Better to use free charging to 100%?

[ebill3]

charging to 100% is really only detrimental if you plan to leave it 100% for extended periods of time.

That is a rather positive statement, Dave. Can you provide a reference? My unprofessional knowledge gained by reading what professional people write, is that merely charging to a high SOC is detrimental. True, leaving it at a high SOC will increase the effects, but my gurus say avoid the high SOC, period.

Bill

 

[surfingslovak]

That is a rather positive statement, Dave. Can you provide a reference? My unprofessional knowledge gained by reading what professional people write, is that merely charging to a high SOC is detrimental. True, leaving it at a high SOC will increase the effects, but my gurus say avoid the high SOC, period.

Bill fair enough. Please ask your gurus to quantify how much better your battery will be off, if you always charged to 80% after five years, and then after ten years. Be prepared to provide them your exact charging and driving patterns, in addition to a complete temperature profile of the environs your Leaf will be exposed to. Then ask them to project the replacement or repair cost of the battery back over the same time horizon, and report back what you have heard.

My point: it's good to err on the side of caution, but you might be surprised by the outcome of this mind exercise.

 

[DaveinOlyWA]

charging to 100% is really only detrimental if you plan to leave it 100% for extended periods of time.

That is a rather positive statement, Dave. Can you provide a reference? My unprofessional knowledge gained by reading what professional people write, is that merely charging to a high SOC is detrimental. True, leaving it at a high SOC will increase the effects, but my gurus say avoid the high SOC, period.

Bill

1) there is no direct reference only because any statement made by Nissan will be blown way out of proportion. to say that leaving a car charged to 100% for any length of time is detrimental would only bring a flood of bad press against EVs. they simply state if storing for a trip, do not let it be fully charged. otherwise they HAVE to assume that if you are paying $30,000 for a car, that you plan to use it...

now a 100% charge is actually only 98% charge which is good since temps can move that 100% target around and yes, charging to 100% can be detrimental since high voltages can break down the battery components (ask Phil for specifics) but we need to weigh that word.

if charging to 100% and then driving right away (within say 8-10 hours) and over 100,000 miles we will lose 5% over if we never charged beyond 80% is detrimental but is it enough to warrant risking being out of charge because we did not charge to 100%?

imm, it is not. it is not worth the worry. if i plan to drive more than 40-50 miles, i charge to 100 % and do so every day when going to work. i have enough range to go there, come home and go there again, but i charge to 100% because i might want to go somewhere else on the way home or i might not.

now, with all that, we have many user experiences to use as a guideline as well.

on the one hand; we have a guy who does 2 100% charges 5 days a week, has had no signs of degradation

on the other; we have a guy who has degradation and only charged to 100% a few times a month.

well, we can suspect that the one who has lost range probably never had it. he reported back in Nov about his charging and his numbers which did not make sense back then, do make sense now knowing his degraded capacity which means he had the degradation very early on. now, his was a demo and we must assume that Nissan probably had it plugged in all the time to demo the charging process and to insure it was full to drive so if it sat for 2 days (holidays?) and did so several times during the time it was a demo, that could account for the rapid deterioration which has seemed to stop.

now, the question; how long is too long? we can assume. Nissan thinks we will plug in at night, take off the next day so guessing that by Nissan not giving us specific warnings on this that they have determined up to say 8-12 hours is safe.

now, we have established not a single syllable towards answering your question.

as far as the detrimental effects of having Li batts at 100%, i leave that to Andy the battery guy to answer that

 

[ebill3]

That is a rather positive statement, Dave. Can you provide a reference? My unprofessional knowledge gained by reading what professional people write, is that merely charging to a high SOC is detrimental. True, leaving it at a high SOC will increase the effects, but my gurus say avoid the high SOC, period.

Bill fair enough. Please ask your gurus to quantify how much better your battery will be off, if you always charged to 80% after five years, and then after ten years. Be prepared to provide them your exact charging and driving patterns, in addition to a complete temperature profile of the environs your Leaf will be exposed to. Then ask them to project the replacement or repair cost of the battery back over the same time horizon, and report back what you have heard.

