Charging Timer Only Works Sometimes

I bought a 2015 Nissan Leaf S and trying to charge my car between the hours of 11pm - 7am. I use about 10 miles a day and will charge it maybe a couple times a week.

I use trickle charge at home, so it often will require more than the 8 hours window between 11pm-7am, since I let the battery drain to about 20% before charging to optimize the battery life.

I understand that you can only set the end time of the timer, which is okay. I'll set it for 7am and then at 11pm plug my charge in. However, every morning when I wake up it is still charging and not stopping at the designated 7am mark.

I've tested the timer during the daytime and it seems to be working fine (i.e. turns off when expected or has a delayed start). However, for some reason when I really want to charge my car (night time), it does not work.

Does anyone know why this is? Is it because it's going overnight (i.e. into a new day) or because I plug my charge in hours after I turn the car off?

Thanks for your help!

The end timer is the time at which the car would complete charging. Since you're using L1 your car has zero chance of finishing charging by that time, so it just keeps going.

What mwalsh said, but if your only running 10 miles a day just don't let it get to 20%, don't skip as many days between charges, give it a charge when you get to 50% or so.

Thanks will give it a shot. Didn't know that if it had a zero chance of finishing that it would just keep going....

I didn't think this was true because when I did my charging during the day and it had a zero shot it stopped still...

sharkie21 said:

... since I let the battery drain to about 20% before charging to optimize the battery life.
...

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You seem to have an incorrect understanding of battery life optimization.
There is not a need to cycle.
But battery life may be a bit better if you avoid time spent above 80% and time spent at very low charge.
Optimal life would be if it was always in 30% to 60% range.
But there isn't a lot of data to prove the effect, and the impact may be very modest.

sharkie21 said:

... I use trickle charge at home ...

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As I have advised many people considering use of 120V EVSE that comes with the LEAF and other plug in vehicles:

TimLee said:

A repeat of my input from previous questions on 120 V EVSE use:
Note that Nissan recommends the 120V EVSE for limited emergency use only.
Some people have used it for a long time without problems yet, but in general that is a bad idea unless you have a newly properly installed dedicated circuit with high grade receptacle using properly tightened screw connections.

Previous info from another thread:

mikelb said:

...
Trickle charging should be safe, though, right? I wouldn't necessarily need to have the circuit certified for it or anything, should I? If I were to go to a friend's house, would I be safe plugging into their outlet?

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How safe 120V charging is depends on how lucky you are.
Very few garages have the correct properly installed high quality single outlet supplied by a single breaker.
Code only allows using 80% of the circuit rating for a long term continuous load.
So on a 15 amp circuit nothing else should be on the same circuit while the car is charging.
And a lot of 120V gets put in poorly using push in connections.
One person had a bad fire most likely from staples that had damaged the cable in the wall.
http://www.mynissanleaf.com/viewtopic.php?f=27&t=15784&hilit=+fire#p352567" onclick="window.open(this.href);return false;

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Another possibility to consider: you need to set the charge (end) timer and turn it "on". It can be set and "off", in which case the car will charge whenever plugged in. FWIW.

dgpcolorado said:

Another possibility to consider: you need to set the charge (end) timer and turn it "on". It can be set and "off", in which case the car will charge whenever plugged in. FWIW.

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Thanks. I'll double check that the timer is set and "on" vs. set and "off" . However, I'm thinking that it might have something to do with the time of day. Since I plug it in at 11pm and tell it to turn off at 7am, how does it calculate given that 7am has already come and gone for the day? When I tested it before I always plugged it in before the schedule end time for the current day.

Either way I'll continue to test out a bunch of things to see what may / may not work and eventually report back.

Thanks.

sharkie21 said:

...
Thanks. I'll double check that the timer is set and "on" vs. set and "off" . However, I'm thinking that it might have something to do with the time of day. Since I plug it in at 11pm and tell it to turn off at 7am, how does it calculate given that 7am has already come and gone for the day? ...

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My experience with LEAF timers is on 2011 SL.
S timers are a bit different.
But on the 2011 timers are set by day.
If the time has already passed when you plug in the timer does nothing.
They did it that way because what a lot of people use the timers for is to charge during low cost time of day rate.

TimLee said:

My experience with LEAF timers is on 2011 SL.
S timers are a bit different.
But on the 2011 timers are set by day.
If the time has already passed when you plug in the timer does nothing.
They did it that way because what a lot of people use the timers for is to charge during low cost time of day rate.

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Thanks I think that is what is happening. I think since I am plugging it in after the end time, the timer is doing nothing. I'll give it a try by plugging it in after midnight and see if it stops at the designated 7am mark. If that is true, I guess it's okay, I just lose an hour of charging or have to reengage the charge after midnight.

It's not plugging in before midnight. My end timer is set for 7am and I plug it in all the time before midnight, sometimes as early as 6pm and let it do it's thing.

Even if we forget and plug the car in at 6am it will start charging and then stop at 7am no matter how charged it is.

You don't by chance have it set for 7pm do you? Or the cars clock set 12 hours off? I left mine in 24 hour so I can't mix it up

BrockWI said:

It's not plugging in before midnight. My end timer is set for 7am and I plug it in all the time before midnight, sometimes as early as 6pm and let it do it's thing.

Even if we forget and plug the car in at 6am it will start charging and then stop at 7am no matter how charged it is.

You don't by chance have it set for 7pm do you? Or the cars clock set 12 hours off? I left mine in 24 hour so I can't mix it up

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Interesting! I am dumbfounded....

I double checked the clock, the charge timer and that the charge timer is on. I'll plug in today after midnight and see what happens. Then I guess I will try again later this week or next week plugging in at 11pm again and see what happens...

Thanks!

I guess the S must be different. I wish Nissan would stop doing stuff like this though, I don't find it especially helpful.

mwalsh said:

I guess the S must be different. I wish Nissan would stop doing stuff like this though, I don't find it especially helpful.

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Agree.
It is strangely reminiscent of VCR programming.
I never came across a VCR that I couldn't figure out how to program.
But each had its own unique approach.
90% of people never could figure out how to set the clock, let alone program it to record.

BrockWI said:

It's not plugging in before midnight. My end timer is set for 7am and I plug it in all the time before midnight, sometimes as early as 6pm and let it do it's thing.

Even if we forget and plug the car in at 6am it will start charging and then stop at 7am no matter how charged it is.

You don't by chance have it set for 7pm do you? Or the cars clock set 12 hours off? I left mine in 24 hour so I can't mix it up

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Plugged it in after midnight and it stopped charging at 7am. I'll try again plugging in before midnight to see if it stops at 7am, however, I don't think I am going to hold my breath.

Looking at your specs, it seems like you have a EVSE Level 2. If that's true you should be able to go from 0 charge to 100% in 8 hours. So if you are plugging in before midnight, you probably would hit full charge before the 7am marker and if you plug it in after midnight, then it will stop at 7am since it's the same day.

Maybe if you can try plugging it in and setting the end timer to 12:30 am and see if it stops or keep going. I will probably give this a try as well to see if I can figure out how Nissan programmed their charging logic.

Thanks!

Yes I have a level 2 evse. I could try using the stock 120vac evse and see if it does the same thing.

I think I see what yours saying about the "day" thing or more importantly crossing midnight. I would think though it wouldn't start charging then either rather than not stop. The next time I am up late I will set it for 12:30 and see what it does, it should still start after 9pm (our off peak rates) and then just sit at 80% overnight.

I did use the 120vac evse when we first got the car for two weeks and never had that issue and I was using the charge timer then as well. But I doubt I ever had it where it wasn't full (80%) by 7am even using the stock evse. I wonder if the evse could play in to the differences here as well?

I'm still a little confused. I plugged it back in at 9am this morning and the charging timer kicked in, (i.e. it was doing a delayed start). So apparently the timer is still engaged even though the end time has come and gone.

I'll try the whole crossing over midnight thing again and see if I figure out how this is working...

If you still need say 40% charge, and your "end time" has passed... if you look at it this way, it means there is 22hrs between now and your end time. That's more than enough to get a 40% charge, so it waits. It waits until it reaches a time where it predicts you be at 100% by the end time you program.

Looking at it another way, the battery degrades a bit for every hour it sits at 100% SOC. So, it is best to reach 100% charge minutes before you get in and drive away. By letting you set the charge end time, the charging will begin when the BMS thinks necessary. But will minimize the time at 100%.

I've been trying to use the timer a bit too, using trickle charge, but the BMS charge time estimate always appears to be overly pessimistic. It reaches 100% hours before my end time. I realize I want some time at 100% to do cell balancing, but I only do that about once a week. So I set my "end time" for about 2.5hrs AFTER I planned departure time. I don't need more than 90% charge. This setting helps assure the charging is still in progress when I go to leave for the day, which is what I want. Then on the weekend, I don't go anywhere before noon anyway. So it gets a chance to cell balance.