Batteries
We use all NiMH batteries this year. Our Main batteries power the engines alone, and are composed of 24 D-Cells, amounting to two parallel packs equaling 19 AH at 15 Volts. The internal battery is composed of 12 C-Cell NiMH batteries and provides 3.8 AH at 15 volts.

This year we chose to use NiMH batteries over Gel Cells because of their power density, that is the ratio of stored power vs. the battery's weight. The entire main battery pack weighs less than a single 12 AH Gel Cell and provides 175% the power.

The major disadvantage to NiMH is the complicated charging circuitry as well as the extraordinary cost. We purchased two Tri-M power supplies, one for charging the main pack, and a special PC/104 power supply for the computer. These supplies are fully programmable for any given battery pack and allow for a very simple charging solution.