I have read many messages about the bamboo gt, which goes to the ECO mode automatically when the battery is less than 50% and after traveling only about 10 km. Is this problem because of the capacity of the battery or the heat of the motors? What would be the best way to expand the battery? In Europe I have only found Kevin Dark’s fabrications but no found official stores that sells Evolve battery replacements. How is it possible to travel 20 miles with a bamboo gt in FAST and GT modes without limitations?