BEVs deals and information

Martyn1981

joefizz wrote: »

Ive mentioned before in this thread Id probably keep an EV between 40 and 80% charge and never charge it on a fast charger unless absolutely necessary (unless it was a hire car and Id thrash the life out of it ;-)). Just looking at the data sheets for all the types of batteries used and this would be a good rough measure to ensure longevity. How much more is anyones guess, there might be enough spare capacity built into some of them to make this not a problem, time will tell but in general fast charging will shorten the life of all current battery chemistries going by their data sheets.

Most of the EV warranties specify a State of Charge percentage so say 70% after 8 years or so which is entirely reasonable. Drill down into the warranties and if it drops below that then they will replace part of the battery with remanufactured parts to get you back over that for the rest of the warranty time. Again thats pretty much in line with white goods stuff these days.
Where that particular bit gets interesting is that its the SOC being used. Thats only one thing that will degrade with time,the charging capability also will as will the discharge and it will also take the bms longer to manage charge which may lead to issues with the ones that will end up overly relying on this for safety. So after 8 years we would be down to a reasonable 60% effective battery from day one with reduced charging capability compared to day 1. Thats again not really that unreasonable and to be expected. Dont see many people on here using that as a basis going forward though despite all the current data charts, warranty information and t+cs point that out. Its all expected normal behaviour.
Whilst the car may have 80% charge in 8 years it will have maybe 2/3 to 1/2 the range and lose more charge overnight etc etc. Again not an unreasonable expectation given the data but certainly not whats being projected by some posters.
Its things like charging time and discharge fall off that dont really get noticed as they wont really be a thing if you mainly leave it plugged in overnight and dont use the range daily. It will mean towards later in life it will have to be plugged in all the time, again not unreasonable.
Its the posts that expect fast charging for most charges and the car to last 8 years that go against the published data (and probably the warranty t+cs as well - depending on manufacturer). Look through the handbooks and they already say that the bms will talk to the charger and deliver the appropriate charge for the state of that particular battery, thats just bloody clever. Even more clever is that it can do all that from the internal sat nav before you even pull up at the station. So its not a case of multiplying x and y and getting z, there are far too many more complex variables. Thats a great USP right now but they will all have it but only if they tie up with certain charging companies, and you will see this play out soon.

I have to say I struggling with almost everything you are saying, especially about battery degradation.

I'd have thought that as we progress, what we see today at the better end will become the norm, and we'll probably do even better.

The TM3 has the highest annual production numbers now of any BEV, and will shortly become the BEV with the highest total production. I appreciate that Tesla may currently be seen as 'special', but this is still a mass production car, that's profitable, and affordable (within its segment) so I'd have thought it totally fair to use its battery degradation as a reasonable marker for future BEV's in the short to medium term.

So, if I recall correctly from the BNEF survey, the TM3 battery average at 40k miles is approx 97%, and appears to level off at around 98-97% from ~25k miles onward.

So based on UK mileage, that's 5-6yrs. And whilst its dangerous to assume, I'd suggest from the leveling off, that perhaps 95% at 100k miles seems reasonable.

I am of course concerned about a 'race to the bottom' in battery technology, but since these issues are being watched, it would be a dangerous move by any company to deploy substandard batteries as that could badly taint them afterwards.

Martyn1981

AAAAAAAAAAwwwwwwwhhhhhhh come on, is there anything that isn't being corrupted these days? Whatever happened to doing the right thing, for the right reasons?

Questions raised over UK's state-backed fund for electric car charging

The private equity firm appointed by the government to manage as much as £400m in investment in electric car charging points has awarded millions of pounds to a company in which it holds a controlling financial interest.

Zouk Capital is the largest shareholder in charge point builder Instavolt, having made an £18m investment in the company. Now Zouk has chosen Instavolt as the charge point fund’s first beneficiary, a decision criticised by the Labour party.

The Conservative government announced its intention to establish a charging infrastructure investment fund in the autumn budget of 2017, amid plans to encourage drivers to choose electric cars, which emit lower or zero carbon dioxide . The £400m government-backed fund initially aims to deliver 3,000 additional rapid-charge points for electric cars, more than doubling the number of electric car charging points in the UK.

joefizz

Martyn1981 wrote: »

I have to say I struggling with almost everything you are saying, especially about battery degradation.

I'd have thought that as we progress, what we see today at the better end will become the norm, and we'll probably do even better.

Martyn, Im not a Star Trek fan but I did learn from it that ye cannae change the laws of physics... ...see below

Martyn1981 wrote: »

The TM3 has the highest annual production numbers now of any BEV, and will shortly become the BEV with the highest total production. I appreciate that Tesla may currently be seen as 'special', but this is still a mass production car, that's profitable, and affordable (within its segment) so I'd have thought it totally fair to use its battery degradation as a reasonable marker for future BEV's in the short to medium term.

