Nissan`s participation on this forum

[davewill]

That's true. I suppose that the GPS would have to be used for altitude which I doubt they have tied in to any of their software yet but it could be done. Thanks for your input, it helps to refine the idea.

I'm not sure that altitude is really that relevant... seems to me the only factors necessary to do the "reversify" are the speed, distance, and energy consumption. Assuming all other parameters are fixed (e.g. outside temperature, weight carried, etc), that should be enough for the computation, right?

Picture it...you live at the top of the mountain and commute to the bottom. You use next to ZERO battery coming down the hill. You aren't going to repeat that performance going back.

 

[jcesare]

I have a suggestion for Nissan. Nissan needs to put in a software enhancement that I'll call "turnaround". Most everyone charges at home, especially until more remote charging stations are out there. Once you put your house address into the navigation unit you could select a button that says "turnaround". It would track the mileage from your home and basically let you know when you've hit the "point of no return". Stay tuned, this is different than how it calculates remaining mileage.

Let's say you go on a 30 mile (i.e. 60 mile round trip) trip. The first 10 miles would be at freeway speeds of 65 mph or more. The second 10 miles would be at stop and go city traffic. The third 10 miles would be up a gentle incline. The "Turnaround" feature would keep track of the mileage vs energy consumption so it would know the last 10 miles on the return trip will use more energy than usual. It would also know by how you are stopping and starting from stoplights how much energy is being consumed by your driving style. And third it would know that the incline will mean you use less energy on the return trip.

I think it would give a much more accurate picture of whether you'll be able to make it home. After 900 miles with our LEAF, my experience has been that it keeps a running picture of the history of the energy usage of the car. It seems to think that whatever your latest usage is (i.e. some have indicated it uses the last mile and a half to gauge future use), is what the car will experience in the future. By keeping track on a turnaround trip the system would know to keep a running total from your home point and not assume that future energy use will always be like the immediate past. It should be very easy just to have the system use the history from when the "Turnaround" feature was turned on and compare that to the amount of energy left in the battery.

If anyone agrees with this, how do you think is the best way to get a decision maker at Nissan to respond to this.

The military uses the brevity code "BINGO" for this. "Minimum fuel for a comfortable and safe return to base." BINGO can only be exceeded in combat situations.

 

[abasile]

I'm not sure that altitude is really that relevant... seems to me the only factors necessary to do the "reversify" are the speed, distance, and energy consumption. Assuming all other parameters are fixed (e.g. outside temperature, weight carried, etc), that should be enough for the computation, right?

Picture it...you live at the top of the mountain and commute to the bottom. You use next to ZERO battery coming down the hill. You aren't going to repeat that performance going back.

If you live where I do, over 6000' elevation in the San Bernardino Mountains, then altitude is quite relevant! :lol: I don't anticipate being able to drive more than about 25 or 30 round-trip miles from the base of the mountain if I want to turn around and head home on the same charge. Thankfully, there are three Nissan dealers (including Fontana) not too far from the mountain. As I personally don't have to go "down the hill" more than once per week or so, most of our LEAF miles will probably be driven up here.

 

[walterbays]

That's true. I suppose that the GPS would have to be used for altitude which I doubt they have tied in to any of their software yet but it could be done.

They could do this, and quite a bit more. Originally I thought they had done it, and was rather disappointed to learn they just had an out of date Navtek map without even any charging stations plotted.

Back to your original scenario: the computer watches you drive on the first leg of your trip slightly downhill on a secondary suburban street. It knows the (Carwings crowd sourced) average mi/kWh for this type of road, adjusted for a fixed kWh/1000ft elevation change, and usage of climate control and accessories. Ditto for the next leg of your trip on a freeway. Different figures, but it watches the variance of your usage from typical.

It knows your entire route to two destinations then back home on a different road than you took at the outset. It constantly projects how much energy it expects you to use based on your comparisons to average, and adjusted for elevation gain. Then it "sees" a traffic jam along your intended route. That might be a good thing from an energy point of view if it just slows you down slightly on the highway. Or it might be quite bad if it's a cold night and you'll be in stop and go traffic for an extended period burning kWh for the heater.

So it tells you. (Something like "I'm sorry Dave, I cannot do that trip as planned." http://www.moviesounds.com/2001/imsorry.mp3 You can detour to a recharging station it suggests. You can put it in Eco mode and plot a slightly shorter but slower route to your destinations. You can forgo your second destination and plot a new route back home. Or you can stop at a cafe - even one without a recharging station - and leave your car off while the traffic clears before you continue.

Reference to HAL notwithstanding, this wouldn't require science fiction AI. It could be done today. And it could greatly ease "range anxiety" as Leafs penetrate the market beyond the initial wave of EV enthusiasts.

 

[earther]

Picture it...you live at the top of the mountain and commute to the bottom. You use next to ZERO battery coming down the hill. You aren't going to repeat that performance going back.

the "division by zero" computation is problematic, but other than that case (uncertain about its real life frequency), I don't think you'd need altitude. Imagine if you will using just a modicum of power going downhill. Then the internal mechanism could then reason "oh, you just went X ground miles at Y mph using just Z amt of battery. Since it's a known parameter that going X miles at Y mph on a level surface should have taken Z++ power, the only way that your result could have been accomplished is if the grade of the path traveled were Q degrees and the rest helped by gravity. Hence on the return trip, X miles at Y mph fighting gravity with a slope of Q must be...." Given that all other parameters remain fixed, seems like just a high school application of proportions and trig; or am I making it too simple?

Of course, none of that works if ANY downhill motion always takes 0 power... and I don't know enough science to know if that's the case.