this eliminator is designed for when you are running a bike with a magneto ignition especially on a cone shovel or evo application where a generator is not used. in order for the solid state regulator to output power it needs a certain amount of "load" to be placed on it to tell it to send power to the battery. when you remove the battery out of the system you need to add one of these units in order to make your electrical system work. this will also help stabilize your lights at low rpm on a mag fired bike.