So, if I recall correctly from the BNEF survey, the TM3 battery average at 40k miles is approx 97%, and appears to level off at around 98-97% from ~25k miles onward.

So based on UK mileage, that's 5-6yrs. And whilst its dangerous to assume, I'd suggest from the leveling off, that perhaps 95% at 100k miles seems reasonable.

I am of course concerned about a 'race to the bottom' in battery technology, but since these issues are being watched, it would be a dangerous move by any company to deploy substandard batteries as that could badly taint them afterwards.

They arent substandard batteries, they just dont meet a higher specification but will meet and exceed a lower specification and can be used there. Thats the way most things work.



This is where your difficulty lies with the degradation discussion Martyn, in all your previous posts you have used various calculations but ignored the laws of physics/engineering principles. You use the output data, not input data, which we dont have access to but we do have published data sets for the chemistry/equipment used. You use output data and assume thats representative of the inputs.


To divorce it from car talk and specific manufacturers I'll use the example of my home batteries. To make it roughly cost effective in 10 years I need the batteries to output about 4.8Kwh throughout that period.
The warranty states they are good for 60% in 10 years in 'standard conditions', conditions that I'll never replicate.

I could buy 4.8KWh batteries and use them but they would degrade over that time so I wouldnt get that end specification.
I could buy 7.2KWh batteries and run them at 4.8KWh for that time and they might just meet that end specification if averaged out.
I could buy 9.6KWh batteries and run them at 4.8KWh for that that time and they definitely would meet that specification barring unusual failures.

I wouldnt be changing the laws of physics, I wouldnt be developing some magic dust algorithm that no-one else on the planet has ever seen or could replicate, Im just using existing degradation curves and working backwards.


Yes, as time goes on I'll get more out of those batteries as management and firmware improves but right here right now thats what I have to do.
So whilst I will get 4.8KWh over the lifetime of the batteries I cant use that as any cost analysis as it took 9.6KWh battery install originally to produce that.




Now, I could buy 4x2.4 kwh batteries brand new or I could use a brand new 11KWh battery that failed to meet its 11Kwh spec (which would probably be around 12) but does meet a 10KWh spec.
Either is equally valid and not substandard, in fact the latter one might be cheaper because its one case/hardware and the company would sell at a discount or I might be in a rush to meet specs and cant wait on 4x2.4 perfect spec batteries to be produced.
The only problems with that approach would be form factor and if I could fit it in and the associated cooling etc in the space I have available as obviously the plant will be built for the full spec and full size.

Either way when its installed and operating I wont care and it wont make any difference to my end usage.



If I have sofware control to limit it to 4.8KWh then all my display will show is physics defying degradation curves....
Its not cheating, its not dodgy, its good engineering and only really causes issues when people see the 4.8KWh and use it for cost calculations or extrapolate out into the future when they really should be using the long tail curves for slightly larger capacity batteries.


Home battery chemistry is different to cars in that its designed for longer life, lower power output and not to require sophisticated cooling to stop it breaking down or going on fire. The degradation curves for this type are less than for car batteries (typically). They are more expensive so you cant compare KWh costs for 'batteries' across the board. Some cars will be designed for slow and steady, others will be designed for speed. The slow and steady will probably cost disporportionately more as people wont see the two different types of chemistry used for different purposes.



Look at the data on different leaf variants, I cant remember which way round they are but one has more degradation over time, the other over cycles. Thats just the data. If I had to guess Id say the higher spec batteries would be more affected by cycles as they are capable of fast charging or have a lesser reserve (so again referring to the data sheets..)
It doesnt make them bad cars or bad batteries, its where we are. I dont know if leaf purchasers are told that or not. Most people see the two headline numbers and think one is better than the other based on the number.



If a particular battery type is more prone to degradation over time then you had better do your 250000 miles quickly. If its more prone to degradation over cycles then youd better do your 250000 more slowly.
Either way its chemistry and entropy applies regardless. So you replace wear and tear in an ice engine with battery chemistry decay, how they are operated will dictate the lifetimes of both.


As Ive mentioned quite a few times, from my discussions with battery folk we are there or thereabouts so any future going forward with existing technology wont be big leaps but rather smaller iterations. We wont get that until the technology changes and we see how that progresses and then we get into the realms of previous discussions about just how green current evs are when we have to replace them with better tech 10 years from now... (another discussion for another time perhaps ;-))

1961Nick

Martyn1981 wrote: »

I have to say I struggling with almost everything you are saying, especially about battery degradation.

I'd have thought that as we progress, what we see today at the better end will become the norm, and we'll probably do even better.

