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Re: 2013 S - 80 or 100%?

Posted: Sat Nov 19, 2016 10:18 am
by DaveinOlyWA
you have to make that decision on your own and looks like you have done the footwork.

now my thoughts on the subject, none of which is based in scientific fact, only my real observations and suppositions.

http://daveinolywa.blogspot.com/2016/11/100-or-80.html

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 12:22 am
by Doomsday
Ok, up front, my leaf wont be here till wednesday. What I do have is 25+ years of electric RC flying experience and countless charging hours of pretty much every battery type. 100% should never hurt your battery unless you are not going to be driving the thing for like a month or two. Even then it depends a lot on the batteries themselves. These cars are mass produced so guess what that means, It means lots and lots of safety features because there is nothing worse than a customers battery exploding.

So without knowing the safety parameters that nissan has set this should be a rule of thumb. You should be able to run your battery down to 0 and fully charge it to 100% without any degradation what so ever and here is why. Nissan had to have set a "limit" on both the 0% and 100% extremes and there should be a nice safety buffer there that prevents damage especially since this is a mass produced car, Overcharging and over discharging can cause explosions. The main damage to batteries is heat since from what I read there is no real thermal management system other than air cooled, then environment temps would play heavily in the degradation of the battery especially during the charging and discharging phases. Extreme cold can damage as well but its usually more about reducing its ability to release that stored energy. Again, not a scientist here just going off my years of experience dealing with batteries. Frankly the thing I see that hurts the leaf the most if the lack of a real thermal control system. Not charging to 100% or running it down to 0. Again we dont how cushioned or how slim the margins are but I would bet heavily on cushioned due to the inherent dangers of lithium going boom in your mass produced device. Just look at the galaxy note 7.

Anyways, just my opinion from brand new used leaf owner.

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 12:40 am
by SageBrush
I chose the car based on my use case of expecting to just about always use less than 80% of nominal capacity*, and daily use quite a bit lower**. I'll also take steps to avoid overheating while charging along the lines that dhanson mentioned.

* 10 -90% SOC range
**30 - 70% SOC range

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 3:47 am
by LeftieBiker
Doomsday, I see a couple of problems with your generally reasonable arguments.

* The risk from storage at 100% isn't explosion, just degradation. The Leaf uses a fairly stable lithium chemistry. The fact that the first generation batteries lose capacity so fast argues in favor of degradation for any reason being a concern. Storage at 100% certainly isn't #1 on the list of contributing factors, but any factor that can be eliminated should be, IMO.

* There should be a large buffer at the top and bottom of the battery, but Nissan was dealing with a car with barely adequate range, and one that had been sold by dealers as having a "100 mile range." So they were pressured to make those buffers as small as possible.

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 5:22 am
by craig
Doomsday wrote:Ok, up front, my leaf wont be here till wednesday. What I do have is 25+ years of electric RC flying experience and countless charging hours of pretty much every battery type. 100% should never hurt your battery unless you are not going to be driving the thing for like a month or two. Even then it depends a lot on the batteries themselves. These cars are mass produced so guess what that means, It means lots and lots of safety features because there is nothing worse than a customers battery exploding.

So without knowing the safety parameters that nissan has set this should be a rule of thumb. You should be able to run your battery down to 0 and fully charge it to 100% without any degradation what so ever and here is why. Nissan had to have set a "limit" on both the 0% and 100% extremes and there should be a nice safety buffer there that prevents damage especially since this is a mass produced car, Overcharging and over discharging can cause explosions. The main damage to batteries is heat since from what I read there is no real thermal management system other than air cooled, then environment temps would play heavily in the degradation of the battery especially during the charging and discharging phases. Extreme cold can damage as well but its usually more about reducing its ability to release that stored energy. Again, not a scientist here just going off my years of experience dealing with batteries. Frankly the thing I see that hurts the leaf the most if the lack of a real thermal control system. Not charging to 100% or running it down to 0. Again we dont how cushioned or how slim the margins are but I would bet heavily on cushioned due to the inherent dangers of lithium going boom in your mass produced device. Just look at the galaxy note 7.

Anyways, just my opinion from brand new used leaf owner.
Since it fits into my use profile, I was glad to read your post.
I have a 2014 Leaf S, 24k miles and 12 bars. I usually drive about 40 miles a day, short errands around town, with a weekly 40 mile round trip freeway run at about 70 mph. When I charge, I charge to 100% overnight, though I don't bother plugging it in if the remaining charge is over 80%. Most times the SOC is down to about 50% when I do plug in, though I do rarely run it down to less than 20%.
II didn't buy this car to baby it, or to abuse it either. I bought it to replace a VW diesel, and with the intent to drive it whenever and wherever I need to, not to be a slave to someone else's idea of optimal battery usage.
Nissan is a big company that is serious about the coming electric car revolution, and would not have marketed a car that can only be optimally utilized by the 'expert' few.

