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Discussion Starter #1
Very much a work in progress, but I thought I would share this little range calculator which I've been working on:

LEAFRANGE

The initial values are those which theoretically give 155 miles (there are are a few rounding-up issues to be ironed out which is why the app says 154 miles!).

In the real world, outside temperature, average speed and use of the heater or a/c massively impact on the range and this calculator attempts to factor those into the equation.

It's not a finished or polished app yet but (polite!) comments are welcome.

If anything, the calculation errs on the side of caution but better that than meeting the dreaded turtle coming the other way!
 

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I have a 30kWh Leaf (only just picked it up 3 weeks ago) with 1,400 miles on the clock and you are in the ballpark with the results. My return journey to work is 84 miles and I have just came back home with 14% battery left. On the way in with heater off (42 miles) after almost 2h preheating whilst plugged in I arrived at work with 64% battery left so I used 36% battery. On the way back this morning (4C outside) with heater on but no preheating (nowhere to plug in at work and I am prohibited from using a standard socket) the car used 50% battery on the same distance. Seems like preheating and using the heater makes quite a lot of difference. Journey profile: about 28 motorway miles where I keep cruise control at 65mph (which shows 60mph on Waze app) and then 12 miles of average speed cameras 50mph (where I set the car at 55mph because Waze then shows 50mph anyway) and final 2 miles of city driving. You may wish to look into whether the car had been preheated or not as another variable - but then again I am not an expert, I have only had the Leaf for 3 weeks.
 

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Discussion Starter #3
Very interesting about the effect of the preheat. I have not had my Leaf that long so my app uses empirical data from my experience but I did not figure on including a preheat variable as I haven't tried it! I tend to just preheat for 10 mins if I am plugged in to get the cabin warm. Never tried it for 2 hours to see the effect on range. I feel a version 2 coming on!
 

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Perhaps other owners can pitch in at confirm (or not) whether they experience the same effect. I mentioned 2h because I believe this is the longest preheating will work for when plugged in (and 15 minutes when not plugged in). Without preheating at today's temperatures my battery temp was on 4 bars, with almost 2h preheating yesterday whilst plugged in before I left the battery temperature was on 5 bars. I am also still in experimenting phase so this is just my educated guess and I may be completely wrong, perhaps preheating has no effect on range at all. Somehow though I regularly use 32-38% of battery on the way in (when I always set preheating) and 48-52% on the way home when the car is stone cold from start.
 

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I've found that preheating for a couple of hours makes a huge difference when the ambient temperature is low. It takes quite a lot of energy to heat up all the mass in the cabin (seats, dash, etc.) from 0C to a comfortable temperature. If you pre-heat then this energy doesn't need to come out of the battery.
 

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Discussion Starter #6
I thought that preheating just heated up the cabin (and seats/steering wheel) not the batteries, but maybe I am wrong. I seem to remember reading somewhere that in colder countries (like Sweden etc.) Nissan fit a special battery preheater which does what you are describing, but in the UK, I think not. Someone on here is bound to know the answer. I rarely preheat when not plugged in as it depletes the battery by about 1% for every 5 minutes of preheating time I find.
 

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Discussion Starter #7
Eddiec, I agree with you. Preheating the cabin means not having to have the heater on (or not so high) when you first get in and therefore must save battery power. The only downside is that in some situations, the whole car gets steamed up on the inside of the windows meaning that you have to put the a/c on from the start to be able to see where you are going which drains the battery too!
 

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On the way back this morning (4C outside) with heater on but no preheating (nowhere to plug in at work and I am prohibited from using a standard socket) the car used 50% battery on the same distance.
In case you are not aware but you can still pre-heat the car when not plugged in via the app and obviously will use some battery %. It will turn off after ~15 minutes.
 

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Just curiosity, how do you preheat the car's battery when it doesn't come with a battery heater?
As to the app, it looks like it could be useful but changing the values still gives the result of 154! Is there something that needs to be pressed to recalculate the value?
 

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Discussion Starter #11 (Edited)
In response to your question about the app, the range should recalculate as soon as you change any of the values automatically if you are using the app on a mobile phone. On a computer if you use the RETURN or TAB key to move between fields after altering values it will recalculate automatically.
 

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Last winter I did a quick experiment running the preheat for a couple of hours and checking the battery temperature with Leafspy. I didn't see any significant increase in battery temperature over a couple of hours. Maybe half a degree.

It's quite a hard experiment to do meaningfully though because unless you leave your car sat for days to reach equilibrium with the outside (and the temperature outside isn't constant anyway) then you don't know what the battery temperature would have been if you didn't pre-heat. It might have been on its way down and pre-heating kept it stable.
 

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Discussion Starter #14
I know what you mean. I only really seem to notice the battery temperature increasing after a long motorway drive or using a chademo charger.
 

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Nice idea , the calculations are wrong on the soc, for example if you put in 32% charge it gives you 0 range
 

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Discussion Starter #16
On my screen entering 32% SOC gives 49 miles with the other parameters left at default (i.e. 20 deg, ave speed 45, heater off).
 

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Discussion Starter #18
I've just found this chart elsewhere on this forum. According to this chart 31% (it doesn't list 32%) SOC gives 46 miles under the same conditions as my default parameters in the app so about the same figure.
 

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Discussion Starter #20
now try at 65mph
Maybe some fine tuning is still needed! Part of the problem is that the battery does not seem to deplete in a linear fashion so the rate of discharge when full is different from the rate of discharge when low. I am sure Nissan will have all the data to create a really accurate version of the app that I am trying to create but they are not likely to do so because it would drive a coach and horses through their highly exaggerated 155 mile max range advertising!
 
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