Another Dead Leaf after Vacation Plugged In - Detailed Info

[Ingineer]

NOTE: Leaving a charge cord plugged into the Leaf, but not charging, can leave some of the Leaf's the ECU's (Electronic Control Units) in a state where they awaken and cause more than normal load on the 12v battery. DON'T DO THIS IF AT ALL POSSIBLE!

If the Leaf is actually charging from the wall, then it will also charge the 12v battery. ALWAYS! (Main battery contactor closed)

Here are my recommendations if leaving the Leaf for 2 weeks or less:
Leave the charge at 50-80%. Do not leave anything connected to the charge port.

If you are leaving for longer, and the Leaf's Solar panel will not have direct sunlight, charge to 50-80% and then disconnect the negative lead on the 12v battery or add a "Battery tender" type trickle charger. (But DO NOT connect it to the negative terminal of the 12v battery directly!) If you are parked where the solar panel (if you have one) will get some sun, then there is no need to disconnect the 12v battery. Either way, the Leaf should be good for a year.

NEVER charge to 100% and leave the Leaf sitting for more than a day. If you accidentally do, then drive the car until 2-3 bars are gone, or leave the defrost on high with all the windows down for an hour or so, which should have the same result.

If you do accidentally discharge the 12v battery (Leaf will appear totally dead), you can jump start just like a normal car, but be ABSOLUTELY SURE the polarity is correct, and make the negative connection on the Leaf to the body or DC-DC junction box (you can see where the black ground wire connects on top).

NEVER connect anything to the Leaf's negative 12v battery terminal, EVER! (except of course the OEM connections as shipped)

The traction pack will hold it's charge for a long, long time, but you should try to store it mid-charge, and never empty or full.

The 12v battery can go dead in certain circumstances, so it's best to disconnect it or add a trickle charger if you are leaving for a long time.

If you must leave an EVSE connected, such as the "airport" scenario, then try to do as suggested and have your time charge a little each day. If the Leaf gets full, then it will no longer charge enough to keep the 12v battery healthy. Even on a "full" Leaf, you can activate remote climate control through CarWings, (provided the Telematics modem is still awake, it shuts down after 2 weeks) and while this is running it will charge the 12v system. This will also work without an EVSE connected, but will deplete the traction battery doing so. Of course if you leave a full Leaf for an extended period, you are a bad owner, :twisted: and will suffer accelerated battery degradation.

-Phil

 

[smkettner]

When you guys say to set the timer for a 20 minute charge (if car left plugged in), are you referring to a normal (240v) or trickle charge? Or does it matter (assuming the full SOC stays below 80%)?

Either way is fine. The idea is to have it charge on a semi regular basis while away.
Carwings can get you to 100% on the last day if needed immediately upon return.
Has worked well for me a couple times on one week trips. I see no reason it would not work for longer duration.
JMHO

 

[Ingineer]

When you guys say to set the timer for a 20 minute charge (if car left plugged in), are you referring to a normal (240v) or trickle charge? Or does it matter (assuming the full SOC stays below 80%)?

Either way is fine. The idea is to have it charge on a semi regular basis while away.
Carwings can get you to 100% on the last day if needed immediately upon return.
Has worked well for me a couple times on one week trips. I see no reason it would not work for longer duration.
JMHO

I mentioned the reason it wouldn't work for long periods (once the pack is full, there will not be enough time to top the 12v off).

If I had a choice, I'd use 120v ("trickle") as it may allow you to keep the traction pack at a lower state of charge, (SoC) while still allowing enough DC-DC time to keep the 12v charged.

-Phil

 

[smkettner]

I agree the idea is to not quite hit 80% until the very end.
Should not be difficult on L1 run down so it needs 12+ hours of charge.
10 minutes a day should give 72 days. 10 minutes twice a week would be way longer.

 

[planet4ever]

Carwings can get you to 100% on the last day if needed immediately upon return. Has worked well for me a couple times on one week trips. I see no reason it would not work for longer duration.

As Phil said, that will not work after two weeks. The car stops communicating with CarWings after 14 days (presumably to keep from running the 12v battery down!)

Ray

 

[RegGuheert]

Thanks to everyone for the detailed explanations on how to manage the LEAF when it is not in use. But at the end of the day, I must agree with the sentiments of the OP:

Bottom line, I think there's a bug in the Leaf software.

IMO, if you leave the car plugged into an EVSE, they should design the car so that neither battery gets fully discharged, regardless of what state you leave it in. I cannot imagine that all EVs suffer from this issue.

 

[Ingineer]

A bug is an unintentional deviation from the way the software was designed. In this case, I don't think it's a bug, but a design shortcoming. Many compromises were obviously made to get the Leaf to market on time and budget, as we have seen. There are so many things that simply don't make sense, and I believe that they simply ran out of time to get it finished.

