Simon's new Xantia V6 and Leaf blog

[white exec]

Does the BMU report right down to individual cells? Are they numbered?

[Mandrake]

Does the BMU report right down to individual cells? Are they numbered?

The BMU monitors and reports a number of statistics.

It reports an overall "usable" Ah capacity of the pack as a whole. This is essentially the Ah capacity of the worst cell in the pack (weakest link in the chain...) minus 1 Ah, which seems to be a buffer to allow for errors in estimation, as it's not always easy for it to measure the true capacity of the cells. This figure is ultimately what affects the range of the car. If it drops, the estimated range drops and so does the actual distance you can drive before it will refuse to go any further.

Brand new it should be about 46Ah. Mine was 39.9Ah when I bought it in Feb 2017 at 28k miles and it is now down to 32Ah at 57k miles with most of that loss being over the last year or so, as the rate of decline changed abruptly in spring of 2018.

To get a better idea of the individual cell capacities is more difficult. There is a battery calibration procedure in Diagbox, which I have run a couple of times in the past which puts the battery through a full charge cycle and estimates the capacity of all the cells. Unfortunately despite there being a place in Diagbox to read the individual capacity of each cell, it always reports zero for all cells!

If I had to speculate on why it doesn't work, I would say that this individual reporting of cell capacities after a calibration may be a new feature that was added in later ECU firmware and later versions of Diagbox - I have a version of Diagbox that supports it but I suspect the ECU firmware in the car would need updating for it to work, and it's not possible for our grey market Lexia's to do firmware updates from within Diagbox unfortunately. Quite likely the car has never received any ECU firmware updates in its life! (Lazy dealers...)

The test does return some data though, the capacity of the best cell in the pack and the worst cell, without identifying which the best and worst cells are. In other words it just tells you the spread between best and worst. The first time I ran the test in April 2018 it reported the best cell was 41Ah and the worst 38.1Ah. When I re-ran the test in May 2019 it reported 40.5Ah for the best cell and 34.8Ah for the worst cell - the spread is increasing. This is very apparent in the data I have been collecting on the Ah figures:

There's a lot of information to unpack in that graph. The blue line represents the Ah for the pack as a whole as reported by the BMS with dots being specific measurements, and this is the figure it goes by to calculate range. The initial blue line up to about 38k miles is fine, and the slope of the line is representative of "normal" cell degradation with age and use. Around 38k miles it suddenly took a turn for the worst and started dropping at around 4x the rate. The yellow line is a linear interpolation as calculated in Excel which gives a good idea of the overall downwards slope.

The green and red lines show the two data-points of best and worst cells from the battery calibration process, from this you can see the degradation of the best cells (green) follows a similar slope to the blue line before 38k miles, while the degradation of the worst cells (red) very closely tracks the linear interpolation of the actual measurements. Uncannily so. (You can also see the 1Ah buffer between the yellow and red lines)

So I know what the spread of capacity is between best and worst cells and that it is spreading further apart with time (worst cells degrading faster than the good ones) but I still don't have actual measurements of individual cell Ah capacities to know which the worst cells are. The nearest you can come to this is by using voltage estimation.

The basic technique is to first fully charge the battery and let it finish balancing the cells. The CMU's and BMU will work together to ensure that all cells reach 4.1v +/- 5mV at full charge.

You then discharge the battery as a whole to a relatively low state of charge - I find about 20% works well, and look at the voltages of the cells. Here is an example that I took just before removing the battery on the weekend:

When all cells are discharged from the same starting point the difference in voltage when they are nearly discharged is representative of their usable Ah capacity. So in this example cell 25 is worst, then 70, then 69 then 35, and those are the cells I have replaced. There are a few others which I would have liked to replace as well in hindsight, however as they're £50 a pop and this replacement is still experimental I'm only replacing four for now.

