Well its bloody marvellous isn’t it? Simply put for those who have not come across it before (apologies to those who have please skip to paragraph 2) the car turns its kinetic energy back into electricity when you press the brake pedal. The drive motor effectively operates in reverse and produces power when it is turned, i.e. when you’re rolling down a hill or when the brake is pressed, which is fed through the charger and increases the battery charge. When you’re almost at a stop the brake pads are applied to the discs, just like in any other car, and the car stops. https://www.youtube.com/watch?v=6LwDY73MuSM
Why is it marvellous? Well there are several big benefits. Firstly it recovers energy that is normally lost as heat and wear in/on your brake pads and discs, which are not brought together under light-moderate breaking only when you press the pedal hard. This means all that kinetic energy you have built up using precious battery charge is not wasted as you roll down a hill or stop.
Secondly you are not wearing your brakes out at anything like the rate you are in a conventional car. I suspect a set of pads will last 40,000 miles or possibly more and the discs might manage 100k miles.
Why clever Nissan? The dashboard shows a lot of information such as the amount of power flowing into the motor – or in this case back out of it, under braking/hill descent. This provides the driver with feedback on how much energy he/she is putting into the motion of the car or extracting from it. This facilitates more economical driving, in much more sophisticated fashion than the typical fuel metering/range display on a fossil fuel car.
Nissan have taken this one step further, a display in the top right corner of the instrument binnacle shows a gauge with the start of a tree inside it. As you drive along the tree grows until you have grown a whole one, then another begins to grow. The more efficiently you drive the quicker the tree grows. Nissan have calculated the amount of CO2 saved by driving the car and the number of trees grown equates to a quantity of carbon saved. You can even upload your score to Nissan via the car’s on board, internet enabled computer and see how you rank next to all the other Leaf (and NV200) drivers.
The other clever if slightly frustrating thing is that the amount of the battery you can access and use is much less than the capacity would suggest. For example it is meant to be a 24kWh battery pack, however I seem to go from about 20kWh down to 8kWh and back all the time (using Leafspy Pro for android), rather than actually using the full capacity of the pack. Its long been known that Li Ion batteries work best when used within a 40%-80% range. Nissan it seems, make sure you stay within this range by calling 40% nearly empty and 80% nearly full on the dash mounted gauge, whilst I accept I am being a bit sarcastic this is how it feels sometimes, not that it is a problem when you consider that battery longevity must be balanced against battery capacity.
It seems Nissan have spent a lot of time and money considering the psychology of converting people to electric cars and encouraging us to drive efficiently. This make sense for an eco-vehicle. However its the sheer torque of an electric car which impresses their owners, and dismays “fast” car drivers at the traffic lights. Nissan and the other electric car makers would sell more if they emphasized this aspect of their performance.
In other news fast home charger to be installed soon, new lighter wheels still on the wish list and spoiler still be chased up via Esso.