i know nothing and may be blowing smoke out of my you know what... but the oem batteries are not Li-Ion but are Li-Polymer see http://en.wikipedia.org/wiki/Lithium-polymer "When compared to the lithium-ion battery, Li-poly has a greater life cycle degradation rate. However, in recent years, manufacturers have been declaring upwards of 500 charge-discharge cycles before the capacity drops to 80%"