Rodney has it right you charge at 1 C not .1C. I find it does best if a bit below 1C and always use the balance connectors. I use both the ICE and the FMA 10S. Depends on which pack has which node connector. Both chargers show the amount of voltage in each cell during and at end of charge. Considering the value of the aircraft and its equipment it's false economy to not use good chargers. As well as use them properly. Extra fast charges may be fine for cars but not for aircraft. Better to bring extra packs then to field charge.