Leaf S Charge Timer

[golfcart]

I'm sure this has been addressed somewhere but I have been searching for about 20min and haven't found my answer...

I have a 2015 Leaf S with the 6.6kW charger, I am also on a time of use plan with Dominion power which gives me a rate of about 5c/kWh between the hours of 1am - 5am. So at first I was setting the timer for 5am under the assumption that the car would do the math and start charging at the right time to stop at 5 exactly.

Long story short, I was up late for new year and happened to glance outside at about 1130pm and noticed that the car was already charging. I had run it down to about 20% capacity remaining that day and am charging at 20a and 240v. Worst case that should take maybe 5 hours to charge given my setup so the car should not have started charging yet at that time. This leads me to believe the car is a bit conservative in estimating its charging time and actually finishes charging before then end time.

I can wake up early for a week and play with it a little and probably figure out when the best time to set the timer would actually be but I'm hoping maybe someone has investigated this already and can save me the trouble or at least give me a ballpark to start from. I already wake up at 530 for work I really don't want to get up any earlier to go out and see what time it actually stops.

Does anyone know how smart the charge timer is? Does it sense input voltage and current then calculate when to turn on? Also, does anyone have an idea of how much it tends to overestimate charge time? I'd really like to do as much of my charging as possible on the "super off-peak" rate. Thanks.

 

[inphoenix]

I have a 2014 S and have the timer setup to have the charge complete by 5 AM (TOU plan). It works just fine. I can see the reports on the dashboard of my EVSE (JuiceBox Pro) and it tells me exact time it started/stopped and the Energy (kWh) consumed.

I am assuming that you have setup the Charge timer correctly. What EVSE do you have?

EDIT: Should've read that you have a 20A EVSE. Still it should not take that long. I charge at 40A so it would be faster for me. Tonight I will note the % of battery when I plug in and will report the exact time it took to charge tomorrow morning.

EDIT 2: While I don't have the % of battery when I started charging last night. Here is some information that may be helpful.

Plugged in at 9.05 PM and plugged out at 6.37 AM. The actual charging started at 1.40 AM and stopped at 4.30 AM. The total energy consumed at 11.127 kWh in 2 hr 53 min.

The charging started at 1.40 AM and continued till 3.13 AM at a higher rate and then the Power (kWh) consumption started dropping. After 4.05 you can see the lines going up and down but the Energy consumption is still going up....I read somewhere that this is when it is equalizing all the cells. The charging stopped completely at 4.30 AM (whereas the timer is set to 5AM) so yes the calculation doesn't seem to be perfect but is in the ball park.

 

[golfcart]

Just to clarify, I am using an EVSE upgrade unit defaulted to 20a at 240v. Unfortunately that doesn't offer an option to see how long it actually charged for. I appreciate you checking that out for me.

Since you charge at 40a I assume you are maxing out the charger while I am not... I wonder if the charge timer only has a couple of default settings that the estimator uses? I just went out to my car and looked at the estimated times to charge. I was surprised the numbers it gave.

Current Capacity: 66%

Time to 100% Charge
240V 6kW: 3:30
240V 3kW: 4:00
120V: 10:00

I have read that usable capacity on the battery is really only about 21kW. Assuming I used 1/3 of my capacity coming into work today and have 66% remaining that should be roughly 21 / 3 kW (or roughly 7kw) required to charge it fully. Why would it estimate 3:30 to charge 7kW at a rate of 6kW/h?? Why would it only take 30 minutes longer to charge at the 3kW the rate? and why would either of them be estimated as taking longer than 2.5 hours? The math just doesn't seem to add up for me... I understand these are estimates but they seem really far off.

I also wonder how much the cold weather we have been having is impacting the timer since I have used the climate control timer as well the past few nights.

From the nissan manual.

When the Charging Timer and the Climate
Ctrl. Timer are set at the same time, the
charging start time moves to an earlier
time.

