Using the Range Chart (is mi/kwh from dash/nav accurate?)

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NYLEAF

Well-known member
Joined
Oct 5, 2011
Messages
574
Location
Long Island, NY
Hello all...

I have been reading/posting/lurking these forums for months, and I have even printed and laminated a copy of Tony's range chart for my car, but I still don't fully understand this...is the mi/kwh shown on the Energy/Status screens accurate for use with the range chart? What about the one from the smaller screen next to the range bars? I reset both at different times (a few days after getting the car), but after about a week of driving, they've both settled on 4.1 mi/kwh. So, if I multiply 4.1 times 21 (or really more like 18.9 since at 30F there's about a 10% reduction in available energy, right?), I should figure out how far I can go, assuming I keep that same average, correct?

What's a best practice for figuring all this out? I've seen some people reset all of their trip counters, energy economy counters, etc, after the end of each trip, but I haven't really seen a consensus on exactly what I should be doing to track all of this. I've also read that the Carwings data differs from the car, and if I had a separate meter, or a Blink EVSE, or a TED device (I have none of these things), I would get different figures. My Carwings, at least for now, shows no data whatsoever (I do press OK every time I turn on the car, so I'm not sure what the issue is...)

Any help would be greatly appreciated!
 
I'm sure everyone has their own experiences. Here's mine:

Most days I don't care about keeping track of mileage because I know I won't come close to needing the 80% charge I put in the night before.

I use the chart only when I'm not familiar with my route. I've taken my LEAF on a few trips over 150 miles and have found the chart useful during those trips. I use it for planning purposes mostly, where I can confirm my expected power-up stops.

Once I've traveled a route, I don't normally refer to the chart again.

Believe me, the chart comes in handy.
 
In order to use the LEAF displays effectively with the chart, you need to reset the display, either the energy display or the one on the main dash, before your trip starts. Then if, for instance, you are doing a lot of fast highway driving, you'll see the impact of those high speeds on your efficiency, which will be lower, and the chart will reflect a shorter range. And vis-versa, of course, for more efficient, steady and slower speed driving. If you don't reset your displays, you'll be working with the average of your previous days of driving, and that won't reflect the driving that you're doing on the trip that you're concerned about.

Does that make sense?
 
NYLEAF said:
...is the mi/kwh shown on the Energy/Status screens accurate for use with the range chart?

That reading should be 0.1 miles/kWh higher than the dash mounted reading. Either is fine to use, to be honest, but my data is based on the lower dash mounted info.


I reset both at different times (a few days after getting the car), but after about a week of driving, they've both settled on 4.1 mi/kwh. So, if I multiply 4.1 times 21 (or really more like 18.9 since at 30F there's about a 10% reduction in available energy, right?), I should figure out how far I can go, assuming I keep that same average, correct?


You need to reset from the point where you'll be measuring. That is normally at a 100% or 80% charge. So, fuel up, reset which ever economy meter you wish to use, and use the chart to guess what your miles/kWh might be. Driving down a level road at sea level, with 70F battery temps, nil wind, no climate control, windows up, tires with 36psi or better, no aerodynamic changes to the car (like a roof mounted bike rack with 3 bikes on it), no exceptionally heavy load, etc....

Then, you should be able to count on 3.9 miles/kWh for that portion of the drive done at 60mph. What many folks don't factor is that if you plan 60mph, it might take some stop and go driving before you get to an open highway to drive 60mph. Depending how you drive, that can raise or lower your average when you finally get to 60mph at a steady speed. If you're curious, you can reset one of your economy meters once steady at 60mph on that flat, no wind highway, and it should settle in at 3.9miles/kWh over 10 or more miles. Of course, the center console data will be 0.1 higher, at 4.0.

To calculate your overall range, I think you got it right. Using the economy meter that was reset at 100%, simply multiply by 21. For 80% charges, use 17. So, 3.9*21=82 miles of range from 100% charge and 3.9*17 for 80%, or 66.3 miles.

Adjustments for temp are based on the battery temperature. Unfortunately, that's a bit difficult to determine without an accurate battery temperature gauge. Generally, if the car hasn't been charged or driven for 8 hours overnight, and was sitting outside, the battery is probably "cold soaked" at ambient air temperature. I say overnight, because even cold temps with the daytime sun's radiation will heat things up.

There is a consideration for cell balancing, but if the car was charged to 100%, and met the threshold for balancing, the BMS automation will do that over a time up to 4 hours after the 100% charge was completed. The car must have been left plugged in during this time.

