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40kW Leaf Tekna & 22kW Zoë Q210 dynamique intens
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Discussion Starter · #1 ·
Hi all, I have now got 2 EV’s and have been a member of this forum since 2019 (I know I’m still a noob!)

Having looked at multiple manufacturers battery claims / warranties there seems to be a picture forming from the manufacturers.

They claim that the batteries are warrantied for a loss of capacity of (x)% generally for 8 years or (x) miles.

When this bites them and they are headed for a situation where they are going to have to replace everybody’s batteries under warranty they release a magical software update that basically says:

“Sorry guys EV’s and batteries were new we didn’t fully understand how to measure their longevity our first software was flawed, but here is some new software that allows us to wriggle out of the promises we made, it sucks to be you right now”

They get away with it because this can’t really be independently verified!

So... here’s the thing, I have an electrical enough background to be thinking that it’s not really rocket science for a clever enough person to add a DC current meter to a car that’s maybe 6 years old fully charge it then drive it to 0% and actually measure how many KWh of energy that battery has actually been capable of supplying and actually quantifying that there has been a real world x% loss of capacity from that battery, regardless of what the manufacturers software is claiming.

The energy an EV battery delivers from 100% SOC - 0% is measurable and it’s simple maths to determine what fraction that is of the new usable capacity, here lies the next dieselgate?

What are your thoughts?

There are a lot of engineers and electricians on here how doable is this?
 

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2018 Nissan Leaf 40kWh Tekna - love it
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It's certainly a reasonable suggestion. I would think, when the car is new, charge to 100% and drive a planned route at 60 mph, as closely as possible, on a day when it's 21 degC and log miles travelled every 10%. Then repeat when the car is 5 yrs old. A problem would be that the battery warranty is based on "loss of charging bars" [as in the Leaf] so the manufacturer would just refer to ther own contractual measure of battery capacity. Still, something to think about.
 

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That is a really interesting issue. Imo when you buy an ev today, you’re not buying new technology. Batteries in ev do exist for quite a while, but yes, manufacturers will surely try to bailout of battery warranty.


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fully charge it then drive it to 0% and actually measure how many KWh of energy that battery has actually been capable of supplying
Except that the kWh you get back will depend on the rate of discharge. If you drive it at 30mph the whole test you'll get a lot more back than if you thrash it down the motorway at 80mph.

So when you present your 'evidence' to the manufacturer they'll just say you did the latter.
 

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40kW Leaf Tekna & 22kW Zoë Q210 dynamique intens
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Discussion Starter · #5 ·
Except that the kWh you get back will depend on the rate of discharge. If you drive it at 30mph the whole test you'll get a lot more back than if you thrash it down the motorway at 80mph.

So when you present your 'evidence' to the manufacturer they'll just say you did the latter.
So does that mean that if you took a 30kW (usable) lithium battery out of a car when it was fully charged and used it to power a 10kW heater for 3 hours that it would discharge it more than powering a 3kW heater for 10 hours?

Both of these theoretical scenarios are asking the battery to deliver 30kW of energy, would the higher rate of discharge reduce the power yield?
 

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So does that mean that if you took a 30kW (usable) lithium battery out of a car when it was fully charged and used it to power a 10kW heater for 3 hours that it would discharge it more than powering a 3kW heater for 10 hours?
Yes.
It's to do with the C rating

But in very simple terms batteries have internal resistance.
Pass current through resistance it gets hot, which is why batteries get warm in use
That heat is kWh used within the battery.
More current = hotter. So the faster you discharge it the more of the battery's stored energy is used in cooking itself and thus doesn't appear as useful power beyond the terminals.
 

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Discussion Starter · #7 ·
Yes.
It's to do with the C rating

But in very simple terms batteries have internal resistance.
Pass current through resistance it gets hot, which is why batteries get warm in use
That heat is kWh used within the battery.
More current = hotter. So the faster you discharge it the more of the battery's stored energy is used in cooking itself and thus doesn't appear as useful power beyond the terminals.
So the answer really would be to bench test the battery in a way that factored in the discharge rate and measured the temperature increase and calculated the total power yield as the terminals and the energy expended raising the temperature of the thermal mass of the battery by the given amount observed.

