BEVs

[Biospace]

The car is described as a Nissan Leaf. I don't think that it was bought from a Nissan "main dealer"?

I haven't found the post which names the 'car dealership' which the OP didn't initially reveal. Are one's legal rights somehow different if you buy a Jaguar from BMW dealership, or a Mini from a general car dealership?

[Jdsk]

There's a reminder here that you need your wits about you when purchasing an EV, even from a main dealer. https://www.speakev.com/threads/yg18xfk ... ud.173915/

The car is described as a Nissan Leaf. I don't think that it was bought from a Nissan "main dealer"?

I haven't found the post which names the 'car dealership' which the OP didn't initially reveal. Are one's legal rights somehow different if you buy a Jaguar from BMW dealership, or a Mini from a general car dealership?

No. But to me "main dealer" implies main dealer for that marque. Otherwise what does main mean?

Jonathan

[Biospace]

The story is from December 2022. The car is currently taxed and has an MoT certificate.
Jonathan

I'm not sure what relevance an MoT certificate has, or its current taxation to a car with faulty battery cells.

However, the conversation has taught me something, that faulty battery condition in a used BEV is not quite as clearly defined as a faulty engine/fuelling system in a conventional car. These two posts summarise what I learned:

My concern, moving forward into an era of electric car ownership by the masses.

Will we classify electric cars with faulty cells causing a BMS to shut down faulty goods, that is not of merchantable quality and not fit for purpose?

If we don’t then it could be a Wild West future with faulty cars being sold and even re-sold to unsuspecting ( possibly numerous ) buyers. We accept in the ICE world that a major engine fault is a serious enough issue for rejection, so should we not accept that faulty cells are of the same magnitude? In the future UK Consumer law might need to be updated in order to set out the legal definition of a faulty electric car.

Just thinking out loud...

followed by

The 'Wild West' route I think.

It's something we discussed here and I was commenting on 'several' years ago, that there is no fit and proper way to determine battery health until one has driven a BEV substantially, at which time in the context of 'ICE' cars, it'd have been considered 'accepted'.

Which does somewhat correspond with my gut feeling - that I wouldn't buy a used BEV without doing a significant amount of research first on potential weaker elements of battery design for given models (the piece reveals 40kWh Leafs are noticed to be more prone to battery warping than others due to the cooling capacity, for example), checking battery condition extremely carefully both via a computer as well as a long drive including at motorway speeds.

[Nearholmer]

that there is no fit and proper way to determine battery health until one has driven a BEV substantially,

There are fit and proper ways to do that for any battery, but the kit to do it isn’t something any of us would have at home. A well-equipped workshop that looks after EVs should have the kit, and a well designed EV will be provided with a system to do it at a basic level on-board.

But, for an owner or potential buyer to get an understanding without employing an independent specialist s, I guess, nigh-on impossible. Independent test houses are just now beginning to offer independent test and certification on a basis that should allow used car dealers to provides meaningful statement of battery health when offering s car for sale, a sort of “battery MOT certificate”.

[Carlton green]

1.
BATTERY QUALITY GUARANTEE
i. 24 KWH LEAF : If the battery capacity level gauge of your 24 kWh Nissan Electric Vehicle falls below 9 bars (out of 12 bars) within 60,000 miles or the first 5 years of the vehicle’s life (whichever comes first), Nissan will repair or replace the damaged battery components free of charge to bring the capacity up to 9 bars.
ii. 30 KWH LEAF : If the battery capacity level gauge of your 30 kWh Nissan Electric Vehicle falls below 9 bars (out of 12 bars) within 100,000 miles or the first 8 years of the vehicle’s life (whichever comes first), Nissan will repair or replace the damaged battery components free of charge to bring the capacity up to 9 bars.
iii. 40 KWH LEAF : If the battery capacity level gauge of your 40 kWh Nissan Electric Vehicle falls below 9 bars (out of 12 bars) within 100,000 miles or the first 8 years of the vehicle’s life (whichever comes first), Nissan will repair or replace the damaged battery components free of charge to bring the capacity up to 9 bars.

Are those guarantees carried forward with the car to multiple owners or only apply to the original owner?

Most are transferrable:

https://www.carbuyer.co.uk/car-technolo ... eries-last

I think that claiming EV makers expect capacity to drop by 30% over 8 years is complete hogwash though - that's their warranty, if they expected that to be the case then they're planning to replace half of all batteries under warranty - and that sounds rather unlikely.