So, back to your example, yes, 70F - 30F = 40 temperature delta / 4 is 10% reduction in battery capacity, and thus range. If your 60mph drive lasts one hour, you'll might use some climate control at 30F outside.

Your battery capacity is 21 - (21*0.1) = 18.9kWh, as you correctly calculated, leaving a 73.7 mile range (18.9*3.9). Don't subtract your heater use from your battery capacity, because it will be reflected in the lower economy, in addition to the lower economy just to extract the energy from the colder battery. I have no idea what might keep you comfy, but let's say you'll use an average of 2kW of heating. Over an hour, that's 2kWh used.

That should equal about a 10% loss of economy, from 3.9 down to 3.5 miles/kWh to travel that 60mph, multiplied by 18.9 battery capacity, will leave 66.1 miles of range (3.5*18.9).

Then, of course, whatever adjustments for elevation changes, headwinds, density altitude, gross vehicle weight, etc.


I've also read that the Carwings data differs from the car, and if I had a separate meter, or a Blink EVSE, or a TED device (I have none of these things), I would get different figures. My Carwings, at least for now, shows no data whatsoever (I do press OK every time I turn on the car, so I'm not sure what the issue is...)!


Yes, there are two versions of CarWings. Newer cars, and those with the 11-041 firmware update, are 2.5% off on miles traveled. Older cars are seemingly more accurate on mileage, but grossly off base on everything else. Data from a TED or Blink don't reflect charger inefficiency of 73% at 120v, and 84% at 240v.
 
I never used Tony's chart and I always charge to 100%. I do have a SOC meter and I try to get 4.0 mi/kwh... I haven't run outta juice operating this way now for almost 16,000 miles... :ugeek:
 
TangoKilo said:
I never used Tony's chart and I always charge to 100%. I do have a SOC meter and I try to get 4.0 mi/kwh... I haven't run outta juice operating this way now for almost 16,000 miles... :ugeek:

Just looking at a Gidmeter (I presume that's your SOC meter), with 281 showing at 100% charge, how does that tell you how far you can go?

Of course, there are thousands who have used neither the Gidmeter, nor the range chart, and not ran out of juice.

I, on the other hand, have both, and have ran out several times.
 
TonyWilliams said:
TangoKilo said:
I never used Tony's chart and I always charge to 100%. I do have a SOC meter and I try to get 4.0 mi/kwh... I haven't run outta juice operating this way now for almost 16,000 miles... :ugeek:

Just looking at a Gidmeter (I presume that's your SOC meter), with 281 showing at 100% charge, how does that tell you how far you can go?

Of course, there are thousands who have used neither the Gidmeter, nor the range chart, and not ran out of juice.

I, on the other hand, have both, and have ran out several times.


Are we still talking about cars? Or other vehicles... :mrgreen:
 
Some folks rarely travel far enough to even bother to think about Range.
They just need to remember to "rE-fuel" occasionally, as suits their E-Fuel usage.

Other folks try to squEEze out every "E-lectron" from the last "edi" (a kWh, after T. Edison) stored in their car's E-tank! They travel amazing distances, and generally have lives filled with far more Ed-venture than I do.

Fortunately for the rest of us, Tony is a leadEr in this fasinating phase in the saga "The Journey of the Humanoids", called: "Rising from the Tar Pits". :eek: :) :D :lol:

Thanks Tony, for all your Contributions, Sharing, Kindness, and Help.
 
if you are having trouble juggling all the variables, don't be afraid to use the chart as a general rule of thumb and also perfect your skills at using the tools the car came with. I find it a bit dizzying to try and factor in all the variables that are constantly changing as I go up and down hills, temperature changes and changes in speed and so on. the car can be pretty good at factoring in all the changes, but it does depend on your commute.

I don't update the MPkW on the main energy screen, I use that to track lifetime MPKw. To get good at driving efficiently, zero out the trip odometer and trip MPkW, ignore the GOM in the beginning, keep the energy meter to 2-3 bubbles rather than focussing on speed... yes, this will mean slowing down some times quite a bit going up hills. I shoot for 4 MPkW or better and have achieved that as low as 28 degrees F. preheat extensively while charging from 80 to 100% to warm up the core of the car and turn off the climate control for the beginning of the drive until you get too cold, then turn it on. using foot/defog mode seems to work the best for keeping the windows clear with Climate control off. it appears that warming and charging at the same time improve both the battery capacity and the MPkW efficiency if driving while still warm. getting the battery temp up to 5 bars seems to be a good target, though we really need a true battery reading to determine an accurate target temp. If you can keep your garage up to 45 to 50 degrees, that seems to be a sweet spot. Once I'm under way I start adding the GOM to the trip odometer and make sure it adds up to my target destination distance (the GOM gets surprisingly accurate towards the end if you are not driving up or down continuously), if I"m falling short I stick closer to two bubbles on the energy meter, if I'm flush I'll drive more in the 3 bubble range. if I have enough that I'm sure I won't run out, I don't bother worrying so much and just enjoy driving.
 
