A major goal when developing the ActiveThree system was to make the battery power supply more reliable and easier to handle for the users. For upmost user convenience, we specified that the ActiveThree system should be powered by a single rechargeable battery with minimal self-discharge, it should be a standard cell (not in a bespoke battery box or battery pack) that is readily available everywhere, and the ActiveThree should be able to run for a full workday (> 8 hours) without battery replacement. Based on these specs, we selected the most produced rechargeable battery in the world: the Li-ion 18650 cell. This cell seems to be the sweet spot in the tradeoff between size, weight and capacity. The cell is used in many battery packs (from power tools to electric cars), but also as a standard replaceable cell in flashlights, camera’s and many other appliances. Therefore, easy and cheap availability of chargers and replacement cells is secured.

Power Consumption of the Active3 system: 0.5 Watt (6 channels) to 1 Watt (142 channels)
Battery capacity of a standard Li-ion 18650 cell: 3500 mAh, 3.7 V
Battery life: 10 hours (142 channels) up to 20 hours (6 channels)