mkjayakumar
Well-known member
Of course, I am very impressed and very encouraged by what I saw today. Perfect conditions though. 80F with no wind.
The high temp may explain most of it. The temp was well above ISA, and the density altitude was probably well above your altitude MSL (depending on the atmospheric pressure), decreasing the drag. You may have gained some battery capacity too.mkjayakumar said:Of course, I am very impressed and very encouraged by what I saw today. Perfect conditions though. 80F with no wind.
garsh said:After charging to 100%, I was down to ~18% after the round trip. I've only been driving 55mph on the highway. I was hoping that I could get away with charging to only 80% regularly, but this now seems unlikely. I haven't used the heater yet. I'm getting about 4.2-4.3 m/kWh. I have to say I'm a bit disappointed.
ILETRIC said:Re: tire pressure.
Leaf tires are rated at 44 psi (the usual). I run them at 38. It is a bad idea to have them at 44. Your center tread will thin out faster
If you were maintaining 4.2 m/kWh, at LBW you should have about 12 miles before turtle and another mile to dead, not 8. The GOM is known to be a bit pessimistic when the battery is low, and optimistic when the battery is high.mkjayakumar said:While the range pretty much matches with Tony chart, the miles/kwh I got was much higher. How is that possible ?
As mentioned above, if you got 76 miles at LBW, you should have been able to drive about 89 miles, not 83 miles - or basically 90 miles - definitely within the margin of error here. 21 kWh isn't conservative, either - it's pretty much the maximum people see.mkjayakumar said:If the 4.2 miles/Kwh was indeed the efficiency, then assuming a conservative 21KWH usable capacity, I should have got a range of 90 miles with sustained speed of 65 mph. But in reality, If I had continued driving at 65mph, I would have got no more than 83 miles. Where did the 7 miles go? battery capacity degradation ?
Herm said:Try it again with the tires at maximum sidewall pressures, or higher.
Didn't you mean to say 0.10%? :lol:Herm said:Inflating to 44psi might give you an extra 10% in range.. try it.
mkjayakumar said:[If there is a topic for this mods please move it, but I couldn't find..]
Now that we all know how much one can get at speeds less than 40 mph, which is around 5.0 miles/kwh, or a range approaching 100 miles to a full charge., I am more interested in knowing what one should expect if I were to drive at a constant highway speed of 65 mph. More than the range, I think the miles/kwh is a better parameter for us to evaluate than the the actual range, because that parameter can tell you with reasonable accuracy how much one can drive on a specific SOC %.
On a test drive today I got 3.8 miles/kwh with the following parameters:
- Cruise control driving at 65 mph
- relatively flat TX 121 in DFW area
- no climate control.
- ECO mode
Is 3.8 miles/kwh a good number for the Leaf ? If so can I assume that on a full charge given that the usable capacity is no more than 21 KWH, I can expect a range of 21*3.8 = 79 miles to VLB ?
Will I get better with or without Cruise control ?
-Jay
garsh said:I've only had my Leaf a few days. I have a 30-mile commute, and I was hoping to only charge after a round-trip (60 miles). But I live in western PA, so the terrain is fairly hilly, the weather has been pretty cold (~30°F in the morning), I usually have to have my headlights on, and it rains a lot so the windshield wipers have been running half the time.
After charging to 100%, I was down to ~18% after the round trip. I've only been driving 55mph on the highway. I was hoping that I could get away with charging to only 80% regularly, but this now seems unlikely. I haven't used the heater yet. I'm getting about 4.2-4.3 m/kWh. I have to say I'm a bit disappointed.
drees said:If you were maintaining 4.2 m/kWh, at LBW you should have about 12 miles before turtle and another mile to dead, not 8. The GOM is known to be a bit pessimistic when the battery is low, and optimistic when the battery is high.mkjayakumar said:While the range pretty much matches with Tony chart, the miles/kwh I got was much higher. How is that possible ?
Tony's chart also has a couple assumptions:
1. You have a perfectly healthy and full battery capacity available, 21 kWh. Unless you have a GID reading before you leave, it's not possible to verify this.
2. His efficiency numbers are slightly pessimistic in my experience. Maybe his car rolls slightly less efficiently? 80*F temps and any elevation above sea level will help efficiency. On the highway, I also find that traveling in a pack of cars going the same speed improves efficiency, too.
As mentioned above, if you got 76 miles at LBW, you should have been able to drive about 89 miles, not 83 miles - or basically 90 miles - definitely within the margin of error here. 21 kWh isn't conservative, either - it's pretty much the maximum people see.mkjayakumar said:If the 4.2 miles/Kwh was indeed the efficiency, then assuming a conservative 21KWH usable capacity, I should have got a range of 90 miles with sustained speed of 65 mph. But in reality, If I had continued driving at 65mph, I would have got no more than 83 miles. Where did the 7 miles go? battery capacity degradation ?
Keep in mind that people have found that occasionally the car will go into VLBW and then turtle a few miles earlier than expected (Tony included) so it's best not to rely on the distance beyond VLBW unless you absolutely have to!
planet4ever said:Didn't you mean to say 0.10%? :lol:Herm said:Inflating to 44psi might give you an extra 10% in range.. try it.
I've been keeping the cruise at 55mph on the highway, and putting it into neutral for long downhill runs. Basically, what I was doing in my ICE vehicle before.lpickup said:I was going to say give it some time to get used to the car (it took us at least a few weeks to improve our driving habits). But you're getting as good mi/kWh as we are so you're probably already doing fine!
I'm currently experimenting with pushing back the charge starting time so that it's not quite fully charged when it's time for me to leave. I thought that would be better for the battery since it will spend less time charged that high. I'll see how close I can get to 80% that way.And even if 80% doesn't quite give you the range, you can get into the habit of charging to 80% and then starting a charge (or pre-heat/cool) 30-45 minutes before your departure time to get you up to 90% (or whatever range makes you feel comfortable).
mkjayakumar said:Next test run with AC ON
- Distance travelled: 40 miles
- Speed: 65mph on Cruise control
- ECO mode
- Temps: Sunny & 79F
- Miles/kwh seen in the dash: 3.8
Observations:
- From 4.2 to 3.8, that is a penalty of 0.4 miles/kwh for the AC, or around 10 miles range to a full charge.
- also noticed that the energy consumption meter for CC stays around the 0.5 mark.
- Keeping the fans running with AC off, has no noticeable power consumption.
- The range impact on AC would be more at lower speeds, simply because you will be on the road longer with stop lights and such.
mkjayakumar said:Next test run with AC ON
- Distance travelled: 40 miles
- Speed: 65mph on Cruise control
- ECO mode
- Temps: Sunny & 79F
- Miles/kwh seen in the dash: 3.8
Observations:
- From 4.2 to 3.8, that is a penalty of 0.4 miles/kwh for the AC, or around 10 miles range to a full charge.
- also noticed that the energy consumption meter for CC stays around the 0.5 mark.
- Keeping the fans running with AC off, has no noticeable power consumption.
- The range impact on AC would be more at lower speeds, simply because you will be on the road longer with stop lights and such.
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