Other conditions apply to life of battery, like chemical used for battery and if it is designed for deep cycles. If using a Nicd battery, these batteries need to be cycled (charged and discharged) occasionally to keep them from obtaining a memory. Memory is if you discharge battery 25% each use and recharge, the battery will get conditioned to this cycle. Nimh and Li-po are not supposed to obtain a memory. With a battery designed for deep cycles, I can probably get 75+ recharges at 90% or greater discharge. Also make sure your charger matches your battery type. A slow charge (saturate) gives longer run time, a fast charge produces more voltage (power) but less runtime. Also a fast charge and discharge produces heat, which lowers battery life. OK DC 101 is over! Any questions?