Thanks for the replies, everyone.

Right now, I am just charging on L1 (waiting for my LeGrand unit to show up sometime this week), and I do not have a garage, so my car will always be parked out on the driveway, in the cold.

I feel as though I've gotten pretty good already with keeping myself limited to the first 2 or 3 bubbles, and using regen effectively. There are no real hills here, though...Long Island is pretty flat! I'm going to be attempting an 80 mile (round-trip) journey to see family in New Jersey in the next couple of weeks. I've already called ahead and confirmed that Staten Island Nissan (conveniently located about mid-way between my home and my destination) has no problem letting me charge up on L2, but I'd really like to attempt the trip without having to stop for charging. According to GPS visualizer, the highest elevation we hit is 240 feet or so, and I'm pretty sure that's actually when we go up and over the Verrazano Bridge. I'm basically just trying to use the chart to confirm to myself that we can make it, but considering the temps are in the 30s and 40s, maybe we can't after all.
 
I visited friends in Pinehurst, NC, over the weekend. It is 68.x miles to their house, and 3 miles from there to the Nissan dealership that let me inaugurate use of their L2 EVSE. Going down there from Chapel Hill, my speeds were anywhere from 20 (small town center) to 65 (limited access highway). The 65 was just for a few miles. Temperature was 56-58 degrees, and we arrived with about 18 miles on the GOM. The energy meter showed 4.7 average mileage. It was sunny :)

Coming home, I was thankful I had read everyone's reports on "what happens as you are about to lose it all". Temperature began at 47 and declined to 41 as we drove north. It was drizzling, and the windshield constantly fogged up. Initially I used the defroster for a half minute at a time, but eventually gave up and opened the windows. The weather folks had been predicting 50 for a high, so I was surprised by the sub-45 temps.

About 23 miles from home, we were warned (GOM read 25) that "we would not make our destination" and the nav system advised us to find a charging station. Around here, the only charging stations are at Nissan dealerships, plus some of the larger cities and towns (my own town has no public charging stations of which I am aware). We also have friends a couple of miles from where we got the warning... we could probably have used their 120V circuit if we'd asked.

Well, had we left at our scheduled time, we would have had time to stop at about the 30 mile mark at a Nissan dealership, warm up the car and get some juice. However, we left late, and I still had to cook some ribs to take to my mom's for a Super Bowl evening. Once we were in locations where passing was easy, I did the "drive like a little old lady" thing and stayed from 5 to 10mph under the speed limit. The last few miles of the drive are all at much lower speeds (35 max), and so I figured that gave us a little leeway. We got home with my first "low battery warning" and 8 flashing miles on the GOM. Odometer indicated 71.4 miles on that charge, 4.2 miles per kw. We used no heat, ever, and opened the windows every little while to clear the windshield. My partner had all the coats piled all over her, but I was warm from being nervous. Didn't even turn on the heated steering wheel until we were 5 miles from home.

Lesson learned - I had recharged the evening before our return and then picked up the car so as to leave at noon the next day. I should have left it plugged in and pre-heated and then gotten the car just before leaving. Also, I better not trust the weather people about temps! And, go a mile off course to the half-way point Nissan dealership!! Leave on time so there's time to do that!!

I never lost any "power bubbles" - which gave me heart to keep going, knowing that all speeds within 5 miles of home were 35 or less.

Thanks to all you guys who shared what to expect. I only swore a couple of times, but driving so slowly was not fun. Fortunately there was very little traffic, and I think only one time did I hold anyone back until we crested a hill and there was a passing location (two lane road - one lane each way).

NYLEAF - maybe this story is helpful for your situation. I had a lot more ups and downs than you describe so you may have a different experience. (I was in the "sandhills" - just hills, not mountains the way the West coast guys have).
 
NYLEAF said:
Thanks for the replies, everyone.

Right now, I am just charging on L1 (waiting for my LeGrand unit to show up sometime this week), and I do not have a garage, so my car will always be parked out on the driveway, in the cold.

