Restart from turtle

[nenik]

40kWh 2021 Leaf. I've got into turtle mode going uphill on a very low battery (>1.5kWh left). I have turned around, shifted to 'P' to drop off a passenger (living up that hill, almost made it) and tried to go downhill to a nearby DC charger (1.1mi). But the car would only go to neutral after that, no 'D'. Got a tow for a bit (home instead, 6 miles), charged the car and all is good. I knew what I am getting into, just needed to calibrate expectations of this new-to-me car (3rd Leaf in 8 years).

So what have I learned:
* Turtle triggers based on voltage (I know that before), so when going uphill, it could trigger earlier then you'd expect
* You can drive in Turtle, but don't park. Once you park, you're done. Well, it's mean't to let you stop (park) safely, right.
* Once you were in turtle, it takes a lot of charge to be able to start again. Someone here mentioned 10% on the dash, which seems to match my experience.
* You can to to 'N', but if you keep the door open, it goes back to P (obvious safety feature, but the tow guy didn't know it and we fought it for a bit trying to reposition the car for the tow truck)

Now a question:
Is there a way to reset this "I was in turtle" flag somehow? There are many use cases that are in the realm of "I need 10 more seconds of power after I parked" and with 1.5kWh left in the battery (and the voltage recovering because you're no longer climbing a steep hill) it would be still somewhat safe for the battery.
* You may not parked well on the first try.
* It helps if you can reposition the car for the tow.
* When the tow truck drops you by the curb, your home charging cable won't fit and charging with the travel 120V adapter to 10% takes ages.

At home, I planned to give it an hour on 120V, then drive it those 30ft to the garage for a proper charger... 2h later, still not leaving 'N', we decided to push it up the driveway instead. Thank goodness I have had enough hands around to help.

 

[Chad E. Mo]

Is there a way to reset this "I was in turtle" flag somehow?

AIUI, LeafSpy Pro can clear the codes including the turtle.

 

[nenik]

Thanks for the reply. I do have LeafSpy Pro. I was hoping there could be something like that when asking this question, but it didn't occur to me back in the situation.

So are you saying that "I've been to turtle" is just a DTC code? If I clear it, I'll have a chance at moving it few more yards?
I don't plan to turtle anytime soon, LOL, but should that ever happen, I'll certainly try.

 

[hornstudio]

Closing the drivers door is "the key". I was stuck with 2,8kWh left. One cell was too low and instead of emptying the battery by heating and leaving windows down I drove with full heating, heated seats, heated steering, heated rear screen and after 1/4 mile with turtle I was stuck.

Same problem you had occured - repositioning the car with drivers door open. Finally would found out the problem and 3 people pushed me home. First time I was stuck after 13 years electric. After recharge BMS opened a nearly 10% wider window.

 

[knightmb]

40kWh 2021 Leaf. I've got into turtle mode going uphill on a very low battery (>1.5kWh left). I have turned around, shifted to 'P' to drop off a passenger (living up that hill, almost made it) and tried to go downhill to a nearby DC charger (1.1mi). But the car would only go to neutral after that, no 'D'. Got a tow for a bit (home instead, 6 miles), charged the car and all is good. I knew what I am getting into, just needed to calibrate expectations of this new-to-me car (3rd Leaf in 8 years).

So what have I learned:
* Turtle triggers based on voltage (I know that before), so when going uphill, it could trigger earlier then you'd expect
* You can drive in Turtle, but don't park. Once you park, you're done. Well, it's mean't to let you stop (park) safely, right.
* Once you were in turtle, it takes a lot of charge to be able to start again. Someone here mentioned 10% on the dash, which seems to match my experience.
* You can to to 'N', but if you keep the door open, it goes back to P (obvious safety feature, but the tow guy didn't know it and we fought it for a bit trying to reposition the car for the tow truck)

Now a question:
Is there a way to reset this "I was in turtle" flag somehow? There are many use cases that are in the realm of "I need 10 more seconds of power after I parked" and with 1.5kWh left in the battery (and the voltage recovering because you're no longer climbing a steep hill) it would be still somewhat safe for the battery.
* You may not parked well on the first try.
* It helps if you can reposition the car for the tow.
* When the tow truck drops you by the curb, your home charging cable won't fit and charging with the travel 120V adapter to 10% takes ages.

