Laptop batteries can be a rather handy source of power, even if it’s not being used in a laptop computer. I built an adapter that converts the knife-blade connector that a laptop battery uses to a car lighter socket.

The connections are made by taking the blades of an ATO or ATC (regular size) car fuse, soldering them to some 16-gauge speaker wire, then soldering the other end to an inexpensive DC lighter socket.

This setup is only good for roughly 5 amps (the overcurrent protection on this battery is set to 6 amps) and the voltage near the end of discharge can be too low for certain devices; power inverters will stop at about 10 to 11 volts which leaves a small amount of battery capacity unused.