The Savage charging system is marginal, and you cannot increase the wattage of the headlight bulb....there is very littel extra capacity in the system for normal riding. There is no extra capacity if you make short rides, stop frequently while running errands, and use the starter a lot.
The stock headlight is 55 watt low beam, 65 watt high beam. It is the standard wattage for the lights used in cars....and when you go to Walmart, Autozone, etc. that is the H4 light bullbs that will be hanging on the rack. The Ultravision is a slight upgrade in whiteness and a bit brighter - and it is a long lasting bulb. When you step up to the Silverstar you get a whiter light, the price doubles and the life is dramatically shorter. Whereas stock bulbs can last for 10 years....most people get a year or less with the Silverstar.......we only go 9 months in my wife's VW but she drives 22,000 miles a year.
I have the Ultravision in my car as I drive 16,000 miles a year, and I have the Silverstar in my motorcycle as I drive it 4,000 miles a year.
Phillips now offers a Crystal Vision bulb in case you want the really bright white look.....no idea about life or what it costs. It is 67/70 watt which is a few more watts.....but not so many that I would expect problems.
http://www.usa.philips.com/c/car-lamps/crystalvision-ultra-9003-12-v-67-60-w-...