Poll: How accurate is your END-only charging timer?

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lpickup

Well-known member
Joined
Nov 17, 2011
Messages
1,188
Location
Raleigh, NC
I use an END-time only charging timer set for 6:30am. I've noticed that the charging actually completes between 2.5 to 3 hours prior to that time. Here is a recent sample of end times:

80% (should be 6:30am): 3:50 3:57 3:54 3:27 4:03 3:33 3:26 3:32 3:25 3:36 3:43 3:43 3:52 3:45

For 100% charges I see about the same thing although it's slightly closer to the end time on average (around 2.5 hours and slightly less consistent).

100% (should be 7:30am): 5:45 4:30 5:24 5:33 5:53 5:33 5:44 4:30 5:44 5:37 5:14 5:22 5:37

Based on anecdotal evidence seen in posts around the forum, it seems like many people have charging that stops much closer to the desired END time, but there are some that experience results similar to mine.

I have a 2012 SL model. I am in the Eastern time zone and all clocks in my car are set to that time zone (and have been since I got the car). It had been suggested that I did not have this set up properly, but I have confirmed. I still wondered if it was possibly time zone related, but one of the people that reported early end times is on the west coast.

FYI, my climate control timer works perfectly.

To determine how widespread this problem is, if anyone else uses END-only timers, could you report your experience here?

Please also comment with your time zone (in case it is somehow related), model year, and any other information you think might be pertinent.

Edit: I thought I could create a poll, but I guess not. Basically what I had in mind was:

If you use END-time only timers, how long before your end time does charging usually stop?
1) 0-30 min
2) 30 min - 1.5 hours
3) 1.5 hours - 2.5 hours
4) 2.5 hours or more
 
Nice post. I am seeing very similar results to you. I charge to 80% with end time set at 5:00 am. Charging routinely stops around 2 am to 3 am depending on the state of charge.
I may move my end time out another hour. I am also in eastern time like you.
 
I never verified but end timer setting seemed to start the same hours as the estimated time on 240v shown on the dash. The more charge needed the more time was left at the end as extra. I find my Leaf will charge to 100% fine from LBW in 6 hours(12a to 6a). But if end timer only is set the charging starts before super off-peak 12a and of course ends before 6a stop of super off-peak rate. I could set to end 7a but then on a short charge I still had some charging between 6a & 7a.

I gave up and just set 100% charge every day 12a to 7a and it very rarely charges into the 7th hour. I think only when charging from VLBW.
 
I thought of two possible variables last night:
  1. How deeply discharged is the battery when you start the charge? I don't charge every night, and rarely charge unless I have 5 or fewer bars left. (And the car consistently stops charging at least 2 hours before the END time.)
  2. There was a firmware update for Carwings last summer, wasn't there? Perhaps that also affected local time prediction in the LEAF. I rarely pay any attention to Carwings, so haven't bothered to get the update.

As an interesting data point on both these possibilities, I charged to 100% last night, rather than my usual 80%, and did it when I had more than 5 bars left. I didn't press the override when I shut the car down, planning to wait for off-peak.

Later I logged in to the Nissan Owner's Portal and asked for a status update. It showed 6 bars and charging estimates of 4:30 normal, 9:30 trickle. I then clicked "Start charging." I got a "Charging Started" email with a timestamp of 11:17 PM and a "Charging Complete" email timestamped 2:16 AM. So, estimated charge time 4.5 hours; actual time 2.98 hours. No wonder my usual charging ends early! And if the estimate was off by an hour and a half on a charge starting at around 55% SOC, it seems quite possible that it would have been off by two hours if I had started at a more typical 45% SOC.

Actually, the difference may be even more surprising than it first appears. It seems likely that "4:30 normal" was calculated assuming a "normal" 240v 16A. But I don't have a 16A EVSE! With my 12A EVSEupgrade it should have taken more than 33% longer (probably at least 35% longer because of the extra cooling system energy needed). Instead it was 34% faster than the estimate!

