User avatar
DaveEV
Forum Supporter
Posts: 6236
Joined: Fri Apr 23, 2010 3:51 pm
Location: San Diego

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 08, 2011 10:32 am

surfingslovak wrote:
Bassman wrote: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.

User avatar
TomT
Posts: 10642
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 08, 2011 10:36 am

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 wrote: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!
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

User avatar
surfingslovak
Vendor
Posts: 3809
Joined: Mon Jun 13, 2011 1:35 pm

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 08, 2011 10:50 am

davewill wrote: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.

LEAFfan
Posts: 4828
Joined: Fri Apr 23, 2010 6:08 pm
Delivery Date: 08 Jun 2011
Leaf Number: 1855
Location: Phoenix Area

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 08, 2011 10:53 am

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.
2013 LEAF SV Del. 2/28/13
2013 LEAF World Record for Most Miles Driven On One Charge-188 miles/8.8 m/kW h
4.8 kW DC PV ($ .91/W fully installed)/ Dec., 2010

User avatar
surfingslovak
Vendor
Posts: 3809
Joined: Mon Jun 13, 2011 1:35 pm

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 08, 2011 10:57 am

mogur wrote: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.

User avatar
EricH
Posts: 324
Joined: Mon Jan 03, 2011 8:54 pm
Delivery Date: 26 Mar 2011
Leaf Number: 0664
Location: Whittier, CA

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 08, 2011 11:46 am

evnow wrote: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.
Blue SL with QC
A/V Charger
Delivery: 3/26/11

ronulrich
Posts: 2
Joined: Mon Aug 15, 2011 5:18 am
Delivery Date: 15 Aug 2011
Leaf Number: 6808

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 15, 2011 5:42 am

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

User avatar
garygid
Gold Member
Posts: 12464
Joined: Wed Apr 21, 2010 8:10 am
Delivery Date: 29 Mar 2011
Leaf Number: 000855
Location: Laguna Hills, Orange Co, CA

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 15, 2011 7:26 am

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.
See SOC/GID-Meter and CAN-Do Info
2010 Prius, now for sale
2011 LEAF, sold in 2015
2018 Tesla Model 3
2014 Tesla S, Model 3 in 2019
PU: SDG&E
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle

User avatar
planet4ever
Posts: 4674
Joined: Sat Apr 03, 2010 9:53 pm
Delivery Date: 02 May 2011
Leaf Number: 1537
Location: Morgan Hill, CA, south of San Jose

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 15, 2011 12:57 pm

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
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

User avatar
DaveEV
Forum Supporter
Posts: 6236
Joined: Fri Apr 23, 2010 3:51 pm
Location: San Diego

Re: Range-Speed-Bars Thumb Rule Table

Mon Aug 15, 2011 1:41 pm

planet4ever wrote: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?

Return to “Range / Efficiency / Carwings”