The EV fact thread

[Will]

AFAIK Nissan ICEs have a pretty good reputation for reliability? I recently posted an Edd China video about the work required to fix a Leaf EV battery that had died after just 21k miles. Turned out to be a failed 'contactor' (essentially a relay) buried deep inside the pack, rather than anything to do with the cells. Anyway there was an update today - he'd pulled another failed one apart and found that (as expected) the contacts had welded together, causing a short. There's some discussion about whether the contactor is actually rated for the current it's potentially exposed here but something was clearly wrong as it had failed (and apparently this is relatively common). Seems crazy to have to remove and disassemble the entire battery pack to get at this cheap moving part. Skip to 4:14 if you're interested:

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I know two people who had Nissan Qashqais that needed new engines at pretty low mileages and not that old either (but out of warranty). And I don’t think I know many people with Nissans in all honesty!

 

[markjay]

...And I don’t think I know many people with Nissans in all honesty!

First line in Google....:

 

[rf065]

Nissan CVT gearboxes are apparently made of chocolate, their reputation has been on a downward spiral since teaming up with Renualt, same for Mitsubishi.

 

[BTB 500]

And, given that EVs have only been around for just under a decade or so (most marques, anyway), I think that it's a no-brainer that over time they'll be far less troublesome than ICE cars, that have been in production for over a century.

The Leaf has been in production for nearly 15 years so you'd hope it would be pretty well sorted by now.

The point of my post was general interest really - I suspect many people aren't aware that there are moving parts prone to wear and premature failure buried inside (some?) EV battery packs. I certainly wasn't.

 

[BTB 500]

And I don’t think I know many people with Nissans in all honesty!

Me neither. Years ago I had two old Micras (a Mk 1 and a Mk 2) as 'shopping cars' and those never missed a beat, but things may have gone downhill since then

A colleague bought both of them as I replaced them, for his kids as their first cars. They both managed to write them off within about a month of getting them - the son rolled his into a ditch, and the daughter pulled out in front of a car on a main road and got T boned Nobody got hurt, which was the main thing.

 

[ChipChop]

I know two people who had Nissan Qashqais that needed new engines at pretty low mileages and not that old either (but out of warranty). And I don’t think I know many people with Nissans in all honesty!

What engine was that? Presumably not the 1.5 dci diesel engine used by a multitude of manufacturers including Mercedes due to its known reliability.

 

[Dryce]

The point of my post was general interest really - I suspect many people aren't aware that there are moving parts prone to wear and premature failure buried inside (some?) EV battery packs. I certainly wasn't.

I wasn't either.

OTOH people are aware of batteries wearing out in their phones, tablets, and laptops.

Which maybe works the other way - that expectation raises an expectation that batteries in cars will wear in the same way and over the same timescales as their gadgets.

 

[rf065]

What engine was that? Presumably not the 1.5 dci diesel engine used by a multitude of manufacturers including Mercedes due to its known reliability.

1.2 petrol eats camchains apparently.

 

[poormansporsche]

What engine was that? Presumably not the 1.5 dci diesel engine used by a multitude of manufacturers including Mercedes due to its known reliability.

The 1.5 DCI, the right engine in the wrong application School run Mum car ....

It was the small capacity petrol turbos that had the issues. Apparently Nissan had more failures than Renault using the same engines due to some manufacturing process or the other.

I have the 8v 1.2 turbo engine in my Clio tip car. It's a old engine that they just slapped a turbo on. It's a great little engine and apparently they are quite indestructible. It's the later 1.3 and 1.4 designed front scratch engines that have the tendency to self destruct at low miles.

 

[markjay]

The Leaf has been in production for nearly 15 years so you'd hope it would be pretty well sorted by now.

And the Tesla has been around even longer (just).

And both are now better than they were 10 years ago.

But these are just two specific products... hardly enough of a technology to be fully developed. Compare this to dozens of marques making millions and millions of cars over 100 years...

Your comment is akin to looking at your children and your grandchildren and then declaring that your genetic line has advanced through evolution as far as it will ever get

 

[poormansporsche]

The Leaf has been in production for nearly 15 years so you'd hope it would be pretty well sorted by now.

Apparently, in the last couple of years the Leaf has actually regressed in quality (end of life cost cutting) and now less reliable than before.

