Range Chart

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surfingslovak said:
Bassman said:
The numbers Nissan reported to EPA for their mpg rating was 24KWHrs. So It should be 24 KWHrs.
Yes, most definitely. Wouldn't this imply ~ 3 miles/kWh for the EPA cycle then? That's quite low. Even with 21kWh, I'm getting ~ 3.5kWh. I don't think that they drove to turtle during the cycle then or did they?
The EPA testing drives the car until it can't keep the required speed any more. This would undoubtedly mean running the car down into turtle mode.
 
I don't know anything about the Tesla system but I doubt that the current draw of the pump in the Leaf amounts to more than an asterisks change in the efficiency... It's a very small, low power pump.

drees said:
None of those efficiencies are counting the power it takes to run the cooling pumps during charging.
Look at what happens to a Tesla Roadster when you charge at 120V - charging efficiency drops in half because of the static charging overhead. Ouch!
 
davewill said:
The whole 24kWh vs. 21kWh debate is very entertaining, but it's been chewed to death in other threads (to little conclusion I might add), and has NOTHING to do with calculating real world range using either speed or the mpk number the car gives us...which is the topic of this thread.
With all due respect, I disagree with this. Perhaps we should take the pack capacity discussion elsewhere, but I hope that we agree about the ultimate goal. We should be able to determine how much available energy is left in the pack and how much energy we are using. Only then we will be able to control our destiny, and know how far we can go.
 
I believe it's rather obvious that we aren't using close to 24kW h just by using the dash meter. If we were really using 24 instead of 21 my miles right now would be 19.2 (80% ch.) X 5.8 =111 which is unrealistic on an 80% charge. However, 22 (100%) and 18 (80%) is probably pretty close to actual for me.
 
mogur said:
Between the TED I have on my EVSE circuit and the data from the Blink, it is pretty easy to get comprehensive data on a regular basis. I've run my down to dead three times now to collect data on a number of variables...
Yes, certainly and I don't mean to sound dismissive, but that's a sample size of 1x3. I will go find that old thread on pack capacity someone mentioned. If the dash MPK indicator can be believed, 21kWh available pack capacity aligns better with the range many of us are getting.
 
evnow said:
I've talked about other options Nissan has in multiple posts.
There are other things Leaf can do - for eg., if I just drove down a hill and there isn't another hill to drive down nearby (or altitude is already 50 ft, not 500 ft like it was ), Leaf can just ignore that regen since it is a one off. It shouldn't increase my range from 90 to more than 110 like it does on my drive to work (on 80% charge).

Essentially, Leaf can become smart about the car's environment when predicting range rather than using a very premitive and simple algorithm it uses now.
I like your topo examples - but that's a ton of extra data (and cost) for what might turn out to be an improvement in predictive capability, but for a minority of use by a minority of drivers. In theory, if the car could sense the loading (passengers/cargo), it could adjust the range accordingly, but what would that self-weighing capability cost?

I'm just asking if Nissan has, in fact, come very close to the "sweet spot" between using all possible data, and all/most significant (and readily available) data, in setting the range algorithm. I would rather use the guess-o-meter as-is, than pay Volt-level prices for a near-perfectly predictive Leaf.
 
Thank you so much for the information. Could have used this yesterday when we picked up our Leaf in Seaside, CA. Drove over the hill home with 4 battery miles left. Nice job on the chart.
ron #6808
 
Battery Capacities:
1. Design Full Capacity - never used, no real way to tell, so not very important in day-to-day use.

2. Allowed Capacity - the part that Nissan allows us to use

3. Wall Capacity - the amount of energy required from the grid/wall/EVSE to charge the battery (maybe 26 kWh)

4. Charging Energy - after the losses in the LEAF's internal charger, the DC energy that is actually delivered to the battery pack (maybe 24.6 kWh, just a guess). The charger's efficiency is not usually as bad as people say.

