In January, I enjoyed greater stability navigating slush patches on the road with this 2 wheel drive! (Optional feet off the pedals is a great way to stay upright, too.) Now I travel in straighter lines, rather than skirting around hills, so my commute is shorter, and I arrive without the sweat previously required to accomplish the same speedy trip. Question: As the battery begins to drain, the motor seems to oppose my pedaling, which seems remedied if I switch the controller off. (The controller reads 1 bar at these times, but the battery indicator seldom goes below 3 lights.) What is causing this increased resistance?