Smidge204 wrote:abasile wrote:johntaves wrote:Spending your kinetic energy on motion overcoming road friction is more efficient than putting it back into the battery.
Generally speaking, that is true. Except when you're going particularly fast and losing a great deal of energy to aerodynamic drag. In that case you're likely better off putting some of that kinetic energy back into the battery, and then coasting at a lower speed if traffic allows.
No, in that case you are still better off coasting freely, letting air resistance slow you down. Every kWh not put into overcoming resistance is a kWh wasted, and putting it back into the battery wastes something like 20% of it.
Air resistance increases exponentially with velocity, whereas moderate regenerative braking can be performed at reasonable efficiency irrespective of velocity. By using regen to slow from, say, 90 mph (to pick an extreme example), you can put some energy into the pack and at the same time greatly reduce the air resistance going forward.
Smidge204 wrote:Ideally you should not have been going that fast in the first place
True enough. On many long downhill sections of freeway here in California, it is easy to exceed 80+ mph simply by coasting. When traffic allows, I like to use regen to hold my speed down to 55-60 mph until close to the bottom of the hill, at which point I'll let it creep up to 65-70 mph. The alternative would be to simply coast at terminal velocity on the entire descent, thus throwing more energy to the wind.