A LiIon battery will do 2-3k cycles, a LiFePo up to 10k, Sodium batteries 5k+
A cycle on a BEV is generally gentle (because the BMS doesn't let you charge to 100% or discharge fully either). Tesla actually specifically enable an absolutely full 100% charge in areas with natural disasters incoming (like hurricanes) - I'd quite like the ability to select 100% charge a few times a year, get a little bit further on that first battery of long journeys.

From Nissans’s warranty it is clear to me that they both anticipate that their batteries will degrade and that they expect that only a small percentage will degrade by over 1/4, 25%, or 9 bars remaining out of 12, but let’s be clear that degradation of 1/4, 25%, or 9 bars remaining out of 12 is considered OK by them .

Rather than say something is hogwash - and for other readers the 30% figure wasn’t, IIRC, mine - why not say what the typical degradation rates that people are experiencing are, or can expect, and cite references for others to check. You’re a clever chap and obviously very interested in EV’s so why not share knowledge, please, that way we all gain. There’s so much to understand … and as is typical of expensive purchases a lot of smoke and mirrors too.

[Nearholmer]

From Nissans’s warranty it is clear to me that they both anticipate that their batteries will degrade and that they expect that only a small percentage will degrade by over 1/4, 25%, or 9 bars remaining out of 12, but let’s be clear that degradation of 1/4, 25%, or 9 bars remaining out of 12 is considered OK by them

Only a loony or a charlatan would claim that s battery doesn’t lose capacity over time and charge-discharge cycles, and only someone who hasn’t thought very hard about it would expect a battery not to loose capacity. It’s inherent in the physics/chemistry, just as it’s inherent in the physics/chemistry of tyres and a host of other things to deteriorate.

Put bluntly: you just have to get used to the idea.

This is a sober summary from an organisation with nothing to gain by fibbing https://www.rac.co.uk/drive/electric-ca ... ries-last/

If you want to go a bit deeper: https://batteryuniversity.com/article/b ... vehicle-ev

[[XAP]Bob]

From Nissans’s warranty it is clear to me that they both anticipate that their batteries will degrade and that they expect that only a small percentage will degrade by over 1/4, 25%, or 9 bars remaining out of 12, but let’s be clear that degradation of 1/4, 25%, or 9 bars remaining out of 12 is considered OK by them .

No it's considered the threshold at which they'll replace the battery

Rather than say something is hogwash - and for other readers the 30% figure wasn’t, IIRC, mine - why not say what the typical degradation rates that people are experiencing are, or can expect, and cite references for others to check. You’re a clever chap and obviously very interested in EV’s so why not share knowledge, please, that way we all gain. There’s so much to understand … and as is typical of expensive purchases a lot of smoke and mirrors too.

The 30% figure was from the quoted article, and is a deliberate misrepresentation.
No-one looks at a car with a three year warranty and says that the car is only expected to last three years, but the moment it's a battery warranty then suddenly that's what it means.


If you want a number then 2% a year (or about 20ishk miles, depending on how you want to measure it) is probably the least bad guess I can get you. Depends on how the battery is treated, the climate you're in etc...
https://www.geotab.com/uk/blog/ev-battery-health/
https://www.nimblefins.co.uk/study-real ... erioration

Tesla batteries are expected to last 300-500k miles before they're degraded enough to "need" replacing.

Of course those are all looking at older batteries, by definition the longevity data we have is on old tech. There have been improvements in manufacture that should boost life, and there is the minor point that since 2010 batteries have dropped in price by 80%...

[Biospace]

I think what's being missed is that we all know batteries lose some capacity and eventually fail - more time related than use related as one of the contributors to that SpeakEV thread has noticed, anecdotally - but quite different is the matter of a prematurely failing battery, where one or more cells are well down on capacity compared with others, but where the SoC meter or whatever on the dashboard may still say 90% or some other hopeful number.

It seems that without a testing drive over a good few miles by someone who knows what to look for or a full diagnosis report on the battery, such a battery can be passed off as in good order at sale time, as appears to have happened by the dealership/garage as related in the SpeakEV thread.

Perhaps XAP{Bob} can fill us all in with his in-depth electrical knowledge as to what is most likely to be the cause of such failures. Are some cells less good than others from new, or is it a stress/heat matter, perhaps combined with poor/marginal cooling as someone mentioned might be the case with the 40KWh Leaf? Or something quite different?

It's one thing buying a MacBook with a dodgy battery as they're inexpensive and fairly simple to replace, but a failing BEV battery is likely a very expensive repair at present. I'm imagining more battery replacement specialists, general know-how and availability will all drive down prices, at some point.

[Carlton green]

Thank you Bob, some useful points and counter arguments. I found this reference helpful and it supports a much earlier comment of mine of 10% loss over five years: https://www.geotab.com/uk/blog/ev-battery-health/
It is a bit unfortunate though that the article is three years out of date (Published on December 13, 2019 ) .