I feel as though I've gotten pretty good already with keeping myself limited to the first 2 or 3 bubbles, and using regen effectively. There are no real hills here, though...Long Island is pretty flat! I'm going to be attempting an 80 mile (round-trip) journey to see family in New Jersey in the next couple of weeks. I've already called ahead and confirmed that Staten Island Nissan (conveniently located about mid-way between my home and my destination) has no problem letting me charge up on L2, but I'd really like to attempt the trip without having to stop for charging. According to GPS visualizer, the highest elevation we hit is 240 feet or so, and I'm pretty sure that's actually when we go up and over the Verrazano Bridge. I'm basically just trying to use the chart to confirm to myself that we can make it, but considering the temps are in the 30s and 40s, maybe we can't after all.

How long is the visit? Do they have 240v available for charging? 40 miles out, charge up, 40 miles home sounds easy even at 35F.
120v might make for a longer stay but not necessarily overnight.

The evse upgrade really shines for these trips. If you have not upgraded, I suggest sooner rather than later.
 
NYLEAF said:
According to GPS visualizer, the highest elevation we hit is 240 feet or so, and I'm pretty sure that's actually when we go up and over the Verrazano Bridge. I'm basically just trying to use the chart to confirm to myself that we can make it, but considering the temps are in the 30s and 40s, maybe we can't after all.

I wouldn't waste any effort on factoring elevation in your neighborhood. The temperature, you can factor. The heater is usually the big variable. Absolutely preheat the interior of the car, and just use the seat and wheel Warner's the first time you try this trip.

Please keep track of those landmark events of Battery Low and Very Low with the odometer, not the GoM. Then report back with the data (again, please no GoM or CarWings) and we can critique and debrief your trip.
 
It's actually a nursing home that I'll be at for a few hours, so I doubt there's any way I could plug the car in while there. I'm a bit too shy to even ask them. There is a Chargepoint about 5 miles away, but it's located in the parking lot of some office complex, with absolutely nothing to do within walking distance, and it would be impossible to get from the car to the nursing home and back without taking a taxi, and it would add 10 miles to the trip, so it's totally out of the question.

I'll keep track of the warnings, although I'm sort of hoping to avoid them all together...I really don't need the stress of thinking I'm going to run out of charge!

It looks like I'll be spending an hour or two at Staten Island Nissan. I looked at Google Maps, I see some restaurants within walking distance, so it shouldn't be too bad.
 
I made the round-trip to New Jersey and back today. The weather was pretty crappy, about 40F and it started raining a few minutes after we left home. On the way there, we took the most direct route, which saved us a few miles and took us on side streets (rather than the parkways), but I felt as though the traffic on this route and the constant red lights actually hurt us more than helped.

40 Miles later, and with 4 full bars remaining, we arrived at the nursing home, where we spent the next 5 hours. A helpful nurse and asked someone from maintenance about charging, and I was permitted to park in front of the building and plug into a regular outlet (I brought a long extension cord). About 2.5 hours later, they made an announcement asking the owner of the blue Nissan Leaf to come to the front desk...apparently, whoever had given me permission to charge (and shown me which outdoor plugs work, and which do not) did not have the authority to do so, and I need to "stop siphoning [their] electricity" and "move your car to a regular parking space, like everyone else. OK, fine. I offered them $0.50 as reimbursement for the electricity I "stole". :lol:

We left with 6 bars and arrived at Staten Island Nissan (11 miles away) with just 3 bars remaining -- I'm assuming that we did not have a full 6th bar when we left the nursing home. I had to keep putting on the defroster because the windows were really fogging up, so that probably hurt my range as well. When we arrived at SI Nissan, they literally had cars blocking the entrances to their (extremely tiny) lot. I parked on the street and went inside, and informed them that I wanted to charge my Leaf. (I had also called ahead, and I was assured that nothing was blocking the charging stations, and I was more than welcome to stop by for some free juice). I have to say, they were actually extremely nice about the whole thing, considering that I did not buy my car from them, and I had no intention of buying anything from them. It did take about 15 minutes, but they moved 3 other vehicles out of the way, and I was able to pull up next to the Red Leaf and black Juke that were occupying the two charging spaces. It was at this point that I really panicked, as I plugged my car in and only heard one beep, not the usual 2 or 3 that sound when the car is charging successfully. The blue lights on the dashboard did not light up, either. I quickly walked over to the charging station, and I saw that no lights were on, at all. The helpful Nissan dude (General Manager?) came over and suggested I press the green "Start" button -- nada. I showed him how the "Power Present" light was not even lighting up, and I suggested maybe they needed to switch on a breaker or something of the sort. He went inside, and 30 seconds later, both stations were lit up and I was charging! Again, I really have to stress just how nice and accommodating the staff at Staten Island Nissan were. They absolutely went out of their way to make sure we got enough of a charge to get home, and there really were quite a few opportunities where I expect a lot of dealers would have just said "Forget it, this isn't worth our effort". We originally arrived at 6pm, and the car was charging by 6:30pm. There's quite a bit of stuff within walking distance -- we went with "Brooklyn's Finest Pizza" (despite the fact that we were in Staten Island, not Brooklyn...).

