Small Unmanned Aerial Vehicles (UAV) are typically driven by LiPo batteries. The batteries have their own dynamics, which changes during discharge. Classical approaches to altitude control assume timeinvariant system and therefore fail. Adaptive controllers require an identified system model which is often unavailable. Battery dynamics can be characterized and used for a battery model-based controller. This controller is useful in situations when no feedback from actuators (such as RPM or thrust) is available. After measuring the battery dynamics for two distinct types of batteries, a controller is designed and experimentally verified, showing a consistent performance during whole discharge test. Unmanned Aerial Vehicles (UAV), Vertical TakeOff and Landing (VTOL), quadrotor, hexarotor, multirotor, altitude control, battery monitoring and modelling