Check on RCGroups or google for "RC lipo fire". Lipo fire in RC world is extremely well documented, and arguably by three major causes: 1. Damaged batteries start fire arbitrarily. This is by large the most frequent cause I've seen and actually experienced myself: RC toys put a = lot of stress in batteries through vibration, large G values and small/large crashes. Some pilots think that if a Lipo survived a crash, it has to be ok. However, in many cases the internals of the lipo started an slow but certain degradation that eventually ignites a fire. 2. Low quality batteries. There are many brands of lipos that are produced for RC only and has limited quality control. They are overrated= on Cs for charge/discharge as well as not very safely manufactured. I've se= en batteries rated for 5C that have loose soldering in the balancing connectors, calling for a short anytime. 3. All RC lipos are unprotected and you certainly want that way. A typical F5B category plane can get burst of 200A for a few seconds out o= f a 4S lipo, there is no protection circuit for that and you do not want the extra weight and consumption the protection circuit will add. Many plane= s and xxxcopters of any kind will take 5-15A only, but same rule applies: = you do not want any extra weight on your flying thing. So this is safe as lo= ng as you know what you are doing, but many don't. Some pilots will not eve= n program the ESC to stop the toy from discharging below 3V/cell, so you a= re calling for problems anytime. Cheers, Ariel Rocholl On Fri, Jan 24, 2014 at 12:22 PM, wrote: > > > > > > Interestingly airlines are happier with lithium batteries inside > > > equipment than with batteries packed seperately. Presumablly because > > > there is less risk of getting a large concentration of batteries > > > stacked together that way. > > > > > > > Also less chance of the batteries being shorted - otherwise with pretty > much > > any battery I've come across you have exposed terminals. I'm still > wondering > > what actually resulted in the LiPo causing that (if indeed it > > did) as I understood the danger is in charging or shorting out a > battery, which > > doesn't seem all that likely with a battery installed in a RC model - > the only > > high current pathway even if stuff malfunctions should be via the motor= , > > which would limit the peak current (any other pathway should be via thi= n > > traces which would act as fuses - they certainly do in my personal > > experience!) Don't see why it should be an issue leaving batteries > installed in > > things. > > I wouldn't be surprised at something like this happening with an > installed battery, especially if the battery has no short circuit > protection circuitry inside it. > > Consider the emergency beacon that caught fire in a Boeing Dreamliner > while it was sitting on the tarmac at Heathrow Airport in London. My pick > for the cause of the fire is a tantalum or ceramic capacitor going short > circuit, a well-known failure mode for both classes of component, and I > have had multiple examples of it happening within my experience. My pick > would be that this is what happened in this toy, causing the battery to > catch fire. > > These days you can get tantalum capacitors with a built in fuse for use i= n > critical positions, see the Kemet 04053/T496 series ... > > > http://www.kemet.com/kemet/web/homepage/kechome.nsf/file/KEM_T2010_T496.p= df/$file/KEM_T2010_T496.pdf > > I believe Tantalum-Polymer versions mitigate against the short circuit > failure mode, but that still leaves ceramic capacitors as a weak point .= ... > > > -- > Scanned by iCritical. > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .