if your going to go through the trouble of building an idler and carrying that why not just carry a spare gen? I carry every thing i can, if you have it you won't need it. I carried a gen and voltage regulator when i used a gen. Now i have an altenator and carry a spare. The alternators i made for my own use have the rectifier and the voltage regulator built into the rear cap where the brushes were. This has a plug on it inside and plugs into the stator and rotor which has the other half of the plug. Have over 5,000 miles on the one in the 39 convertible and it charges perfect all the time with a steady output. When my optima went bad i was able to continue 800 miles with the alternator, the generator would have left me dead where i was. G.m.