Six miles, Low Battery Warning to Turtle (Sans Effect)

[TonyWilliams]

1) Battery level is low warning, both dash display and audio alert, vehicle still performs as expected (about 17% battery SOC)
2) "a few" miles later, Battery is very low warning (also dash display and audio? and does the car slow down at all at this point?) (no, full power available, about 8% SOC)
3) soon after that, "turtle mode", more visual and audible warnings, max speed like 20mph, maybe you get another mile (maybe a half mile on level ground... going up a hill could be 300 yards)
4) Complete immobilization, but the lights and flashers (and anything else on the 12 volt system) still work at least until the 12v battery dies (yes)

From dead, and not just Turtle, are two entirely different things. DON'T KILL THE CAR> There is nothing to be gained, and it will take a long time with a 120v generator to get the car to power up again (maybe and hour or more even at 240v... I've done it).

I don't know if the climate control will turn off, because I always turn it off when you're pushing it to the end. Presumably, Turtle mode's "limited power" will do that, just like ECO mode also limits climate control.

I'm hoping I got some balancing last night, with a stop charging text message at 4:32am, and another at 7:39am.

For guys charging to 100% regularly with the timer set to just before they leave, I think you're missing out on this valuable 3 hours of balancing.

 

[shay]

I'm hoping I got some balancing last night, with a stop charging text message at 4:32am, and another at 7:39am.

For guys charging to 100% regularly with the timer set to just before they leave, I think you're missing out on this valuable 3 hours of balancing.

Thank you for the tip. I wish that was in the manual.

 

[GaslessInSeattle]

Tony, how often do you recommend balancing? Now that more people are relying on charging closer to the time they leave, this might be important.

1) Battery level is low warning, both dash display and audio alert, vehicle still performs as expected (about 17% battery SOC)
2) "a few" miles later, Battery is very low warning (also dash display and audio? and does the car slow down at all at this point?) (no, full power available, about 8% SOC)
3) soon after that, "turtle mode", more visual and audible warnings, max speed like 20mph, maybe you get another mile (maybe a half mile on level ground... going up a hill could be 300 yards)
4) Complete immobilization, but the lights and flashers (and anything else on the 12 volt system) still work at least until the 12v battery dies (yes)

From dead, and not just Turtle, are two entirely different things. DON'T KILL THE CAR> There is nothing to be gained, and it will take a long time with a 120v generator to get the car to power up again (maybe and hour or more even at 240v... I've done it).

I don't know if the climate control will turn off, because I always turn it off when you're pushing it to the end. Presumably, Turtle mode's "limited power" will do that, just like ECO mode also limits climate control.

I'm hoping I got some balancing last night, with a stop charging text message at 4:32am, and another at 7:39am.

For guys charging to 100% regularly with the timer set to just before they leave, I think you're missing out on this valuable 3 hours of balancing.

 

[GaslessInSeattle]

could the cold be having a disproportionate effect on the low end of the battery?

I suspect that if all the cells degrade at about the same rate, they aren't going to cover loss but if a few fall outside the curve, they will cover them under warranty. One of the Tesla folks around here told me to expect a good chunk of degradation to happen in the first year or so and then level off, for whatever that's worth.

These are all valid points, and given the amount and type of information we have received from Nissan, it's no wonder that everyone is looking for the first sign of battery degradation practically on a daily basis. Based on what I have seen elsewhere, I would like to assure you that the cells Nissan used in the Leaf will very likely perform well. Not only that, they will likely exceed your expectations, especially if you live in a temperate climate, and go by the initial estimate of 30% capacity loss in 10 years.

That being said, I saw somewhat diminished performance yesterday as well. Typically, I can get at least 15 miles between LBW and turtle, but I only managed to get 10 the other night. My commute is fairly short, and I usually don't explore the lower reaches of the SOC range if I don't have to.

 

[DaveinOlyWA]

I would go no longer than every few Weeks or so. Less often when pack I'd new, more often as pack ages

 

[Herm]

I'm hoping I got some balancing last night, with a stop charging text message at 4:32am, and another at 7:39am.

Because some of you can be a bit OCD, there is no need to balance cells very often, unless they are going bad (and you KNOW your cells are perfect).. start at once every 2 weeks..

