Charging to 80% and 100% at different times

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Ne0hlithic

New member
Joined
Nov 17, 2014
Messages
2
Hi all. I've discovered a bit of arcane knowledge that I wanted document here and share in case some might find it useful.

I wanted to achieve the following behavior with my 2012 SL:
1) to begin charging automatically whenever I plugged in
2) to only charge to 80% so that the battery spends the majority of its time at this level
3) to charge from 80% to 100% shortly before leaving for work on weekdays

My reasoning is that I want to minimize the amount of time the battery is sitting at 100% and warm the battery a bit before departing for better performance in the cold. Setting this up with the charging timers wasn't possible due to the limitation that you can only set one timer per day. I was charging to 80% overnight and increasing to 100% manually by using the app when I woke up in the morning, but wanted to automate the process and start the charging a little earlier than that. Another option was to set a 100% timer that only ran in the a.m. hours, but this left the car uncharged if I decided suddenly that I needed to go somewhere at night before the charging started.

The answer I found was to use the CarWings Portal at leafic.com as I found here: http://www.mynissanleaf.com/viewtopic.php?p=104160. Using that, I could send commands (like begin charging) via CarWings non-interactively by visiting the webportal using a web address that looked like:

www.leafic.com/cwportal/index.php?username=USER&password=PASS&a=startcharge

Once that was set up I wrote a script on my computer that loads that page (via cURL) and set up the script to run every weekday at 0600. The script could easily be modified to only run in certain months, only at certain temperatures, or whatever else.
 
Just set an end charge timer and NO start timer to go to 100% . By charging immediately you actually keep your car at 80% longer and have two charge cycles cooling and heating the battery, it's splitting hairs. Using a end only timer is a very good option and likely better for battery longevity and mental health. I used this method for 3 years with almost no battery degradation.
 
I use the Leaf almost everyday and charge it up to 100%, 98% of the time. I'm at 26K and have all the bars. I started doing this after some Nissan charging research was published late in 2012 that seemed to indicate there was no problem with this. I also use multiple DCQC charges ( 3 or more) daily during longer trips. Basically, I don't baby the battery one bit. I've gotten very close to the red battery temperature zone a few times, but not into it. I live in the more temperate part of the Pacific NW.
 
It would be great if they had a minimum reserve setting. I would like to be able to set it to charge as soon as I plug in up to some minimum, then wait until the charging window to charge the rest of the way. But as they say, poop in one hand and wish in the other, see which fills up first...
 
When I log into my SDG&E account and view the daily graph of my usage, I see the last hour or so of charging taper off linearly to zero at my end time. It looks like the car manages it's charge rate so as to minimize the negative impact on the battery. Maybe it's keeping it from heating up or maybe it's reducing the charge rate as it gets close to full or close to the time I set.

By the way, after reading about this famous 80% rule online, I downloaded a PDF of my manual and searched for "80%". I can't find any mention of it. If someone could point me in the direction of a research study or manual quote or page that references it, it would be helpful.
 
ElectricMonkey said:
When I log into my SDG&E account and view the daily graph of my usage, I see the last hour or so of charging taper off linearly to zero at my end time. It looks like the car manages it's charge rate so as to minimize the negative impact on the battery. Maybe it's keeping it from heating up or maybe it's reducing the charge rate as it gets close to full or close to the time I set.

By the way, after reading about this famous 80% rule online, I downloaded a PDF of my manual and searched for "80%". I can't find any mention of it. If someone could point me in the direction of a research study or manual quote or page that references it, it would be helpful.

From your delivery date I'm guessing you have a 2014 or 2015 model year. The 80% option was discontinued after the 2013 model year and is not mentioned anywhere in the manuals.

In the 2011 and 2012 manuals 80% was called "long battery life mode" as at the time it was thought that charging to 100% would hasten the degradation of the battery. Since then we've found no public data to support that. Nissan, of course, has all of our battery data from yearly battery checks and carwings updates but hasn't shared it. However, they softened the language around the 80% option in 2013 and in 2014 removed it entirely. If you call the LEAF support line today they'll tell you that this is not considered necessary with 2014 and later LEAFs.

So, is there more to this story than is officially acknowledged? Possibly. In 2013 the EPA surprised Nissan by publishing the range of the LEAF as 75 miles. Actually the LEAF rated at 84 miles but the EPA decided to average the range with 80% and 100% charge to get 75. This was pretty stupid, as "range" implies "with full energy" but it's what they did, so a lot of LEAFers speculate that the major reason for the change in 2014 was to get the EPA range up to 84.

We do know that in fact the original LEAF battery performed differently than expected in a number of ways. For example, on the positive side they found that quick charging didn't hasten battery wear and so gradually softened the language that in 2011 cautioned against more than one quick charge per day to eventually removing that caution altogether. So perhaps that occurred with the 80%.