Depending on the Li-ion battery condition
and the power source status, charging
may end earlier than the charging end
time. This is not a malfunction

Cold here is SE Virginia only means upper 20s, I don't think the battery warmer even kicks in at that temp. LOL too many variables to consider.

 

[golfcart]

I

Plugged in at 9.05 PM and plugged out at 6.37 AM. The actual charging started at 1.40 AM and stopped at 4.30 AM. The total energy consumed at 11.127 kWh in 2 hr 53 min.

The charging started at 1.40 AM and continued till 3.13 AM at a higher rate and then the Power (kWh) consumption started dropping. After 4.05 you can see the lines going up and down but the Energy consumption is still going up....I read somewhere that this is when it is equalizing all the cells. The charging stopped completely at 4.30 AM (whereas the timer is set to 5AM) so yes the calculation doesn't seem to be perfect but is in the ball park.

So this confirms my suspicion that the car is actually fully charged well before the end time. It doesn't really impact you since you are charging at a higher rate than me and your entire charge took place within your 1-5am window. I am typically charging anywhere from 14 - 18 kWh each night due to my 55mile round trip commute and I am charging about 25% slower than you so it makes my window a lot tighter.

Maybe I will try setting it for 5:30am tonight and see how that goes. I'll try to get up at 5 and see if it is still charging. I wish I had a report like that to look at, it would make this a lot easier. Thanks for the info that is a big help.

 

[inphoenix]

Since you charge at 40a I assume you are maxing out the charger while I am not... I wonder if the charge timer only has a couple of default settings that the estimator uses?

I don't think I am charging at full 40A. I bought this EVSE with some future proofing in mind. I believe it drops down to a lower rate as current gen leaf handles a little less than what it can offer.

I just went out to my car and looked at the estimated times to charge. I was surprised the numbers it gave.

Current Capacity: 66%

Time to 100% Charge
240V 6kW: 3:30
240V 3kW: 4:00
120V: 10:00

Experts can chime in but I don't think those estimates are correct. I've never really paid attention to them. I can try tonight and see what these numbers forecast and what my EVSE tells me. It'd be a good test.

I also wonder how much the cold weather we have been having is impacting the timer since I have used the climate control timer as well the past few nights.

Cold here is SE Virginia only means upper 20s, I don't think the battery warmer even kicks in at that temp. LOL too many variables to consider.

Ha ha yes, our cold is very different than yours. We get our jackets out and call it hiney freezing cold when it is in 50s. I've never tried the climate control timer but from what I've read it only works when the vehicle is plugged in, so I'd assume it is not running off of battery. But again, someone who knows more can chime in. I am a newbie myself.

 

[golfcart]

I don't think I am charging at full 40A. I bought this EVSE with some future proofing in mind. I believe it drops down to a lower rate as current gen leaf handles a little less than what it can offer.

Correct, a 6600W (6.6kW) charger operating at 240V would only draw 6600/240 = 27.5a in theory. I am just saying that you should be maxing that out with a 40a EVSE. My EVSE only supplies 20a so I will not be maxing my charger out. But I am not sure how smart the charge timer is and whether or not it can calculate my exact input amperage and voltage when it decides when to turn on.

Ha ha yes, our cold is very different than yours. We get our jackets out and call it hiney freezing cold when it is in 50s. I've never tried the climate control timer but from what I've read it only works when the vehicle is plugged in, so I'd assume it is not running off of battery. But again, someone who knows more can chime in. I am a newbie myself.

No doubt, my father in law lives in Surprise, AZ and y'all have a much different climate than here. Much drier, way less humid, and generally warmer. LOL Thanks for your help with the charts and stuff, I'm sure this will all get sorted out as more folks chime in. Seems like a useful topic.

 

[golfcart]

It looks like setting it for 5:30am resulted in it being complete by 5. I went out at 5am this morning and the car was fully charged already. Maybe I'll try 5:40 tonight. I suppose without a nice charging report like some of the EVSE's give this will just be kind of a trial and error thing for about a week to get it dialed in.