 

[Herm]

could the cold be having a disproportionate effect on the low end of the battery?

It depresses the voltage at start up when the pack is cold.. presumably that is when the 281 meter calibrates itself.. perhaps after a long drive the pack has warmed up, voltage increases and fools the BMS into thinking it has more power in reserve than it does based on the old calibration.. thus the premature end to turtle mode. I would assume Nissan uses extensive temperature modeling in their BMS algorithms but perhaps it needs more work. They could also add a mild siren type sound when you get into turtle mode, so that the driver understands the severity of the situation.

I think the lesson to learn here is that the BMS gets touchy in winter with temperature changes.

 

[HighDesertDriver]

How often do you recommend balancing?

The chemistry is different, but the NiMH batteries in the RAV4-EV are balanced by the BMS every 10 charges. Most owners are over 100,000 miles before deciding for range or acceleration issues to have their pack reworked.

 

[LTLFTcomposite]

From dead, and not just Turtle, are two entirely different things. DON'T KILL THE CAR> There is nothing to be gained, and it will take a long time with a 120v generator to get the car to power up again (maybe and hour or more even at 240v... I've done it).

So if turtle gives you half a mile at best, you really don't want to do anything more than pull off to the shoulder or whatever you can do immediately to get into a safe location. I should not attempt to limp along the shoulder to an off ramp unless it's right there, and the ramp is downhill

For guys charging to 100% regularly with the timer set to just before they leave, I think you're missing out on this valuable 3 hours of balancing.

OK so just when I thought I understood the "best way to charge" there's another curve ball. You are saying that this balancing happens after the battery reaches full charge, so it is better to *not* have charging complete shortly before you leave?

Oh and one more thing someone needs to add "Turtle your LEAF" to urban dictionary.
Dude, I turtled my leaf last night on the wrong side of the tracks.

 

[abasile]

OK so just when I thought I understood the "best way to charge" there's another curve ball. You are saying that this balancing happens after the battery reaches full charge, so it is better to *not* have charging complete shortly before you leave?

On occasion, it might not be a bad idea to let the car remain plugged in to the EVSE for a bit longer than usual at 100% SOC. But on a day-to-day basis, for the long-term health of the battery pack, it seems best to finish charging right before driving off. Personally, I don't get too concerned about balancing. Overall, it's less stressful just to attempt to leave oneself a cushion at the bottom of the range. "Low battery warning" is the threshold that I happen to feel comfortable with.

 

[DaveEV]

I'm hoping I got some balancing last night, with a stop charging text message at 4:32am, and another at 7:39am.

For guys charging to 100% regularly with the timer set to just before they leave, I think you're missing out on this valuable 3 hours of balancing.

Was that charging without a timer?

Going back to a thread from last year it appears that only setting an stop time will also induce a top-off charge when charging to 100%.

Look here: Charging timer: start time based on END time?

 

[abasile]

20 miles is too much to give away - might as well be driving a Volt. 10 mile buffer (planning to get home around LBW) is much more reasonable. This is actually one of Toyota's arguments against BEVs and using a smaller battery in the plug-in Prius - regularly using 100% of the battery maximizes one's return on investment and "range anxiety" keeps most people from using the bottom of the pack regularly.

That seems like a fallacious argument against BEVs. Supposedly the Volt only uses 65% of its battery. I'm sure the Plug-in Prius doesn't use "100%" of its battery either. Cycling the LEAF battery within an SOC range of 15% (just below the "low battery" threshold) to 89% might be roughly equivalent to how the Volt cycles its pack, assuming the LEAF has a usable capacity of 21 kWh and an ultimate capacity of 24 kWh. Plenty of us are comfortable within that SOC range, actually greater since I have no problem charging to 100% whenever needed.

 

[LTLFTcomposite]

On occasion, it might not be a bad idea to let the car remain plugged in to the EVSE for a bit longer than usual at 100% SOC. But on a day-to-day basis, for the long-term health of the battery pack, it seems best to finish charging right before driving off. Personally, I don't get too concerned about balancing. Overall, it's less stressful just to attempt to leave oneself a cushion at the bottom of the range. "Low battery warning" is the threshold that I happen to feel comfortable with.