Unfortunately the voltage to state of charge relationship of Lithium Ion cells is very non-linear and "stretches" out a lot once you get below about 30%. As a result, the lower the state of charge of the pack as a whole when you take the voltage measurement the larger the differences in cell voltages will be. So it's important to choose a reference SoC to use in measurements and stick to it, but also keep in mind that while you can rank cells from worst to best using this measurement method you can't determine the actual Ah figures of the cells, apart from the worst and best cells that the battery calibration routine will report. It's just too non-linear to read too much into the specific voltage readings apart from rankings.

While there's only 70mV between best and worst cells in that table and that might seem small, it actually represents a capacity spread of more than 6Ah, or about 15% capacity.

A second test that can be done on the cells is an indirect test on the internal resistance of the cells. Cells that are damaged or have suffered abnormal deterioration such as through overheating, physical shock, or perhaps which have hidden manufacturing defects that come to light over time often show signs of increased internal resistance.

Measuring this directly is nearly impossible on the bench as the normal resistance of one of these cells is 1.5mO or about 0.0015 ohms - good luck measuring that with alligator clips and a tester of some sort... However it can be inferred by observing the decrease in voltage under heavy load or increase in voltage during rapid charging. The former is not feasible as heavy load means driving with your foot to the floor - which makes it unsafe to try to look at voltage readings, however monitoring during rapid charging is easy.

So if you start at a low SoC and start rapid charging at ~40kW it's charging the cells at over 100 amps, and this is high enough for small differences in internal resistance to show up as the cell terminal voltage rising unusually high relative to other cells. And here is an example of this:

The guilty cells highlighted in red. Moments before the rapid charge started those same cells were the lowest voltage of all the cells, and within about 30 seconds to a minute after starting to charge they're on the order of 30mV higher than other cells. This sudden change from being lower voltage than the other cells to higher voltage when charging starts is a sure sign that the cells have high internal resistance.

This 30mV spread may not seem like much but the charging system will not let any cell go above 4.105 volts during rapid charging, this means the current must be throttled back to keep the weak cell down to a safe voltage, this causes the charge rate to throttle back a lot on what it should be - the cells that are currently at 4.075 volts could handle a lot more current without going over 4.105 volts.

Notice that cells 25, 69 and 70 all show high internal resistance but 35 and some of the other so-so cells do not. So it's possible for a cell to have only low capacity but internal resistance is OK, or to have both low capacity and high internal resistance. High internal resistance is usually a sign of either a latent fault, damage or the cell is just getting close to the end of its life and chemical/physical changes are happening like the SEI layer on the electrodes starting to get excessively thick.

I hope that explains how the cells have been diagnosed and identified. In truth there are another approx 5 cells that are "so-so" - not terrible but not great either which could have done with swapping as well, maybe next summer when the days are long and warm, and assuming this current cell swap is validated.

[Mandrake]

Getting close now but still not quite finished!

On Friday night I reassembled the cover on the pack which should have been an easy job except for all the rusted bolts. The original arrangement is an M6 x 16mm bolt with a semi-washer head, with a ferrule like spacer (presumably to prevent too much torque cracking the plastic cover) into a threaded insert similar to those you would use in wood except into ABS plastic here.

I ended up replacing all 48 (!) bolts as they were badly rusted, some had snapped etc. The spacers were rusted solid to the bolts so I couldn't retrieve those but I decided they weren't really needed when I was using a much larger washer than the original washer heat bolt, and the bolts clamp down a metal frame that goes around the plastic as a load spreader anyway, so as long as I didn't over tighten them they didn't need a spacer. So that was the pack ready to go back in the car on Sunday:

On Sunday I started refitting the pack. First I had to deal with eight snapped off M6 bolts for holding the bottom plastic covers on... I tried to remove the stubs with vice grips, hacksaw the protruding ends of (not successfully due to limited access) and all sorts of different approaches, in the end I was forced to drill out and re-tap every single one of them. I discovered I had an M6 tap that I'd previously ordered to do a thread repair on one of the Xantia's and it literally saved my bacon. It took me nearly 2 hours but I was able to repair and re-tap all the mounting holes on the bodywork so that they all work perfectly now. There are still a few more that need repair but they're on the bottom of the battery pack chassis so I couldn't do those ones until the battery was in!