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 7:30 am
by joeriv
Going on three years for my 2013S and I doubt if I charged to a100% more than 20 times - as a "local" car, I just don't need the miles. The research I read about lithium battery chemistry clearly points to heat as the number one degrader and leaving the battery at full charge for extended perionds close behind, as many others have pointed out, so routinely charging to 80% is desirable.

Luckily for my Leaf, it's garaged where the temp during the summer is not more than 85 degrees and the weather in CT is not extremely hot for extended periods during the summer, so maybe I'm in a battery friendly environment.

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 8:45 am
by Doomsday
LeftieBiker wrote:Doomsday, I see a couple of problems with your generally reasonable arguments.

* The risk from storage at 100% isn't explosion, just degradation. The Leaf uses a fairly stable lithium chemistry. The fact that the first generation batteries lose capacity so fast argues in favor of degradation for any reason being a concern. Storage at 100% certainly isn't #1 on the list of contributing factors, but any factor that can be eliminated should be, IMO.

* There should be a large buffer at the top and bottom of the battery, but Nissan was dealing with a car with barely adequate range, and one that had been sold by dealers as having a "100 mile range." So they were pressured to make those buffers as small as possible.
Except I see arguments saying that leaving it at 100% for just a few hours causes degradation and it doesnt. It takes a long time for that to set in. In fact, heat plays no role in this function because there is no charge going into it.

I dont think those buffers are small, They cant be for one main reason, It only takes 1 battery exploding from charging or discharging to ruin a company, The reason there was so much degradation in gen 1 batteries is simple, Heat and bad batteries. I suspect changes were also made to the battery compartment to facilitate better airflow as well. Now its possible that the charging circut wasnt doing cell balancing properly that could have helped towards the degradation as well but again, its pretty much all heat causing it, not sitting for a few days at 100%. Again, look at the damage that has happened to samsung for their phones exploding. Estimates are they lost in the billions and not just from recalls but from sales losses afterwards.

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 8:57 am
by RonDawg
I'm surprised nobody picked up on this:
lionsfan54 wrote:2013 SV, 21,xxx miles. I always fill it up to 100% for a few reasons

1. We always drive it within an hour or 2 after that charge
2. With the 8 year battery warranty I kind of want to wear it down rather than take it easy on it. My thinking is "let's beat this thing up now rather than nurse it along so that it never quite hits the warranty replacement number of bars".
3. Not sure if it matters or not but we only charge with 110v
4. Our Leaf was manufactured very late in 2013 (Dec) so I think we got the new battery formula/chemistry

Currently holding steady at 12 bars
The 8 year/100k mile warranty is only for defects in workmanship. It does NOT cover premature degradation; that warranty is only 5 years/60k miles.

For the OP: I charged my car primarily at 80% because above say 95% I have no regen braking. That's important to me as I live in a hilly area and my drive away from home is almost always in the downhill direction. Even with 4 wheel disc brakes, friction-only braking isn't as good as when regen is doing much if not most of the work.

Re: 2013 S - 80 or 100%?

Posted: Mon Jan 02, 2017 9:20 am
by Doomsday
RonDawg wrote:I'm surprised nobody picked up on this:
lionsfan54 wrote:2013 SV, 21,xxx miles. I always fill it up to 100% for a few reasons

1. We always drive it within an hour or 2 after that charge
2. With the 8 year battery warranty I kind of want to wear it down rather than take it easy on it. My thinking is "let's beat this thing up now rather than nurse it along so that it never quite hits the warranty replacement number of bars".
3. Not sure if it matters or not but we only charge with 110v
4. Our Leaf was manufactured very late in 2013 (Dec) so I think we got the new battery formula/chemistry

Currently holding steady at 12 bars
The 8 year/100k mile warranty is only for defects in workmanship. It does NOT cover premature degradation; that warranty is only 5 years/60k miles.

For the OP: I charged my car primarily at 80% because above say 95% I have no regen braking. That's important to me as I live in a hilly area and my drive away from home is almost always in the downhill direction. Even with 4 wheel disc brakes, friction-only braking isn't as good as when regen is doing much if not most of the work.

Now thats a good reason not to go to 100% Saves you a few pennies in electric grid fees and instead of engine breaking just to be slowing down, now you have a good reason for it in regen.

Re: 2013 S - 80 or 100%?

Posted: Tue Jan 03, 2017 12:01 pm
by lionsfan54
RonDawg wrote:
The 8 year/100k mile warranty is only for defects in workmanship. It does NOT cover premature degradation; that warranty is only 5 years/60k miles.
From Nissan's site...

"the Nissan LEAF® Lithium-ion battery is also warranted against capacity loss below nine bars of capacity as shown on the vehicle’s battery capacity level gauge for a period of 96 months or 100,000 miles"