We also know that the battery changed in 2015 to the "lizard" battery that is designed to tolerate extreme heat (which the 2011 battery most certainly did not), and a lot of us suspect that this battery was introduced in earlier model years in some or all of the cars, which may also explain improvements in battery wear that we've started to observe with 2013s. We know that the 2013 batteries were different in some way because replacements for earlier model years require adaptive harnesses while later model years do not.

All of this is interesting history and in some ways creates a situation where new LEAFers are hearing about the accumulated wisdom from early LEAF adopters that actually may not apply to the new LEAFs. I still charge to 80% as standard practice on my two LEAFs, but when I upgrade to a 2013 or later I'll stop that practice.
 
This is an old thread, but I will add to it anyway. When I just got my 2015, I went CRAZY trying to keep the battery to 80%!! I got a timer for my stock 110v charger, and everyday I had to worry about the maximum level. I then got a Schneider Electric (fantastic by the way) 240v charger, and it turns off at 100%. I say, forget going crazy with the 80% rule so that MAYBE your battery will last a little longer. Also, following the 80% rule, you cut down on your range and drive the car to a lower battery level, and then have to worry about POSSIBLY damaging your battery from the other end ----- depleting it too much...

I have been driving cars for 40 years, and have for years been keeping my regular car 12v batteries at full charge ALL THE TIME with a solar charger that is permanently installed into the car. That way, even a car that I don't use much will have a fully charged battery any time I want to use it... I have kept the original batteries in my cars for 10 years or more by having them FULLY charged all the time. I have also heard on the internet that batteries like to be fully charged. So, I say, charge to 100% of the battery YOU PAID FOR!, and let time be the judge of how it works out.
 
powersurge said:
This is an old thread, but I will add to it anyway. When I just got my 2015, I went CRAZY trying to keep the battery to 80%!! I got a timer for my stock 110v charger, and everyday I had to worry about the maximum level. I then got a Schneider Electric (fantastic by the way) 240v charger, and it turns off at 100%. I say, forget going crazy with the 80% rule so that MAYBE your battery will last a little longer. Also, following the 80% rule, you cut down on your range and drive the car to a lower battery level, and then have to worry about POSSIBLY damaging your battery from the other end ----- depleting it too much...

Another way to manage this is through an end timer, set an hour or two AFTER you typically leave. It took my 2012 SL about 1:30 when new to charge from 80-100%. But it always finished sooner than expected. So in theory you could set the end time for about 2 hours past when you leave and it will be charged to roughly 80%.

To the OP's point, though, an end timer cannot help if you want to charge immediately, and have some juice for an unexpected evening trip.

As an engineer who tries to optimize everything I can, battery charge management is a frustrating topic. I know the best way to manage my battery SoC for my use case, but I cannot do it automatically. The EVSE doesn't know the SoC of the car, so it cannot adjust times accordingly. The charge timers in the car are very limiting. I've learned to let it go, though, since the net benefit is very low.

powersurge said:
I have been driving cars for 40 years, and have for years been keeping my regular car 12v batteries at full charge ALL THE TIME with a solar charger that is permanently installed into the car. That way, even a car that I don't use much will have a fully charged battery any time I want to use it... I have kept the original batteries in my cars for 10 years or more by having them FULLY charged all the time. I have also heard on the internet that batteries like to be fully charged. So, I say, charge to 100% of the battery YOU PAID FOR!, and let time be the judge of how it works out.

Your 12V battery is a Lead-Acid battery. It is a completely different beast from the Lithium battery under the floor in your Leaf. Lead batteries like to be full all the time, but Lithiums do not. Ideally, they want to rest in the 40-50% SoC window. 20-80% is a safe range, although less than ideal.

http://batteryuniversity.com/
 
So if at some point the 80% level became not helpful/necessary in prolonging battery life, who are these people who've lost capacity pips? What models do they own and what did they do "wrong" to be losing bars?

I like the idea that going to 100% gives you more range & convenience (and may offset any added "wear" by allowing fewer recharge cycles and reducing deep-discharge incidents) and greater margin of safety at the bottom--but, wait, Do we still "know" that getting below 10% is bad???"Experts" used to say keep the car between 2 and 10 bars, but now we're letting ourselves go up to 12 should we also let ourselves get down to 1?

After reading this, I'm still a little leery to move my 2013 S with Charge Package to 100% charging every day (at 6kW/30A JuiceBox). Should I be? I feel like the guy who's learned that bike helmetsand child car seats don't make you safer (in most cases), but it is hard to give up the old "safety" practice, even if it is no safer.

2013 was the leaf's "breakout" year for sales as US production ramped up. There must be a lot of users here with 2013 who have the uncomfortable feeling of being the "borderline" case between the old 2-and-10 rule and a new go-to-12 rule.
 
