Use your laptops battery to power a Cradlepoint CTR350 or like router without access to AC power.
First, find a usb cable:
Cut off the end that does not fit the usb port and strip the red and black wires, disregard the green ground:
Plug it in your laptop and check the voltage. Do not let the black and red wires touch. Make sure the usb port is outputting at least 5v but not more than 6 volts. Do this while the laptop is on battery power so you know you will have the minimum required voltage:
Take a connector, in this case a 5mm for the CTR350, and solder the red (+) lead to the center pole and the black (-) to the outer pole:
Slide the cover over the solder joints and you have the cable completed:
Plug it in the laptop and test for continuity and voltage output:
That's it. Plug it in the router and you can share the connection with multiple computers even though there is no wall power available.
How long you can use it depends on the condition of your laptop battery. But in a pinch this is a easy way to create a hotspot. You could also use it with the laptop plugged into a power outlet (if you only had one outlet available) and share the net.
This should work with any router or device that uses a converter which changes its output to 5 volts. Check the specs first to make sure that is what the device requires.
No automobile (or adapter) needed ;-)
You can also pick up a battery holder at Radio Shack and make a power supply using rechargeable batteries. This lasted about 3.5 hours on one set:
So, you can be really portable if you want to.
