My low battery warning did not show up until I had 8 miles left. I had already gone 82 miles and expected that the low battery warning would show up at 20 miles left but it never did. Is this normal? I thought that low battery warnings should begin at 20 miles left and then at 8 miles it would say very low battery and direct me to a charging station. There were no charging stations, except for my home, within 8 miles when the low battery warning registered at 8 miles
Low battery warning not early enough
- Thread starter stanley
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turbo2ltr
Well-known member
How many bars did you have left at that point? Range is not a good way to determine when you have to charge.
91040
Well-known member
This is normal with the new firmware.
The first warning appears as you are using your second last bar. Typically for me, the guessometer shows around 6-8 miles. The "very low" warning appears as your last bar disappears. The guessometer goes from 2-3 miles remaining to ---. Then you have a hidden reserve before you get to turtle.
There are charts describing this behavior in better detail. See http://www.mynissanleaf.com/viewtopic.php?f=31&t=4295
Also Turtle topic: http://www.mynissanleaf.com/viewtopic.php?f=31&t=2386
Be alert to whether posts refer to the original firmware or the new firmware (changed in April 2011)
The first warning appears as you are using your second last bar. Typically for me, the guessometer shows around 6-8 miles. The "very low" warning appears as your last bar disappears. The guessometer goes from 2-3 miles remaining to ---. Then you have a hidden reserve before you get to turtle.
There are charts describing this behavior in better detail. See http://www.mynissanleaf.com/viewtopic.php?f=31&t=4295
Also Turtle topic: http://www.mynissanleaf.com/viewtopic.php?f=31&t=2386
Be alert to whether posts refer to the original firmware or the new firmware (changed in April 2011)
LEAFfan
Well-known member
stanley said:
My low warning usually shows up at around 11 miles left, which means at 38Mph I actually have 22 miles. Most of the time I'm in town, so I can get even more at a lesser speed. I much prefer the new to the old firmware. Tony did a great job with the SOC chart.
smkettner
Well-known member
My warning starts when I turn on the car. The miles undulate a bit at first, then steadily drop as the miles driven continues. What else is needed?
I just pulled in with 9 miles remaining. No other warning needed.
I just pulled in with 9 miles remaining. No other warning needed.
turbo2ltr
Well-known member
The fact that you had no bars left didn't give you a clue that maybe you might be low on efuel?
It's no wonder Nissan changed the way they display range and SOC bars...
It's no wonder Nissan changed the way they display range and SOC bars...
Dah, I absolutely knew I was low . I was experimenting to see when visual and audible warnings would occur. So that I could prepare a person who might borrow the Leaf as to whether they would have enough battery left to find a charging station when the car signaled that the battery was low. Given the lack of infrastructure, the warning system is of little use.
TomT
Well-known member
Take a look at the charts that I and others have posted here. It will give you all the particulars that you need. You can look in this thread: http://www.mynissanleaf.com/viewtopic.php?f=31&t=4295
stanley said:
smkettner
Well-known member
The person borrowing the car should have plenty of warning from you that there are pretty much no random recharge places to just push a button to find and pull in.
They need to plan and pay attention.
They need to plan and pay attention.
TonyWilliams
Well-known member
LEAFfan said:
Grasshopper, when you can take the pebble from my hand, it will be time for you to leave. But, there is much to learn.
38mph is the IDEAL speed for the absolute highest miles per unit of stored battery power. Going faster, OR SLOWER, will decrease your range.
Think of 38mph as X in the center of the bell curve. Any speed to the left or right of X results in a lower range.
I'm surprised at that, 38 mph is high enough that aerodynamic forces start to come into play, I'd expect a lower speed to be ideal. I think the Tesla Roadster ideal speed is around 25 mph. How did you, come up with the 38 mph figure? Is that from Nissan?
TomT
Well-known member
According to Nissan, the drop-off in motor system efficiency below 38 is more than the aerodynamic gain of the slower speed.
JRP3 said:
Interesting. That seems to relate to Tesla's choice of AC induction for better variable speed efficiency over PM's peak efficiency.
http://www.teslamotors.com/blog/induction-versus-dc-brushless-motors
http://www.teslamotors.com/blog/induction-versus-dc-brushless-motors
edatoakrun
Well-known member
Nissan does report lower power train efficiency below 38 mph, but if you look at the efficiency curve on p 17 here:
http://www.electricauto.org/resource/resmgr/media/nissan_leaf_sae_2_11.pdf
You will see that efficiency is above 85% at all rpm levels. So the loss of range below 38 mph is probably negligible, at least down to 20 mph or so. The much more significant loss of range, due to wind resistance at higher speeds, is compounded by drive train efficiency lose. So the resulting range curve is highly asymmetric, rather than bell-shaped, declining only slightly at lower speeds, and dropping off rapidly at higher speeds.
I believe there is really little reason to speed up to increase range. I frequently drive on narrow winding roads, at less than 38 mph. If I increase my speed to 38 mph, I figure I'm wasting much more energy (and tread) scrubbing the tires, than I am saving by speeding up to the car's "most efficient" 38 mph.
http://www.electricauto.org/resource/resmgr/media/nissan_leaf_sae_2_11.pdf
You will see that efficiency is above 85% at all rpm levels. So the loss of range below 38 mph is probably negligible, at least down to 20 mph or so. The much more significant loss of range, due to wind resistance at higher speeds, is compounded by drive train efficiency lose. So the resulting range curve is highly asymmetric, rather than bell-shaped, declining only slightly at lower speeds, and dropping off rapidly at higher speeds.
I believe there is really little reason to speed up to increase range. I frequently drive on narrow winding roads, at less than 38 mph. If I increase my speed to 38 mph, I figure I'm wasting much more energy (and tread) scrubbing the tires, than I am saving by speeding up to the car's "most efficient" 38 mph.
TonyWilliams
Well-known member
edatoakrun said:
I didn't find an asymmetric jpg in my quick internet search !!!
From one of the articles in the above quote links, "the information panels show downtown New York in traffic jam where average speed is 15mph (24 km/h) at an ambient temperature of -10C (+14F) [pretty cold!] where the car may attain a 62 (100-km) range."
It's difficult to say how much the range is impacted by the slow speed, or the cold battery, but my point was that really slow is not super efficient.
LEAFfan
Well-known member
The reason I said I could go a lower speed to get more miles is because of that utube video of those guys running the LEAF around the track at 17Mph and they obtained a high number of miles...140? I can't remember the miles they achieved.
TomT
Well-known member
It's unclear from that article and graph whether or not the efficiency stated is the motor only or the entire inverter/motor/power train... If it is the motor only, there may be other factors at work at slower speeds that affect efficiency as well that make 38mph the sweet spot. Certainly parasitic loses would be a consideration since they are essential constant and thus contribute more to total power consumption at slower speeds.
edatoakrun said:
91040
Well-known member
If 38 mph is the sweet spot for a flat road, does that sweet spot become a lower speed as the grade increases?
TonyWilliams
Well-known member
LEAFfan said:
I think they were actually going 35mph.