Laptops that can charge battery via typing on keyboard. Think bicycle generator.
User will expend energy to type. This energy can go towards charging battery.
This method would no completely recharge the battery of course. However much like hybrid cars using braking, it would recharge the battery partially and extend the life.
This method would no completely recharge the battery of course. However much like hybrid cars using braking, it would recharge the battery partially and extend the life.