I hope Nissan will address many of these issues in the next model year.

-Phil

 

[RegGuheert]

I hope Nissan will address many of these issues in the next model year.

I hope that Nissan will address many of these issues through firmware updates to the LEAFs which have already shipped.

I seem to remember that some of the first-generation Prii were draining their 12V batteries under certain circumstances and Toyota was able to resolve that pretty quickly.

 

[smkettner]

Carwings can get you to 100% on the last day if needed immediately upon return. Has worked well for me a couple times on one week trips. I see no reason it would not work for longer duration.

As Phil said, that will not work after two weeks. The car stops communicating with CarWings after 14 days (presumably to keep from running the 12v battery down!)

Ray

I am not sure what unattended events might reset the 14 day timer. Anyone?
Hard to test as most drive their LEAF nearly every day.

 

[TomT]

Apparently only turning the car on resets the TCU timeout...

I am not sure what unattended events might reset the 14 day timer.

 

[rpmdk]

I am currently on a 14 day vacation with my Leaf plugged in at the airport. To avoid the dead Leaf syndrome when I return, I set the timer to charge for 20 minutes only each day. I left the car with ~20% SOC and it should reach 80% the day before I return. Before our flight back, I will manually initiate a charge to 100%.

I believe this will charge the 12V battery each day so everything should be topped off when we return.

That doesn't seem lke a good strategy to me. If someone comes along and sees your car isn't charging, I think it would be perfectly acceptable to plug in their car. You'd be screwed. Of course you could leave a sign not to unplug your car, but you've rendered a charge point useless for two weeks so you can charge 20 minutes a day.

Just doesnt seem like good public charging etiquette to me.

I think the airport should just provide 110 outlets so many many cars could be charging at once and employing your strategy.

 

[gonefishin]

Thanks to all the replies about people who were able to leave their cars plugged in >8 days and lived to tell the tale. I see now that the 12v is being charged while the charger is actively charging the battery, and that's a good workaround strategy. Interestingly, sales & service at my dealership said that while the car is plugged in the 12v won't be charged!

I find smkettner's reply most interesting because it's closest to refuting my theory:

Yes I left mine off and plugged in almost three weeks last summer while visiting the UK. No issues. Although about halfway through the trip I was checking carwings and did inadvertantly start charging that of course continued to 100%.

Clearly, he left the car at less than full charge and was taking advantage of the workaround until "halfway through". My evidence suggests that after 5 days of full charge, the timer kicks in and the EVSE (I'm using Blink) will stay active and presumably keep the car active and drain the car within 36 hours. Depending upon the 12v SOC that 36 hours will vary. If smkettner was gone 21 days, and after 11 days fully charged the car, I'd think it would have been dead by day 18. However, if he activated it 3 days later he wouldn't have noticed a problem. It's a little too close to tell.

I think this thread has just about run its course. I proved that I did not leave my Leaf in any state other than OFF, despite my dealer's evidence otherwise. Many people have provided workarounds to avoid killing the 12v, but the easiest is simply to leave your car disconnected if possible. I still think my theory about a "bug" (I'm a professional software engineer and project manager so I think I can use that term accurately) which kills the car after 8 days of being plugged in without charging is a good one.

I would still be interested in hearing from anyone who left the car with a "full" charge (100% or 80% on timer) such that the traction pack needed no further charging for >8 days? Similarly, anyone else whose battery died after 8 days connected with no charging? I'm going to push back on the issue with my dealer & Nissan and if I can provide more data it will help.

 

[planet4ever]

I proved that I did not leave my Leaf in any state other than OFF, despite my dealer's evidence otherwise.

I guess I missed that proof. In your first post you proved that you did not leave it in READY mode, but there are four modes (in addition to LOCK): READY, ON, ACC, OFF. It is true that the car will not start charging if it is in READY or ON mode (though it can be changed to ON mode while it is charging). So, yes, you proved that you didn't leave it in either of those modes. But what about ACC? The car can start charging if it is in ACC mode, and that does cause extra 12v battery drain. Furthermore, as I said back on the first page of this thread, it is very easy to accidentally leave the car in ACC when you think you are leaving it OFF. The power button does not have anti-jitter logic, so an unintended jiggle of your finger is all it takes. The screens go black and you get out of the car. There is a silly beep-beep, but if you are like me you don't always pay attention to random beeps like that. Perhaps not until after you have closed the door does the center console stealthily complete its reboot and put up the stupid nag. The dash (behind the wheel) remains black.

Ray

 

[jkirkebo]

That doesn't seem lke a good strategy to me. If someone comes along and sees your car isn't charging, I think it would be perfectly acceptable to plug in their car. You'd be screwed. Of course you could leave a sign not to unplug your car, but you've rendered a charge point useless for two weeks so you can charge 20 minutes a day.

