jlsoaz wrote:...Does anyone know if other EV manufacturers (Tesla? Honda?) offer a hassle-free energy-saving ability to coast in neutral and then go back to instant-on power as needed? Is this part of how Honda is able to attain excellent mpge? ...
The Honda Fit EV does not go to neutral, but in the ECON mode, with Drive selected, the regen level is very low. The motor is also limited to 63 Hp, and the Cruise Control lets the speed vary +- 5 miles per hour reducing peak battery drain. If the terrain does take a sharp dip the regen will increase to keep the car from running away (Grade Logic Regen), while allowing instant acceleration if needed, and Servo Brake reduces Friction to Regen ratio. Additionally, ECON reduces the A/C and Heater draw and lets temp vary more widely. Honda claims ~15% overall improvement. I was able to get 6.2mi/kWh from 17kWh available battery (105 miles) including a 4,000 foot climb/decent. Also works well over rolling terrain. Very efficient.
Thanks KeiJidosha, this is an answer I was looking for. A few thoughts upon reading this:
In considering this idea of whether sometimes it is more energy efficient to coast in neutral, I have sometimes thought back to when I was younger and used to ride a 12 speed road bike. Since our own bodies are providing energy, there is a visceral feel that one gest.... this doesn't mean we are right, and it is not comparable in all ways since the bike didn't have regen, but some thoughts:
- There are times when it seems best to coast and let the road do the work.
- If one were to have to maintain constant speed within one or two mph, and if one did not have the ability to see ahead and anticipate points where less or more power could be applied, then this would make for a harder bike ride. The Honda appears to be somewhat smarter than some other cars about trying to balance out cruise-control versus energy savings both by employing some flexibility about constant speed, and by trying to let the car "catch its breath" a little bit when encountering a grade.
- I don't recall as well the experience of riding a bike that would not go into neutral.
Anyway, when Honda (having noticeably resisted for years and years making any PEVs) was compelled (by the California ZEV mandate and/or competition, etc.) to make at least a compliance BEV, and has also I think announced coming out with a PHEV soon, they emphasized that they were able to apply lessons from their hydrogen vehicle program and thus attain very high efficiency. There was not only I think some face-saving in this but some corporate justification - I think Honda has probably spent some decent money on its H2 vehicle program and so it is natural to try to make arguments to show how it has paid off, if only in a side way. The Fit, even if a Compliance vehicle only, and even if under-equipped in battery pack kWh for many US drivers needing to cover longer intra-municipal distances, does seem to employ some smart energy saving methods that bespeak of some significant engineering effort on Honda's part. While the exact efficiency measures Honda uses are not exactly what I have suggested in this thread, and others have explored for years (using neutral judiciously to enhance range and efficiency), they are in the same vein of "all other things and kWh being equal, there is more that can be done to get better range".
From the standpoint of working with Nissan to help them prioritize Leaf improvements, I think we can use this a bit to help them understand that there is more to be done in the area of efficiency, and that their worthy competition has helped to point this up.