That sounds like good advice abasile. The other thing I am wondering is "they" say the battery is most stable at 50% charge, and it's the extremes that shorten its life. Is hanging with the turtles just as bad as 100%?

 

[TangoKilo]

1) Battery level is low warning, both dash display and audio alert, vehicle still performs as expected (about 17% battery SOC)
2) "a few" miles later, Battery is very low warning (also dash display and audio? and does the car slow down at all at this point?) (no, full power available, about 8% SOC)
3) soon after that, "turtle mode", more visual and audible warnings, max speed like 20mph, maybe you get another mile (maybe a half mile on level ground... going up a hill could be 300 yards)
4) Complete immobilization, but the lights and flashers (and anything else on the 12 volt system) still work at least until the 12v battery dies (yes)

From dead, and not just Turtle, are two entirely different things. DON'T KILL THE CAR> There is nothing to be gained, and it will take a long time with a 120v generator to get the car to power up again (maybe and hour or more even at 240v... I've done it).

I don't know if the climate control will turn off, because I always turn it off when you're pushing it to the end. Presumably, Turtle mode's "limited power" will do that, just like ECO mode also limits climate control.

I'm hoping I got some balancing last night, with a stop charging text message at 4:32am, and another at 7:39am.

For guys charging to 100% regularly with the timer set to just before they leave, I think you're missing out on this valuable 3 hours of balancing.

As a test, I ran the battery past the turtle mode a while back. It quit after one mile at a max speed of 30mph and then popped into neutral. I coasted into my driveway, ala Bob Hover, and parked my LEAF. I noted that I could not move my LEAF out of park (parking brake on) until there were two charge bars back on the gauge, which was roughly one hour at L2... :ugeek:

 

[TangoKilo]

1) Battery level is low warning, both dash display and audio alert, vehicle still performs as expected (about 17% battery SOC)
2) "a few" miles later, Battery is very low warning (also dash display and audio? and does the car slow down at all at this point?) (no, full power available, about 8% SOC)
3) soon after that, "turtle mode", more visual and audible warnings, max speed like 20mph, maybe you get another mile (maybe a half mile on level ground... going up a hill could be 300 yards)
4) Complete immobilization, but the lights and flashers (and anything else on the 12 volt system) still work at least until the 12v battery dies (yes)

From dead, and not just Turtle, are two entirely different things. DON'T KILL THE CAR> There is nothing to be gained, and it will take a long time with a 120v generator to get the car to power up again (maybe and hour or more even at 240v... I've done it).

I don't know if the climate control will turn off, because I always turn it off when you're pushing it to the end. Presumably, Turtle mode's "limited power" will do that, just like ECO mode also limits climate control.

I'm hoping I got some balancing last night, with a stop charging text message at 4:32am, and another at 7:39am.

For guys charging to 100% regularly with the timer set to just before they leave, I think you're missing out on this valuable 3 hours of balancing.

As a test, I ran the battery past the turtle mode a while back. It quit after one mile at a max speed of 30mph and then popped into neutral. I coasted into my driveway, ala Bob Hover, and parked my LEAF. I noted that I could not move my LEAF out of park (parking brake on) until there were two charge bars back on the gauge, which was roughly one hour at L2... :ugeek:

Hoover....

 

[HighDesertDriver]

Hoover...

I'm sure he would forgive the missing "o". :lol: Just make sure you do not roll your Leaf while pouring drinks for the passengers. . .

I haven't shared this except in PMs, but you may appreciate it. I've said I like to know the limits of our machines. Several years ago we encountered very high unexpected headwinds in our small plane while returning to our home airport. Not having a lot of options, I pressed ahead and told myself "That is what the reserve is for." Keeping a eye on every road and field we passed, I called ahead to the tower and asked for expedited handling due to potential low fuel. They gave me a straight-in and cleared me with a preemptive call on 3-mile final. Everything was normal for the remainder of the landing, but just after I cleared onto the taxiway, the engine sputtered to a stop. Way too close in 20/20 hindsight, but at least I knew how to eek the most out of the plane. That plane has a new home (for other reasons) and I rarely land anymore with less than 90 minutes of fuel.