This sounds like a standardised test is required to stand any chance of rationalising manufactures claims when it comes to warrantied capacities of batteries.

Maybe we already have one the NEDC test could be repeated on a used vehicle to determine how it’s performance has dropped with use.

I guess this requires the original test to have logged the battery SOC at the beginning / end to be able to quantify how much battery degradation has occurred?
 

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Leaf 30kWh, HS PHEV
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Capacity as advertised is at a certain C rating. If you find the underlying cell used by the pack, datasheet will supply the required data.

This issue is that numbers of bars is subjective and due to lack of data, they can do whatever they please


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So the answer really would be to bench test the battery in a way that factored in the discharge rate and measured the temperature increase and calculated the total power yield as the terminals and the energy expended raising the temperature of the thermal mass of the battery by the given amount observed.

This sounds like a standardised test is required to stand any chance of rationalising manufactures claims when it comes to warrantied capacities of batteries.

Maybe we already have one the NEDC test could be repeated on a used vehicle to determine how it’s performance has dropped with use.

I guess this requires the original test to have logged the battery SOC at the beginning / end to be able to quantify how much battery degradation has occurred?
All of the above, pretty much. :)

Basically if you are in dispute over a small difference you have little chance of winning, in court for example.
 

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GOLF GTE PHEV
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Hi all, I have now got 2 EV’s and have been a member of this forum since 2019 (I know I’m still a noob!)

Having looked at multiple manufacturers battery claims / warranties there seems to be a picture forming from the manufacturers.

They claim that the batteries are warrantied for a loss of capacity of (x)% generally for 8 years or (x) miles.

When this bites them and they are headed for a situation where they are going to have to replace everybody’s batteries under warranty they release a magical software update that basically says:

“Sorry guys EV’s and batteries were new we didn’t fully understand how to measure their longevity our first software was flawed, but here is some new software that allows us to wriggle out of the promises we made, it sucks to be you right now”

They get away with it because this can’t really be independently verified!

So... here’s the thing, I have an electrical enough background to be thinking that it’s not really rocket science for a clever enough person to add a DC current meter to a car that’s maybe 6 years old fully charge it then drive it to 0% and actually measure how many KWh of energy that battery has actually been capable of supplying and actually quantifying that there has been a real world x% loss of capacity from that battery, regardless of what the manufacturers software is claiming.

The energy an EV battery delivers from 100% SOC - 0% is measurable and it’s simple maths to determine what fraction that is of the new usable capacity, here lies the next dieselgate?

What are your thoughts?

There are a lot of engineers and electricians on here how doable is this?
I agree that this needs investigating as does the real world range.

Honda did exactly this to stop warranty claims on their Insight & CRZ hybrids - reprogrammed the dash display to read upto 100% of the remaining capacity, when it used to (and should) display the actual remaining capacity which drops over the years.

It's only a matter of time until EVgate and TV ads by lawyers encouraging claims against the EV manufacturers.
 

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GOLF GTE PHEV
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When my Leaf was serviced last month, the garage presented me with a report on battery condition and also told me I had treated it well and not done too many quick charges etc.
This suggests another excuse is available to the manufacturers for rapid battery degradation - "you have abused the battery by driving to hard and doing too many quick charges so you're to blame".
 

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When my Leaf was serviced last month, the garage presented me with a report on battery condition and also told me I had treated it well and not done too many quick charges etc.
This suggests another excuse is available to the manufacturers for rapid battery degradation - "you have abused the battery by driving to hard and doing too many quick charges so you're to blame".
Unless we can push for 12 bars to 100% and each bar being 8.33 logically as being true it’s unlikely we’d get anywhere


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Unless we can push for 12 bars to 100% and each bar being 8.33 logically as being true it’s unlikely we’d get anywhere


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No, we won't. No government can take on a motor industry giant and big employer, and make them provide the accurate battery state. They may build in more reserve / buffer so the 62Kw Leaf could have 58kw advertised capacity meaning there's 4kw to be reallocated when the 58kw drops to 54 and pro rata.
 

