My Experiments With Turtle

[DaveinOlyWA]

what i prefer is user settable alerts by text msg. tell me when i am at 80, 90% etc...

 

[LEAFfan]

what i prefer is user settable alerts by text msg. tell me when i am at 80, 90% etc...

+1! I like that idea! :mrgreen: Did you put that on the survey?

 

[DaveinOlyWA]

what i prefer is user settable alerts by text msg. tell me when i am at 80, 90% etc...

+1! I like that idea! :mrgreen: Did you put that on the survey?

yep. along with production schedules

# of reservationist by area, dealer and their expected delivery dates as well

 

[planet4ever]

Interesting...did you start with 100%?

Funny you should ask. It was a most unique day for me! I normally charge to 80%, and that is what I had done Thursday night. Friday morning my wife had a doctor's appointment in San Jose, 15 miles from home, and was taking forever to get ready. We finally left home about ten minutes before her appointment time, so I broke all my normal rules. I flew up 101 at 80 mph all the way. :shock: (It didn't help, incidentally. She got bumped, and had to wait an hour to get in.)

Coming home I tried to make up for it, but I was down to 2 bars when I pulled into the driveway, and I knew I was going to have to drive 25 miles or so later in the day. So I broke my other rule, and plugged in for two hours of immediate charge, even edging a bit into PG&E peak rate time. I had four bars when I started my afternoon ticket pickups at outlets (I do box office for a community theater group) and, as I said, I was down to one bar and "low battery" by the time I finished and was driving home after the play.

Ray

 

[Bassman]

Tried a different route home from work yesterday, 66.5 miles instead of 63 and a little more up and down hills. Started out 100% charged and a 82 mile ECO range estimate. Got home with 1 bar and 6 miles of range estimated remaining, so I decided to go for turtle mode. Low battery warning came immediately as I started to continue uphill on my street. It's about 3 miles to Highway 4 from my home and it's a 600 feet climb (1500 to 2100 ft elevation). Made it to the top and then back plus another mile, Range estimate showed no miles and got very low batter warning drove another 6 miles up the hill and back and got turtle mode. Drove 0.8 miles back to the house but never died completely (0.5 miles uphill and about 0.3 miles downhill in turtle mode). Pulled into garage with 78.8 miles on the odometer. So 100% charge to pretty close to dead on my route home (a lot of uphill and downhill {an overall 1500 foot elevation change plus a couple 300-400 foot climbs and decents} and 55-65 mph, mostly 55mph) got me 78.8 miles in 90 degrees outside temp.

 

[LEAFer]

Nice ! Thanks for the "turtle" experience report.

Suggestion: your signature says "so far" ... might be better to also include a specific "Sig updated <date>". And ... since work-charging is not included ... the m/kwh could become confusing ...

 

[GregH]

So today I tried to see how low I could go... With the 281/SOC display (mine only tops out at 278 now) in hand I set out on the freeway to burn kWhs..
In the data I was looking at a number I suspected was max current (it wasn't).. I saw the range go down 7..6..5..4.. (blinking at 7 or lower I think..)
The bars went to zero and more warnings went off in the car.. then the range went down to triple dashes (triple diamonds in EV1 speak) but I was still
getting full power. I think to 281/SOC thing was in the 20s by this point... I kept going. I got bored of driving around in circles near my house so I set out on some arterials.. The 281/SOC thing got down to single digits (no bars, --- range) and I still could get full power!! wtf? I was waiting for the some of the little double bubble power bubbles to go single (the way regen does when you're full) but it didn't happen.. then at around 5 SOC# I lost one bubble then within seconds lost a bunch and had just a few available bubbles.. I made a U-turn and headed back towards my house at max speed 30-35mph. Turning into my neighborhood I lost all power. This was only about 1/2 mile from where I first started seeing any physical signs of reduced performance. I pushed the car into a safe spot in front of a strangers house and asked if I could plug into 120V for a while.. merely 1/2 mile from my house.. sigh.. I little more reduced performance (turtle) warning would have been nice... It's possible that as a newbie pack (600 miles, only a few "full" charges) it wasn't well balanced and my hard acceleration at extreme low SOC set off a slow response alarm. I'd like to think real turtle mode/reduced performance is more graceful than this. I've driven electric for years (EV1s and a RAV4-EV).. I've taken EV1s from coast to coast. I don't think I've ever had an EV completely STOP on me. Not cool.
-Greg

 

[evnow]

I was waiting for the some of the little double bubble power bubbles to go single (the way regen does when you're full) but it didn't happen.. then at around 5 SOC# I lost one bubble then within seconds lost a bunch and had just a few available bubbles.. I made a U-turn and headed back towards my house at max speed 30-35mph.