We left at about 8pm with 6 bars and the GoM saying 55 miles for our 27 mile drive home. On the return trip, we took the parkway route (the Belt Parkway, for those keeping score), instead of the more direct route with the millions of red lights (Linden Blvd.) Thanks to the weather, the average speed on the Belt was more like 40 mph instead of the posted speed limit of 50, so I was able to conserve quite a bit of power, I think. We made it home with 3 (maybe 2.5) bars and the GoM saying 26 miles -- car is predicting 18 hours to recharge on 120v.

Before the rain started in the morning, I was averaging 4.9 mi/kwh, and by the end of the trip, our overall energy economy for the trip was 4.3 mi/kwh. The rain definitely had a noticeable effect.

I'm left wondering just how much kwh I actually used, and how much I actually had available. I should note that the elusive (for me, anyway) 5th battery temperature bar appeared after plugging the car in at SI Nissan. Did we really need to stop at SI Nissan? The GoM was saying 25 miles when we pulled up, and we had a 27 mile trip ahead of us, so of course we stopped -- but did we need to? I originally thought the 80 mile round trip should be do-able, especially if we took the short route through Brooklyn and really made it a 72 or 73 mile roundtrip.
 
NYLEAF said:
... averaging 4.9 mi/kwh, and by the end of the trip, our overall energy economy for the trip was 4.3 mi/kwh. The rain definitely had a noticeable effect.

I'm left wondering just how much kwh I actually used, and how much I actually had available. I should note that the elusive (for me, anyway) 5th battery temperature bar appeared after plugging the car in at SI Nissan. Did we really need to stop at SI Nissan? The GoM was saying 25 miles when we pulled up, and we had a 27 mile trip ahead of us, so of course we stopped -- but did we need to? I originally thought the 80 mile round trip should be do-able, especially if we took the short route through Brooklyn and really made it a 72 or 73 mile roundtrip.

Your overall 4.3 miles/kWh suggests 90 miles of range, less about 8% reduction for temp, so about 82 miles. Sure, I think you would have made a 73 mile trip, however, you would have seen the LBW, but not the VLBW. The fifth battery temp bar suggests a battery that just went over 50F.

The GoM is not data that I use ever.
 
Congradulations on a good "first trip".
For any trip, especially a "new" trip, it is good to have a Plan B.
You did well, it seems.

Not knowing where you are in a Fuel-Bar ... can be frustrating.

As you do the trip again, you will gradually learn your LEAF's limits, and amazing capabilities!

Thanks for sharing.

Do you have the excellent free Range Estimator chart by "TonyWilliams"?
 
I actually keep a modified copy of Tony's range chart in my car. There are four versions, one for 70F, one for 50F, one for 30F, and one for 10F. I modified the chart in Excel so that it's smaller (I got rid of the gid information) and fits on half a page of paper. I also added the phone number for road-side assistance. The four charts are laminated and stay on the driver's side sun visor in the little strap thing that is there. My only regret is that I didn't make them double sided, as I could have only had two charts instead of four (and saved myself a sheet of lamination paper).

On this particular trip, I was really trying to avoid any battery warnings, which is also what motivated me to stop. Also, I don't have L2 at home currently, so coming home with an entirely dead battery would have meant a very long recharge time, and as I had work the next day, that wouldn't have worked too well.
 
The displayed digital miles/kWh value (not the bar-graph) is an "approximate" average of the PAST (since it was last cleared). It does not attempt to predict the FUTURE, you have to do that yourself, probably using past experience (yours and others) to estimate (or guess) what your future "mileage" will be.
 
Right, I understand this. I've been resetting the dashboard's mi/kwh meter each morning when I leave to track my progress for the day. On days where I'm being careful, it's easy for me to be in the 4's...on a day like today, when I knew I was barely driving 20 miles (and I knew that my destination was actually a Nissan dealer (buying an Altima), where I could charge if necessary), my economy is in the 2's. The highest I have ever seen was 4.9, and that was when I was first starting out on my journey to New Jersey. As soon as the rain started, the number dropped down to around 4.5, and that was before I started any highway driving. I know it was the rain doing it, and not my driving style -- the speeds stayed the same during that time, and my driving style really didn't change at all.
 
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