Intelligent Nav System

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dsurber

Member
Joined
Jul 17, 2010
Messages
9
Location
San Francisco, CA
One of the biggest concerns about the Leaf and electric cars in general is "range anxiety", the fear of running out of power. Due to the short range of EVs many drivers will frequently push the limits of the vehicle's range. Considering the wide variation in range due to driving conditions it will be difficult for the driver to accurately predict what the range is. Most of us fill up a gas vehicle at around 1/4 tank. Assuming a 400 mile range that means we typically have a 100 mile cushion. That's more that the typical range of a Leaf.

Nissan is aiming to mitigate this by having the NS (nav system) display the estimated range and charging stations along the route. Pictures of the NS display have shown two concentric circles. I assume the inner one is the high probability range and the outer one is the best that can be expected range, or something like that. This display is useless IMHO.

I live in the SF Bay area. We have hills and traffic. Roads don't go straight from point A to point B. There is a Regional Park just a few miles from my house, yet it can easily take an hour to get there due to the round about route required. I could get in my partially charged Leaf at home, look at the NS and see the park is well within range, yet run out of power long before I get there. If the NS does nothing more than what is described above, it will do nothing to alleviate my range anxiety.

On the other hand, it is well within the bounds of current technology to do much, much more. I sincerely hope that Nissan has programmed the NS to do the following. If not then I suggest they get their programmers to work ASAP.

Range depends on a number of factors:

  • actual battery capacity
    level of charge
    maintenance level of the vehicle
    actual travel distance (not as the crow flies)
    terrain
    traffic
    weather
    driving habits

All of this information is potentially available to the NS. When I tell the NS I want to go to the Regional Park, it knows how many miles I will actually drive. Using available topographic info it can know about changes in elevation. Using available traffic info it can know about traffic conditions. Using available weather info it can know about local weather along the route. And it knows how I drive. Further since I frequently drive to this park, it can know how much power it takes to make the round trip in a wide range of circumstances. It is my hope that when I tell the NS I want to go to the park and back the NS can say with very high accuracy whether that trip is in range or not given the current conditions.

My house is just a few miles from the nearest freeway exit, yet it is over 250 feet higher in elevation. I drive that few miles frequently. If the NS does not take into account the elevation gain and the many historical trips up that road, it will undoubtedly over estimate my ability to get home and will leave me stranded at the bottom of a hill, one quarter mile from home. This will not make me happy.

The Leaf's range (50-130 miles) is at the border line of what is usable. As battery capacity declines with age, it becomes less and less capable. As a puny human I cannot predict the range for any given trip very accurately. If I have to guess at the range I will need to leave a large cushion or risk being stranded. Because of the wide variation in range I will tend to assume something toward worst case range and then add a cushion to that. So I may look at a 60 mile trip and decide I can't be certain of making the trip even though the Leaf is perfectly capable of it. If the NS takes all the available info into account and accurately predicts whether a trip is feasible or not, then I would make that 60 mile trip. An intelligent NS would greatly increase the real world range of the Leaf and thus its value to consumers like me.

Nissan, I hope the nav system is as intelligent as I describe. If not then you should have a very pointed discussion with the software development team.
 
Yes, "Savy-Nav" would be great, but unlikely to be provided. Even SSN (Semi-Savy-Nav) would be a big help, without weather, wind, and traffic information, but including real routes, elevations, car performance and SOC, and a few driving styles.

Traffic info is only rarely collected anywhere off highways and a few main roads. Sometimes, even knowing the present traffic does not help enough with the traffic a half-hour later.

Karen's range estimator used detailed car performance parameters, route, and elevation. She also included estimates of speeds, but not traffic, since it was not a real-time calculator, but a trip planner.
 
garygid said:
Yes, "Savy-Nav" would be great, but unlikely to be provided. Even SSN (Semi-Savy-Nav) would be a big help, without weather, wind, and traffic information, but including real routes, elevations, car performance and SOC, and a few driving styles.

I will be very disappointed if you are correct. I can well imagine myself standing in the driveway deciding whether to take the Leaf or not. Being risk-adverse I may often choose not to when in fact it would have been fine. That is 100% the result of poor information. If the Leaf will tell me "yes, this trip is feasible" then I'm more likely to drive it. And the first time I over estimate the range and get stuck with a dead car, I'm going to be seriously not happy. If I imagine too many of these scenarios, I may not buy the car when my reservation comes up.

Savy-Nav is cheap inoculation against range anxiety.
 
The nav in my Ford Escape Hybrid takes into account the route and traffic. It's point to point but using the road/traffic info. I'd be surprised if the Leaf didn't do the same.

IIRC, the two circles were for range....one circle was round trip, the other was max distance before a charge.

The circles would be informational, but once you put in a destination, I'd expect the Nav system to tell me if I wasn't going to make it.
 
I sincerely hope that we are surprised with how capable the LEAF-Nav is. But, so far, we have no "route" screen-shots, just circles on maps.

