let me change my statment on its junk. its the batt because i found out that if i fly my plane long enough with the tunder power 860 it will start to pulse but i have had a lot of troubl with my electrifly 720mAH i think that the little safe charge chip is not letting it charge correctly because i tryed charging it today and it would not register on the charger and yes i had it hooked to the charge lead but once it took it it charged for about 20 min and then i took my plane and ran it and sure enough it cut out i have never had it cut out with the thunder power as i orignaly stated sorry for bad mouthing Eflight becasuse after flying 4 packs through today it worked flawlesly!