BUT that's got £uck all to do with it being a EV and more to do with Nissan being skint. As the cost cutting components could just be on a ICE car as well.

 

[BTB 500]

First line in Google....:

Only just spotted that you were quoting What Car? data there. As mentioned their recent reliability survey results (for cars up to 5 years old) don't indicate that - overall - EVs are any better than ICE. They're described as 'mid-league', with electric cars (as opposed to electric SUVs) scoring lower than in the 2023 survey:

With many new models and brands entering the electric car class, this is one of the most exciting sectors of the new car market.
This year the What Car? Reliability Survey gathered data on 34 electric models. They are reported on in two separate reliability charts: one for electric SUVs and this one which contains all other pure electric models.
When it comes to reliability, electric cars are mid-league; those in this chart scored 90.7% last year and 87.7% this year. Electric SUVs are a bit more robust, with a rating of 89.3% this year.

The situation may change in years to come, but it doesn't appear that being simpler and more reliable than ICE is a valid claim for EVs right now. Unless other data is available that does support this?

 

[BTB 500]

Apparently, in the last couple of years the Leaf has actually regressed in quality (end of life cost cutting) and now less reliable than before.

BUT that's got £uck all to do with it being a EV and more to do with Nissan being skint. As the cost cutting components could just be on a ICE car as well.

But replacing the type of component where cost-cutting could be a factor (e.g. a bought in contactor/relay) on an ICE wouldn't typically require the removal and disassembly of the engine.

 

[Bellow]

From Inside Mercedes F1 book (Matt Whyman), written in 2023:

''Over the course of the previous year, the team's investment in sustainable aviation fuel reduced their overall air travel emissions by 21%. In addition, a recent conversion of their European fleet of trucks and generators to biofuel use will see emissions drop this season by 67%.''

 

[poormansporsche]

But replacing the type of component where cost-cutting could be a factor (e.g. a bought in contactor/relay) on an ICE wouldn't typically require the removal and disassembly of the engine.

Barring battery degradation, which is an accepted and measurable factor on the Leaf, Nissan actually did in a pretty good job in the first place, hence the minimal changes throughout it's lifespan, the second gen Leaf is pretty much the same car underneath as the gen 1 (You can actually see the old curvy design when you open the doors and boot )

I was more referring to "overall" reliability measurements cocked up by replacing suspension components and the like with cheese.

Although I agree with your statement on the whole, replacing timing gears with plastic and plastic control arms could be just as costly ....... Prince engine etc etc etc

 

[190]

AFAIK Nissan ICEs have a pretty good reputation for reliability? I recently posted an Edd China video about the work required to fix a Leaf EV battery that had died after j

I found the Edd China video fascinating. Switching high voltage and high current is quite demanding on the electrical contactor that in this case welded it's contacts shut. At first sight it looks like the failed contactor was underrated for the job in hand which Edd noted but it's more complex than it looks. Edd hinted at the complexity when he referred to a pre-charge resistor (he's cleverer than I thought).

First thing to recognise is that the current that a contactor can handle with the contacts closed is much greater than the current that it can open or close on. So the contactor may have been up to the job when closed but it wasn't up to the job if it was asked to close on a very high current.

Why high current because an EV doesn't demand maximum power just as you are pulling away so why did the contacts see high current and weld shut ?

The answer seems to be something to do with very large capacitors in the motor controller which look very much like a near short circuit when the power is initially applied. They can pull thousands of amps if the power is applied suddenly which is where the pre-charge resistor comes in. The idea is to pre-charge the capacitors slowly for a few seconds via the pre-charge resistor before the main contactor closes. If that doesn't happen for some reason perhaps due to the resistor failing or a minor fault in the control circuits then the contactor is doomed to weld its contacts closed. This pre-charge delay of a few seconds must all be automated and unknown to the driver but I'd be curious to hear from EV owners how quickly you can jump into an EV and set off.

The point of all this is to illustrate that EV's are perhaps not quite as simple as they seem. Controlling the application of power from the battery to the motors is really quite a complex and demanding thing to design and operate reliably. I wonder if the claim that EV's are simpler than ICE's is entirely justified.

 

[Will]

What engine was that? Presumably not the 1.5 dci diesel engine used by a multitude of manufacturers including Mercedes due to its known reliability.

I’m not up on Nissan models but they were petrol AFAIK.