Ray
 
planet4ever said:
...It seems likely that "4:30 normal" was calculated assuming a "normal" 240v 16A. But I don't have a 16A EVSE! With my 12A EVSEupgrade it should have taken more than 33% longer (probably at least 35% longer because of the extra cooling system energy needed). Instead it was 34% faster than the estimate!
The LEAF samples the voltage when you plug in, and can read the amperage from the J1772 pilot signal, so I would expect the END timer to take your 12a EVSE into account when calculating the start time.
 
planet4ever said:
I thought of two possible variables last night:
  1. How deeply discharged is the battery when you start the charge? I don't charge every night, and rarely charge unless I have 5 or fewer bars left. (And the car consistently stops charging at least 2 hours before the END time.)
  2. There was a firmware update for Carwings last summer, wasn't there? Perhaps that also affected local time prediction in the LEAF. I rarely pay any attention to Carwings, so haven't bothered to get the update.

I'm all over the map as far as how deeply discharged it is when I start the charge. I'd say usually it's anywhere between 2 and 6 bars, so that's quite a range. Hardly ever below 2 bars though (although I'm down to 1 tonight--it was a good day today!)

I have a 2012, so presumably have the latest firmware. It sounds like you think you have the old firmware. But we both see the bad prediction, so we can potentially eliminate that variable.
 
I've already given my answer in the other thread, but I'm including it here for completeness.

2) 0.5 - 1.5 hr.

Actually, it is proportional to the amount of charging done. 80% to 100% is 10-15 minutes early while VLB to 100% is typically 1.25 hours early.

MY2011, latest firmware (AFAIK), Pacific time.
 
The dashboard time-to-recharge predictions are probably based on the last voltage and current you actually used while charging in the corresponding voltage range.

Or, to be conservative, they might always use 208v to estimate for the dashbard display?
(That would explain a 12% longer time being displayed.)
 
I have a 2012 that arrived in Dec. I would see the same results, finishing 2.5 to 3 hours early. I also had a climate timer set to finish when I was leaving for work. The last week I have turn off the climate timer, and now the charge end message is only 30 minutes early. When using the climate timer, I gave the charging timer priority, I wonder if it was trying to make sure the battery was charged so that it could run the climate timer as requested. Because once I turned the climate timer off, the end time is now within 30 minutes.
 
NuclearLeaf said:
I have a 2012 that arrived in Dec. I would see the same results, finishing 2.5 to 3 hours early. I also had a climate timer set to finish when I was leaving for work. The last week I have turn off the climate timer, and now the charge end message is only 30 minutes early. When using the climate timer, I gave the charging timer priority, I wonder if it was trying to make sure the battery was charged so that it could run the climate timer as requested. Because once I turned the climate timer off, the end time is now within 30 minutes.

Very interesting observation. When you say you turn the timer off, do you mean completely off? I "skip" days on the climate timer by using the assign days function and turning the timer off for a particular day and this doesn't appear to change my early charge ending, but maybe I'll try turning the climate timer COMPLETELY off and see if that makes a difference.
 
garygid said:
The dashboard time-to-recharge predictions are probably based on the last voltage and current you actually used while charging in the corresponding voltage range.
My dash estimate most definately adjusts based on the last charge current. If I use 12a 240v the dash shows about 2 to 1 ratio 120v vs 240v. If charged at 16a 240v it is closer to 3 to 1 ratio 120v vs 240v.
 
lpickup said:
NuclearLeaf said:
I have a 2012 that arrived in Dec. I would see the same results, finishing 2.5 to 3 hours early. I also had a climate timer set to finish when I was leaving for work. The last week I have turn off the climate timer, and now the charge end message is only 30 minutes early. When using the climate timer, I gave the charging timer priority, I wonder if it was trying to make sure the battery was charged so that it could run the climate timer as requested. Because once I turned the climate timer off, the end time is now within 30 minutes.

Very interesting observation. When you say you turn the timer off, do you mean completely off? I "skip" days on the climate timer by using the assign days function and turning the timer off for a particular day and this doesn't appear to change my early charge ending, but maybe I'll try turning the climate timer COMPLETELY off and see if that makes a difference.

