Range question

[sproqitman]

My commute to work one way is 70 miles, ending at about the same elevation as I start, but along the way, there's 5 or 6 hills of 100-200 feet up/down and then at the 60 mile mark, I have a 900 foot climb and descent. The majority of the drive (45 miles) is a nice two lane road from Santa Cruz to Half Moon Bay and I plan to cruise at about 62 mph. This is a "one way" question as I have several days to recharge before heading home.

I haven't seen it mentioned on this thread, but I'd be more concerned with headwinds than hills. From Santa Cruz to Half Moon Bay, you're going to be fighting some pretty stiff headwinds (I know, I used to windsurf in the Bay Area). On the other hand, you'll have a nice tailwind on the return trip. Here's an outside-the-box suggestion: take 17/101 northbound, and Highway 1 southbound. You have the climb up and over the Santa Cruz mountains, but you are within easy reach of several Nissan dealers along the 101. And you can save the nice (downwind) cruise along the coast for the trip home.

 

[corwin]

I haven't seen it mentioned on this thread, but I'd be more concerned with headwinds than hills. From Santa Cruz to Half Moon Bay, you're going to be fighting some pretty stiff headwinds (I know, I used to windsurf in the Bay Area). On the other hand, you'll have a nice tailwind on the return trip. Here's an outside-the-box suggestion: take 17/101 northbound, and Highway 1 southbound. You have the climb up and over the Santa Cruz mountains, but you are within easy reach of several Nissan dealers along the 101. And you can save the nice (downwind) cruise along the coast for the trip home.

Good point on the wind factor. Perhaps I can find a truck to draft behind...
You did just hit on my alternative. The Hwy 17/85/101 route is about 7 miles shorter, puts the one hill early in the drive, and plenty of charging options along the way. But, giving up the most beautiful commute in the world is a tough pill. Fingers crossed that this won't have to happen, though I could handle it in one direction. Maybe.

-Corwin

 

[DaveEV]

My personal opinion is that coasting is unsafe, illegal, and antisocial, but wastes less energy than regen.

I think you're mixing up coasting (by feathering the throttle) with putting it in neutral. And that there are plenty of ways to do it without any of your listed drawbacks.

 

[planet4ever]

My personal opinion is that coasting is unsafe, illegal, and antisocial, but wastes less energy than regen.

I think you're mixing up coasting (by feathering the throttle) with putting it in neutral. And that there are plenty of ways to do it without any of your listed drawbacks.

Oh, I feather the throttle all the time in our Prius. I love seeing that display where nothing is coming out of the battery, the engine, or the wheels. My comment was in response to rmay635703's advocacy of barreling down hill as fast as possible in neutral so you can coast uphill on the other side.

 

[garygid]

Coasting "in Neutral" would appear to be illegal only if the "gears" are in "neutral". Since the gears in the LEAF are always engaged, the use of "N" to coast would seem to be technically "legal" (at safe speeds and at or under legal speed limits), right?

Perhape "N" should be labeled "C" instead?

Using coasting (however achieved), even downhill, does not imply unsafe or illegal speeds.

Unsafe driving, under power or not, can always be achieved, at any speed or power setting, and we do NOT suggest that kind of driving here, RIGHT?

 

[rmay635703]

Coasting is 100% efficient,

Rubbish! Coasting could only be 100% efficient in a vacuum when there are no law enforcement officials or other cars around.

• The faster you coast the more energy you lose to air resistance.
• The faster you coast the more likely you are to have to stop to receive a ticket.
• The more you vary your speed the more you will anger other drivers, and the more likely they become to try to cut you off or even force you off the road.

Please note: I am not claiming that coasting uses more energy than regen. I am only saying that in a real world nothing is 100% efficient.

Please post the code and state you found that law (I am curious)

My comment was in response to rmay635703's advocacy of barreling down hill as fast as possible in neutral so you can coast uphill on the other side.

I'm not sure what rubbish your thinking, I've never been pulled over in over 900,000 miles of driving for coasting (I don't think I've managed to speed while coasting unless I was already speeding to begin with)
I've never been cut off when driving slowly but have been cutoff plenty of times when speeding. I've also avoided a rather large number of severe pileup accidents because I was driving slowly with proper distances. You should also note I have never had an accident, If what you say is true I should have totalled about 30 cars by now.

Anyway In most vehicles including the leaf it is very difficult to gain speed coasting above the speed limit because its like pushing a brick wall of air, you need a rather extreme hill to speed by coasting alone. So likely if you bleed speed going up the hill and coast down you are probably moving more slowly on average and loosing less energy to wind resistance. Ideally you try to set an average goal speed that is a bit lower than the speed limit when encountering hills. (also slow driving is not illegal, most every roadway either has no lower limit or has a limit 10-30mph below the normal speed limit) What is very illegal is exceeding the speed limit by any degree. You can be pulled over for 1mph over in this state. Also I mentioned using regen only when needed, I would estimate exceeding the legislated speed limit would be a time to use it to avoid that situation.