The TM3 has the highest annual production numbers now of any BEV, and will shortly become the BEV with the highest total production. I appreciate that Tesla may currently be seen as 'special', but this is still a mass production car, that's profitable, and affordable (within its segment) so I'd have thought it totally fair to use its battery degradation as a reasonable marker for future BEV's in the short to medium term.

So, if I recall correctly from the BNEF survey, the TM3 battery average at 40k miles is approx 97%, and appears to level off at around 98-97% from ~25k miles onward.

So based on UK mileage, that's 5-6yrs. And whilst its dangerous to assume, I'd suggest from the leveling off, that perhaps 95% at 100k miles seems reasonable.

I am of course concerned about a 'race to the bottom' in battery technology, but since these issues are being watched, it would be a dangerous move by any company to deploy substandard batteries as that could badly taint them afterwards.

Some early TM3s have done 100K miles with less than 10% (apparent) battery degradation. That's quite remarkable & much better than anticipated ... unless Tesla deliberately decided to 'undersell'.

GreatApe

1961Nick wrote: »

Some early TM3s have done 100K miles with less than 10% (apparent) battery degradation. That's quite remarkable & much better than anticipated ... unless Tesla deliberately decided to 'undersell'.

You have to remember all of the high mileage model 3s are motorway mileage

It's said 10 mile of urban for an ICE is equal to 50-100 miles of motorway
That's probably true for BEVs too since acceleration and deceleration are much harder on all components Inc batteries than is stray speed mileage

Also Tesla's have very big batteries so it's likely they will last longer because they will much less often go to the extremes of charge and discharge range and less often to the extreme ability of power in and out

That great but Tesla's cost $40-100k
More mainstream models like the e golf which are more affordable but have much smaller battery packs. These will see extremes of charge and discharge more often and will see peak charge and discharge rates more often thus will degrade more

Overall it's still an unknown factor. If the manufacturers are confident they should offer better guarantees to help boost sales.
12 year 150,000 mile on the battery and motor would be perfect it would greatly help second hand prices which will lower lease prices and more people could buy

ABrass

Joefizz, you don't really seem to know what you're talking about here. In particular with the model 3 which uses a type of battery that is bespoke for it.

In at least the PowerWall it is the same type of battery used in the model S. The same battery just in a different case.

Reality says you're wrong. Reality says that despite your talks with battery people you haven't done the required reading.

Martyn1981

joefizz wrote: »

Martyn, Im not a Star Trek fan but I did learn from it that ye cannae change the laws of physics... ...see below

I'm responding to the whole post, but have cut it down as it just seems to go in circles, and your first sentence says it all, and therefore gets it all wrong quite concisely.

As I said, and I believe it's a fair assumption, Tesla are currently displaying the best technology, this is real not SF, and break no laws of physics.

Their kit, according to the recent Bloomberg survey is displaying a degradation rate down to about 98% to 97% by 25k miles, and approx 97% by 40k after appearing to level off.

I see no reason why all BEV batteries won't improve to at least this Tesla level going forward, and of course Tesla (and others) will most likely improve further.

So your use of 80% or 60% figures makes no sense in a forward looking discussion. You seem to be ignoring todays reality (and physics) and instead relying on older and worst case scenarios.

I suspect your claims that I'm ignoring the laws of physics and engineering principles is simply a desperate distraction given that I'm using real facts, not hopelessly negative assumptions.

The weird thing is that in your last paragraph you actually state that we will make small advances on where we are today, yet you claim I'm breaking the laws of physics when I point out where we are today, and assume all will rise to that level, at least.

Solarchaser

The pylontech batteries I have are warrantied for 10 years, 4500 cycles at 90% DOD.
The sofar only goes to 80% so far... and at 80% its 6000 cycles, so over 20 years at my current use

joefizz

Martyn1981 wrote: »

Their kit, according to the recent Bloomberg survey is displaying a degradation rate down to about 98% to 97% by 25k miles, and approx 97% by 40k after appearing to level off.

Martyn, agree we are going round in circles.
Battery degradation is a function of time (amongst other things). Its a rapid drop off after a certain period and accelerates after a certain percentage useful. (becomes difficult to manage below a certain percentage).
You can do 200k in 2 years no problem but thats not an indication you can do 200k over 15 years.

We've said our bits so lets revisit in 5-8 years time and see what percentage of the current EVs are still on the road.

ABrass

Martyn, agree we are going round in circles.
Battery degradation is a function of time (amongst other things). Its a rapid drop off after a certain period and accelerates after a certain percentage useful. (becomes difficult to manage below a certain percentage).

Source? The information I can find points almost entirely at use rather than any passive degredation. How much should we expect over time with minimal use? Without a source it sounds like FUD.