At home, I planned to give it an hour on 120V, then drive it those 30ft to the garage for a proper charger... 2h later, still not leaving 'N', we decided to push it up the driveway instead. Thank goodness I have had enough hands around to help.

A lot of unpack, so I'll start at the top.
In my experience with my (2012, 2013, 2018, 2020) Leaf(s) I've driven over the years, this is the behavior I've recorded. I'll go from my 2018 viewpoint as that probably is closer to matching what you'll see with your 2021 Leaf since they both use the 40 kWh battery pack. Turtle mode seems to kick in when the lowest voltage cell drops below 3.0 volts for some extended amount of time. This quickly reduces your max power to around 10 kW. While in turtle mode, it is possible to stop somewhere, turn off the Leaf, come back and power-on again to drive some more (in turtle mode still usually), but only if the remaining capacity (that the BMS shows in LeafSpy) is above 2.0 kWh remaining. If you try to do this under that amount, it will just complain that you need to charge it up more before you can drive. As such, I've never seen it generate a DTC or read about anyway to reset this as it comes directly from the BMS itself. I believe the only reason you can stop in turtle mode, power off, come back later and it still let you drive is that the cell voltages climbed back up above 3.0 volts after a short rest, but the BMS remembers that you are still in turtle mode.

What happens if you drive a Leaf (any year model) all the way to shutdown. Well you can't just charge it "enough" to get the lowest cell voltage back above 3.0 volts, you have to actually wait until you get about 50 gids of energy put in before it will let you power back up to drive around. Of course, putting that much in takes a while and why does it need you to bet at like 9% SOC instead of 1%, that is just how Nissan coded it.

My wife has a lot of experience driving in turtle mode for some insane amount of miles. I myself managed to drive over 5 miles in turtle mode one time (it was her Leaf actually that time ) This is what I told me wife when she calls and tells me "I'm only 1 mile away from the house and I am in turtle mode". The first thing I ask her is when it happened and how far have you been driving on it. If it just happened, I tell her to pull over somewhere safe and just turn it off. Every-time I go to help her (and bring my EVSE in-case I have to do a Leaf to Leaf power transfer), she usually has at least 2 or 3 kWh left on the battery when I fire up LeafSpy, so I tell her just to drive back, very gently to the house, turn on her hazard lights and ignore the long line of cars behind her.

 

[Jerther]

and bring my EVSE in-case I have to do a Leaf to Leaf power transfer

Power transfer? Can you elaborate on that?

 

[knightmb]

Power transfer? Can you elaborate on that?

I use a 12VDC to 120AC inverter to power an EVSE that I can plug into another Leaf to charge it. Not fast by any stretch as it is like plugging into a 120V outlet at home to charge, but useful when another Leaf is depleted and is nowhere near another outlet.

 

[Jerther]

AFAIK the Nissan EVSE pulls the full 1500W on 120V. First, finding an inverter that provides that power must not have been easy And second, 1500W on 12V is like 120 amps. How do you manage that on the leaf!? Oh, do you have one of those EVSEs that the amperage can be adjusted?

 

[knightmb]

Plenty of 2000 watt, pure sine-wave 12VDC to 120VAC inverters for sale on the web. I use a 200 amp quick connect/disconnect with 1/0 wire gauge copper. The Leaf 12V system can run up to 2000 watts of power, so running an EVSE at only 12 amps (Nissan Default) is pretty much the max the system can handle due to inverter efficiency loses. If you max out the 2000 watts, the Leaf shut downs completely and it takes a 12V battery power cycle to get it out of it's safe mode.

 

[Jerther]

Impressive! So the leaf must be in ready to drive state so it's own inverter is on, but with all accessories off so not to exceed 2000w. Right?

