LEAF Battery capacity loss and battery life

conventional wisdom is that it's high heat in general, so leaving the car in the sun in a hot climate, like Phoenix. Or Florida, I'm sure 30C and sunny gets a car pretty hot.

also, battery degradation can happen in cold weather if the battery is charged to 100% and then the temperature drops a lot, meaning the battery's capacity goes down so it has extra lithium ions stuck to the cathode. I'm not sure what happens to them, but it might be the situation where they start to form dendrites into the electrolyte. Consequently, I try to keep my Leaf below 80% during the winter.

 

What I wrote could be wrong, but it's what I read on the Leaf forums. It kind of makes sense, that if you have 28kwh worth of ions on the cathodes, and then you cool the battery so its max capacity is 26kwh, that something has to happen with those extra 2kwh worth of Li ions.

Also, in cold temperatures, I believe that Tesla's battery management system prevents charging over 80%, so they've built that idea into the vehicle.

 

I'm sure I've read that online, from an apparently authoritative source, altho my Google-fu fails to find any such reference at the moment. I haven't seen much if any that this is a cause of premature aging in production BEVs, but that doesn't mean it doesn't happen. However, some people have reported premature battery aging in Leafs, even in areas where it gets very cold in the winter. It had not occurred to me that freezing almost fully charged batteries might be the cause of that, but I suppose it's possible.

One reason that it may happen less frequently than theory suggests is that all EV makers reserve a certain amount of capacity, below the battery cell manufacturer's rating for fully charged. So what we should worry about, with overcharging in very cold weather, is exceeding the battery pack's actual capacity (for that temperature). Fortunately, we can only charge to the usable capacity, which will always be less than the full capacity.

 

You might be right, the manufacturers might be counting on that buffer to prevent damage from a 'full' battery cooling off and shrinking. I suspect that the Leaf's 2kwh buffer might sometimes not be quite enough for and extreme drop. if say the car is charged to 100% at 0C and then the temperature drops to -20C overnight, which can happen here in Canada. The Ioniq has a 3kwh buffer so maybe they decided not to push it quite as far as Nissan.

 

Don't worry. UK climate is not a problem for the LEAF. Look for London at the battery aging model and you'll see it's one of the best place to operate a LEAF will little capacity loss over time.
http://www.electricvehiclewiki.com/Battery_Capacity_Loss#Battery_Aging_Model

 

As my wife and I continue our quest to find a replacement for my 2013 Leaf, this battery issue has me more than a little concerned. If the 30 kWh packs go bad quicker than the 24s, then I would guess that 40s, built on the same tech. would be even worse, or at least no better than the 30s.

My 2013 with it's piddling 24 kWh pack is still showing all bars, but it's been coddled. My car has only 25,000 miles, it's never been used or stored in a hot climate, and it's been recharged exclusively via a 110v socket in my garage. I also hum lullabies to it while driving, but there's no peer-reviewed science to say that's a contributing factor.

I suspect this is part of the reason why Leaf leases run over $5,000/year for the SV trim level. (Nissan's site currently lists an SV lease at $3,979 + $355/month.)

I find it astonishing how badly Nissan has screwed up. They are going to be in a world of hurt when thousands of batteries start failing (even by their very loose definition) and they have to pay for replacements.

Which reminds me -- how the heck do they replace a Leaf battery? Surely that's not something a dealer can do; I can't believ they have the specialized equipment and the training. Do they transport the car to a regional service center and do it there?

 

I also have 2013 Leaf (one bar lost so far, ~55,000 miles, no lullabies while driving). My understanding is the battery cage pretty much unplugs and drops down as one piece, so replacing the battery isn't too hard. I am not 100% about this, though. I'm sure the info is out there as I'm also sure you are not the first person to wonder about this.

 

My point about the battery replacement had to do with the physical challenges of such a big, heavy piece being lifted up into the bottom of a car. I remember seeing video of a Leaf battery being bolted into a car on the assembly line, and it required, at a minimum, a very special lift that could precisely position a coffee table-size battery that weighs hundreds of pounds.

Put another way, after enduring "service" from many dealerships over decades of car ownership, I'm not exactly awash in faith in their service departments.

 

If you saw the Bolt battery removal video, clearly there is a lift that is available for purchase. If the dealership has the lift, then it shouldn't be that big of a job removing and replacing the battery.

https://www.bing.com/videos/search?q=bolt+battery+removal+video&view=detail&mid=D421B2840ADAF38C8F76D421B2840ADAF38C8F76&FORM=VIRE

 

My dealer (AutoFair Nissan, Chelmsford, MA) has replaced a battery. They have two licensed Leaf techs and they're the only guys allowed to touch the car - even for tire rotations, to my chagrin when I just want to get in and out! I talked to one of the front desk guys rather than a Leaf tech about the replacement, and he said they have big yellow safety tape all around the area and no one is allowed inside. He also told me that techs have died swapping batteries, which I hadn't heard before and I deem apocryphal but if it keeps the non-Leaf techs from doing stupid stuff it seems like a good rumor to spread ;-)

Here's a pic of Tom replacing my brake pads/rotors/lines/fluid. You can see they have nice lifts.

