Reasons for a battery not delivering its rated power/capacity are: 1. Charger used cuts off power too early, and also, doesn't "trickle" towards the end. 2. Current draw from the charger is too big, essentially a "rapid charge," which may shorten battery life significantly. 3. Climate too cold. Lithium batteries almost refuse to charge completely (some not even halfway) in such cold environments, leaving you with not enough usable charge. 4. Like number 3, in extreme cold conditions, Lithium batteries almost refuse to expend stored charge because the medium in which the charge is stored slows down the transfer of electrons. This is a known problem with Lithium batteries. 5. Faulty charging cable. Try replacing the cable and see if it helps. Fatter cables have less resistance in the wire, making charging more efficient. 6. Faulty charging circuit. Contact support.sjcamhd.com if you strongly feel this is the case.