Mundane stuff like drilling out snapped bolts and re-tapping the holes really spoils what would otherwise be a relatively satisfying job, and makes it take twice as long as well!

Here are the promised pictures of just how hollow and empty the underneath of the car is without the battery fitted!

Towards the front:

Towards the rear:

Ready to go back in:

Half way up:

The technique I adopted was to have one jack at each end, jack one end up a few inches then spin the two support nuts for that end up by finger, then jack the other end and spin those up etc.. Took less than half an hour to actually raise it using that method. Once nearly in contact I installed the remaining bolt 4 bolts, removed the threaded rods one by one and replaced them with their own bolts and then it was in! A couple of little brackets to fit as well.

After that the high voltage and data cables were refitted, the high voltage access hatches were refitted and extractor fan reconnected and the safety link plug refitted! I'd managed to snap the locking lug on the high voltage connector for the PTC heater so I had to use a cable tie to make sure the plugs stay pulled together. Whoops.

One snag I ran into is that the air inlet vent for the battery is just in front of the passenger seat under the carpet, this allows cold air from the aircon to blow into the pack during rapid charging. This has a big rubber grommet to seal against the body and simply raising the battery up and bolting it into place does not engage this grommet properly and ends up partially crushing it and leaving a non-water proof gap, so not OK to leave it like that.

So I then had to pull up the carpet and disconnect the air vent pipe that attaches to it under the carpet so I could pull the rubber grommet through and clip it into place for a good seal on the bodywork. While it's probably covered in the workshop manual this is a step that could easily be missed in a DIY repair because you can't see that it's not sealing from underneath or from inside the car unless you lift the cabinet and remove the air vent pipe!

When I moved the air vent across on the floor it then detached itself from whatever it's attached to in the heater unit in the centre console... So before I can finish properly I'll now have to pull the passenger side front footwell carpet right out and disassemble the lower middle console to fix up the attachment of the air vent pipe as I'm not sure whether it just pushes into place or whether I've disengaged something. Annoying but not a big deal.

By that point it was getting dark again so I couldn't do anything more mechanical. However I had the traction battery all connected up and safe so I thought it was time to run some diagnostics and verify the status of the cells, BMU etc. As expected there were 18 fault codes logged in the BMU due to me reconnecting the 12v battery for the week that the traction battery was out of the car... including lost communication with the CMU's, lost communication with the "leakage" sensors, (electrical, not water, I think!) and so on. So I cleared all the faults then tried putting it on charge while monitoring cell voltages.

Success! All cell voltages were reporting in (meaning all the CMU units I removed are working properly) and the car was happy to charge. I couldn't try driving the car as it's still up on stands but I did turn on both the AC and heater to put a load on the battery for a few minutes, they both worked fine, so I left it on charge overnight.

This morning when I checked the voltages I realised I'd made a slight error which is going to cost me a couple of weeks before I can run the battery calibration. I mentioned earlier that it's important to match the state of charge/voltage of the replacement cells when fitting them in the pack. If the error is small the cell balancing system will sort it out, however if it's too large it will set a fault code and refuse to charge. I set the cells to be the same voltage at 20% SoC of around 3.8 volts however I should have realised that because the replacement cells have greater capacity they would take longer to reach 100% from the 20% starting point and sure enough, after it finished charging and all other cells were at 4.1 volts the four replacements were only at 4.05 volts.

That doesn't sound like much but it corresponds to about 5% of the cell capacity, so the new cells are only 95% charged when the others are at 100%. It's not enough to set a fault code thankfully, and the cell balancing system will eventually sort it out, but until that happens I can't meaningfully run the battery calibration which means I won't actually be able to access any of the extra range/capacity that the replacement cells might offer until that happens.

