Nissan Leaf / e-NV200 range extender and regenerative force improvement – LEAF Box
Leaf Box is a range extender controlling load applied to engine via throttle control. No problems with warranty – undetectable by dealer. It is easy to install, as it uses factory plugs. It delivers following extensions to standard Nissan Leaf:
- range extender – it bases on adding „N-mode on demand” (aka glide mode) to D-mode, along with alternative torque delivery strategy (read below). Range extension is around 10% (ECO mode, 24kWh/30kWh battery). With normal mode, Leaf Box is off.
- mimic of some functions of “e-pedal” from new Nissan Leaf 2018 is possible.
- the regenerative force at D mode can be increased by about 20% (from 20kW to 24kW). If you have the version of Nissan Leaf with B mode – lucky you. But I can have B-mode even in the basic version of Leaf.
- max power of Leaf can be increased from 80kW to 83kW (option).
- works also for e-NV200
Alternative accelerator pedal interpretation for efficiency
Until now all Leafs have simple “accelerator pedal (acc) position → power” transition. The position of an accelerator pedal is converted to power demand. This we can see at energy usage panel in the car, but I have verified that also with a chassis dyno.
This method suffers from two negative effects:
- Acceleration of the car is not stable at all. The car first speeds up better, then falls down with acceleration – as acceleration simply depends on torque, and because car has almost constant power for any rpm and any desired acc pedal position – it is logical that torque MUST go down (see graph – thin lines in the big graph – torque of car (=acceleration) for various acc pedal positions (verified with dyno).
- Some parts of our acceleration are not crossing optimal motor efficiency (red and orange areas). In some areas it is impossible, but of course, everything can be optimized.
I have prepared an alternative power demand curve (presented as the bold line in the small graph vs. thin line with same colour – factory) that promotes two things: more constant acceleration and more efficiency.
Constant acceleration is, in my humble opinion, something perfect for our Leafs. I have been driving for few days with this setup – it is so nice that now when I press the pedal to some position – acceleration is much more stable. There is no rapid power demand, and power demand changes in time (as the power is now not constant, but rather torque is more constant). This is visible on the power usage panel.
Remaining more in the optimal efficiency area – this is a “side effect”, as we have “constant torque” strategy instead of “constant power” strategy. I cannot say whether or not this will extend the range (or maybe a bit) because I haven’t tried this on my test route.
For acc pedal levels over 70% torque demand curve becomes increasingly „constant power” type. For 100% pedal, it is just factory 100% power line, not altered.
Below 30% of acc pedal, I have used less flat torque curves (not shown on the graph) because of the need for a jump start at lights or crossroads.
Nissan Leaf LeafBox feature of N-mode on demand. While driving in D-mode you can almost remove the leg from acc pedal. LeafBox will set motor power to exactly zero (0 kWh) so you will be rolling without energy conversions. This increases efficiency with long distance trips and is good for overall range (autonomy). Power gauge is visible on right side.
Nissan Leaf LeafBox feature of N-mode on demand. While driving in D-mode you can almost remove leg from acc pedal. LeafBox will set motor power to exactly zero (0 kWh) so you will be rolling without energy conversions. This increases efficiency with longer distance trips and is good for overall range (autonomy). Power gauge is visible on right side.