does anyone have simple instructions for safe way to connect battery?
I did not find 12v battery with
2.55.59mm barrel + centre
http://www.ebay.co.uk/itm/121266750218
Check out [url]Jetson/Jetson TK1 Power - eLinux.org for important information about the range of voltages that the Jetson can accept and the kind of batteries to use.
One can use a barrel plug terminal block like [url]Pololu - DC Barrel Plug to 2-Pin Terminal Block Adapter to wire it to the battery with relative safety.