The easiest way to power your Jetson TK1 using batteries is with a Turnigy 3S 2200mA Li-Po battery for $8.50 giving roughly 4-6 hours of moderate use (0.8 efficiency * 2.2Ah * 11.1V / 3W). Beware that Li-Ion and Li-Po batteries should never be charged from a NiCad/NiMh or SLA charger, they need a charger that specifically supports LiIon/LiPo batteries. The Turnigy Accucell-6 for $23 is a popular universal charger for batteries like this, it can charge it in less than an hour if needed, but for longer battery life you are recommended to charge it at the 0.7A setting for around 5 hours.
For example, you could simply attach a standard 2.1mm DC barrel plug to the mentioned Turnigy 3S 2200mA Li-Po battery with a Voltage & Current Monitor for $5 in-between the battery and DC plug, to have a full battery-powered Jetson TK1 system that easily shows the total current draw of the device (multiply the Current in Amps by the Voltage in Volts to get Power in Watts) as well as to see when the batteries need recharging.
- More details about battery options as well as expected running times are shown in the Powering the Jetson TK1 board with a battery section of the Jetson TK1 Power page.
- There is also a page showing a detailed list of Typical Power Draw for Different Computer Vision Algorithms.