Most LIPO battery chargers wont charge when the battery get that low because it can blow up. It is a safty feature. On RC batteries I have known guys to use a NIMH or NICD battery charge mode on a LIPO battery in order to just make the charger charge since there is no low voltage safty feature for those types of batteries. It is kind of dangerous to do and I wouldnt recomend trying it in your house.