Ah, come on. You know I can't do that, nor can you. So why propose such a ridiculous scenario? Even if I could, the guru would not be able to provide the answer you want with out replicating my experience and comparing it to a sanitized long term run.

My point: it's good to err on the side of caution, but you might be surprised by the outcome of this mind exercise.

No surprise - it ain't gonna happen. :lol:

Bill

 

[surfingslovak]

As far as the detrimental effects of having Li batts at 100%, i leave that to Andy the battery guy to answer that

Dave, with all due respect, there is no need to start another heated and almost religious debate over battery management care. The OPs question was nonsensical, since nobody can provide an accurate estimate how much more his battery would degrade in the two scenarios he presented. We can make an educated guess, but we don't have any lab data for Leaf's battery cells, and even if we did, our cars don't live in the lab. Andy, and others, have stated several times that there is no need to fret over 80% charging. I have come full circle on this issue, mostly based on data gleaned from other owners and comparative research. I can categorically tell you, that these debates are as useless as the QC debates were earlier, before NIssan decided to debunk that topic.

For what it's worth, the ActiveE I'm driving now does not even have a 80% setting, you charge to full by default. I fully expect the i3 to behave the same way. And I hope that you won't mind if I corrected you, charging to 100% does not correspond to 98% true SOC. It's about 94%. If this topic interest you, you might want to review our earlier threads. Please be careful with the information you provide to others. Take care not to give inaccurate or obsolete data.

 

[ebill3]

1) there is no direct reference only because any statement made by Nissan will be blown way out of proportion. to say that leaving a car charged to 100% for any length of time is detrimental would only bring a flood of bad press against EVs. they simply state if storing for a trip, do not let it be fully charged. otherwise they HAVE to assume that if you are paying $30,000 for a car, that you plan to use it...

now a 100% charge is actually only 98% charge which is good since temps can move that 100% target around and yes, charging to 100% can be detrimental since high voltages can break down the battery components (ask Phil for specifics) but we need to weigh that word.

if charging to 100% and then driving right away (within say 8-10 hours) and over 100,000 miles we will lose 5% over if we never charged beyond 80% is detrimental but is it enough to warrant risking being out of charge because we did not charge to 100%?

imm, it is not. it is not worth the worry. if i plan to drive more than 40-50 miles, i charge to 100 % and do so every day when going to work. i have enough range to go there, come home and go there again, but i charge to 100% because i might want to go somewhere else on the way home or i might not.

now, with all that, we have many user experiences to use as a guideline as well.

on the one hand; we have a guy who does 2 100% charges 5 days a week, has had no signs of degradation

on the other; we have a guy who has degradation and only charged to 100% a few times a month.

well, we can suspect that the one who has lost range probably never had it. he reported back in Nov about his charging and his numbers which did not make sense back then, do make sense now knowing his degraded capacity which means he had the degradation very early on. now, his was a demo and we must assume that Nissan probably had it plugged in all the time to demo the charging process and to insure it was full to drive so if it sat for 2 days (holidays?) and did so several times during the time it was a demo, that could account for the rapid deterioration which has seemed to stop.

now, the question; how long is too long? we can assume. Nissan thinks we will plug in at night, take off the next day so guessing that by Nissan not giving us specific warnings on this that they have determined up to say 8-12 hours is safe.

now, we have established not a single syllable towards answering your question.

as far as the detrimental effects of having Li batts at 100%, i leave that to Andy the battery guy to answer that

Well, OK, I guess. Think I'll go pour an adult beverage.

https://docs.google.com/viewer?a=v&q=cache:bwUczMtCThUJowerelectronics.com/portable_power_management/battery_charger_ics/804PET22li-ion-battery-life.pdf+proper+care+extends+li-ion+battery+life&hl=en&gl=us&pid=bl&srcid=ADGEEShTgDpt7upvpyBu104YBgyUgC8p03jnadCqXEfdD9f3Rtn3X6RMKfrAJR5hhvA0gPwjoOyWwia8XE6nEULSBSAxLwrdIl7n-cekFz9tJnxdeGx6dAPHBpRIO4Zmv_J18A1zsjVt&sig=AHIEtbR27HdjliaGKlC7F2rFtLH_2VSgIw" onclick="window.open(this.href);return false;