How many miles did you finally get - and at what m/kwh ?

 

[planet4ever]

You're seeing basically the same sort of thing the rest of us are seeing. Three dashes happens at the same time as the "Very Low Battery" warning and the exhortation to find a charging station. After that you get maybe 5 to 10 miles (depending, of course, on how and where you are driving) before the turtle lights up. Turtle means dramatically reduced power, and maybe half a mile of range.

My interpretation of the indicators is:
LB (flashing range indicator): Slow down and get off the freeway when convenient.
VLB (three dashes): Decide on some place to charge within 5 miles of where you are.
Turtle: Find a safe place to stop the car off the road.

You had the significant advantage of a true SOC gauge. I look forward to having one.

Ray

 

[DaveEV]

then at around 5 SOC# I lost one bubble then within seconds lost a bunch and had just a few available bubbles.. I made a U-turn and headed back towards my house at max speed 30-35mph. Turning into my neighborhood I lost all power. This was only about 1/2 mile from where I first started seeing any physical signs of reduced performance.

Very informative - now we know at what SOC# (~5) we'll get to turtle and know that shut-down is eminent.

Any idea how far you drove after you lost all the bars?

 

[davewill]

I've driven electric for years (EV1s and a RAV4-EV).. I've taken EV1s from coast to coast. I don't think I've ever had an EV completely STOP on me. Not cool.
-Greg

I'm very confused. Just what did you expect to happen? The battery was empty and you had to stop. I'm sure all those other cars also stopped when you ran them all the way down. You got a low battery warning, a very low battery warning, and finally turtle. Are you complaining because it didn't limit power sooner? Or because you weren't allowed to run the pack down till you were in danger of damaging it?

 

[Coffee_Slurry]

Very informative - now we know at what SOC# (~5) we'll get to turtle and know that shut-down is eminent.

I've had it lower than 5, but was not driving at the time.. just running the heater.
The heater cut out at around SOC 4, if I remember correctly.
I couldn't get it lower with just the fan, and wasn't about to go for a drive. No turtle.

 

[GregH]

I was upset that the transition to reduced performance mode ("turtle" I suppose) was not more graceful. I had 100% power and then extreme RPM.. and then I could only drive about 1/2 mile in RPM before it conked out completely. In most other EVs I wouldn't expect full power so close to empty. I would also appreciate a more gradual transition to RPM.. I was expecting to see the double "bubbles" of usable power get ticked off one by one over the course of a mile or two... Not suddenly from 100% power to 10% power. And lastly, when in RPM you should have more than 1/2 a mile left.. I suspect I might have had a low cell in there that set off a slow alarm when I did the full power acceleration so close to zero. Perhaps if I'd babied it, it would have gone longer.. but still the car shouldn't have let me do that. I think the RPM should start kicking in as soon as you get to zero miles ("---").. just knock one or two bubbles off the top to reinforce with the driver that he's running out. Yes in a normal gas car, when you run out of gas, it stops.. but with batteries you have the opportunity of gracefully going from full power to zero power... The RAV4-EV even had a voltmeter on the dash and if you gunned it on empty the turtle would come on only if you dipped below a set voltage (and only then).. so if you babied it you could get more out. My Prius could go over 100 miles with the "low fuel" warning on.. I understand that the software on the Leaf has been updated to provide more reserve below "zero".. I wanted to know where zero was.. and I was surprised I hit it so dramatically. just say'in.

 

[evnow]

I was upset that the transition to reduced performance mode ("turtle" I suppose) was not more graceful. I had 100% power and then extreme RPM.. and then I could only drive about 1/2 mile in RPM before it conked out completely. In most other EVs I wouldn't expect full power so close to empty. I would also appreciate a more gradual transition to RPM.. I was expecting to see the double "bubbles" of usable power get ticked off one by one over the course of a mile or two... Not suddenly from 100% power to 10% power.

Not sure why you want them to do this - they are giving you enough warnings ...

 

[planet4ever]

I would also appreciate a more gradual transition to RPM.. I was expecting to see the double "bubbles" of usable power get ticked off one by one over the course of a mile or two... Not suddenly from 100% power to 10% power.

I don't think I would like that. I really appreciate having consistent performance for as long as possible. I might, for example, need to accelerate to switch lanes so I can make a turn to get to my charging point.

My experience with the Prius "low fuel" indicator is that you can get 50 to 100 miles once it comes on. Based on a nominal 500 mile tank, that is 10% to 20%, and that is what you get in the LEAF as well.

