IS THIS NORMAL FOR A LEAF?

[ELROY]

I raised my pressures to 40psi the first day I picked up the car. Going to raise it to 44psi next.
Also I assume that the 7hrs of estimated charge time taking only 6hrs is typical..and not a result of reduced battery capacity?? I am using the 16ampto EVSE upgrade.

I would go to 44psi. Like I said, I'm running 50. (But I don't recommend that!)

If you run the pack down all the way until it cuts off after turtle, it can take almost 7 hours for a full charge on 240v 16a. If you don't run it until it cuts off, then it will be a shorter time. If it's cold, it could take a little longer. You can't go by charge time as a reliable indicator of capacity loss.

-Phil

After driving 24 miles yesterday, I charged it back up to 80% (have been trying the 80% limit for the last couple of charges). Estimated charge time was 3.5 hrs...actual was 3hrs. 2.9m/kWh efficiency. So if I didn't have the 16a ESVE upgrade, would it have been closer to the 3.5hrs to charge?

 

[shay]

[ Like I said, I'm running 50. (But I don't recommend that!)

Is the the recommendation for not running 50 for safety, wear, or ride reasons?

 

[ELROY]

Raised the tire pressures to 44psi the other day.

Today I ran it down to VLB warning ------. On a 80% charge, I covered 60.2 miles. Supposed to take 6hrs to charge back to 80% on L2.

This was done on 4.2 mi/kWh according to the dash.

Did a lot of driving at 25-35mph to bring it up from 4.0 to 4.2 in the last 10 miles of driving.

Also, wondering what is the clunk noise that happens in the front end when you drive first drive off in the morning. It like some heavy solenoid clunks once....normal??

And what is under the thing that looks like a filler cap in the rear trunk area under then cargo liner. It looks like some vent or something?

 

[surfingslovak]

Today I ran it down to VLB warning ------. On a 80% charge, I covered 60.2 miles. Supposed to take 6hrs to charge back to 80% on L2.

This was done on 4.2 mi/kWh according to the dash.

Did a lot of driving at 25-35mph to bring it up from 4.0 to 4.2 in the last 10 miles of driving.

These are nearly textbook numbers based on the metrics established for new LEAFs awhile ago on the forum:

80% charge: 17 kWh usable
VLB: 3.3 kWh usable

(17 - 3.3 ) x 4.2 = 57.6 miles

 

[planet4ever]

Also, wondering what is the clunk noise that happens in the front end when you drive first drive off in the morning. It like some heavy solenoid clunks once....normal??

Normal - ABS self check

And what is under the thing that looks like a filler cap in the rear trunk area under then cargo liner. It looks like some vent or something?

Access to emergency release for brake. See "Parking brake mechanical release" in the owner's manual, under "In case of emergency."

Ray

 

[ELROY]

Today I ran it down to VLB warning ------. On a 80% charge, I covered 60.2 miles. Supposed to take 6hrs to charge back to 80% on L2.

This was done on 4.2 mi/kWh according to the dash.

Did a lot of driving at 25-35mph to bring it up from 4.0 to 4.2 in the last 10 miles of driving.

These are nearly textbook numbers based on the metrics established for new LEAFs awhile ago on the forum:

80% charge: 17 kWh usable
VLB: 3.3 kWh usable

(17 - 3.3 ) x 4.2 = 57.6 miles

So heres something interesting..The 6hrs predicted charge time only took 4.66hrs actual to 80% charge again
On L2 16amp. How consistent is the charger stopping right at 80%? Will do the same test on this charge.

 

[ELROY]

Also, wondering what is the clunk noise that happens in the front end when you drive first drive off in the morning. It like some heavy solenoid clunks once....normal??

Normal - ABS self check

And what is under the thing that looks like a filler cap in the rear trunk area under then cargo liner. It looks like some vent or something?

Access to emergency release for brake. See "Parking brake mechanical release" in the owner's manual, under "In case of emergency."

Ray

Thanks...makes perfect sense. My GM ABS used to do that. The BMW not at all.

 

[surfingslovak]

So heres something interesting..The 6hrs predicted charge time only took 4.66hrs actual to 80% charge again
On L2 16amp. How consistent is the charger stopping right at 80%? Will do the same test on this charge.

Assuming 3.3 kWh net into the battery and about 95% to 97% battery efficiency, then the observed L2 charge time is spot on. The exact numbers would depend on your line voltage, among other things.

3.3 x 0.95 x 4.66 = 14.60 kWh
14.60 kWh x 4.2 m/kWh = 61.35 miles

Drees found a nice NREL report, which measured some of the internal metrics and efficiencies, which would could only guess at based on the measure numbers before.