One was owned by a family friend who was literally in tears at the time due to the situation - new engine from Nissan was thousands and at first Nissan didn’t want to help (known issue, but out of manufacturer’s warranty)

Other one I think they gave up on and sold the car on as it was. Now down to one car!

Maybe historically Nissan were better with cars like the Micra but certainly the Qashqai was known for ICE issues.

 

[MikeInWimbledon]

Do Audi or Porsche have a bad reputation for reliability?

Don't all German manufacturers have a poor reputation for reliability?

I haven't gone into all the detail on this, but does the Porsche have the same problem as the Audi BECAUSE it's essentially the same company / battery set up?

(As in Taycan is the Audi E-Tron GT platform with more battery and motor options)

 

[MikeInWimbledon]

AFAIK Nissan ICEs have a pretty good reputation for reliability? I recently posted an Edd China video about the work required to fix a Leaf EV battery that had died after just 21k miles. Turned out to be a failed 'contactor' (essentially a relay) buried deep inside the pack, rather than anything to do with the cells. Anyway there was an update today - he'd pulled another failed one apart and found that (as expected) the contacts had welded together, causing a short. There's some discussion about whether the contactor is actually rated for the current it's potentially exposed here but something was clearly wrong as it had failed (and apparently this is relatively common). Seems crazy to have to remove and disassemble the entire battery pack to get at this cheap moving part. Skip to 4:14 if you're interested:

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Qashqai ICE's seem pretty unreliable, coming 31st out of 46 cars in the ICE SUV class

Used Nissan Qashqai - 2014-2021 Reliability & Common Problems

What to look for when buying a Nissan Qashqai 2014 - 2021, covering common problems to check for and overall vehicle reliability.

www.whatcar.com

 

[BTB 500]

I found the Edd China video fascinating. Switching high voltage and high current is quite demanding on the electrical contactor that in this case welded it's contacts shut. At first sight it looks like the failed contactor was underrated for the job in hand which Edd noted but it's more complex than it looks. Edd hinted at the complexity when he referred to a pre-charge resistor (he's cleverer than I thought).

IIRC Edd has an engineering degree as well as lots of practical experience and generally seems to know what he's talking about.

First thing to recognise is that the current that a contactor can handle with the contacts closed is much greater than the current that it can open or close on. So the contactor may have been up to the job when closed but it wasn't up to the job if it was asked to close on a very high current.

Why high current because an EV doesn't demand maximum power just as you are pulling away so why did the contacts see high current and weld shut ?

The answer seems to be something to do with very large capacitors in the motor controller which look very much like a near short circuit when the power is initially applied. They can pull thousands of amps if the power is applied suddenly which is where the pre-charge resistor comes in. The idea is to pre-charge the capacitors slowly for a few seconds via the pre-charge resistor before the main contactor closes. If that doesn't happen for some reason perhaps due to the resistor failing or a minor fault in the control circuits then the contactor is doomed to weld its contacts closed.

I've been using this technology set (Li Ion batteries, brushless motors and electronic speed controllers) on a much smaller scale for 25 years in r/c fixed-wing aircraft and 15 years in multirotors ('drones'). Battery packs are charged externally so the 'contactor' consists of me plugging in the pack connectors (either 60A or 90A rated) This is fine on smaller stuff, but with larger (or multiple) motors the initial current surge to charge the ESC capacitors is high enough to cause arcing on the connectors, damaging the contact surfaces. The answer is then to use 'anti-spark' connectors which contain an integrated pre-charge resistor. On initial contact current only flows through the resistor, which is then bypassed as the plug is pushed fully home. Sample 'bare' connector below, showing the black resistor around the entry point - the contact ring inside this has a diameter slightly greater than the internal bore of the connector body, so the male pin doesn't touch it once pushed home:



As you said automating this connection process with much higher voltages and currents in a safe/robust/reliable way isn't trivial.

The point of all this is to illustrate that EV's are perhaps not quite as simple as they seem. Controlling the application of power from the battery to the motors is really quite a complex and demanding thing to design and operate reliably. I wonder if the claim that EV's are simpler than ICE's is entirely justified.

100%. Cell monitoring/charging/balancing/temperature control/etc. is also not as straightforward as most people seem to think, and the consequences of getting this wrong (as a number of major companies have done, leading to various recalls) can be pretty serious.