The bulbs aren't designed to drain your battery and with the way motorcycles and scooters work these days, the lights only come on and stay on when the engine is running so the power is generally supplied by the engines power and not the battery, what your issue sounds like is with the engine, you may have a vacuum line leak, check your valves, clean your carb with some seafoam through your gas lines, because I've had a similar issue to yours, but in your case your bike dies and you don't have a battery to restart it with utterly stranding you, your CDI, Carb, Vacuum lines, Air Filter, and Valves are what you need to check, and if your scooter sits for a while without being driven then gas cleaner will clean out the ethanol.