 

[LTLFTcomposite]

I haven't shared this except in PMs, but you may appreciate it. I've said I like to know the limits of our machines. Several years ago we encountered very high unexpected headwinds in our small plane while returning to our home airport. Not having a lot of options, I pressed ahead and told myself "That is what the reserve is for." Keeping a eye on every road and field we passed, I called ahead to the tower and asked for expedited handling due to potential low fuel. They gave me a straight-in and cleared me with a preemptive call on 3-mile final. Everything was normal for the remainder of the landing, but just after I cleared onto the taxiway, the engine sputtered to a stop. Way too close in 20/20 hindsight, but at least I knew how to eek the most out of the plane. That plane has a new home (for other reasons) and I rarely land anymore with less than 90 minutes of fuel.

Great story. At the risk of overstating matters, EV driving is a little like flying in that you need to know how much fuel you are taking off with and what your flight plan is. EV charging points here are almost as rare as fuel trucks are in the sky :lol:

I have to tip my hat to people like you, Tony and others who have made turtling a way of life:

http://www.youtube.com/watch?v=TuEdU_lrtZk" onclick="window.open(this.href);return false;

 

[Herm]

Tony is channeling Bob Hoover, if you dont know who that is just go to youtube and type his name in..

 

[DaveEV]

20 miles is too much to give away - might as well be driving a Volt. 10 mile buffer (planning to get home around LBW) is much more reasonable. This is actually one of Toyota's arguments against BEVs and using a smaller battery in the plug-in Prius - regularly using 100% of the battery maximizes one's return on investment and "range anxiety" keeps most people from using the bottom of the pack regularly.

That seems like a fallacious argument against BEVs. Supposedly the Volt only uses 65% of its battery. I'm sure the Plug-in Prius doesn't use "100%" of its battery either. Cycling the LEAF battery within an SOC range of 15% (just below the "low battery" threshold) to 89% might be roughly equivalent to how the Volt cycles its pack, assuming the LEAF has a usable capacity of 21 kWh and an ultimate capacity of 24 kWh. Plenty of us are comfortable within that SOC range, actually greater since I have no problem charging to 100% whenever needed.

I think you're missing the point. If you are talking about maximizing the reduction in gasoline consumption with a fixed amount of battery production, then definitely, yes, in general smaller battery packs are more effective when used in more vehicles.

Think of this example: You have the choice of either producing 1 LEAF (24 kWh battery) and completely eliminating one person's gasoline consumption or producing 6 plug-in Priuses (4 kWh battery) and nearly eliminating 6 people's gasoline consumption for short trips (< 15 mi) and significantly reducing it for long trips (>15 mi).

Even if you never plugged the Prius in you'd reduce gasoline consumption by at least 17%, but best case your 1 LEAF is only going to reduce gas consumption by the same amount across 6 drivers.

Let's compare a best case scenario for the LEAF: 73 mile trip where you completely drain it and the plug in Prius where you drive 15 miles on electricity and 57 miles on a bit more than a gallon of gas. Typical gas car you'd burn at least 2 gallons of gas on a 73 mile trip - in the Prius you'll burn 1.16 gallons or a 40% reduction in gasoline consumption for all 6 people.

Scenario 1: 6 gas burners each drive 73 miles: consume 12 gallons of gas
Scenario 2: 1 LEAF 5 gas burners each drive 73 miles: consume 10 gallons of gas
Scenario 3: 6 Plug-in Priuses each drive 73 miles: Consume 7 gallons of gas

And the numbers only favor the plug-in Prius more on shorter trips.

 

[abasile]

If you are talking about maximizing the reduction in gasoline consumption with a fixed amount of battery production, then definitely, yes, in general smaller battery packs are more effective when used in more vehicles.

Totally agree with this. The only thing is, battery production doesn't appear to be a constraint at this time, nor for at least the next few years. Still, there is the question of optimal allocation of government subsidies. I think the current subsidies are fine, but an argument can be made for increasing subsidies on small battery packs relative to large packs. See http://www.mynissanleaf.com/viewtopic.php?f=7&t=7304" onclick="window.open(this.href);return false;