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Dream on I would say. The batteries are warrantied for a certain life. This will be honoured obviously . After that they don't have any responsibility do they from a legal point of view

This is absolutely nothing like dieselgate in any shape or form. Ie lying about efficiency and cheating emmisions regulations via cheat devices.

Really they have been upfront in terms of what the minimum battery life will be after a certain period of time.

The batteries have a certain warrantied life after that that are under no legal obligation. They haven't lied and it's a consumable item at the end of the day.
 

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You've missed the point. It's about whether manufacturers are issuing BMS updates to hide the real state of the battery as Honda did, and maybe Nissan with Leaf ZE0 update which magically boosts the SOH (more bars on the gauge so no warranty claim, but range is the same)
 

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You've missed the point. It's about whether manufacturers are issuing BMS updates to hide the real state of the battery as Honda did, and maybe Nissan with Leaf ZE0 update which magically boosts the SOH (more bars on the gauge so no warranty claim, but range is the same)
Similar with BMW i3’s in the USA, cars going into the dealer with SOH such that they’d be able to claim on the battery warranty and coming out with a mysteriously higher SOH after a “software update”.

Perhaps they re-allocate some of the top/bottom buffers to usable battery as mentioned above, which would of course exacerbate the problem, but SOH might be high enough until the warranty has expired.
 

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The perverse issue here is that it makes even more sense to lease or PCP. Then it's someone else's problem. Therefore, what is needed is a recognised and accepted way of testing battery capacity to protect second hand EV purchasers.
 

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I’d have thought a reasonably strong argument would be range lost. Messing about with software soh metering isn’t going to change how far the car can travel before it runs out of electrons. If the car spec said 200 miles and it could cover 200 miles but some years later will only cover 100, it doesn’t matter what the display says.
 

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I’d have thought a reasonably strong argument would be range lost. Messing about with software soh metering isn’t going to change how far the car can travel before it runs out of electrons. If the car spec said 200 miles and it could cover 200 miles but some years later will only cover 100, it doesn’t matter what the display says.
I agree but range depends on speed and temperature and many other factors that would need to be standardised.
 

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Discussion Starter · #20 ·
This is absolutely nothing like dieselgate in any shape or form. Ie lying about efficiency and cheating emmisions regulations via cheat devices.
This is exactly like dieselgate, I purchased a 22kW 2014 Zoe 5 weeks ago that with its current software is reporting a battery SOH of 71% (according to CanZE which reads these values directly from the CanBus) my battery is still leased and is warrantied @ 75% if I challenge them and request they “repair“ my battery they will not touch it, instead they will apply a “software update” that will fudge the figures and report that the battery is now at 97% (on a 5 year old car)

I knew exactly what I was getting myself into when I purchased this vehicle and it was cheap, also with its current battery does everything my wife needs but does that mean I shouldn’t hold Renault’s feet to the fire?

No absolutely not, if you sell a product and make claims about its performance you should be held accountable if it falls short, pure and simple.

Similar with BMW i3’s in the USA, cars going into the dealer with SOH such that they’d be able to claim on the battery warranty and coming out with a mysteriously higher SOH after a “software update”.
The difference between the UK and the USA is that people club together and launch class actions against big organisations, so when Audi discovered that a certain generation of the piston rings were failing on the A5 and it started to drink huge amounts of oilif you had purchased one in the US Audi would rebuild the engine FOC.

The very same customers in the UK that had purchased the very same cars (minus all the American chrome bits! 😉) were quoted........ circa £6000 to fix the problem!

Go figure!

We need to grow teeth like sabre tooth tigers here, we would be treated a lot better!

PHEW! Rant over...... 😊
 
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