To get from one point to another, there is
1, the "direct", straight-line method, also called "airline", "cross-country", or point-to-point method, or
2. the via-roadways "routed" method that is usually the more useful measure for cars.

The "routed" distance is always at least as long as the "direct" route, sometimes MUCH longer.

Since the "circles" on the maps tend to indicate "airline" distance, they are almost useless for determining "usable" EV range. At least, they should be used with considerable caution.

Best to "calibrate" your own driving and conditions with shorter trips, working up to longer trips, possibly including charging away from home.
 
Savvy Nav as described by dsurber would go a long way toward alleviating Leaf range anxiety. This is particularly important if Nissan expects to penetrate beyond the relatively small EV fanatic market.

How many powerless Leafs stranded along the side of highways does the ICE motorist need to encounter to convince himself not to buy a Leaf? Maybe just one. It behooves Nissan to do what it takes to minimize that risk.

I also want to know how much range I'm estimated to have left at the end of a route I enter into the Leaf Nav. I'm not interested in cutting it too close, that risks not making it to my destination.

There are car nav units that already take into account real time traffic conditions to calculate fastest route, so there's no reason why real time traffic data couldn't be incorporated into a calculation of Leaf range along different routes.

Mapping programs that have a built in database of terrain elevation already exist so again there's no reason why this data could not be incorporated into Leaf Savvy Nav system range estimates.

Savvy Nav is only software programming, and the technology to do it already exists. Savvy Nav would be a tiny cost compared to the equipment cost of each vehicle. It would be a tiny cost compared to building a network of Level 3 charging stations, which Nissan seems to view as important to alleviating range anxiety.

I cringe when I see videos and photos showing off the Leaf Nav system, displaying concentric circles on a map that are supposed to depict theoretical range. That is a piss poor way to determine realistic remaining range.
 
I wonder, will the Nissan-Nav have full map coverage, or just coverage of "some" (many) areas, like Toyota has in the Prius?

Or, will one need to have on-line "connectivity" (like a cell phone nav-app might need) to get detailed maps?

Such "connectivity" will be needed to get real-time charging-station status.

Will one be required to subscribe to XM in order to get traffic reports for the Nav system (like the Prius)?

Will the LEAF's Nav-Maps contain altitude information?
 
I had my test drive today in San Francisco. I spent more time playing with the nav then I did driving the car. The test drive was inside Moscone Convention Center. Not a lot of room.

It is my understanding that these are pre-production cars and will be crushed. So there's no reason to believe that the nav software is the same as we'll get in production. Further it is possible that the nav software can be updated, so even after you get the car home, you might still get new features. The Leaf I was playing with thought it was in Renton, WA, not San Francisco. I suppose that's not surprising as it wasn't going to get a GPS signal inside Moscone.

The Good News:
The nav reported actual road miles to your entered destination. I entered Bremerton, WA as a destination. That's about 25 air miles from Renton, but the nav correctly reported 56 road miles. Zero indication whether the remaining 83 miles of charge was sufficient to make the trip.

The Bad News:
The nav did not in any way seem aware than range was of interest. From what I could tell the actual navigation feature may be exactly the same as in an ICE vehicle. I entered Moses Lake, WA as a destination, about 180 miles away largely up hill. No indication that a recharge would be necessary. No indication of any kind at all that range or state of charge was of interest. Sad.

I'm a geek. I love gadgets. I don't read instruction manuals. Between us, my wife and I have something like 8 GPS devices. I did not find the use of the nav intuitive. I was able to get it to do what I wanted, but only with lots of false starts and blind alleys. Even after I had sort of learned my way around, I still got lost in the screens. Admittedly that's not the end of the world. Maybe I'm spoiled by Google Maps on my iPhone.

One thing I found irritating is that the US is broken into regions. You have to tell it which region; state alone is not enough. The regions appear to be split on state boundaries. How silly is that.

I sincerely hope that this is not the production nav software and that the production cars will have savvy nav. Or than Nissan releases a nav software update with savvy nav fairly soon. Or in the best of all possible worlds that Nissan releases the nav software under an open source license and we can collaborate to write the best savvy nav imaginable. Are you listening Nissan?

My wife just told me that CarWings supposedly phones home with info on the route being driven. Given that info a savvy nav should be able to compute the energy cost for a given trip based on current driving experience, even over routes you personally have never driven. If that's true and the Leaf nav doesn't take advantage of the info, then what's the point?
 
I live in SF and have owned several factory EVs with no NAV and never had a single range issue. The NAV is smart enough to calculate indirect routes on the range not just direct line estimates. If one expects to drive with the hope of using the last few miles to reach home then an EV is not the right choice for you. I have spent quite a bit of time reviewing the Car Wings feature and as far as a tool for range I have not seen better. I don't see any reason for concern and one should always leave a bit of a buffer zone in range just like not driving on empty in a car.
 