And 2000w... That is some nice useful power right there. With 40kwh. And portable. Not exactly v2h but still

 

[knightmb]

Yes, otherwise the 12V battery will take the brute of that power load and the inverter would shutoff right away for safety reasons. Correct on the accessories too. You have enough buffer to run the AC/Heat system on a medium cabin fan speed, radio, etc. But I wouldn't try turning on all the seat heaters, steering wheel heater, rear defroster, all lights and flood lights, cabin fan on max, wind shield wipers, etc.

This is an old setup too, actually I had in my 2013 Leaf setup for this and moved it (wires wise) to my 2020 Leaf when I traded in 4 years ago. I think it was back in 2016 when I put this together, so it's quite old now.

Yes, actually I do use it for house backup power (the original reason I built it that way), but it also happens to work for L1 EVSE portable charging as well.

I made a video of this since I needed to do my yearly testing of the setup anyway. This is why my wife will carelessly run her Leaf down to nothing. She knows I can come rescue her, for good or bad.

 

[Jerther]

Wow! I'll keep that in mind! Thanks!!

 

[nenik]

A lot of unpack, so I'll start at the top.
In my experience with my (2012, 2013, 2018, 2020) Leaf(s) I've driven over the years, this is the behavior I've recorded. I'll go from my 2018 viewpoint as that probably is closer to matching what you'll see with your 2021 Leaf since they both use the 40 kWh battery pack. Turtle mode seems to kick in when the lowest voltage cell drops below 3.0 volts for some extended amount of time. This quickly reduces your max power to around 10 kW. While in turtle mode, it is possible to stop somewhere, turn off the Leaf, come back and power-on again to drive some more (in turtle mode still usually), but only if the remaining capacity (that the BMS shows in LeafSpy) is above 2.0 kWh remaining. If you try to do this under that amount, it will just complain that you need to charge it up more before you can drive. As such, I've never seen it generate a DTC or read about anyway to reset this as it comes directly from the BMS itself. I believe the only reason you can stop in turtle mode, power off, come back later and it still let you drive is that the cell voltages climbed back up above 3.0 volts after a short rest, but the BMS remembers that you are still in turtle mode.

What happens if you drive a Leaf (any year model) all the way to shutdown. Well you can't just charge it "enough" to get the lowest cell voltage back above 3.0 volts, you have to actually wait until you get about 50 gids of energy put in before it will let you power back up to drive around. Of course, putting that much in takes a while and why does it need you to bet at like 9% SOC instead of 1%, that is just how Nissan coded it.

My wife has a lot of experience driving in turtle mode for some insane amount of miles. I myself managed to drive over 5 miles in turtle mode one time (it was her Leaf actually that time ) This is what I told me wife when she calls and tells me "I'm only 1 mile away from the house and I am in turtle mode". The first thing I ask her is when it happened and how far have you been driving on it. If it just happened, I tell her to pull over somewhere safe and just turn it off. Every-time I go to help her (and bring my EVSE in-case I have to do a Leaf to Leaf power transfer), she usually has at least 2 or 3 kWh left on the battery when I fire up LeafSpy, so I tell her just to drive back, very gently to the house, turn on her hazard lights and ignore the long line of cars behind her.

Thank you for a detailed reply. I am trying to correlate your experience with my data.
For one thing, my leaf didn't "shut down" - or perhaps it did and I didn't recognize it? How would such a shutdown look like?
Regardless of that, when I parked, my battery state was both under 2kWh (about 1.5kWh IIRC, will check LeafSpy logs) and _most_ cells under 3V.
But when charging it back home, I have to get it over this 9 or 10% SOC to be able to drive again into the garage.

 

[eximage]

Yes, otherwise the 12V battery will take the brute of that power load and the inverter would shutoff right away for safety reasons. Correct on the accessories too. You have enough buffer to run the AC/Heat system on a medium cabin fan speed, radio, etc. But I wouldn't try turning on all the seat heaters, steering wheel heater, rear defroster, all lights and flood lights, cabin fan on max, wind shield wipers, etc.

