Hi i have an esky dauphin heli which takes a 2 Cell Lithium Battery 800mAh 7.4v

Anyway with exams recently and what not i used the heli, then for some reason did not charge it up before doing nothing with it for a month..

The guy in the shop originaly (when i purchased) said that these batteries don't like to be run too low, and when you feel the heli losing power you need to land it and charge, DONT RUN IT FLAT. now it appears not to be charging at all. would that happen? while left for a month all power drains out of it and it is effectively dead?

when i say appears not to be charging, there is the red light on the charger indicating power, but no flashing green light to indicate charge.

Ive never heard of a battery doing this but happy to be put right, if so i will purchase another.

Thanks for help!

Yeah, when a LiPo discharges beyond a certain point, it will no longer take a charge. Batteries will self discharge over time, and NiMh and LiPo are supposed to charged before putting them away. NiCad is the only one you discharge before putting away because they develop "cell memory". If it is left at a full charge, eventually, for lack of a better way to put it, the discharged level will move up the scale toward the charged level and the overall capacity is greatly reduced. Best thing to do is get a new one, and maybe look into a voltage level alarm. It will warn you with a light, an audible sound, or by just shutting the heli down when the battery reaches a certain voltage level.