Let’s say your home, work, shopping, and entertainment destinations are all located at some point along a more or less straight sloping road. Let’s say the slope is a generally monotonic 10% grade more or less. The distance between destinations is not so important, but let’s say between 5 and 50 kilometers. Let’s say you put water bags in your tesla and use them as follows: When driving uphill, the water bags are empty. When driving downhill, the water bags are full, and you drive slowly to avoid aerodynamic drag. The slope of the hill is such that you have to keep your foot on the brake at all times when driving downhill. Assume your battery charge level is around 50% so the battery can accept charge from the regenerative braking. How many pounds of water must you carry downhill to overcome overall systemic roundtrip uphill and downhill losses?