In this Airsoft GI Uncut episode, they talk about the Li-On batteries from Titan Power and how they last longer making them a good choice for AEGs... "Titan Power batteries are a newcomer to the airsoft battery market by being the first to introduce Lithium Ion batteries to the airsoft market. These batteries are, by mAh rating, smaller than standard LiPO battery packs. The Lithium Ion packs are much more durable than standard LiPO packs, and only risk being hazardous when excessively discharged. The C-rating on these batteries is comparable to standard LiPO batteries, as well as having a slightly better resistance to self-discharging over time. Further, Titan lithium ion battery has about 3x energy than a NiMH battery. There is no memory so the battery can be charged from empty to full without damaging the battery. This pack can be charged over 300 times and still have about 80% of its original capacity. Additionally, the battery can hold its charge for months and still be ready to use. Simply charge this battery with a Titan 3S & 2S LiPo / Lithium ION Balance Charger and you are all set."