In terms of charging, I invariably charge at home with a 7.4kWh slow charger, which could help battery life, but there are so many tales of improved battery life:-
20-80%
Light right foot
Avoid constantly fast charging
Etc etc…
However some manufacturers like BYD claim battery technology is far more durable, and the media are promoting the scare stories as the latest fashion!!

 

I wonder how the technician worked out the 99.2%?? Did he do a full 100% charge, balance and full discharge at what C rate to a real 0%, including the buffer and then a 100% recharge at what temperatures etc etc??
Or did he just look at the cell voltages and battery percentage?
It is a fiendishly complex issue as other topics here have confirmed.

 

Previous Zoe - 22kWh, owned from 2.5 years old and BMS update was done back then. 44.5k miles when I moved it on at just under 9 years old, 95% SoH on the battery (drops sometimes in winter worst I've seen is 89 but it recovered, it's just a rough indicator of general "state of health" i.e. balancing etc.) 21.5kWh used when I tried to flatten it as a test a year or two ago (30mph area and I was still able to do 30mph, gave up as I didn't want a rescue situation).

I never once worried about charging to 100% and had it below 20% on several occasions - I find it silly to only ever use 60% of what you paid for just to try and save a tiny amount of the capacity for the next owner (who won't give you any extra for it) and so far this outlook hasn't bit me. I find this level of apparent degradation absolutely fine. Besides the Leaf which I wouldn't touch due to lack of battery cooling, I'm not worried about degradation in EV batteries. The car has probably got what, another 10 years before it falls to bits, something like that, unless someone does way more mileage and knackers the motor bearings before then? The battery would be the least of my worries in that time.

Current Zoe, 4 years old 38k miles, 95.7% SoH.

 

I just had my first service on my Genesis Electrified G80 after two years and about 8,900 miles.
The technician reported the battery was at 99.2%. As I understand the quickest degradation is within the first year and then the curve flattens off over subsequent years. Obviously my mileage is very low, and I try not to run the battery much

It's quite possible there is a hidden unused capacity at the top end. If it reports SOC based on the usable capacity you'll have a initial period where degradation is "free" and only after that's used up it'll start to drop. But by that time you'll like you say be in the flatter part of the curve.

 

It's quite possible there is a hidden unused capacity at the top end.

And buffers at both ends. Tests driving below 0% to get absolute max range. Some buffers are huge eg a Mercedes EQ? with 10-15kwh.

 

Traction battery state of health is a value calculated according to whatever rules the battery designer thought sensible. It's derived in the battery management system (BMS) from whatever measurements the BMS has to hand. This means a LEAF battery SOH is measuring the same thing as another LEAF, a ZOE the same scale as another ZOE, etc, but different battery models, different manufacturers, are not necessarily comparable.

My own LEAF-like van-based car reported about 95% when I bought it with 7000 miles and 6 months on the road, and is now about 90% with over 30,000 miles and about 3½ years. The useful summer range has, however, increased a bit -- A rated tyres and learning to drive an EV efficiently have more than balanced the battery deterioration. (I notice the range. With the aerodynamics of a young cathedral and a small battery, the range can most politely be described as modest.)

 

We've just come back from a long trip in our Kona which I charged to 100% before leaving and got back with 11% and 240+ miles mainly motorway although there was lots of speed restrictions and traffic.

When I worked out the total capacity based on the % and mi/kWh I got nearly 60kWh which is 7% degradation not bad after 70,000 miles and nearly 6 years, with and obd dongle though it reports 83% state of health though so 🤷‍♀️

 

As I said, I think this subject is being used in the media to attract readers/viewers! Like yourself I'm sure most owners see no adverse effects in long term use.

 

I wonder how the technician worked out the 99.2%?? Did he do a full 100% charge, balance and full discharge at what C rate to a real 0%, including the buffer and then a 100% recharge at what temperatures etc etc??
Or did he just look at the cell voltages and battery percentage?
It is a fiendishly complex issue as other topics here have confirmed.

The BMS is always tracking and monitoring all these paramaters and reports a health figure. So no, the tech did not to a charge/discharge cycle, he'll have queried the BMS with the diagnostic computer and reported what it provided.

Ofcourse the BMS could be wrong. Early LEAFs had an issue where the BMS would lose track of health over time and report the battery had less capacity than it actually held. Nissan fixed it in a software update, and then the conspiracy types started suggesting they were fiddling the figures to avoid warranty claims... The Zoe had a similar problem, also fixed in a software update.

For the vast majority of people however, it'll be accurate enough.

As I said, I think this subject is being used in the media to attract readers/viewers! Like yourself I'm sure most owners see no adverse effects in long term use.

And your right, degredation on most modern EV's is pretty low and really not a concern. Older models with small batteries were affected to a more significant level. Companies learned from those early errors and newer cars have better thermal management and better battery chemistry. Even the simple fact that the battery is (say) 60kwh instead of 20 gives a massive boost to limiting degredation, as it sees less cycles for the same mileage.