 

[ELROY]

So heres something interesting..The 6hrs predicted charge time only took 4.66hrs actual to 80% charge again
On L2 16amp. How consistent is the charger stopping right at 80%? Will do the same test on this charge.

Assuming 3.3 kWh net into the battery and about 95% to 97% battery efficiency, then the observed L2 charge time is spot on. The exact numbers would depend on your line voltage, among other things.

3.3 x 0.95 x 4.66 = 14.60 kWh
14.60 kWh x 4.2 m/kWh = 61.35 miles

Drees found a nice NREL report, which measured some of the internal metrics and efficiencies, which would could only guess at based on the measure numbers before.

Its very interesting to see how all the little steps in the charging process takes it "toll" on efficiency.

Still amazing how 14.60 kWh of the 24kWh battery will take 10 of 12 bars of charging, especially when the 11th and 12 bar only get me a few miles extra of driving. It almost doesnt make sense.

So what is VLB warning considered?

At first the range flashers around 7 miles or so.
Then the yellow fuel pump warning comes on......

Then the -- -- -- range shows and a voice comes on asking to find a nearby charging station....is that considered VLB warning?

 

[surfingslovak]

Then the -- -- -- range shows and a voice comes on asking to find a nearby charging station....is that considered VLB warning?

Yes, exactly. VLB represents 2 kWh of stored energy, which translates to about 1.3 usable. LB is 4 kWh of stored energy, and only about 3.3 kWh usable. About 0.5 kWh is left in the battery as an iron reserve after turtle. This energy is not accessible to us. The remaining discrepancy between stored and usable energy can be attributed to battery losses. That said, both the drivetrain and the battery are pretty efficient. Hopefully, charging will get better over time. Too much waste heat is generated, and the cooling required to dissipate that heat, lowers the overall efficiency further.

Looking at my earlier post, I might have gotten the references between LB and VLB mixed up. If you drove to VLB instead of LB, then a larger portion of the battery was used (17 - 1.3 = 15.7 kWh), and more miles should have been driven (65.94). One possible explanation for the discrepancy would be a cold battery. The difference in available energy is about 10% between a battery at room temperature, and a battery that's in the low 30s. Either way, it's fairly close to what you saw.

 

[ELROY]

Then the -- -- -- range shows and a voice comes on asking to find a nearby charging station....is that considered VLB warning?

Yes, exactly. VLB represents 2 kWh of stored energy, which translates to about 1.3 usable. LB is 4 kWh of stored energy, and only about 3.3 kWh usable. About 0.5 kWh is left in the battery as an iron reserve after turtle. This energy is not accessible to us. The remaining discrepancy between stored and usable energy can be attributed to battery losses. That said, both the drivetrain and the battery are pretty efficient. Hopefully, charging will get better over time. Too much waste heat is generated, and the cooling required to dissipate that heat, lowers the overall efficiency further.

Looking at my earlier post, I might have gotten the references between LB and VLB mixed up. If you drove to VLB instead of LB, then a larger portion of the battery was used (17 - 1.3 = 15.7 kWh), and more miles should have been driven (65.94). One possible explanation for the discrepancy would be a cold battery. The difference in available energy is about 10% between a battery at room temperature, and a battery that's in the low 30s. Either way, it's fairly close to what you saw.

In my latest test session, started with 80% charge.
Temps 45-60F
Friday till Saturday...Mostly in town...0-35mph...dash read 5miles/kWh (my highest so far)
Then today (Sunday).. went on a 15mile trip...40-55mph speeds.....economy dropped down to 4.7miles/kWh
Then did the rest of the driving around town...25-35mph..to bring the economy up to 4.8 mi/kWh.

Hit the VLB warning at 67 miles.....5:30/19:00 estimate charge time till 80%.

Decided to drive it on the VLB warning till I hit 70 miles.
Estimated charge time till 80% is 6hr/20hr

I don't know how many more miles I would have achieved if I charged to 100%, but usually those 11-12 bars disappear really quick. Sometimes in just a few miles.

Still surprised I was able to drive 80miles when I first got the car with mostly highway driving and a much lower m/kWh economy rating. This 4.8 mi/kWh is one of my highest so far.

Edit: Monday morning. Actual charge time back to 80%: 4hr 52min.
So my economy seems ok...but why do others get so much better range without these crawling speeds? Its almost as though my battery capacity is smaller.

I have no idea how Sean (Right Lane Cruiser) from Clean Mpg forum can get 5.9 m/kWh. I am driving, and accelerating as slow as I possibly can. I am taking all the side roads with no traffic, etc. Trying to keep the motor below 10kW when accelerating to even 30mph takes forever (while you are holding up traffic). Sometimes, I wonder if it is better to accelerate at 20kW and get up to speed sooner so you can level off on the throttle. Perhaps all this slow acceleration isn't much better than getting up to speed somewhat quicker?