5% of 40Ah is 2Ah. The cell balancing circuit uses 41 ohm resistors for each cell that can draw a maximum of 100mA, so to equalise a 2Ah imbalance will take 20 hours of cell balancing time! As it will only balance for about 1-2 hours at the end of a charging session that means it is probably going to take 10-20 discharge/charge cycles before these replacement cells are fully in balance with the rest, or about 2 to 4 weeks of regular commuting.

The car will work fine but the range will be similar or perhaps slightly shorter than it was before until the balancing is completed at which point I'll then be able to run a full battery calibration to unlock the full usable capacity the pack now has. So all going well I'll be driving it to work from Wednesday and hopefully in a couple of weeks I can run the calibration process. The frustrating thing is until then I won't actually know what the new capacity of the battery will be!

Still to do on Tuesday (I'm taking the day off work to get it done as the Xantia is costing too much to run) is to lift the carpet and centre console to reconnect the air vent pipe and check everything is OK there, refit the passenger seat and reconnect the airbag, then underneath I still have a few bolts to drill out and holes to re-tap so that I can fit the bottom protective covers, then bring the car down off the stands and the mechanical part of the job will be done!

After that I'll keep an eye on the cell balance for the next few weeks until the cells are fully balanced and then run the full battery calibration.

[Skull]

Simon I won't pretend to know what you're on about, as even conventional electrics isn't my strong point but I'm impressed that you can sort all this out yourself.

[white exec]

Would like to thank Simon for finding time to explain the processes for identifying suspect cells. A lot of well-explained detail. Thanks for finding the time to write it up.

You do seem to have a high tolerance for rust, though, Simon. Before refitting the battery unit, I really would have treated those rusty chassis parts with some protective wax. I know you have an aversion to the stuff (it shows on the Xantia underside) but with the cars spending their time in Scotland, it seems a shame not to provide protection against all that winter weather and salt.

A good job on the electrics, though!

[NewcastleFalcon]

Pioneering electric car DIY Simon, and great that you are documenting it within the pages of the French Car Forum. I think many follow with interest including myself.

You may have seen from other posts on the forum that as of last Friday I have also joined the ranks of electric car ownwership after a bit of back of a cigarette packet calculation, and today had the joy of my first top up at the "filling station" being free, and have discovered free to use public chargers at many locations in Northumberland.

So far so good and enjoying the change.

REgards Neil

[lexi]

Top marks for ant mechanicis in the freezing cold!

[RichardW]

That is above and beyond....!

It's just as well these electric cars are totally reliable and maintenance free eh???

[Mandrake]

You do seem to have a high tolerance for rust, though, Simon. Before refitting the battery unit, I really would have treated those rusty chassis parts with some protective wax. I know you have an aversion to the stuff (it shows on the Xantia underside) but with the cars spending their time in Scotland, it seems a shame not to provide protection against all that winter weather and salt.

I think the whole of the UK has a high tolerance to rust on the underside of cars... When I first moved here from NZ I was flabbergasted at how badly all cars rust underneath here, especially on suspension and steering arms etc... back in NZ rust on suspension components was something that just didn't happen even on old cars due to no road salting and a generally warm dry climate, so unless you drove the car on the beach (which you could do in many places) and didn't wash it afterwards underbelly rust wasn't an issue, and you could do things like remove old drop-links using the interior hex to hold the joint from turning....

My first Xantia over here would have failed the warrant of fitness in NZ without doubt due to severe corrosion on the suspension components and I was extremely worried taking it in for it's first test yet it passed here with nary a comment from the MOT man. My current Xantia has very little in the way of body rust including underbelly due to good under-sealing from the factory but once again suspension components have a lot of corrosion that would fail in NZ - here it's a pass without a batted eyelid presumably due to the expectation of high levels of surface rust due to road salt.