 

[inphoenix]

It looks like setting it for 5:30am resulted in it being complete by 5. I went out at 5am this morning and the car was fully charged already. Maybe I'll try 5:40 tonight. I suppose without a nice charging report like some of the EVSE's give this will just be kind of a trial and error thing for about a week to get it dialed in.

I do love these reports of JuiceBox Pro and that's why I upgraded to PRO after buying a classic initially. Take a look at the pics below as these might help you fine tune your end time.

I came back with 9% battery remaining and GOM saying --- miles left. It was at 9 miles left a minute ago. I guess this is the VLBW. I usually don't go that low but ended up driving extra yesterday.

The car says I will need to charge for 4 hours and 30 minutes on 6kW 240V. (Surprisingly this was spot on. It took 4 hours to charge and then 30 minutes to "equalize". )

JuiceBox shows that it took a total of 3Hr and 55 minutes to charge the car and used 17.086 kWh of Energy.

Though plugged in at 6.07 PM it started to charge at 12.29 AM. Started dropping the charge rate at 3.02 AM. Finished the charge by 3.57 AM and then "equalized" till 4.24 AM.

Hope this helps!

 

[golfcart]

Thanks for all of that it is exactly what I was looking for.

The car says I will need to charge for 4 hours and 30 minutes on 6kW 240V. (Surprisingly this was spot on. It took 4 hours to charge and then 30 minutes to "equalize". )

Though plugged in at 6.07 PM it started to charge at 12.29 AM. Started dropping the charge rate at 3.02 AM. Finished the charge by 3.57 AM and then "equalized" till 4.24 AM.

Hope this helps!

One clarification though... Didn't it only take 3.5 hours to charge and 4 hours total with equalization if it started at 12:29 and finished at 3:57 the equalized until 4:24? It seems to me like it overestimated by 36 minutes. I expect it has about 30 minute resolution on this 'estimate' feature. I think the juicebox reported time includes charging and equalization.

Good info either way. It looks like setting the time at 5:30 - 5:40 will probably do the trick for me. I must have just missed it cutting off this morning at 5. thanks again.

 

[Jefe]

Anecdotally, I have noticed that when charging with the Nissan-supplied trickle charger that the estimates are no where near the real time to charge. For instance where inphoenix's screen shows 20+hrs to trickle charge, mine would end up probably taking 14 or less when it thought it would take 20. So if the timer is firing based on the initial estimate, it might be off.

Seems like it would be better to put a timer on the EVSE.

 

[golfcart]

Anecdotally, I have noticed that when charging with the Nissan-supplied trickle charger that the estimates are no where near the real time to charge. For instance where inphoenix's screen shows 20+hrs to trickle charge, mine would end up probably taking 14 or less when it thought it would take 20. So if the timer is firing based on the initial estimate, it might be off.

Seems like it would be better to put a timer on the EVSE.

Yeah, the car definitely overestimates charge time a bit. There are a lot of threads on the forum that talk about this but there doesn't seem to be any solid advice as to exactly how much it tends to overestimate. There just seem to be too many variables (state of charge, temperature, volts, amps, are you using climate timer as well). If I could turn back the clock this issue may have pushed me towards a different EVSE with a built in timer... but that ship has sailed for me at this point.

I'm just going through the process of dialing it in now... I did 5:40 as the end time this morning and it was done charging by 5 already so I'll try 6 tomorrow. My daily usage is almost identical from day to day so I should be fine once I get this nailed down. Even if I can't get it all at super off peak I would like to get the vast majority of charging done during that window. In the winter it is $0.0856/kWh from 10pm - 1am and drops to $.0579/kWh from 1am - 5am so it does make a difference.

 

[billg]

I wouldn't spend too much additional time worrying about this. If you charge 2 kWh every day at the higher rate, it's less than $2.00 a month. (2 kWh x 30 days x .03 = $1.80)

 

[BrockWI]

The other plus side is if it is still charging at 6am (which I would highly doubt) it will be in the balancing portion, consuming WAY less power in that last hour than in the first hour of charging. Also even if you need to jump in and leave before it's done it is often right up there at 98, 99 or 100 already anyway. We leave at 7:30 and I have ours set for 8a (end of our peak time) and I can't remember the last time I saw it charging even at 7:15.