Just doesnt seem like good public charging etiquette to me.

I think the airport should just provide 110 outlets so many many cars could be charging at once and employing your strategy.

Why would anyone unplug me ? The neighbouring spaces all have their own 230V sockets. In fact the whole row of 40 spaces have sockets available and is reserved for EVs. The spaces also are reservable, so anyone who reserves is guaranteed to get a charging spot.

If I can't be plugged in the whole time the charging spoTs would be unuable for me. I need a full charge to get back home (85 miles) but I refuse to let my Leaf sit with a 100% charged battery for two weeks. In that case I'd rather take the VW TDI.

Btw, no 110V in Norway, and no public EVSEs either. It's all 230V 16A sockets so we must use the included Panasonic EVSE everywhere.

 

[gonefishin]

The proof was provided by a combination of the Energy Detective logs and DaveInOlyWA's observation:

1) if you had left it in ready mode, the 12 volt battery would have remained charged
2) if you had left it in ready mode, there would have been greater than a constant draw of 30 watts.
3) the code reset by the dealer was probably due to what Roadside did.

I expand his point that if I had left it in ACC or ON while the "plugged in" icon is showing rather than READY the car would still have drained rather quickly and not been waking up at midnight for the next 5 days, or the charger would have had to continue to supply enough power to recharge the car. The charger logs show exactly what's happening

1) full charging to 80% capacity the first night I left it
2) no current draw except 30 watts at midnight when it wakes up and see's there's no need to charge anything
3) after 5 days of this, 36 hours of about 30 watts/hr as it tries to negotiate with the car to charge or not
4) no activity even at midnight until the car is found dead

His point #3 explains why the dealer thought I left it in READY mode in the first place. When service pointed out the code I didn't notice any timestamps on the codes. I didn't give them a full timeline so they probably weren't even paying attention.

 

[planet4ever]

I expand his point that if I had left it in ACC or ON while the "plugged in" icon is showing rather than READY the car would still have drained rather quickly and not been waking up at midnight for the next 5 days, or the charger would have had to continue to supply enough power to recharge the car.

That's not clear to me. Of course there would be no "plugged in" icon in ACC mode, since the computer or computers running the dash are shut down, along with most of the rest of the car. I think only the Nav unit and the remote key sensors are powered up. Is there enough energy in the 12v battery to power the Nav computer and screen for five days? I don't know, but that battery has something on the order of 10-15 times the capacity of my laptop computer battery, so it seems feasible that it might be able to power a nearly idle computer and a screen 1/3 the size of my laptop for 30-40 times as long as my laptop can run.

His [DaveinOlyWA] point #3 explains why the dealer thought I left it in READY mode in the first place. When service pointed out the code I didn't notice any timestamps on the codes. I didn't give them a full timeline so they probably weren't even paying attention.

No argument there. The ready mode code was not my reason for proposing that the car might have been in ACC mode.

Ray

 

[rpmdk]

Why would anyone unplug me ? The neighbouring spaces all have their own 230V sockets. In fact the whole row of 40 spaces have sockets available and is reserved for EVs. The spaces also are reservable, so anyone who reserves is guaranteed to get a charging spot.

If I can't be plugged in the whole time the charging spoTs would be unuable for me. I need a full charge to get back home (85 miles) but I refuse to let my Leaf sit with a 100% charged battery for two weeks. In that case I'd rather take the VW TDI.

Sorry, my bad, I'm imagining LAX, every time I've been there there have been more cars than charge stations and I have yet to charge, I just limp home, happy for the free parking.

I really just want a bigger, better battery so I can charge at home and not have to deal with all this etiquette.

 

[smkettner]

My LEAF sat for a week just fine at LAX plugged into the 120v outlet on I think level 2 P6.
Timer charged a few hours each night. Less than a week so last day was programmed to 100%.
Worked perfect. And I definately needed the charge or I was not getting home.
With just two L2 at the time I did not even bother trying.

 

[Ingineer]

Yes, it's possible the Leaf was left in ACC mode. This would fit into the facts so far provided, but definitely isn't proven.

IIRC, The ACC mode (assuming low volume or off on audio) will pull about 2 amps. I'd say this will run about 12-16 hours at most.

On mode (not ready) pulls 10 amps minimum, and more with options like headlights. You are looking at 1-2 hours in the Leaf.

-Phil

 

[rpmdk]

My LEAF sat for a week just fine at LAX plugged into the 120v outlet on I think level 2 P6.
Timer charged a few hours each night. Less than a week so last day was programmed to 100%.
Worked perfect. And I definately needed the charge or I was not getting home.
With just two L2 at the time I did not even bother trying.

What did you do to secure the EVSE, or did you bother?