Duke Robotics - AUV Overview

Power System

The Duke Robotics Team uses four 14.8V 8000mAh Lithium Polymer battery packs made by ThunderPower to supply the necessary power to the AUV. Two packs are connected in series to supply 29.6V, 8000mAh to the thrusters (System 1), and the other two packs are connected in series to supply 29.6V, 8000mAh to the Electronics Tube (System 2). Both System 1 and System 2 enter the electronics tube through a 4 pin Low Profile Subconn Connector. System 1 is connected to the thruster input on the power board and is immediately routed back out to the thrusters. System 2 enters the power board where it is routed to the DC/DC converters (see DC/DC for more information). Both systems contain safety fuses in the battery tube before the power enters the Subconn connector. The power in System 1 is fed through an electrolytic capacitor in the battery tube in order to condition the power to the thrusters and prevent voltage spikes in the system. Extreme care should be taken when replacing the electrolytic capacitor, as connecting it in the reverse direction can cause the capacitor to heat up and eventually catch on fire.
Lithium polymer batteries provide the greatest energy density available to consumers. The batteries supply the AUV with 6-8 hours of computer use depending on the sensors attached. Typical thruster use allows the AUV to maneuver for one hour before a recharge. Care should be given when using the batteries, as draining the system below 10% (about 24V over system 1 or 2) will cause permanent damage to the batteries. The batteries must be charged with a lithium polymer compatible battery charger. Currently, the Duke AUV team uses the Orbit Microlader Charger. This charger is capable of fully charging each battery in about 4 hours.