5. Stored Energy - after modest cell heating and small chemical losses during charging (or Regen), the amount of energy that actually gets stored in the battery (maybe 24 kWh). The charger often gets blamed for this loss.

6. Recovered Energy - the real usable energy, significantly less than the Stored Energy (maybe around 21.4 kWh). Regen energy, stored in the battery for later use, also suffers this loss. This is the most often overlooked energy loss, and the source of much confusion. The cell-heating losses can be substantial, depending upon the rate of energy extraction from the battery - higher power drain usually means a higher percentage of heat losses. There would also be some small chemical-process losses, and some self-discharge losses. Finally, cell equilization might have removed some energy from the higher-charged cells.

8. Motor Energy - the energy used by the motor, after inverter losses. This "energy" is sometimes used to display "inflated" miles per kWh figures.

So, depending upon WHICH energy you are talking about, you are all (almost) correct.
 
Great summary, Gary, and I have often wondered about losses in the battery, and why no one seems to allow for them. But you are suggesting more than 10% loss in (stored energy) - (recovered energy), which seems astonishingly high to me. All that "lost" energy must be converted to heat, no? Since the LEAF battery has no active cooling, I would think that would make it heat up rapidly under load, such as when climbing a mountain. Why has no one reported this?

Ray
 
planet4ever said:
But you are suggesting more than 10% loss in (stored energy) - (recovered energy), which seems astonishingly high to me. All that "lost" energy must be converted to heat, no? Since the LEAF battery has no active cooling, I would think that would make it heat up rapidly under load, such as when climbing a mountain. Why has no one reported this?
Because that heat isn't lost in the batteries - it's lost in the inverter and motor. Basically the LEAF's batteries have an extremely low internal resistance.

The fact that the pack is able to supply 100% power all the way down to near empty (turtle mode) and the lack of any active cooling (not even a fan to circulate air in the pack!) supports this. No one has reported any user-visible change in battery temp under load. I suspect that it's measurable, but it will take CAN-bus eavesdropping and some spirited driving to see it.

Back on topic - I drove a bit over 81 miles yesterday, mostly highway at 65 mph with the AC on in the mid-70s in recirc mode.

Got to destination ~38 miles away using just over 6 bars and dash indicated 4.0 mi / kWh. GOM indicated just right around 40 miles remaining IIRC.
L1 charged for 4 hours picking up 3 bars and drove ~44 miles home - took a bit of a detour to take the scenic route home - dash now indicated 4.2 mi / kWh (thanks to the scenic route, dash was at 4.0 mi / kWh before we left the freeway), had one bar remaining and 13 miles on the GOM. All as planned.

I'm a bit surprised at the dash indicated mi / kWh - the last time I took a very similar trip I took it at 60 mph and recall getting very similar mi / kWh numbers. At 65 mph I would have expected 3.6-3.8 mi / kWh indicated - perhaps the car is breaking in a bit?
 
drees said:
planet4ever said:
But you are suggesting more than 10% loss in (stored energy) - (recovered energy), which seems astonishingly high to me. All that "lost" energy must be converted to heat, no? Since the LEAF battery has no active cooling, I would think that would make it heat up rapidly under load, such as when climbing a mountain. Why has no one reported this?
Because that heat isn't lost in the batteries - it's lost in the inverter and motor. Basically the LEAF's batteries have an extremely low internal resistance.
Gary puts inverter and motor losses losses in a different category: (recovered energy) - (motor energy). So, drees, you are also suspicious of a 10%+ loss in the battery.

Ray
 
planet4ever said:
drees said:
planet4ever said:
But you are suggesting more than 10% loss in (stored energy) - (recovered energy), which seems astonishingly high to me. All that "lost" energy must be converted to heat, no? Since the LEAF battery has no active cooling, I would think that would make it heat up rapidly under load, such as when climbing a mountain. Why has no one reported this?
Because that heat isn't lost in the batteries - it's lost in the inverter and motor. Basically the LEAF's batteries have an extremely low internal resistance.
Gary puts inverter and motor losses losses in a different category: (recovered energy) - (motor energy). So, drees, you are also suspicious of a 10%+ loss in the battery.
No - I think his numbers are way off. Stored energy is too high. Direct charge/discharge efficiency is only a percent or two at most at the battery level. The big losses are in the inverters and motor.
 