 

[tkdbrusco]

I think some of this might have already been said, but I'll go ahead anyways. (1) I think you pointed out that you were using a 20A EVSE, which means that you'll add at most 20% per hour while charging. Considering that the battery takes longer to top off, you'll need over 5 hours for a full charge. (2) You probably want to set the end time to 6:00 AM if you have a day when you need much more power. The topping off and balancing portion of the charge (from about 90% onward) will use much less power and cost you less money.

I have an S as well and think that the charge timer is ridiculous in that car. If I knew it was so bad I'd have bought a WIFI enabled EVSE.

 

[inphoenix]

The other plus side is if it is still charging at 6am (which I would highly doubt) it will be in the balancing portion, consuming WAY less power in that last hour than in the first hour of charging. Also even if you need to jump in and leave before it's done it is often right up there at 98, 99 or 100 already anyway.

+1

I have an S as well and think that the charge timer is ridiculous in that car. If I knew it was so bad I'd have bought a WIFI enabled EVSE.

Very true!! I'm glad I realized this in time after buying a JuiceBox classic (non WiFi) and then swapped it for a JuiceBox PRO (WiFi model). I believe the only other "connected" EVSE is the "ChargePoint Home" at a much higher price point.

 

[golfcart]

I wouldn't spend too much additional time worrying about this. If you charge 2 kWh every day at the higher rate, it's less than $2.00 a month. (2 kWh x 30 days x .03 = $1.80)

Point taken LOL, but worrying about these little details is what makes it fun... Also, given the data that inphoenix showed, its probably gonna be higher than that since the highest rate of charging seems to be at the front of the window.

Going off this thread

http://www.mynissanleaf.com/viewtopic.php?t=13008

at 240v and 20a I will get about 16.3 miles of range per hour (or roughly 4.1kW of actual charging per hour). My typical daily commute is 55-60 miles depending on if I get lunch or run to the Kroger before dinner. So lets say 3.5 to 4 hours of actual charging is required each night plus that half hour balancing.. So lets call it 4 - 4.5 hours. If the car is turning on an 60 - 90 minutes early and I set it to 5am that would mean up to 2hrs a night of charging happening during off-peak vs super off-peak and all of that would be at my highest rate of charge.

If I assume a rate of roughly 4.1kW/h that could mean 6 - 8kW a night so instead of $1.80 a month it could be $5 - $7. Not the end of the world but not chump change. Could be $75 a year or so. Plus it's kinda fun to try and optimize things.

The other plus side is if it is still charging at 6am (which I would highly doubt) it will be in the balancing portion, consuming WAY less power in that last hour than in the first hour of charging. Also even if you need to jump in and leave before it's done it is often right up there at 98, 99 or 100 already anyway. We leave at 7:30 and I have ours set for 8a (end of our peak time) and I can't remember the last time I saw it charging even at 7:15.

My window is kinda tight, I've got 4 hours of super off-peak which ends at 5am and I leave between 545 and 6 for work and need at least 80% charge to feel comfortable with the commute. So I can't be too far off, but I agree with you and tkdbrusco that I'd rather miss on the back end than the front given that the end of the charge seems to be low draw balancing while the front end is where the big juice is flowing.

 

[BrockWI]

Your on the right track, just keep tweaking the setting and you should find the sweet spot, I am guessing your really close with the 5:40 or 6:00, I am guessing 5:50, just because of the 10 minute interval settings

 

[golfcart]

Your on the right track, just keep tweaking the setting and you should find the sweet spot, I am guessing your really close with the 5:40 or 6:00, I am guessing 5:50, just because of the 10 minute interval settings

Looks like 6am is just about right, it turned off a little after 5 so all of my big charging should be happening during the super off-peak.