An accessory outlet is not needed, but its nice. The BMW style plug is just easier to use, especially when you forget to plug in before you get going, and realize it just as you are merging into traffic. The "BMW style" plug is becoming a standard style for bikes, but it is not the same as an outlet in your car or truck, its a different size, but allows for positive enguagement. You can get plugs and recepticles cheap from your local John Deere dealer, or get a full kit from
Jastek. I have the Jastek kit and it is nice. Clean install on the left side panel looks almost stock. And you can easily use it to charge the battery when in storage and get adapters to run your ciggy plugged stuff.