This is an old setup too, actually I had in my 2013 Leaf setup for this and moved it (wires wise) to my 2020 Leaf when I traded in 4 years ago. I think it was back in 2016 when I put this together, so it's quite old now.

Yes, actually I do use it for house backup power (the original reason I built it that way), but it also happens to work for L1 EVSE portable charging as well.

I made a video of this since I needed to do my yearly testing of the setup anyway. This is why my wife will carelessly run her Leaf down to nothing. She knows I can come rescue her, for good or bad.

Hi knightmb
Good info, I have a setup similar to yours but with a Modified Sine Wave, Does that matter?
also I had it primarily for emergency power outage. Can I run if off of my Prius to charge a turtled Leaf?
thanks

 

[Jerther]

Ohh modified sin wave... I personally wouldn't run anything but incandescent light bulbs, resistive heaters or electronics I don't value off of these. It may work well for a while but I wouldn't trust it for any length of time

 

[cornbinder89]

I'd be surprised a modified sine wave would damage the car, the EVSE may not like it however. The reason is all incoming AC gets rectified to DC before being sent to the charger. The EVSE may see it as a lower voltage and reject or trigger the fault light. If you are brave, try it and see.

 

[knightmb]

Thank you for a detailed reply. I am trying to correlate your experience with my data.
For one thing, my leaf didn't "shut down" - or perhaps it did and I didn't recognize it? How would such a shutdown look like?
Regardless of that, when I parked, my battery state was both under 2kWh (about 1.5kWh IIRC, will check LeafSpy logs) and _most_ cells under 3V.
But when charging it back home, I have to get it over this 9 or 10% SOC to be able to drive again into the garage.

If you are driving it, the turtle icon will be lit up, you'll probably get a dash message (they vary by model year) that tells you you have no motor power, etc. You will only have neutral or park to work with on the shifter (when inside with the doors closed). I'm not exactly sure of what "logic" Nissan is using (other than remaining capacity) to determine that if you park and turn off the Leaf in turtle mode, that it will allow you to turn back on and drive around a little more instead of forcing you to charge it to 50 gids before it will allow you move it again.

 

[knightmb]

Hi knightmb
Good info, I have a setup similar to yours but with a Modified Sine Wave, Does that matter?
also I had it primarily for emergency power outage. Can I run if off of my Prius to charge a turtled Leaf?
thanks

I've never tried a modified sine wave inverter with the EVSE. I don't think the EVSE would care, the modified sine wave on the internal battery charger itself might be an issue, but I don't know anyone here that has tried it. If the Prius 12V system can handle 1,650 watts of power, otherwise you would need an adjustable EVSE so you can set the power levels lower. I don't know what the Prius 12V system max is. A quick google search seems to suggest that it will max at 75A, so that would be around 75 x 12 = 900 watts of power. You would need an EVSE that can be set to 6A to be within safety limits, but it would be a very, very long recharge time at only 6 x 120 = 720 watts of which half of it is taken by the charging and cooling system itself.

 

[Jerther]

Modified sin waves are composed of "abnormal" amounts of noise. Sometimes you can even hear it. Best (most likely) case scenario, the EVSE is well designed, and will filter it all out and will work just fine. Else, the noise can cause the EVSE to misbehave or get damaged. Worst (less likely) case scenario, the noise makes it to the car, causing it to misbehave or get damaged.

If you are brave, try it and see.

Agreed

 

[cornbinder89]

Since the EVSE is more or less a contactor along with some "handshake authentication", so it wouldn't filter it. Because MSW is more or less a square wave, the peak voltage "visable" to the EVSE and the car will be lower than it expects to see. That may or may not be a problem. Once rectified the pulsing DC gets further "conditioned" before being sent on to the step-up and final rectifying.
Since the initial rectifying is at a much smaller voltage and current than the system is designed for, I doubt it would do any damage.
My guess is it would work or not but not damage anything. That said, I am not offering my stuff to run the test.