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2014 Leaf 24Kw
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Discussion Starter #1 (Edited)
Hi Guys,

So after 2 months of owning my 2014 Leaf 24, which when bought had 96% SoH, I have mostly driven it in ECO mode. I then started noticing a few threads here and there suggesting that permanent ECO use was noted on Leafs with batteries that had developed bad cells etc

So for contrast over the last 2-3 days I decided to give up using ECO especially when several sources suggested they had improved mpk not using it.

My commute is 44 miles and today I was quite shocked at what I found...

128237

31-01-20

128238

28-02-20

There are a couple of notable differences which aren't immediately obvious from the photos...

* It was a lot milder at the end of Jan. Today was 2degC all of the drive and I had to use the heater to clear the screen on about 6 occasions (can't remember if I did that on the 31/01)

* Top one was granny charged until lights went out

* Bottom one was Rolec to about 97% before setting off

* Top commute was entirely ECO whilst bottom one entirely D

All the same, it seems like a big jump, no?

Anyway so I checked on LeafSpy and can report that the SoH had dropped from 96% to 91%

In 2 months???

I admit my charging has been rather erratic over the last two months although only one RAPID to 80% but mostly on my Rolec up to about 80%

Could the cold weather AND not using ECO be enough to account for this drop in miles?

Also, what about the drop in SoH?

Comments invited :)
 

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The cold weather (mainly) and not using ECO (less so, more dependant on your driving style) would be very likely to account for that. Only my regular commute consumption drops from around 4.4 - 4.6 m/kWh to 3.6 - 3.8 m/kWh when the temperature drops below 5C, mainly because I use the heating. The drop can be reduced by pre-heating and only using the seat-heaters.

The drop in SoH is strange. Do you know whether the car had been rapid charged to 100% before the first reading? That can give a higher reading in the short-term.
 

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2014 Leaf 24Kw
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Discussion Starter #3
Tnx. Has very low number of RC's [9] and I only did one RC myself in mid Jan. I know the previous owner only ever used overnight trickle charge, had a 60 commute then rinse & repeat. Compared to that I have been completely erratic charging especially since I got my Rolec setup.
 

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That all explains how your battery is in such good condition - my 64 reg with similar mileage is at 89%.
All that ECO does is reduce the max power going to the motor, and hence the maximum power draw from the battery which can be at a much higher level than even a rapid charger. Hence using ECO is potentially not just better for range but also for battery life (meaning that I am surprised at your earlier statement "a few threads here and there suggesting that permanent ECO use was noted on Leafs with batteries that had developed bad cells etc". If you drive out of ECO but only ever use part throttle it is effectively no different.
 

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Discussion Starter #5
Funny thing is, the previous owner told me he hated ECO and never used it! Makes me think that going back to overnight trickle charge to 100% is actually a GoodThing(tm)
 

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42k miles on public charging. Am I an expert yet?
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I can't think of any possible reason why eco mode would be bad for the battery.

Erratic charging though I would say probably is good for the battery - Lithium Ion batteries are happiest when they are being worked. The longer they spend at any one state of charge, the worse. If they're constantly going up or down, they're generally happier, with the occasional full charge to 100% to allow the Battery Management System to balance out all of the cells in the pack, and the occasional drive right to as low as you dare and charge all the way back up again to let it recalibrate it's estimation of the actual capacity.

Compared to similar cars in age and mileage, my car having been erratically charged (and to be honest erratically used in terms of miles per day) with roughly 50/50 between rapid and slow charging seems to be holding up better than others that have been used much more predictably.
 

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Discussion Starter #7
Neither could I Andy. It was something I picked up on, on Twitter then on a forum thread a few weeks ago, from someone who sounded like they had a lot of experience with EV's / problems. If I can find it I will post it.

Also, I think you are right about 'exercising' the cells and keeping them active / working.
 

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I'm hoping that eco mode use isn't a battery degradation issue as from my initial 1week+ ownership of my new 66plate 30kw I have used it almost exclusively in Eco. The only time I've not had Eco was for motorway overtaking or to pull out rapidly at a junction and I've only ever then used the Eco button to turn it off kinda like a turbo boost button - I found this worked really well on the motorway.
 

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42k miles on public charging. Am I an expert yet?
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Neither could I Andy. It was something I picked up on, on Twitter then on a forum thread a few weeks ago, from someone who sounded like they had a lot of experience with EV's / problems. If I can find it I will post it.

Also, I think you are right about 'exercising' the cells and keeping them active / working.
It seems like everyone and his dog has some theory about how to keep an EV battery from degrading - the fact of the matter is that they all slowly degrade, like all batteries, and almost none of these theories actually make a difference.

Ultimately, so far as I can tell from all of the evidence I've seen, the best way to keep an EV battery from degrading is the same as the best way as any other battery - use it! Use the car, charge it when you need to and don't worry about it :) the very worst thing you can do is not use the car...

I'm hoping that eco mode use isn't a battery degradation issue as from my initial 1week+ ownership of my new 66plate 30kw I have used it almost exclusively in Eco. The only time I've not had Eco was for motorway overtaking or to pull out rapidly at a junction and I've only ever then used the Eco button to turn it off kinda like a turbo boost button - I found this worked really well on the motorway.
My Leaf is now just under 4 years old, with 53,000 miles on the clock and quite literally every sort of journey under it's belt - three miles into town with the heating on full all the way in the snow, 400 miles in one go charging it right up to the redline in a 10-hour epic voyage of bad traffic and open roads in the height of summer, and literally everything in between. I'd estimate it's spent 51,000 of those miles in Eco mode bring driven in B not D, and it's battery seems to be degrading slower than lower mileage cars, equivalent cars with more regular journey types, and even some younger cars.