I don't plan to keep the Ion for more than another couple of years I think - by then I can hopefully find and afford something a bit bigger with a bit more range. It's been a good foot in the door for EV ownership that has taught me a lot about what I want for my next EV but its limitations are starting to wear on us a bit now, mainly range, limited space and uncomfortable (for me at least) seats, and just a lack of refinement - when new it was basically a cheap car with a very expensive battery! It's based on the Japanese market only Mitsubishi i-car which is a Kei car format car never intended to be sold outside of Japan, and apparently not rust proofed for salted roads either... There is under seal in the wheel arches but none whatsoever on the rest of the belly of the car vs the Xantia where the full underbelly is under sealed from the factory.

Also I noticed in the photo looking towards the front the rush patch you see on the cross member on the right hand side actually had water dripping out of the bolt holes from ice melting on the window while the battery pack was out - so clearly there is a flawed drainage design that leads to water draining from the top of the car running down inside the cross members under the floor that the battery pack mounts to...

Pioneering electric car DIY Simon, and great that you are documenting it within the pages of the French Car Forum. I think many follow with interest including myself.

I'd like to say I pioneered cell replacement in the Ion but I'm standing on the shoulders of others who have already done it - the youtube video showing the cell swap was from 2015 and the threaded rods approach for lowering the pack without a 2 post hoist was devised by someone on SpeakEV and also used by a couple of other people before me. So while I'm fairly early in on it I'm by no means the first.

You may have seen from other posts on the forum that as of last Friday I have also joined the ranks of electric car ownwership after a bit of back of a cigarette packet calculation, and today had the joy of my first top up at the "filling station" being free, and have discovered free to use public chargers at many locations in Northumberland.

I haven't had a lot of time to browse the forum recently other than updating my blog so I had not noticed your thread but I am subscribed to it now.

Top marks for ant mechanicis in the freezing cold!

Don't get the idea that I enjoy working in the cold... Yesterday was long joggies, woolly jumpers, overalls, scarf, beanie and gardening gloves and I was still cold and miserable.

Once started in for a penny in for a pound though - it had to be completed as every day I drove the Xantia to work was costing us money...

That is above and beyond....!

Yeah, it's a far bigger job than I anticipated, by a factor of about 4x.... the notion of you coming over for one day and helping get it done the same day was pure fantasy in hindsight. You really dodged a bullet.

To be fair, a lot of the time it took was due to cold short days, and also the usual suspects, rusted and snapped bolts - I'd say dealing with the bolts and having to drill and tap holes etc added an extra several hours of work, easy. I reckon it might have been possible to get it done in two long summer days with two people working on it. No chance in winter.

It's just as well these electric cars are totally reliable and maintenance free eh???

Ha. Unlike many EV fans I've never been under the illusion that EV's are totally reliable or maintenance free. Maybe they are in the 0-5 year old range but once they are pushing 9 years old wear and tear and rust is going to take it's toll. They are still machines after all.

I've already done drop links, brake discs, replaced the 12v battery, etc... I think I'm a bit unlucky with traction battery in this car though. There are plenty of other Ion/C-Zero's of the same age and similar mileage whose traction battery is in much better, normal health - and I've seen the Canion screenshots to prove it.

My opinion is that the manufacturing quality control of these early (2010-2013 ish) EV cells wasn't up to snuff... so if you got a car with all good cells in it you're fine, but if you got a couple of bad cells (made on a Friday ?) then it was a ticking time bomb waiting to eventually cause trouble. Also due to the very small capacity (16kWh) the cells are being worked very hard and without active cooling while being driven.

More modern EV's with much larger batteries (30-40kWh or more) don't cycle the cells as much per mile and don't work them nearly as hard, add better quality control and active cooling and I think the traction batteries in current models being made in the last couple of years will last much MUCH longer than the early EV's to the point where the car wears out or rusts away before the battery gives up.