The value of a vehicle is its ability to take me from A to B. The more limited the range the less valuable the vehicle. A 100 mile range (that might be 60 in the hills of the Bay Area in summer) is not a lot to start with. If I have to lop another 20 or so off for insurance, that really cuts into the value of the vehicle. Maybe Car Wings has some magic fairy dust to make these concerns go away, but the nav system in the car does not and that's all I've seen.

I'm not an EV zealot, but if the Leaf is supposed to be a mass market EV, then I am for sure the target consumer. Range anxiety is a real issue. I do not want to get stuck on the side of the freeway with a dead car. Nor at the bottom of the steep hill leading to my house. A savvy nav would go a long way toward addressing this issue. Compared to the overall cost of the Leaf program the development cost of savvy nav would be minuscule. It is simply unfathomable to me that the Leaf will not have savvy nav.
 
There is presently technology being refined that uses GPS for elevation and many other factors to assist in range calculation, these are all things that could be upgraded to the telematics via a software update since the hardware is all there. You will find in short practice that you will become good at understanding how hills and other factors influence your range and how to accurately estimate your range with better confidence. One of the key factors in EV range besides aero is weight, this is something Leaf drivers will soon Learn but not have a gauge against unless they have drive a lower weight EV, it's a fundamental EV design premise. When is your expected delivery date?



PS- I live at about the highest geographic point in the city.
 
I have the same problem; it's down hill to anywhere for me. And this, of course, is the worst possible scenario since I will presumably be leaving the house with close to a full charge and thus gain little by regenerating down the hills, but will require substantial extra energy to make it back up the hills again. Thus, I'll have to be sure to keep this in mind when calculating my maximum range - it'll be less than indicated by the car. It'll be interesting to see how it works out.

EVDRIVER said:
PS- I live at about the highest geographic point in the city.
 
Ahh... BUT - you won't use much of your battery going down the hill so you'll be at the bottom with almost a full "tank". I don't think you'll have a problem.
 
cdub said:
Ahh... BUT - you won't use much of your battery going down the hill so you'll be at the bottom with almost a full "tank". I don't think you'll have a problem.

Actually, if you run the numbers, that doesn't help. Think of it as being at the bottom of the hill with a full tank and then having to drive 26 miles up that hill... Plus you've wasted all the energy that you could have recovered from regenerating. Now, what might at least make sense for the latter - though it will do nothing for range - is setting the vehicle to charge to only, say, 80 percent, and then using the downhill run to regen back up to 100 percent. Ideally you want to be the other way around: At the bottom of the hill with the first part of your trip uphill...
 
It's better to live at the bottom of a hill so you climb when your SOC is high and voltage sag is low, at return when a charge is lower and sag is higher you are traveling down hill.
 
For me, the NAV system will probably be like the cruise control, something that gets little use. For the occasional longer trip, it will be useful, especially if I need to find a public charge point along the way. But for daily use, unnecessary; I know my daily route like the back of my hand and it's less than 40 miles round trip, well within range so I can charge overnight at home.
 
Google Maps is now going to version 5.0.. in the past year or so, it keeps evolving so fast when compared to old fashion car sat nav system - that look primitive and stagnated.
http://erictric.com/2010/12/10/google-demonstrates-new-google-maps-5-0-on-nexus-s/
Google Maps also has a terrain layer information, so it should be easy to take into account this info when estimating range...
 
I think a certain amount of the decision is simply going to have to be driven by our own internal savy-nav. The leaf nav does not (currently) take in to account weather or elevation and though it does have traffic, that will often be of limited value for the reasons that have previously been pointed out. It will simply be up to the driver to take in to account factors that the nav does not know and at times to take a different route than it suggests based on personal experience and local knowledge.

If this truly is a big issue and concern for you, you might be happier with the Volt.

dsurber said:
I will be very disappointed if you are correct. I can well imagine myself standing in the driveway deciding whether to take the Leaf or not. Being risk-adverse I may often choose not to when in fact it would have been fine. That is 100% the result of poor information. If the Leaf will tell me "yes, this trip is feasible" then I'm more likely to drive it. And the first time I over estimate the range and get stuck with a dead car, I'm going to be seriously not happy. If I imagine too many of these scenarios, I may not buy the car when my reservation comes up.

Savy-Nav is cheap inoculation against range anxiety.
 
Just because your destination is within the big "max range" circle does not mean you can "make it", because the actual driving distance might be MUCH more than the "airline" distance.

After "setting" your destination on the Nav, and having it calculate a route, it (and you) will know the real trip length.

Presumably the Nav will warn you when the indicated trip is longer than the remaining range. You will have to adjust mentally for hills, wind, and other conditions that the Nav does not know about ... like, there is no charging available at the destination.

In that case, you might be able to add a charging "mid-point" to your Nav route, or make your destination a mid-point "on the way" to a charging location.
 
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