I've just fitted the Enduralast as well -brilliant. Yesterday, riding down to Ace Cafe, had the headlamp on, heated grips on full blast, and heated jacket as well. Not a problem.
The Enduralast system starts charging at very low revs as well. Not cheap to buy, but very pleased I did, as , it seems to me, the existing type charging system on the Airheads is not the most reliable of systems.
Fit an Enduralast, from EME, and you dispense with the alternator brushes, rotor, and the dodgy diode board, and the inadequate voltage regulator. And, the whole system does not rely on the integrity of the red ignition bulb -I mean whose idea was that !!!
Granted you still have to have an "all in one" rectifier/voltage regulator, but it's a bit more reliable than the BM system, providing it has sufficient airflow to it, and that it is well grounded.