Sean's economy data (Is he on this forum?)

http://www.cleanmpg.com/forums/showthread.php?t=45554&page=4" onclick="window.open(this.href);return false;

Re: Week of November 5th - November 11th (Nat Avg: $3.50)--------------------------------------------------------------------------------

I couldn't quite make the mark this morning. The relative humidity is fairly high and the windows kept fogging...

34F (29F windchill), 6mph tailwind from the NNE, clear:
•5.9 mpk (169.5 Wh/m) over 14.7 mi --> 198.0 MPGe (Home to work)
Day Total: 5.9 mpk (169.5 Wh/m) over 14.7 mi --> 198.0 MPGe
Tot. Used: 2.5 kWh
Adj. Cost: $0.38
Cost/mile: 2.6¢
__________________
- Sean

 

[dgpcolorado]

ELROY, Looks as if you are doing quite well with your mileage. Don't obsess over what other people can get, there are too many variables. If you've got your tire pressure up at 40 psi or so and are driving carefully you are doing about all that can be expected. I get similar mileages at your temperatures but I have the advantage of altitude—fewer air molecules to push out of the way—and the disadvantage of steep hills.

One device on every LEAF that helps learning to drive efficiently is the "tree meter". Ignore the trees, but if you can keep that arc of dots filled you are driving quite efficiently.

There are lots of variables and it appears to me that you are doing quite well. Keep resetting your mileage meter to track your mileage but otherwise just relax and enjoy your LEAF!

 

[ELROY]

ELROY, Looks as if you are doing quite well with your mileage. Don't obsess over what other people can get, there are too many variables. If you've got your tire pressure up at 40 psi or so and are driving carefully you are doing about all that can be expected. I get similar mileages at your temperatures but I have the advantage of altitude—fewer air molecules to push out of the way—and the disadvantage of steep hills.

One device on every LEAF that helps learning to drive efficiently is the "tree meter". Ignore the trees, but if you can keep that arc of dots filled you are driving quite efficiently.

There are lots of variables and it appears to me that you are doing quite well. Keep resetting your mileage meter to track your mileage but otherwise just relax and enjoy your LEAF!

Thanks for the insight. I was at 5.0 mi/kwh for the last 30 miles of driving, but a couple of brisk acceleration episodes at the intersection lowered it to 4.8. I drove very slowly through the neighborhood and am back up to 4.9mi/kwh now. I am still wondering what the relationship is between accelerating a little quicker and reaching the cruise speed plateau compared to turtle speed acceleration which goes on for much much longer to reach the speed?

 

[planet4ever]

I am still wondering what the relationship is between accelerating a little quicker and reaching the cruise speed plateau compared to turtle speed acceleration which goes on for much much longer to reach the speed?

You aren't the only one wondering about that. We've debated it quite a bit, and I'm not sure we've come to any resolution. One thing is clear, though: If you accelerate quickly and overshoot your desired speed, or if you end up slowing down or stopping for an upcoming traffic signal because of your jack rabbit start, you lose.

One other factor is probably safe to assume. If your cruise speed is high, say 50 or more, getting to that speed faster means you lose something because you are fighting air resistance for a (slightly) larger part of your trip. If your cruise speed is low, that's insignificant.

Ray

 

[EVDRIVER]

Accelerating quickly is not more efficient.

 

[planet4ever]

Accelerating quickly is not more efficient.

In a purely theoretical sense it's not less efficient, either ... if you are dealing with a frictionless mass in a vacuum being accelerated by an energy source whose efficiency does not vary with speed.

Of course none of those conditions apply here, so the answer is: It's complicated.

Ray

 

[ELROY]

I am still wondering what the relationship is between accelerating a little quicker and reaching the cruise speed plateau compared to turtle speed acceleration which goes on for much much longer to reach the speed?

You aren't the only one wondering about that. We've debated it quite a bit, and I'm not sure we've come to any resolution. One thing is clear, though: If you accelerate quickly and overshoot your desired speed, or if you end up slowing down or stopping for an upcoming traffic signal because of your jack rabbit start, you lose.

One other factor is probably safe to assume. If your cruise speed is high, say 50 or more, getting to that speed faster means you lose something because you are fighting air resistance for a (slightly) larger part of your trip. If your cruise speed is low, that's insignificant.

