winston07

Hey sal I bought this new Li-Po and I have put about the 10th charge on it with the Electrifly polycharge, I charged it at 1000 mah until the charger said it was fully charged. Ok so I go out to fly, flys great for about 20 sec then battery dies dramatically, just cant figure what is wrong with it, I even charged it at 250mah until the charger said it was full, same problem when flying. The battery is a 3 cell 11.1v 1500mah li-po running on a c-35 mini esc powering a 380 geared prop. thanks

salnsp

if the battery is a new Electrifly battery the bext you can expect for output is 15C (actually I think that 12 C is what you will get) This means that you can expect to get an output of approximately 20 amps. If the motor is a speed 400 sized (please let me know what motor you are using specifically) it might demand more amps. Is the battery getting hot?

Another possibility is cold. Flying in temperatures below or close to freezing will sap a li-poly battery very quickly.

With that said, if you are keeping within the battery parameters, you either have a bad battery (Li-Pos will keep voltage but not have any capacity), or a bad charger. Testing the charger is easy. simply find out if it is charging another battery properly. If your charger has a good display it may show you what amount of charge you are putting into the battery. If the battery is falling off, then the charger should put in at least 1200-1500 mah. Let us know what you find.

winston07

sal I have the stock setup for the Great Planes flight flex Yak 55. It has a T-370 size ball bearing motor by Great Planes. It has a 5:1 gearbox also. The battery does not get hot, just slighty warm like usual. Yes I did fly it with snow on the ground still, maybe that affected it. The charger is great brand new and I charged a diffrent battery same kind and it works great in the Yak. Im just bummed out that i lost 40$ on a dumb mistake i did, flyin in the cold. Is there any way I could rejuvinate it back to life? Heres the link for the Yak 55 at Towerhobbies.com thanks again.

http://www2.towerhobbies.com/cgi-bin...&I=LXKVY7&P=ML

salnsp

If the battery went to full discharge of below 2.8 volts per cell there is likely damage to the battery. I would charge it again, slowly discharge and try to use if again. generally, the cold does not damage the battery so much as reduce its usable capacity. The battery used in a warmer enviorment should work fine assuming it has not been damaged by very low discharge.

Take my word for it. I live in Vermont and have lots of experience with flying in cold weather.

Semi Retired Aviator

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salnsp

How did you make out with the batteries?