On the down side the range of loss is much higher for a Leaf and they are what is most commonly available and affordable. Tesla did well but at the price they are they really ought to be somewhat good. More data needed on various Leaf models - though mostly it’s of academic interest - and that does appear available on that site but it doesn’t have data for different battery sizes.

[Nearholmer]

Are some cells less good than others from new, or is it a stress/heat matter, perhaps combined with poor/marginal cooling as someone mentioned might be the case with the 40KWh Leaf? Or something quite different?

My experience of industrial batteries is that, provided the whole installation has been managed correctly, the early death of odd cells is a function of what might be called “manufacturing defects”, something about those particular cells being outside of specification, and escaping detection during inspection and testing. Suppliers were usually keen to get such cells back to the factory for a post-mortem examination, to see if that revealed anything that might allow them to improve their processes.

In an environment where forced cooling is used, those cells which happen to draw the short straw in terms of their place in the cooling circuit will be at higher stress, but unless the cooling system itself is faulty they should survive the design lifetime.

Of course, as the whole assembly approaches the end of life phase, some cells will be first to die, but if they have survived the intended design life, they can’t really be said to have failed.

I think the Leaf vs Tesla difference is attributed to the difference between air and liquid cooling. Again drawing on industrial experience, liquid cooling is often avoided if practicable because it adds first cost, complexity, and its own failure modes …. My guess is that Tesla chose to accept all those issues in order to be able to get more capacity in the same space, and possibly to extend the life. I wouldn’t read one option as “inherently good” and the other “inherently bad”, just different choices, much as air and liquid cooling were chosen by different IC engine makers historically.

[Biospace]

Tesla did well but at the price they are they really ought to be somewhat good.

Tesla motor and battery technology leads the field from what I read and in conversation, many suggest in other respects they've some way to go, yet.

I'm reminded of the old saying that you bought a Ferrari engine, and the rest came for free. I'm not suggesting things are like that with Tesla and hesitated to even write the two names in the same paragraph, but there's no doubt their electrical tech is very good.

[[XAP]Bob]

Basically any vehicle that has some thermal battery management (which the tesla has, and the leaf doesn't) will give better results immediately and in the long term.

You can do management with air or liquid, though liquid does allow for more flexibility in terms of things like using a heat pump to use the heat elsewhere (which can increase the efficiency of cabin heating further) or using the heat pump to heat the battery (more efficient than resistive heating).
Things like conditioning batteries on approach to DC chargers helps reduce the damage that DC chargers inevitably do (or allow for even faster charging).

[Carlton green]

Basically any vehicle that has some thermal battery management (which the tesla has, and the leaf doesn't) will give better results immediately and in the long term.

You can do management with air or liquid, though liquid does allow for more flexibility in terms of things like using a heat pump to use the heat elsewhere (which can increase the efficiency of cabin heating further) or using the heat pump to heat the battery (more efficient than resistive heating).
Things like conditioning batteries on approach to DC chargers helps reduce the damage that DC chargers inevitably do (or allow for even faster charging).

Tesla have different - arguably better - battery chemistry too. So Tesla have batteries that have better thermal control and better chemistry … but at a premium price.

Of course in practice there’s nothing particularly wrong with the (relatively) simpler approach that Nissan have taken; and it takes a lot of clever thought and expertise to refine designs such that they end up being simple, (relatively) cheap and effective. If a problem has several solutions then whilst one might be the best the others can still be quite practical and acceptable.

[[XAP]Bob]

And it's fairly easy to replace cells in a leaf battery as well, so they've got that going for them.

[Carlton green]

And it's fairly easy to replace cells in a leaf battery as well, so they've got that going for them.

I’ve heard of folk replacing whole Leaf batteries too but in practice my search for folk who do that in the UK hasn’t turned up any results. One expert company that used to do it - funnily enough the same one as in the video above - has stopped: https://www.cleevelyev.co.uk/battery-upgrades/
That’s a pity really because ready supply of replacement and capacity upgraded batteries would allow otherwise good cars to remain in use rather than end up as scrap - amongst other things that’s a waste of the embedded CO2 from their original manufacture.

The video did highlight an extreme use issue with Leaf battery thermal control and I anticipate that the Taxi was charged a lot and not necessarily at low rate either. I’ve read elsewhere that the end position cell(s) are cooled least and so more subject to this failure, but really don’t currently know enough to more constructively comment on that.

120k miles, as in the video for the Taxi, sounds a lot but these days I’d expect that out of any car. Forty years ago my family parted with a 2CV , it was running well and had 150k miles on the clock.