Ray

 

[Herm]

I was expecting to see the double "bubbles" of usable power get ticked off one by one over the course of a mile or two... Not suddenly from 100% power to 10% power. And lastly, when in RPM you should have more than 1/2 a mile left.. I suspect I might have had a low cell in there that set off a slow alarm when I did the full power acceleration so close to zero. Perhaps if I'd babied it, it would have gone longer.. but still the car shouldn't have let me do that.

It probably was a single low cell warning that shut you off "prematurely".. but the BMS had no choice unless it wanted to permanently damage that cell. Your pack may have a cell that has a tiny bit lower capacity than the others, or the pack is baddly out of balance. If I was in charge the BMS would automatically recalibrate and lower your total usable kwh capacity a bit, so that you never get that low again. This must be expected, capacity will decrease gradually as the car approaches 80-150k miles.

Other Leaf owners may experience different things while in turtle mode.. it is an emergency mode of operation.

 

[DaveinOlyWA]

I was upset that the transition to reduced performance mode ("turtle" I suppose) was not more graceful. I had 100% power and then extreme RPM.. and then I could only drive about 1/2 mile in RPM before it conked out completely.

in my turtle mode experiment when i started losing power bubbles, i went over 2 miles before parking and had 4 bubbles left. but that was at low speeds 20-25 mph.

not sure i understand what you want here. also not sure why you would care. other than experimentation, how the Leaf reacts when the pack is that low is much more elegant than simply losing power and coasting to the side of the road like a gas car.

turtle mode aka "3rd and final" warning is exactly that. final.

 

[edatoakrun]

Is it safe to assume that LEAF brake regen will charge the battery and take the car out of "turtle"?

I want to try a big ascent, and expect to be close to turtle at the top. If I don't make it, I can always turn around as soon as I hit turtle, and recharge with regen, right?

 

[LEAFer]

Is it safe to assume that LEAF brake regen will charge the battery and take the car out of "turtle"?

I want to try a big ascent, and expect to be close to turtle at the top. If I don't make it, I can always turn around as soon as I hit turtle, and recharge with regen, right?

Good question ... I don't think anyone's tried that ... and I won't risk guessing what Nissan has "up its sleeve" once the car enters turtle mode. But we're all ready for YOU to try it and answer your own question :lol:

 

[GregH]

Knowing exactly when the car is going to stop is EXTREMELY important!! I suspect in this situation it was an abnormally low cell that was triggered when I did a full throttle acceleration. Probably not indicative of normal turtle mode on a balanced/mature pack. Simply having the car say "you are empty and could die at any moment!" is not satisfactory.

From the time the range hit "---" and the 12 bars were all gone, this is about what happened.
Drove 2-3 miles with full power capability and no physical sign that the end is near (yes yes, plenty of dashboard warnings, but no physical feedback)
Dropped from full power to 3-4 power bubbles and drove 30mph or so (max!) for about 1/2 mile then it stopped cold.

What I would have liked to have seen for those last 3 miles was more like this:
The turtle icon, and the steady loss of power double bubbles over the course of the 3 miles such that the last 1/2 mile was just as I observed above (3-4 power bubbles, 25-30mph likely top speed). I suspect that had my pack been more mature, this is probably what I would have seen.

I take full responsibility here btw.. I was driving in circles around my neighborhood and despite reaching "---" and zero bars I was surprised to still have full power and was getting bored (and the neighbors were looking at me funny) so I opted to go out on a major arterial where I did a full acceleration with no signs of hesitancy (this is a few miles into the --- "you are empty" etc etc). When it dropped into RPM I made an immediate U-turn and headed back to my neighborhood @30mph. When I turned into the subdivision I was about 0.1 miles from my friends house (where we were going to meet for the fireworks show) and about 0.9 miles from my house. I thought I could make it to my house, but did not. I coasted to the side, pushed the car into a decent curbside parking position and asked the guy whose house I was in front of, if I could plug in for a bit (he was in the garage).. Total stranger, funny it turned out he (BJ) used to work for GM in Detroit back in the day and was very familiar with the EV1 program.. After 15 minutes on 120V I tried to power up but the contactors still wouldn't close. While we were there talking, someone else drove up (looking for parking for the fireworks show) and said they were interested in buying a Leaf and asked me a bunch of questions.. sat in the car etc... So anyway with the BJ's permission I left it there for a few hours while I went to the fireworks show with friends. Oddly the show was called off early as they set off a brush fire off to the side of the stadium in Irvine near the 5 freeway.. oops. Anyway, when I got the car a few hours later I had 5-6 miles of range and drove the 1/2 mile home no problem.

Now I know.