Waste heat can help keep the batteries warm. For example, Teslas have a battery heater which really eats power when you start out in the cold, but after you're cruising it reaches a steady state. Range still suffers, but at that point it's cabin heating and air resistance. Assuming the batteries are in the wings, you'll probably have voids between the batteries and the skin (since batteries don't have very a aerodynamic shape) which could be insulated without too much of a weight penalty.
Battery weight is a huge problem, of course. A Tesla battery pack is 1200 pounds. That's more than many light airplanes weigh total! The motor and inverter are only about 350 pounds, by comparison.
Battery weight is a huge problem, of course. A Tesla battery pack is 1200 pounds. That's more than many light airplanes weigh total! The motor and inverter are only about 350 pounds, by comparison.