Yes, I turned the climate timer completely off.
 
NuclearLeaf said:
Yes, I turned the climate timer completely off.

I think you figured it out!

I had the opportunity to experiment today. I disabled both Climate timers and the LEAF finished charging only 30 min ahead of its scheduled time this morning. Apparently it's not enough to just have the climate timer disabled for the day in question (which I do all the time) but it has to be completely disabled by turning both timers off.

That is really strange (and I believe unwarranted) behavior. Even if the car is attempting to finish charging before it's going to turn on the climate control, it's way overestimating the climate control time. I've noticed that it turns on either 20 or 30 minutes before my scheduled departure time (which is a LONG time by the way--I suspect it limits the power to what it can pull from the EVSE when using the climate timer, as it only takes 5 minutes to get the car super toasty even when sitting outside on batteries only). Even if it backed up the charging timer that half hour I'd expect it to finish an hour early on days that I had a timer set, and even then I believe it should intelligently determine if there is even a conflict. I already programmed in a staggered charging end/climate departure time when I set it up to avoid any conflicts.

Example:
Scheduled departure time is 7:20am
Set climate timer to 7:20am
Set charging END timer to 6:30am

Even if the car stops charging at 6:30am, the climate control doesn't start until 6:50am so there is no conflict.
 
I have never set any kind of climate timer, nor ever done any climate preconditioning before leaving home. Yet my charging continues to end roughly two hours early. I will say that after an apparent cell balancing 5 days ago (two Charging Ended emails on the only night recently that I charged to 100%) I have seen charging stopped 103, 105, and 110 minutes early. Before that it was stopping more than 120 minutes early on most nights. But, as I mentioned before, I do not have the Carwings firmware upgrade that came out last summer, and I suspect that is causing the behavior I see.

Ray
 
Not very. :(

My charging ends 3 to 3-1/2 hours before the end time is set on the car's timer. I originally set the end timer 1 for every weekday at 4:30 am (to allow for some leeway for the CC timer set at 5:30 am (end time). Now that I am more aware of battery capacity issues, cooling before charging and not leaving the battery in a high SOC for long periods, plus getting my email messages working, I'm paying more attention to this. I was getting charge ending emails at 1:30 am or earlier with a 4:30 am END time timer setting. Same at work with Phil's EVSE Upgrade at 240V. Given the daily one-way commute is very repeatable and leaves me at or maybe 3 bars from 80%, I've taken to setting timers with START times and estimating the charge duration (usually under 4 hours). This usually gets me to within one hour before my estimated end time.

I have a Canadian model 2011 (the "cool climate" US 2012 model?) built in April 2011. I have had the CW firmware update performed. I use the CC timers regularly (and they always work). I'm in the Eastern Time Zone. I have a Schneider L2 dock at home (which has a delayed start option, but I never have used it -- only the timers in the car). I otherwise have had no issues with the timers working as they are supposed to, other than this extremely pessimistic calculation of charge duration/early charge initiation.

I'd really like to not have to second-guess the timers and simply set the END time for maybe 30 to 60 minutes before my departure, and have the CC kick in at 15 minutes or so before the departure time. My error with the charging timer is of the same order of magnitude as the charging itself!

Renny
 
When traveling through space it is best not to set your end timer in a black hole or in the event horizon. This may yield undesirable results.


Deeper thoughts....
 
My 80% end-timer seems to be typically around 1 to 1.5 hours early. It seems the smaller charge it needs, the earlier it finishes. More often than not I'll park it with 4-5 bars though. Pacific time zone.
 
I use to charge to 100% with an end-only timer. My observation was that it ended at most 1.5 hours early and then only if the battery started nearly empty. The less it needed to charge, the less early it started. I'd assumed that the car timer was calibrated for Japanese 200V mains instead of US 240V and thus, assumed that it would take longer to charge than it actually did.

I haven't used an end timer in 6 months so I don't know if the latest software update changed anything.
 
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