To add some fuel to the fire, I'm a 2013 case that tries to always charge to under 100% - usually 92% (by having the car charge to 80%, then using a timer to add 30 more minutes in the morning before I leave for work) - to prolong battery life. Time will tell if it helped - I'm currently at 34k with all bars on deck, but that's not super unusual.

Just a quick comment as something caught my eye that I don't want spread:

I feel like the guy who's learned that bike helmets and child car seats don't make you safer (in most cases)

...the situation is that cars are less likely to collide with bicyclists if they're NOT wearing helmets - but helmets absolutely save lives, and your risk of brain injury/death is greatly increased by not wearing a helmet - just your odds of being hit by a car are slightly reduced. A bit more nuanced than "don't make you safer".

Best,
Tal
 
Hey i hear you say that after 2013 the option to charge to 80% in the chargetimer went away. I bougth in november 2015 a brand new Leaf Nordic 24kw this car have the charge 80% option. Have they sold me an 2013 as 2015mod?!?
 
Doubtful. The reason they got rid of the 80% option (likely only for the American market) is a stupid one: a regulatory agency that governed car manufacturers took the range as the average between the two options - so 80% + 100% / 2 = 90%.

They said it was false advertising to list the range at 100% - and so just like that they cut 10% out of the listed range.

To get around that Nissan simply removed the 80% option for model years 2014+ and now 100% of the range is listed.

Stupid.

But fortunately other countries aren't as silly, so there was no need for such a silly workaround. Enjoy your car!

From across the pond,
-Tal
 
ElectricMonkey said:
I see the last hour or so of charging taper off linearly to zero at my end time. It looks like the car manages it's charge rate so as to minimize the negative impact on the battery. Maybe it's keeping it from heating up or maybe it's reducing the charge rate as it gets close to full or close to the time I set.

I recently learned (from this forum) that for the last 5%, the LEAF does some cell balancing. Maybe that's what you are seeing.
 
Arlington said:
So if at some point the 80% level became not helpful/necessary in prolonging battery life, who are these people who've lost capacity pips? What models do they own and what did they do "wrong" to be losing bars?

Heat, heat, heat. Unavoidable heat.

Basically where you live matters more than the charge level. It's still better for the car if you don't leave it charged over 40% any longer than you have to but the effect is so minor it is swamped by the heat issue.

Parking in the shade will probably do more good than charging 20% lower each day.
 
taloyd said:
Doubtful. The reason they got rid of the 80% option (likely only for the American market) is a stupid one: a regulatory agency that governed car manufacturers took the range as the average between the two options - so 80% + 100% / 2 = 90%.

They said it was false advertising to list the range at 100% - and so just like that they cut 10% out of the listed range.

To get around that Nissan simply removed the 80% option for model years 2014+ and now 100% of the range is listed.

Stupid.

But fortunately other countries aren't as silly, so there was no need for such a silly workaround. Enjoy your car!
Yep, basically it was so that the Leaf could look more competitive against other US EVs since 99% of potential EV customers will not know the below backstory and 75 miles doesn't look so good vs. all the others but 84 looks much better.

http://insideevs.com/2013-nissan-leaf-rated-at-75-miles-but-84-miles-using-the-old-system/
http://insideevs.com/2014-nissan-leaf-mostly-unchanged-as-range-technically-moves-up-to-84-miles/

The 80%/100% averaging rule is stupid. It seems like Tesla for some reason doesn't get bitten by it even though the offer the driver far more choices as to % to stop charging at.

I've seen a report of a Leafer in Ireland with a 2014 or newer Leaf which still had the charge to 80% setting.
 
powersurge said:
I say screw all that 80% crap.

I charge my leaf every day to 100% overnight, and after 20K miles the battery checks out like new...

Charging to 100% is not an issue. Letting it sit at 100% for extended periods, especially in the heat, is what causes problems. The 80% option is most beneficial (to the battery) for those who like to keep the battery charged, but don't regularly drive the car.
 
baustin said:
Charging to 100% is not an issue. Letting it sit at 100% for extended periods, especially in the heat, is what causes problems. The 80% option is most beneficial (to the battery) for those who like to keep the battery charged, but don't regularly drive the car.
How extended (how infrequent is "don't regularly drive"), how hot?
 
Arlington said:
baustin said:
Charging to 100% is not an issue. Letting it sit at 100% for extended periods, especially in the heat, is what causes problems. The 80% option is most beneficial (to the battery) for those who like to keep the battery charged, but don't regularly drive the car.
How extended (how infrequent is "don't regularly drive"), how hot?

I consider 'regular driving' to be three days (or more) per week. From what I've read, ambient temperatures below eighty degrees (and above freezing) seem to be best for extending the life of the battery.
 
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