Also it is pure rubbish to state coasting is illegal. It is an urban legend. I have heard this over and over and when I finally did find the circa 1958 law it was in regards to coasting in Neutral when big rigs were going down a hill. It had absolutely nothing to do with a car in gear not pushing on the gas pedal. It also is only legitimately a valid law in 5 or 6 states that I know of and usually a very very old law. So in this regard the leaf is always in gear and it isn't a big rig so that law doesn't apply does it?

Next Coasting is 100% efficient if you only consider when you are coasting as part of the equation, in other words, it requires 0 energy from your motor or battery pack to coast but it would always requires some level of throttle to maintain speed. I'm not sure how you define efficiency but if you use no energy and travel a distance you are 100% efficient over that distance, actually more so since you bring up the fact that you are overcoming resistance which requires energy but exerting no force to overcome it.

My personal opinion is that coasting is unsafe, illegal, and antisocial, but wastes less energy than regen.

It is one of those 3 but speeding is all of those 3, you would be surprized at how much happier you would be if you would try and change your driving habits to those of a hypermiler, the roadway becomes a pleasure as opposed to an aggrivation fest.

My guess is you are the guy that trips the red light for me so I can drive past you as it turns green? I've often wondered how people cannot comprehend the futility of driving 90mph up to red lights to almost spin out to stop and wait. They do it over and over week after week at the same lights never realizing they just have to sit there longer if they drive faster.

Odd if the doors locked try it again and maybe it will open this time?

 

[planet4ever]

I'm sorry I upset you so much, and I apologize for misunderstanding what you were saying. I did assume that you were talking about speeding (above the limit) down hill, and I do now see that you didn't say that. That takes the wind out of my "unsafe and illegal" points. I could still find ways, by stretching a point, to argue for them, but I know I couldn't convince you.

I will, however, continue to argue for two points I made. (As in all things, I am willing and able to be convinced of my errors, so don't give up on me.)

Point 1: Coasting is either not 100% efficient, or is pointless in contrast to using regen. If a downhill slope is so gradual that coasting does not speed you up, then you don't gain any kinetic energy from it and you wouldn't gain any electrical energy from regen. That is the pointless case. If the slope is steep enough to speed you up, then the higher speed causes you to lose additional energy from air resistance, energy that you would not lose if you held your speed constant, as you would with regen. Clearly a loss of efficiency. (Again, regen also has efficiency losses. I'm only saying that neither is 100% efficient.)

Point 2: Coasting, as practiced on a through road without speed impediments, is antisocial. Now, antisocial doesn't matter if you aren't interacting with other people, so I have no objection to how unevenly you drive if you are the only car on the road. But I do object strongly to trying to follow someone who is constantly changing their speed. And I also object if I decide to go around them while they are going slowly, and then they speed up as I attempt to pass. I call those behaviors antisocial because you are making it more difficult for others to share the road with you. Also, many of our highways are heavily traveled, and the most efficient way to use them is for all cars in a line to move at a steady speed. Speeding and slowing can cause traffic jams, and that is highly antisocial.

Finally, in my defense, let me say that, just as I have misjudged you, you have also misjudged me as a driver. I normally drive in the right lane of a freeway at a constant 60 mph when the traffic allows. When I see slow traffic ahead I tap my brakes twice and then use engine braking (ICE) or regen (Prius) to reduce my speed if feasible. On city streets I watch traffic signals as far ahead as I can and try to coast up to red lights, with a goal of not having to stop completely at all.

 

[garygid]

p4e,
Your description of energy use in Point 1 is a common, but incorrect, perception. Please allow me to TRY to explain, because MANY folks are confused about Regen and Coasting.

Use of UNNECESSARY braking (Manual or Regen), WHEN pure coasting would be sufficient for the driving situation, is always an unnecessary loss of energy (and usually speed, but it can be unnecessarily limiting a speed gain when going downhill), thus an unnecessary loss (or use) of kinetic or potential energy.

When you NEED to slow or stop, and the drag forces during coasting are NOT sufficient to slow the vehicle enough, then some form of additional braking becomes NECESSARY. In this case braking using Regen recovers SOME of the kinetic (or potential) energy, converting it into electrical energy, used to charge the battery, to be used again later. This process of (re)generation, charging, and using again has its own (often substantial) losses, but it is better than "throwing away" the energy (as heat) in the mechanical brakes.

So, developing the driving "habits" (perhaps skills) to NOT require extra slowing (braking), thus keeping a more UNIFORM speed, would seem to address your Point 2. Many confuse the "hypermiler" technique of "Pulse & Glide" (NOT a uniform-speed technique) with appropriate coasting (a MORE uniform-speed technique). Example: noting the timing of the red light a block ahead, you decide to quit accelerating earlier, and coast up to the light, going slower, but avoiding much of the unnecessary braking (just before stopping becomes necessary, if it does at all). Yes, this "slowpoke" technique is not as "macho" as traveling FAST up to the light, braking, and sitting there in line waiting for the light.

HOWEVER, the "slower" (but MORE uniform speed) driving is likely to frustrate the "more macho" drivers behind you, because they might be "anxious" that others will pass you, and cut in line in front of you, so that they will then be a car (or several) further back when the light changes. True, the more energy-efficient driver is blocking the path for the "race to be first at the next light" folks. So, staying well to the right is the more polite thing to do.