With what I know now I would not buy an EV made before approx 2014 and expect the battery to last a long time. Buying an EV this old today should be considered a "punt" where you may be OK but you may lose out.

[Mandrake]

As of last night the cell swap is finished and the car is back on the road, and I drove it to work today. Quite a big job in hindsight however persistence and necessity saw me over the finish line eventually, and I learnt a lot in the process. If there was a next time then I would be a lot quicker and more confident doing the job, and already have all the tools necessary like the trolley.

The plastic covers went on without too much trouble:

Then I disassembled the bottom of the centre console which turned out to be very easy and lifted the carpet, revealing the ill fitting rubber gasket that is now snugly clicked into place:

I then refitted the air vent:

And all back together - you would never know there was an air vent for the battery under the passengers feet.

Quite a clever arrangement. At a time when most EV's had no cooling for the battery at all (The Leaf still doesn't have any!) Mitsubishi were smart enough to connect the A/C system to the battery pack and blow air through it when rapid charging.

If the cells are below 20C no air is blown through as the object is to warm the battery up above 20C to speed up charging rates and improve efficiency. If the cells go above 20C the blower fan is diverted through this pipe into the battery enclosure (ambient air only) and the exhaust fan in the enclosure kicks in as well to suck air out the back. If the cells go above 30C the A/C compressor kicks in as well to cool the air blowing into the pack and it will automatically work harder the hotter the cells get above that. Above 40C the car will start to throttle the charge rate back. Ideal cell temperatures for rapid charging is between 20C - 40C.

The seat then went back in and I then went for a test drive and test rapid charge, all of which worked fine. I'm still quite miffed that I got the cell state of charge balance between old and new cells so far out, this can be seen in the following screenshot taken at 100% charge where the new cells are about 35mV below the others:

Normally balancing happens while charging between about 80% and 100% SoC and by the time the cells reach 100% they are all balanced +/- 5mV and charging stops. However it's so far out that once it reaches 100% it continues balancing for approximately 2 hours before giving up and stopping. I worked out earlier that it will take at least 20 hours of balancing over the next 20 charge cycles or so (several weeks driving for me) before it comes right, but at least it will do it automatically.

So far the BMU has not reported any difference in Ah capacity of the traction battery but I wasn't expecting it to - it's not aware that some cells were changed out from under it and the battery has not been discharged low enough yet for it to perform an opportunistic measurement, and with the cell balance a fair way out the usable capacity will be down a bit from its full potential anyway.

I don't plan to run the battery calibration routine in Diagbox until the cells finish balancing, however it will be interesting to see whether the BMU detects any change for itself and revises the Ah figure. I believe that if the battery is discharged below about 30% and then fully charged and it sees an increase in capacity across several such measurements it will revise the Ah figure upwards but only by about 1Ah per time, whereas performing the battery calibration does an explicit calibration which will jump immediately to the measured value.

Until then I'll just have to wait and wonder whether it has made enough of a difference in range for all the work to have been worthwhile...!

[Mandrake]

The long road to reach cell balance continues... Still 30mV out when fully charged, with the car continuing to perform balancing for about 3 hours after reaching full charge.

Normally I get home and plug in around 6:30 to 7:00pm and the charging is finished by 10:30pm at the latest however due to the balancing it is still going until after 1am in the morning...not charging as such as it's drawing next to no power, it's just sitting there running the small bleed resistors for all cells except the lowest ones, bleeding them very slowly at 100mA...

The Ah figure reported by the BMU has changed by itself a couple of times since the battery was reassembled - it was at 33.0Ah when I first reassembled, then it dropped to 32.9Ah the day afterwards, then this morning it has jumped up to 33.9Ah by itself.

The 0.1Ah drop was just part of the normal degradation model - in the absence of measurements it will slowly tick down the Ah figure at the expected rate of battery degradation (which seems to be 0.1Ah / 1000 miles roughly) and then over the last couple of nights charging from <30% to 100% it must have measured significantly more than the capacity it was expecting, so it has made an upwards correction of 1Ah.