 

[surfingslovak]

No surprise - it ain't gonna happen. :lol:

Bill, exactly :lol:

If you settled for a very rough conservative estimate and assumed that the battery would hypothetically lose additional 5% capacity over 10 years in the scenario the OP described above, and estimated the replacement cost of the pack in ten years to be $10K, then the incremental capacity loss would represent a monetary equivalent of about $500, which is about $0.20 per workday.

I would argue that in this particular scenario the projected loss of battery capacity will be less than that, but it's nearly impossible to predict with a reasonable level of accuracy. Given the dollar amounts involved, we are literally splitting hairs.

 

[ebill3]

Peace.

I've got my adult beverage and a plate of sliced apple and cheese.

 

[EdmondLeaf]

I think is about time to re-post my first answer to OP

There is no real life data on 80 vs. 100% charge on battery degradation. Just charge, drive, and don't worry about it.

but to be completely honest I only charge to 80% (always).

 

[surfingslovak]

Adult beverage and a plate of sliced apple and cheese.

Cheers! Which reminds me, time to leave the office. Let's see if I can rustle up a good bottle of wine

But to be completely honest I only charge to 80% (always).

I happily removed all charging timers a few months ago, but I had to put the Leaf back on an 80% regimen after someone charged it to full and let it bake all weekend in the sun. Don't want that to happen again, so it's back to the training wheels. I provided instructions on how to override the timer when needed.

 

[DaveEV]

Andy, and others, have stated several times that there is no need to fret over 80% charging. I have come full circle on this issue, mostly based on data gleaned from other owners and comparative research. I can categorically tell you, that these debates are as useless as the QC debates were earlier, before NIssan decided to debunk that topic.

Unless Nissan's cells are made of some magical chemistry (and they're not), it is very well known that to get the most energy in/out of a battery, you need to do these things:

1. Keep SOC around the middle of the capacity and minimize SOC swings.
2. Keep discharge/charge rates as low as possible.
4. Keep the batteries around 50-70*F.

Deviating from any of these parameters will increase the rate at which the battery degrades. Period.

Any paper/study on battery life will tell you this. Here's a slideshow that discusses a lot of these issues with pretty graphs: http://www.nrel.gov/vehiclesandfuels/pdfs/48933.pdf" onclick="window.open(this.href);return false;

The only question is how much faster capacity will be lost if you deviate from these parameters - if you don't care - then don't worry about it!

For what it's worth, the ActiveE I'm driving now does not even have a 80% setting, you charge to full by default.

Well sure - if you only need the battery to last 3 years and perhaps less than 400 full cycles there's no reason to worry. You don't care if the battery has degraded 5%, 10% or 50% when you give the car back to BMW.

 

[surfingslovak]

1. Keep SOC around the middle of the capacity and minimize SOC swings.
2. Keep discharge/charge rates as low as possible.
4. Keep the batteries around 50-70*F.

Deviating from any of these parameters will increase the rate at which the battery degrades. Period.

The only question is how much faster capacity will be lost if you deviate from these parameters - if you don't care - then don't worry about it!

OK, I hope you realize that you are preaching to the choir. I believe that I did not contradict these universal truths in any way, and if you had a chance to read my earlier posts on this forum, you would see that I have done my homework. All I'm saying is that for the average use case, when a Leaf is driven on a frequent basis and charged at night, the difference between a 80% and 100% charging protocol will be immaterial. Yes, if you take a large enough sample of vehicles, it will be measurable, but for the individual owner, the difference will be immaterial. We are talking a few percentage points over a ten year period. There will be far larger differences than that between individual vehicles following the same charging protocol.

Well sure - if you only need the battery to last 3 years and perhaps less than 400 full cycles there's no reason to worry. You don't care if the battery has degraded 5%, 10% or 50% when you give the car back to BMW.

