RC Helicopters 
Bad Battery !
1500mAh LiFe from HobbyKing
 photo IMGP0420_zps1902d2cf.jpg 

The other day I was out trimming a helicopter when my Tx voltage alarm went off . I was a little surprised as I checked the voltage and it was 9.3v and it should not have dropped from there so quickly .  I have the same battery in another transmitter and so have a little history with the battery . This battery had only been charged twice , so was practically new . On recharging , only some 250mAh went in and the charger said the battery was fully charged .

 Well , that was a serious warning sign , I discharged the battery @ one Amp to see what would happen ..  C2 or cell 2 was dropping voltage seriously . With the other two cells at 3.11v C2 was down to 2.5v and the charger was throwing up a Battery voltage error . 

 I did order a new battery pack for my Tx , just in case . The LIFE in question has been cycled several times over two days , 6 or 7 times now , and it looks like C2 may have come good [ looks like ] . Through out the continuous cycle of charging and discharging , capacity has increased and C2 has stabilized to the point of matching the other two cells in the pack .

 Currently I'm giving the battery a final charge , to see how much current goes in , and then I will test and see how the battery goes over the long term [ holds capacity ] . Its always a bit of a gamble with multi cell batteries , as one or two cells may not be as good as the other(s) .  Cycling a battery is a good way to condition and test a pack before trusting it . But with such a low Amp demand from a Tx , I was not expecting any issue from these batteries . Usually these things show up in high Amp situations [ battery pack for 450 helicopter ] where the batteries are put under much higher load [ strain ] , so this came as a bit of a nasty shock I can tell you . 
Battery = 1500mAh LiFe from Hobby King
Charger = Turnigy Accucell 8158
Charge rate = 500mAh
Discharge rate = 1A