Ray

For the most part I am driving slower speeds during much of this testing. I am back at 5.0mi/kWh right now. But seriously...i am accelerating in general below 10 kW. Taking forever to hit 25 miles per hour. Often I barely reach 20 miles per hour in the neighborhoods and 30 miles per hour in a 45 mile per hour zone. Avoiding traffic at all costs to keep from holding them up. And yet through all this I only have 2 bars left after driving 36 miles. 28 miles range on the GOM. So I am wondering if I will actually get 60miles on this charge till VLB. If not, perhaps it short charged on my last charging a session to 80%...making me think I was getting better economy than actual . If I keep it at 5mi/kWh, shouldn't I at least get the 70miles I achieved on my last charging session to 80% at 4.8mi/kWh? Just talked to another leaf owner today, he made his 70 mile freeway round trip commute to work and back with mileage to spare. Hearing things like this really makes me question my battery range .

 

[dgpcolorado]

^ It does sound as if you aren't getting the range you should. 80% to VLB is about 71% of the approximate 21 kWh usable battery in a new car. At 5 miles/kWh that would be about 74 miles range. If you aren't getting that while driving at 5 miles/kWh for a given trip something could be wrong.

As for whether you are charging to 80%, you should see ten fuel bars, although you will lose the tenth one quickly because it is really about 9.6. If you see only nine, that suggests that the battery is degraded, although with such a high VIN that would be surprising. I presume that you have all 12 capacity bars. If not, that would explain the range issues. Another possibility is that you have a bad cell in the battery. The dealer ought to be able to check that.

Regardless, if you can't make your commute without getting to VLB you need to start charging to more than 80%.

 

[RLC]

I have no idea how Sean (Right Lane Cruiser) from Clean Mpg forum can get 5.9 m/kWh. I am driving, and accelerating as slow as I possibly can. I am taking all the side roads with no traffic, etc. Trying to keep the motor below 10kW when accelerating to even 30mph takes forever (while you are holding up traffic). Sometimes, I wonder if it is better to accelerate at 20kW and get up to speed sooner so you can level off on the throttle. Perhaps all this slow acceleration isn't much better than getting up to speed somewhat quicker?

Sean's economy data (Is he on this forum?)

http://www.cleanmpg.com/forums/showthread.php?t=45554&page=4" onclick="window.open(this.href);return false;

Re: Week of November 5th - November 11th (Nat Avg: $3.50)--------------------------------------------------------------------------------

I couldn't quite make the mark this morning. The relative humidity is fairly high and the windows kept fogging...

34F (29F windchill), 6mph tailwind from the NNE, clear:
•5.9 mpk (169.5 Wh/m) over 14.7 mi --> 198.0 MPGe (Home to work)
Day Total: 5.9 mpk (169.5 Wh/m) over 14.7 mi --> 198.0 MPGe
Tot. Used: 2.5 kWh
Adj. Cost: $0.38
Cost/mile: 2.6¢
__________________
- Sean

ELROY, DGPColorado is correct -- you shouldn't try to compare results from two different drivers in different climates with different terrain and traffic patterns too closely. There are simply too many variables to make it an easy effort.

With that said, I will echo what many others have said on this thread; the more you drive the better you'll get. I'm not unique in managing high miles per kWh numbers (though perhaps I achieve them in somewhat colder temps than most) but my habits behind the wheel are about as far removed from the typical driver as you can get. I've been honing my efficiency skills for many years now and though I've only had an EV for 8 months, energy efficiency is pretty much the same regardless of onboard fuel source.

When it comes right down to it, momentum conservation is the main goal. Ditch cruise control because it aims for constant speed instead of constant power use (a trained right foot is much better). Driving in such a way that you don't need to use regenerative (or worse yet, friction) braking to slow down in most cases and you'll avoid the conversion losses (and just plain losses) associated with those mechanisms. It is always better to keep the vehicle moving than to change the momentum, though you can play games with exchanging kinetic energy and potential energy (useful for getting over hills) which allow changes in speed without as much of an efficiency hit. If you imagine what you would do on a bicycle with no brakes, you'll have the right idea; speed up on flat land and downslopes where it isn't as hard to gain momentum, slow down as you go up hills, speed back up on the other side, coast to stops, and try to time lights by adjusting your speed to the average needed to arrive just as the light turns green.

There is no one magic technique which will get you higher numbers but there are a lot of little things you can do which will add up to big differences. Driving in traffic (which I've done all over the country -- notably LA, Chicago, Atlanta, NY Times Square, Washington DC) requires very different techniques for efficiency than driving on the highway. Most of the techniques have been discussed to at least some extent in the forums here but if you'd like a cohesive picture of the whole spectrum and how they are used together from one person you are welcome to PM me for offline discussion.

 

[EVDRIVER]

Accelerating quickly is not more efficient.

In a purely theoretical sense it's not less efficient, either ... if you are dealing with a frictionless mass in a vacuum being accelerated by an energy source whose efficiency does not vary with speed.

Of course none of those conditions apply here, so the answer is: It's complicated.

Ray

Do you post in a frictionless vacuum? It is less efficient, period For those flooring it in a vacuum they may have better results than those not in one.