Herm said:
I think evnow should just buy a module at the dealership and put us out of our misery. He's rich anyways..
LOL. You really thought I didn't get the Roadster because of the small trunc ? ;-)

I think the important thing to note is that 21 kwh is what the battery capacity "seems" to be - when considering the m/kwh displayed by the Leaf dash.

In practice that is what matters - if you multiply the m/kwh by 21 - you get close to the range. So, the figure 21 helps us figure out the range ...

"Actual usable" capacity may or may not be different. At this point, I couldn't care less about it.
 
evnow said:
"Actual usable" capacity may or may not be different. At this point, I couldn't care less about it.
Precisely. It would good if we could coalesce around a usable battery model. It may not be accurate, but as long as it provides practical range predictions, it would be quite useful. Would it perhaps make sense to start a new thread on that or should we continue here?
 
surfingslovak said:
evnow said:
"Actual usable" capacity may or may not be different. At this point, I couldn't care less about it.
Precisely. It would good if we could coalesce around a usable battery model. It may not be accurate, but as long as it provides practical range predictions, it would be quite useful. Would it perhaps make sense to start a new thread on that or should we continue here?


I think many / most of us frequent forum participants already are comfortable with 21. Sure, it may be 21.4, or 21.6, but for the purpose of hitting a target miles/kWh number, it works.

What different battery model do you have in mind?
 
TonyWilliams said:
I think many / most of us frequent forum participants already are comfortable with 21. Sure, it may be 21.4, or 21.6, but for the purpose of hitting a target miles/kWh number, it works.

What different battery model do you have in mind?
Yes, 21kWh works very well to predict total range. However, we have more data points now. Some of use are counting bars, others have an SOC meter from Gary or use your table and their speed to predict range. It would be nice if we could tie it all together.
 
surfingslovak said:
Some of use are counting bars, others have an SOC meter from Gary or use your table and their speed to predict range. It would be nice if we could tie it all together.


We will get there, I think!! My next project is a simple app that would key in many of the key ingredients to predict range... but that's another thread. I'll post that up later.

Here's my latest revision, #5, to the range chart. Like always, I appreciate critiques to make it better. The biggest change is that about 12.5 mph is the best range speed.

Everybody FORGET 38 MPH !!!

Tony

LeafRangeChartRevision5.jpg
 
mogur said:
Now if there was only some place that one could actually DRIVE at 12.5 mph without dying! :lol:

Fiesta Island, San Diego!!! I had old folks on bicycles passing me. Wind surfers, too.

The fuel bars are centered between the possible range with each bar. The previous charts did not reflect that.

If I jump in the car, and see 10 fuel bars, how do I know how much of that eFuel has been burned? I don't. That 10th bar may have 72 miles, or 66 miles remaining (at 60 mph). We don't know, and now the chart now better reflects that.

If you're driving along at 60 mph, and watch the 10th fuel bar disappear, now you know you have 66 miles from that point.
 
TonyWilliams said:
Here's my latest revision, #5, to the range chart. Like always, I appreciate critiques to make it better. The biggest change is that about 12.5 mph is the best range speed.

You're saying your results aren't based on 'dash data'? But I had thought we've proven that the dash/console data is similar to what you have found. When I went 15 miles at a steady 15 mph and the console showed 9.1 (prob 9 on the dash if it would go farther) I know I could have gone 200 miles if I had kept going (21 X 9.5 = 200m). Every so many miles that I went, the m/kW h meter kept going higher. So who knows where it would have been after another 15 miles? As soon as someone figures out how to 'fix' the CC, I'll prove it with the odometer.
 
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