 

*sigh* So the fact that I charge to 100% from October-April might be a problem? Ouch. I'll have to play with the charging timer. It's set to finish charging to 100% at 7am and start pre-heating the cabin at 7:10 am. Thanks to the conservative/paranoid charge estimate which overestimates time to charge, the car sends me an e-mail at 4:30 am telling me that charging is complete. That gives it 3 hours every morning for the battery to cool. In early January when it was -8 F I bet it cooled pretty rapidly!

For what it's worth my car's capacity loss has tracked the Battery Aging Model from Electric Vehicle Wiki pretty spot-on for Boston, MA. I have a 2012 Nissan Leaf SL manufactured in November 2011 in Japan.

1. First Bar lost: 39,879 miles, July 2015.
2. Second: 50,225 miles, August 2016.
3. Third: 62,960 miles, November 2017.

Looks like I'll make it to January 2019 and 74,000 miles before I lose that 4th bar.

No lullabies here, and primarily 3.6 kWh charging at home on the Clipper Creek LCS-20.

 

It is astonishing how badly Nissan screwed up, if that study is correct. The 40kwh battery might behave differently, because it has to be a different chemistry than the 30kwh since the modules are the exact same size.

 

On one hand, you might be ok, if indeed the issue is that there's a temperature drop after charging to 100%. Since the battery has a bit of a buffer, it might need to be a bigger temp drop than the buffer can handle for it to be damaging. Since you basically start driving it right away, and temperatures usually go up in the morning, you're probably ok. ???

On the other hand, we're supposed to keep the batteries between 20-80% for best longevity, so daily charging to 100% might be a factor for you. Who knows though, mine says SOH is 86%, and it has less than 5000km on it, and I've rarely charged to 100%. Then again, I've never calibrated the BMS by running it down to turtle mode and then charging to 100%, so I'll have to do that first and see what happens to the SOH.

 

One more update on our saga...

We finally landed on a decision (which won't be popular here; save your hand wringing for someone who didn't research this purchase to death, please). We bought a 2018 Leaf SV, which we will charge overnight at 110v, as we did our 2013 Leaf for 5 years with no bars lost.

Why a Leaf and not the only other real alternative for a 100% EV, the Bolt? Even with a dealer discounting three 2017 Bolts still on their lot, it was nearly $4,000 more than we paid. (Through my wife's employer we got a sizable discount, plus there was a $1k "loyalty" promotion and some other financial incentives, including a decent enough trade-in on my 2013 Leaf.) Also, we test drove the Bolt a second time, and to be blunt, it just feels too weird for us. As I said elsewhere above, I drove a Scion xA for 7 years, so the size of the Bolt didn't bother me. And I like the exterior. But the overall feel of the car's interior is (to me) noticeably cheap. Plus all that very light gray/white on the dash -- and that steering wheel -- would have made me cringe every time I drove it.

Why buy instead of lease? The current lease deals on Leafs are nothing to write home about, and it would lock me in to a 36-month term. By buying, I can bail out at any time I'm willing to take the depreciation hit or simply keep driving it. We plan to have the car a bare minimum of 3 years, highly likely 5 or 6.

To be blunt, I was very angry at the whole car industry by the time we took delivery of my new Leaf. The foot draggers, GM being GM with every little detail of the Bolt, Nissan forcing customers to choose between high lease rates and playing battery roulette -- Bah!!! We struggled for weeks trying to find a good solution and fell well short of what we'd hoped for. In the end, we bought because it made sense as a way to bridge between today and EV Nirvana in a few years, when there should be several very strong competitors on the market. (My wife and I decided to name my car Kobi, after the unsolvable Kobiyashi Maru training exercise from Star Trek. Unlike Kirk, I was unable to rig the simulation.)

The local Nissan dealers are not exactly covering themselves in glory re:EVs, either. Two refuse to carry Leafs, and the other two have no one in sales who knows anything about them. How these dimwits manage to sell any EVs is a minor miracle.

My guess is that Kobi will work out well for us. The purchase made financial sense thanks to our circumstances, and it gives us an EV to make our frequent trips that were just barely beyond the range of my 2013 Leaf, allowing us to leave my wife's Rogue home.

More than anything, I'm delighted that I'm out of car shopping mode for at least 3 years.

 

Congrats! Hopefully the battery degradation curve of the 30kwh doesn't hit you, although since it's a different chemistry, it won't necessarily have the same issues. Let us know how it goes.