 

[DaveinOlyWA]

+1 Gary.

we all (most of us anyway) weigh our actions and interactions with the multitudes around us 24/7 and driving is no different.

so bringing up points about hypermilers impeding traffic is not really appropriate here. that is OFF TOPIC.

despite driving Priuses for 7 years and always getting better than EPA, i am not a hypermiler. just a sensible driver who has chosen to spend most of my commuting time moving. so i have opted out of the "spent the most time at the light" contest.

so how many times has someone gone flying around me just to slam on their brakes at the light? almost every fricking day and on a multi lane road, i really dont care what they do or why they did it. i am doing NOTHING wrong

 

[EVDRIVER]

I'm sorry I upset you so much, and I apologize for misunderstanding what you were saying. I did assume that you were talking about speeding (above the limit) down hill, and I do now see that you didn't say that. That takes the wind out of my "unsafe and illegal" points. I could still find ways, by stretching a point, to argue for them, but I know I couldn't convince you.

I will, however, continue to argue for two points I made. (As in all things, I am willing and able to be convinced of my errors, so don't give up on me.)

Point 1: Coasting is either not 100% efficient, or is pointless in contrast to using regen. If a downhill slope is so gradual that coasting does not speed you up, then you don't gain any kinetic energy from it and you wouldn't gain any electrical energy from regen. That is the pointless case. If the slope is steep enough to speed you up, then the higher speed causes you to lose additional energy from air resistance, energy that you would not lose if you held your speed constant, as you would with regen. Clearly a loss of efficiency. (Again, regen also has efficiency losses. I'm only saying that neither is 100% efficient.)

Point 2: Coasting, as practiced on a through road without speed impediments, is antisocial. Now, antisocial doesn't matter if you aren't interacting with other people, so I have no objection to how unevenly you drive if you are the only car on the road. But I do object strongly to trying to follow someone who is constantly changing their speed. And I also object if I decide to go around them while they are going slowly, and then they speed up as I attempt to pass. I call those behaviors antisocial because you are making it more difficult for others to share the road with you. Also, many of our highways are heavily traveled, and the most efficient way to use them is for all cars in a line to move at a steady speed. Speeding and slowing can cause traffic jams, and that is highly antisocial.

Finally, in my defense, let me say that, just as I have misjudged you, you have also misjudged me as a driver. I normally drive in the right lane of a freeway at a constant 60 mph when the traffic allows. When I see slow traffic ahead I tap my brakes twice and then use engine braking (ICE) or regen (Prius) to reduce my speed if feasible. On city streets I watch traffic signals as far ahead as I can and try to coast up to red lights, with a goal of not having to stop completely at all.

Many of your points are correct, there are theorists vs those with real world EV driving experience and also those that believe a hybrid driving experiences are the same. In addition not all people drive in the same topography, traffic conditions or style (for many reasons). You can at times get more regen with the technique you describe and the LEAF has a COMPROMISE regen system for an EV that WILL cost some drivers efficiency under certain conditons, even Nissan would admit this if you asked a competent person and it has been alluded to in some descriptions by Nissan marketing execs. Use your real world experiences to validate your theories as that will provide good evidence, the LEAF is not an ultra efficient EV so to see these differences is not always clear and also more difficult to monitor because of gauges and reporting and the detail needed at specific moments to identify and learn these changes. Coasting has other loads besides wind as well. Stick to your theories and don't worry about those from some that don't own EVs and or never will or internet "ICE experts". This is not as much a question of "if" but when and how much.

 

[planet4ever]

p4e,
Your description of energy use in Point 1 is a common, but incorrect, perception. Please allow me to TRY to explain, because MANY folks are confused about Regen and Coasting.

Use of UNNECESSARY braking (Manual or Regen), WHEN pure coasting would be sufficient for the driving situation, is always an unnecessary loss of energy (and usually speed, but it can be unnecessarily limiting a speed gain when going downhill), thus an unnecessary loss (or use) of kinetic or potential energy.

It doesn't sound to me as if we disagree, Gary. I didn't repeat it in my latest post, but earlier I had said, "My personal opinion is that coasting ... wastes less energy than regen." (Yes, I left part of the quote out, because we have disposed of the unsafe and illegal contentions.) Isn't that what you are saying, that coasting can be more efficient than regen? I hope I'm not belaboring this too much, but my point was that there is no real loss for either coasting or regen on a gradual slope, and that there is some loss for each approach on a steeper slope. If you have a valid argument against either part of that statement, I have missed it, and you will have to try again. Remember, this whole thing started because of rmay635703's statement that, "Coasting is 100% efficient."

 

[DaveinOlyWA]

what it really boils down to is that there just as many ways to drive efficiently as there are driving situations and that is a lot and its all dependent on the "here and now"

take the same route every day for years and you will not drive it the exact same way more than twice because you must constantly weigh dozens of variables a minute.

its like the carwings competition. its really meaningless since the playing field cant be equal even if living in the same area.

many times i have talked with co-workers who took the same general route to work and they would be caught in an accident and i wouldnt when we were on the same road but just a few minutes apart.