I have done an incredible amount of work gathering data on the MINI-E trial, and it's one of the reasons I decided to go for the ActiveE. As I said above, I'm reasonably convinced that the production car won't have an 80% charging timer either, and the claims you are making about battery degradation are totally off the mark. I would encourage you to go and look at the available data, if this is something of interest to you.

That being said, I don't mind the 80% charging timer, but I no longer believe that it's particularly useful. It's a conservative choice, sure, and I wouldn't mind recommending it to folks as such. But it's not mandatory. It can be even detrimental, since it reduces the effective range of the vehicle, and new owners universally struggle with range anxiety. And I happen to think the same about the stern warning not to use QC more than once a day as well. This has been debunked. It would have been better if Nissan provided a bona fide storage mode, so that folks wouldn't let their car sit fully charged or run the risk of draining their 12V battery when going on vacation.

 

[TonyWilliams]

I happily removed all charging timers a few months ago, but I had to put the Leaf back on an 80% regimen after someone charged it to full and let it bake all weekend in the sun. Don't want that to happen again, so it's back to the training wheels. I provided instructions on how to override the timer when needed.

I did that when I left my LEAF for three weeks. Just set the timer to perpetual 80% with no instructions how to override. The SO's parents are driving it, and not once have I seen over 83% on the iPhone.

 

[LEAFfan]

* Driving at 80% is more efficient - you get no to very little regen the first 10 miles or so after a 100% charge.

Actually, it isn't more efficient to drive with regen at 80% vs. little or no regen at 100% because coasting uses zero motor energy. It's always more efficient to coast than use regen unless you're going down a steep hill or mountain.
I guess I have a bad module since I still have a regen circle right after a 100% charge. My SoC gauge only goes to 83% now for a 100% charge. It used to go to 94-95%. Also, I've had the 'EV battery system' light stay on a couple times and had to restart to make it disappear.

 

[planet4ever]

Actually, it isn't more efficient to drive with regen at 80% vs. little or no regen at 100% because coasting uses zero motor energy. It's always more efficient to coast than use regen unless you're going down a steep hill or mountain.

... or you have to slow down or stop at a traffic signal. It is always more efficient to use regen than friction brakes, and where I live I nearly always end up having to use the brakes when the battery is at 12 bars. Our traffic signals are frequent, traffic actuated, and not coordinated. I don't have to drive in rush hour traffic, but I expect a similar argument could be made there.

Bottom line: Except in ideal situations where only extremely gradual slowing is used, it is more efficient to drive with regen at 80% vs. little or no regen at 100%.

Ray

 

[DaveinOlyWA]

Bottom Line; charge to the level you are comfortable with.

so what we dont want to do is charge to 80% thinking you will get 60 miles while taking a trip of 50 miles. you might be ok with that and that is something i would probably try in some circumstances but i better be doing it alone because my family does not have the same confidence in that little box on my dash that i have.

if i plan to drive more than say 40-50 miles and i wont have time to charge in the morning, then i go 100%. sure i frequently come home with 40-50% SOC left over and i am ok with that. sure, letting the batteries sit at 100% charge for 4-5 hours is not ideal but lets keep in mind, that is about all its not. lets not make mountains out of mole hills.

now, i am preaching to the preachers here, because many members of the "choir" maybe new and confused by all this back and forth bantering. i am. i now find myself having to go back a few pages just to understand why some of you have said what you said.

now, in my situation, i have frequently made a habit of charging to 90-95% by simply estimating the time it takes to get there, set alarm on cellphone and go from there. or charging to 70-80% the night before, then plugging it in for a few hours before my planned drives.

today is a great example. my day off. its 8 am , have been up since 5:45...ya, it sucks. i hate myself sometimes but that is how it goes. yesterday, when i got home at 4 PM i had 35% charge. was unsure of any driving needs, so i plugged in just in case and charged for 2 hours and unplugged. so now i am around 70% give or take (dont know, have not checked) but i am close enough that if i needed to i could have plugged in this morning and be at or near 100%.