From what I've seen of a couple of other people who have done battery or cell swaps in their cars without access to a diagnostic tool to do a battery calibration, the BMU will bump up the capacity 1Ah at a time every few hundred miles if it continues to measure a higher capacity than the current figure over a full charge cycle. So even without a battery calibration it will eventually increase the usable capacity, but it could take a long time compared to running an explicit calibration.

The fact that it went up at all, by itself, is a good sign that the BMU is seeing an increased capacity when it charges and is willing to increase its estimate.

[Skull]

Simon

I'm looking at an Ion ad which looks tempting 2011 Silver 26K for @ £5,700 but MOT history shows rear tyres near wear limit when at less than 15,000 miles, I remember you saying the front and rears are not interchangeable so was wondering if you've managed to wear one down and what mileage you achieved on the rears?

[Mandrake]

Front and rear are not interchangeable - the front rims and tyres are narrower and the front hubs are keyed to prevent fitting the rear wheels on the front by mistake.

I've been running Vredestein Quatrac 5's on mine for most of the time I've had it - as they're All Season's they probably wear a bit faster in Summer than a dedicated summer tyre. The front tyres have done at least 25k miles since I fitted them and still have plenty of tread in the middle however the one that was on the front left (now swapped to the right) is bald on the outer edge and probably needs replacing for the MOT in March.

I'm not sure if that's just due to speeding around roundabouts too fast in a car with skinny front tyres or whether it was a result of the bent front suspension arm I had to get replaced. Although when I hit the traffic island I definitely bent the front left arm well out (wheel position visibly back about 10mm) I only drove it for three days before getting the arm replaced, so not long enough to cause that degree of wear. I suspect the arm might have been slightly bent before that probably due to pothole impacts but not enough for me to notice it on the steering.

After the arm was replaced I swapped left and right tyres and there hasn't been any unusual outer edge wear since.

The rear tyres I couldn't honestly tell you - after fitting two new rears a few months after I got the car I've had to replace the rear left again twice for un-repairable sidewall punctures, and then had to replace the rear right again once due to extreme abnormal wear on the inside edge caused by a dented wheel rim that went unnoticed for a long time. (I replaced the wheel rim at the same time of course)

So I don't know what mileage I'm getting from the rear tyres. My gut feeling is that despite being RWD the front tyres wear faster because they're narrower and therefore tend to scrub/slip first to induce understeer if you go too fast around corners. Also, at least in the Quatrac 5, the narrower front tyres have tread that is not as deep as the larger size on the rear to begin with, especially on the shoulders.

I would say 25-30k on all the tyres is achievable if you don't drive like an idiot - the car doesn't really have the grip to go around corners too fast, trying to push it too fast around corners just understeers and wears the front tyres.

I've decided to sell mine some time in the next few months by the way. Many factors played into the decision but at the end of the day as a family we have outgrown the capability of the car - not just range, also size and comfort. It has been our daily driver for 3 years but we now need an EV that is closer in size and comfort to the Xantia with about double the usable range of the Ion, something that can do all our commuting and errand running with ease which has a lot better heater (heat pump) better ride, more space, more comfortable seats, and other creature comforts lacking on the very 2CV like Ion...

I hate to say it but after a bit of research it seems like a 30kWh Leaf is probably the best option for us at the moment in our price range! Lots available in the 3-4 year old range at reasonable prices, and I could pay for more than half of it with what I can sell the Ion for. The Leaf is not a car I aspire to, (I think it's ugly, but I can live with it...) but as a stepping stone on the way to something better still in a few years time I think it could do us well.

[NewcastleFalcon]

Get one with shiny ears Simon....they grow on you

Regards Neil

[Skull]

Thanks for the in depth answer Simon and a wear/grip overview.

Good Luck with the sale/next purchase......