 

Interestingly the ZE50 had the same BMS issue as the original Zoe. Not a conspiracy theory, just an observation - a couple of lessons weren't learned between models, that was one of them

 

8900 miles in 2 years….. I’ve done 26k since October, and I’m not a road warrior in sales, that’s just ‘driving as required’

 

I’m currently on 38063 miles in the Tesla Model Y RWD. The car was first registered 18/6/23 so 14 months old. It is 95% charged at Superchargers or Ionity rapids and I always charge to 100% or at least when it says ‘calibrating’.

The Tessie app reports the battery health at 98.5% and a capacity of 58.6kWh. This is after 205 charge cycles with the battery estimated to be good for 1500 charge cycles or better. This plots to about 1.5kWh more than what Tessie describes as ‘Fleet Average’ so I either got a good one or the LFP batteries don’t mind being hammered.

But, if the 1500 cycles is accurate, the car will need a new out-of-warranty battery within 6 years. But at that point it will have done about 180,000 miles. I’d be OK with that I think.

 

I’m currently on 38063 miles in the Tesla Model Y RWD. The car was first registered 18/6/23 so 14 months old. It is 95% charged at Superchargers or Ionity rapids and I always charge to 100% or at least when it says ‘calibrating’.

The Tessie app reports the battery health at 98.5% and a capacity of 58.6kWh. This is after 205 charge cycles with the battery estimated to be good for 1500 charge cycles or better. This plots to about 1.5kWh more than what Tessie describes as ‘Fleet Average’ so I either got a good one or the LFP batteries don’t mind being hammered.

But, if the 1500 cycles is accurate, the car will need a new out-of-warranty battery within 6 years. But at that point it will have done about 180,000 miles. I’d be OK with that I think.

Nice to see another road warrior on here…. Keep chucking those miles on it….

 

When they say good for 1500 cycles that will be to 70 to 80% state of health the car will still be fine to drive it just won't go as far on a charge.

For some people that will make a difference but for the vast majority it won't be a real problem, not saying it won't cause then anxiety though we all know that 99.9% of drivers want the ability to do a 600 mile journey without stopping at a moments notice at 90mph of course!!

 

This was the point I was making in another thread. It’s OK if you have an 80kWh+ battery but if you have a Mazda MX-30, Honda e, Mini Electric etc. then you’re looking at a change from a car that’s just about usable to one that’s only any good for going to the shops a couple of times without a 45 minute charge for every hour of driving on the motorway. Those cars will effectively prove the FUD-merchants correct. And none of those are cheap cars.

On the flip side of that argument I’m looking at something like a 2-year old Zoe for £12K and thinking I’ll just write that off over 4 years and if it’s worth anything after that it’s a bonus. And you can get a decent extended warranty on a Zoe when you buy an approved one from a dealer, especially the ones with a 5-year factory warranty to start off with.

I‘m not in this for the environment, I’m in an EV primarily because it’s the least cost option for me. And I love the way EVs drive. Smooth and torquey. They are good. I just always have one eye on the money side of things.

 

But you two are not the norm, you're doing high miles. You're responding on a thread about someone who's done 8900 miles over 2 years.

An MX-30 with 20% battery deg is still 28kwh, which is perfectly fine for most people on their daily errands.

 

I think we’re going to have to disagree on the MX-30. According to EV database it has a real world range in the summer of 120 miles and 85 miles in the winter. That’s on 100% battery. If we’re saying that at 10 years of age it will have 80% of its battery capacity left then that car will do 65-85 miles winter to summer. And it only charges at 38kW maximum so if you did need to go any distance at all in it, you could drive for 1 hour on the motorway then charge for 50 minutes to get it back to 80% indicated (20kWh) then drive 45 minutes to charge for 50 minutes. Do you REALLY think anyone is going to buy that, even just to go to the shops, knowing you could never realistically go away in your nice car? Sorry - but people will just buy a 1.2 petrol and use it as they need to.

Then, based on the fact that many, many, ex-lease cars are clocked then how would you know that the lovely 2-year old MX-30 you’re buying for a bargain price is low mileage? And has low battery degradation? You don’t. It is the same with ICE of course, but you also have to factor in the neophobia - everything new is attractive to some people but many people fear change. And avoid new things until they’re thoroughly proven. That will come in time.

As for the mileage we’ve covered, the OP has done 4500 miles per year and got 0.5% and I’ve done 38000 miles in less time and got 1.5% degradation. Are you more or less reassured by the fact that both scenarios give low battery degradation? I’m much happier with this experience. My last EV, a Hyundai Kona, did almost 100,000 miles in just under 3 years and as far as I could tell, it had more range at the end than it did at the beginning of the lease. Again, hopefully confidence inspiring. But these are new cars, not 7-10 years old. And we just won’t know about that longevity until we get to 2029 at least.

The best way to overcome any FUD is an informed discussion.

 

440 miles today, yawn… two five minute stops for Greggs 🤣 traffic today was terrible.

370 on Tuesday…. One 5 minute Greggs stop 🤣

 

440 miles today, yawn… two five minute stops for Greggs 🤣 traffic today was terrible.

370 on Tuesday…. One 5 minute Greggs stop 🤣

The advice is to stop every 2 hours at least & take a rest or walk for safety reasons & counteract your yawn