I found that my original 6 volt alternator put out fine with a Boyer Powerbox, I did end up running a battery with it as I seemed to get some missing at low rpm with the headlight on(and a dull headlight). At some point I had a coil short in the windings and had to replace the stator, I used stock one off of a more modern Bullet 500 with the separate lighting circuit, I ran connected these in parallel with the charging circuit into the Powerbox and always seemed to have good charging except at the lowest idle, not sure what you are planning on powering....(My bike was originally 6 volt positive ground with a rectifier, I converted to 12 volt negative ground)