It's approximately equal between slow and rapid charging - and I'll add anything between 10% and 99% to the battery in those charges. There's no pattern whatsoever, and the car seems to like it that way :)
 
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BMW 300e 2020 model and Leaf 40kW 2019 model
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Don't worry about it, enjoy the car. Eco driving will not degrade the battery life. The charge % can change dramatically over one single trip if weather conditions, or your drive pattern change, even if you drive the exact same roads. Drive a little more aggressively and you lose 10% easily on that distance. Remember that switching off ECO mode means it will react faster to any pedal movement, accelerate faster and so on. Also, was the battery FULLY charged in both cases? I don't mean "charged until lights went out" but charged to 100%. In ECO mode the heater may also have some limitations, and if the weather was much colder then no wonder you have used a lot more, the heater takes a lot of power. Also note that driving in rain and darkness is also a serious enemy... :)

But if you worry, I'd suggest you contact Nissan and ask for their opinion and for a battery charge control. However, degradation due to ageing should not come from one day to the other, unless a large portion of the cells fail at the same time, which is not very likely, but an authorized Nissan service centre should be able to check out the state of the battery. In fact, if I'd buy a second hand EV then I'd demand such test to be performed AND documented before I'd pay for the car. Did your car come with an 8 years battery warranty or only the later models have that? Check it out.
 

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I don't think permanent 'eco' driving would harm or benefit the battery.

What it WON'T do though is to improve economy ! All it actually does is to 'stiffen' accelerator pedal response, reduce aircon system output and increase the already excessive regenerative braking - all of which can be done better by an alert driver.
 

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What it WON'T do though is to improve economy ! All it actually does is to 'stiffen' accelerator pedal response, reduce aircon system output and increase the already excessive regenerative braking - all of which can be done better by an alert driver.
Sure, an alert driver can do a lot to improve economic driving, in fact can also do better than the automatic systems, but isn't it better in the long run to have that as an automatic function? At least I think it is. Regarding AC/heater, isn't that up to the temperature I set? If the AC cools faster it means it doesn't have to run as much later on, or if the heater heats faster it means that the desired temperature is reached faster, so it can be kept at a lower power sooner. In fact, I doubt that reducing efficiency of climate control makes any difference, unless you switch it off. While on a short trip if the AC is set to 80% efficiency, it may make a difference, but on a 10+ miles trip I don't think it matters because it would just mean that it runs at 80% for a longer period then it would run on 100%. Once the desired temperature is reached it will run at the same level, since keeping the temperature requires the same power. So what's the benefit of ECO in regard of the climate control function?
 

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Unless & until someone changes the Second Law of Thermodynamics, it will never be possible to regain as much energy by 'regenerative braking' as would be needed to restore the kinetic energy before it was applied.

However, Nissan have decided that every time a driver lifts foot off the accelerator the car has to be slowed down (when most of the time Gravity & Friction would achieve all the slowing necessary.
 
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42k miles on public charging. Am I an expert yet?
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Personally, I'd like more regenerative braking.

I'm more than capable of keeping the car at a constant speed by controlling the throttle.

@EricM your point only really stacks up on a fast moving road with little to no traffic. Outside of that scenario, you're so rarely in enough control of when and how fast you must slow down that any regenerative braking you can get is good because it's better than friction brakes.

As the Leaf is ultimately not designed as a motorway mile cruncher, and most Leaf's are used primarily around town, having regenerative braking be the default is the more sensible option in the vast majority of cases.
 

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When you want more regen, there's a 'B' setting or on recent models e-Pedal gives even more than that. If you're into 'hypermiling' then Nissan's obsession with regen makes it near impossible.
 

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42k miles on public charging. Am I an expert yet?
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Yes, I know. I want more than B. The Leaf 24/30 doesn't have ePedal.

Hypermiling is not a particularly common thing - Nissan aren't in the business of building cars to specialist desires, they mass produce them. It's an electric car, regenerative braking is a fairly important part of that.

Most people don't coast, and most circumstances don't allow it.
 

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But lots of people do drive down a steep hill then up the other side. In the ICE vehicle Nissan claim to be emulating, you'd continue to accelerate without trying on the way down (and in an EV might limit that with some regen) then slow down a little on the way up before accelerating again when you've slowed enough.

That scenario also works in a VW EV; it's not possible in a Nissan
 

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42k miles on public charging. Am I an expert yet?
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But lots of people do drive down a steep hill then up the other side. In the ICE vehicle Nissan claim to be emulating, you'd continue to accelerate without trying on the way down (and in an EV might limit that with some regen) then slow down a little on the way up before accelerating again when you've slowed enough.

That scenario also works in a VW EV; it's not possible in a Nissan
It is? Just press the accelerator a little until you're power neutral. Not really very difficult, especially if you're as good at controlling the accelerator as you claim to be.
 

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42k miles on public charging. Am I an expert yet?
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But lots of people do drive down a steep hill then up the other side. In the ICE vehicle Nissan claim to be emulating, you'd continue to accelerate without trying on the way down (and in an EV might limit that with some regen) then slow down a little on the way up before accelerating again when you've slowed enough.

That scenario also works in a VW EV; it's not possible in a Nissan
It is? Just press the accelerator a little until you're power neutral. Not really very difficult, especially if you're as good at controlling the accelerator as you claim to be.
 
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