3S cells not over powering them and after a normal flight guess what 2 packs swelling, strange as these have not given any problem before. Upon closer inspection I came to the conclusion they are not swollen batteries but the heat shrink is so close that its just air pockets created by the heat. Back at home and checking the batteries they have cooled right down and normal shape ?? Quote Link to comment Share on other sites More sharing options...
Robert Alexander 1 Posted May 20, 2014 Author Share Posted May 20, 2014 Hi there, are you talking about the same brand/model of batteries ? I apologize but am not sure I understand what you write since for what I have read I believe the swelling is always caused by gas production and not the swelling of "air inside" ... Take care Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted May 20, 2014 Share Posted May 20, 2014 Hello Richard yes I was commenting on my Turnigy Nanotech 20/50C rating Quote Link to comment Share on other sites More sharing options...
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