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TomT
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 1:11 pm

I'm curious what caused you to accept 21Kwh as the usable... My experiments to dead with a recharge to 100 percent have consistently shown that I put close to 24Kwh of power back in to the battery (after subtracting charger efficiency - about 26.67 KwH from the wall)... The EPA's numbers show the same. So, as far as I am concerned, based on my experiments and measurements - and those of others, it is a 24Kwh usable pack...
TonyWilliams wrote:Ok, I've tossed out revision 3 of my range chart. I've used the 21kWh of usable battery power that many have adopted. Also, I added the average kW based on the 21 number for each speed as suggested.
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evnow
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 1:51 pm

mogur wrote:I'm curious what caused you to accept 21Kwh as the usable... My experiments to dead with a recharge to 100 percent have consistently shown that I put close to 24Kwh of power back in to the battery (after subtracting charger efficiency - about 26.67 KwH from the wall)... The EPA's numbers show the same. So, as far as I am concerned, based on my experiments and measurements - and those of others, it is a 24Kwh usable pack...
See here

http://www.mynissanleaf.com/viewtopic.php?f=31&t=4344

Essentially, if you accept that m/kwh shown on the dash is correct - then about 21 kWh is what leaf shows as usable. This has been verified using stats from many.
1st Leaf : 2/28/2011 to 5/6/2013
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evnow
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 2:00 pm

TonyWilliams wrote:Ok, I've tossed out revision 3 of my range chart. I've used the 21kWh of usable battery power that many have adopted. Also, I added the average kW based on the 21 number for each speed as suggested.
Looks good - esp. I like the Turtle explanation.

Some things to be corrected, though :
- The top says 24kw/h battery. Should be changed to 21 and kWh (not kw/h).
- 6.4kwh, 5.2kwh etc should change to 6.4 m/kWh

Also, only a constant 38mph run might give 138 mile range. I think that 38mph mentioned along with other range by mph figures, confuses people (eg. why does 25 to 45 mph give only 108 miles if 38 gives 238 ?).
1st Leaf : 2/28/2011 to 5/6/2013
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TomT
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 2:00 pm

I believe the total KwH of power put in to the battery when charging to be a more reliable indicator of capacity since it leaves little room for error or interpretation... Basically, the only variable is the actual charger efficiency, but that is pretty well known at this point. My numbers from TED have been very consistent in this regard and show close to 24KwH usable when I run it down to dead or turtle...
evnow wrote:Essentially, if you accept that m/kwh shown on the dash is correct - then about 21 kWh is what leaf shows as usable. This has been verified using stats from many.
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 2:09 pm

EricH wrote:What would the alternative be? In order to predict range, the car would need to know where you were going (I use the Destination setting less than 5% of the time), as well as your planned speed, the topography details, and the traffic situation (XM here in Los Angeles only has freeway info, not city streets).

Nissan's "future performance is likely to resemble past performance" approach seems the only practical option here. Everyone realizes by now that if they drive 10 miles toward a freeway, then get on the freeway and drive 70+, their indicated range is going to basically collapse before their eyes. Absent a way to notify the car before you leave the driveway, that that's where I'm headed and how fast I'm going to drive, the Leaf is doing the best it can.
I've talked about other options Nissan has in multiple posts.

If a destination is entered, Leaf can figure out the range using known speeds, traffic, topology etc along the route.

If no destination is entered, they can use previous trips' average m/kwh instead of last 5 or so miles to calculate the range. When someone recharges and leaves home, invariably Leaf shows high miles since, likely the drive to home was using lower speeds than average.

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.
1st Leaf : 2/28/2011 to 5/6/2013
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TomT
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 2:13 pm

A number of Garmin units now use predictive algorithms whereby it watches where you drive, how you drive, and how traffic varies from day to do, even if you are not using it for destination guidance. It then uses this info to pick the best route and give a better prediction of travel time when you do set a destination or route. Nissan could and should do the same with the Leaf Nav...
evnow wrote: 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.
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 2:42 pm

mogur wrote:A number of Garmin units now use predictive algorithms whereby it watches where you drive, how you drive, and how traffic varies from day to do, even if you are not using it for destination guidance. It then uses this info to pick the best route and give a better prediction of travel time when you do set a destination or route. Nissan could and should do the same with the Leaf Nav...
Exactly - esp the part about travel time i.e. Garmin is predicting your avg speed and that is one of the important inputs Leaf needs to figure out the range.
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davewill
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 4:50 pm

mogur wrote:I believe the total KwH of power put in to the battery when charging to be a more reliable indicator of capacity since it leaves little room for error or interpretation... Basically, the only variable is the actual charger efficiency, but that is pretty well known at this point. My numbers from TED have been very consistent in this regard and show close to 24KwH usable when I run it down to dead or turtle...
evnow wrote:Essentially, if you accept that m/kwh shown on the dash is correct - then about 21 kWh is what leaf shows as usable. This has been verified using stats from many.
Have to strongly disagree. Everyone is simply guessing about charger efficiency. At least the 21 kWh number is useful when combined with the dash mpk.
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 4:57 pm

TonyWilliams wrote:
johnr wrote:I've found that in most cases my best range reference is actually that number next to the bar graph! Assuming reasonably constant speed, the car is very accurate and precise in indicating how many miles remain.

Which bar graph? Have you run the car to turtle to verify those numbers?
that is the same number on the driver dashboard.
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Re: Range-Speed-Bars Thumb Rule Table

Sun Aug 07, 2011 6:09 pm

thankyouOB wrote:
TonyWilliams wrote:
johnr wrote:I've found that in most cases my best range reference is actually that number next to the bar graph! Assuming reasonably constant speed, the car is very accurate and precise in indicating how many miles remain.

Which bar graph? Have you run the car to turtle to verify those numbers?
that is the same number on the driver dashboard.

That's the number that you think is super, mega accurate?

Not only myself, but virtually anybody here will disagree. So, when I start in the morning showing 100 miles on the "Guess-O-Meter", I should just go 100 miles... right? Even when it drops to 70 miles in 5 miles of driving?

I think you're just pulling our leg. But, if that's what you believe, happy motoring then !!

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