BEVs deals and information

joefizz

almillar wrote: »

The cost you pay, in your house, per kWh is whatever the charger uses (takes in). You will receive slightly less than that in your car. That's just non 100% efficiency. Rapid chargers will be more efficient, in general. Where's the lie?

You just dont understand the points being made.
You cant multiply cost per kwh made x delivered power to get a meaningful useable measure (not saying manufacturers are, posters on here are).
The kwh capacity installed > kwh delivered > kwh gone through your meter > kwh generated > kw potential of the source.


kwh capacity installed to produce the required kwh delivered is a combination of battery chemistry, battery manufacture, battery management, charge management, power delivery,losses and a lot of other things.


Take your 105% thing. Thats what the OBD reads from the ECU. So as far as the ECU knows theres an extra 5% in the installed battery thats reserved to stop it bricking (for talk sake). Thats a number in the ECU. Thats a margin also limited by the ECU. Thats not to say there are your rating x1.05 installed capacity. Thats the minimum installed capacity. To ensure 8 year life they may have to install 1.1 or 1.2 times the capacity. Unless you have the closely guarded battery stats you dont know,none of us do so using them as a measure on forums is just pointless (as is capex in different countries and market cap etc)



At some point in the future (as with one of the latest tesla releases) they could look at it and think by better management we can put more charge than previously thought into the battery. Doesnt mean the battery magically grows in size.
On the other side you could have batteries which never produce close to the nominal value under any circumstances and may need say 75kwh installed to give 60kWh out, so that makes a nonsense of the multiplying 60kwh by x amount to give the cost of batteries (again a poster thing, not a manufacturer thing).

almillar wrote: »

You're way off here. Nissan sold their Leaf as 24kWh. The battery inside was.. 24kWh. AFAIK, this is the exception to the rule.

To be technically correct it was a 23.4kWh battery run at a lower voltage. Only 80% of it was used...
Technically.. (and yes you can look up the cell specs on the internet - they arent closely guarded secrets)

ABrass

joefizz wrote: »

You just dont understand the points being made.
You cant multiply cost per kwh made x delivered power to get a meaningful useable measure (not saying manufacturers are, posters on here are).
The kwh capacity installed > kwh delivered > kwh gone through your meter > kwh generated > kw potential of the source.

There a mistake in there, or more likely several mistakes. To pick out one the power through your meter is unlikely to be greater than the power generated somewhere else. I don't mean to be cruel but if people don't understand the points you make then there's a chance it's the way you're making the points that's at fault.

You've spent several hundred words to say little more than "I don't like that the reported battery sizes are different from the physical sizes, and it's annoying that manufacturers don't use the same inaccessible storage proportions to allow comparison."

joefizz

ABrass wrote: »

There a mistake in there, or more likely several mistakes.

Indeed! I shouldnt have used the greater than symbol!
Not equal would have been the proper symbol to use.

almillar

At some point in the future (as with one of the latest tesla releases) they could look at it and think by better management we can put more charge than previously thought into the battery. Doesnt mean the battery magically grows in size.
On the other side you could have batteries which never produce close to the nominal value under any circumstances and may need say 75kwh installed to give 60kWh out, so that makes a nonsense of the multiplying 60kwh by x amount to give the cost of batteries (again a poster thing, not a manufacturer thing).

You're right, I don't understand all your points. Are you simply saying that the kWh that comes through your meter, or out of a power station, is not the same as the amount of kWh delivered to the wheels, as there are losses and calculations in between? Well, I know that.
I do understand this bit. You seem to be saying that manufacturers can play around with the BMS to get better performance or storage out of the same batteries, shortening their life. I understood this in your previous post too, and I asked you why they would do this, whilst handing out these big warranties. You didn't answer.

ASavvyBuyer

A couple of news items concerning the expanding public charging facilities.

https://www.zap-map.com/virgin-media-park-charge-project-adds-vattenfall-as-partner/

https://www.zap-map.com/milestone-for-public-ev-charging-as-10000-locations-reached/

joefizz

almillar wrote: »

You seem to be saying that manufacturers can play around with the BMS to get better performance or storage out of the same batteries, shortening their life. I understood this in your previous post too, and I asked you why they would do this, whilst handing out these big warranties. You didn't answer.

Theres a lot in there so here goes...
Some manufacturers need a more complex bms due to the type of battery chemistry used. The chemistry varies from the more conservative in terms of longevity and safety but at reduced charging/power delivered and more cost, to the opposite (cheap, not as safe but higher up the charge/deliver power bands).
The latter are probably most abundant and have a range of types as well but to get the safety aspect up they need more detailed bms or require installed supply to be over and above measured output. If you think about it if you need to charge in a hurry a set of batteries that dont charge completely safely in a hurry, to reach the published output you would need more of them and spread the charge, then manage it later.
One manufacturer has recently signalled that they are going to a cheaper version of the fast type of battery chemistry, they probably have enough data to show that the longevity they have already seen can take a downgrade to the next price point and still meet warranty (or tighten up warranty). Time will tell but its a gamble now to save money now and maybe pay for it later 6,7, 8 years down the line (or never).
Thats a normal business cost reduction exercise, everyone does it.



One manufacturer is very clever with its BMS but it needs to be with heavy assisted cooling to keep to specified values. Not usually a problem but its adding weight, adding complexity and needs more actively managed. Even more complicated when they used best available cooling liquid which turned out in some cases to be flammable.. ..not great for thermal runaway protection.
This will be particularly crucial down the line with the likes of MOTs and corrosion checks as these are particularly fail deadly if not managed correctly, perhaps not infernos on the motorway but a lot of bricked batteries not covered by warranty. It will be very important for people to have their high power/long range EVs serviced and visually checked regularly, particularly in places like northern uk with the temperature ranges and salt on the roads in winter. I would be very reticent about buying the current crop of EVs if I lived near the sea (as in right next to it). Id be tempted to waxoyl the lot but its easy to say that coming from a petrol/diesel car environment, wouldnt like to know the ramifications of that if it got hot/fumes etc around a big battery, probably best not to go there.



These are all design decisions and all perfectly valid, some just need a lot more management than others. Some manufacturers just stick their cells in modules, modules in the battery pack and thats it, but they are the ones with lower capacity and a lower fast charge capability, thats the trade off at this point in time.

You can find out most of this information from ebay ads selling old versions of batteries!



So its not really like for like comparing delivered kwh with published cost per kwh produced and using that for price comparions. The cheaper batteries need more cooling and management and more of them to deliver the "same" or nominal power output. This isnt an issue and wont become one until someone tries to get stupid ranges out of a normal form factor car (unless theres a jump in battery technology).



Its not quite the same as diesel v petrol but its a similar analogy, the power output might be the same but one has generally more low down torque vs later power band switch. Add in turbos etc and its analagous to how different battery chemistries are used.


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.



All the published warranties and cycles have caveats and all are probably within normal operating procedures, although what normal is you have to drill down into your own user manual and warranty T+Cs to see what they mean. Some specify a specific charging pattern etc.
Just to refer to the home battery thread my home battery specified normal operating conditions are IIRC something like 25C ambient and 40% humidity. Neither of which would be deemed normal by any stretch of the imagination in Northern Ireland. Thats why I often refer people to the datasheets and where people talk about company finances, their SEC or financial filings because they generally have to tell the truth in both (although not always).
Similarly with most news, the most likely source of the truth about all this stuff are papers like the financial times, you cant lie to the money people.


Does that make any more sense? Im not anti EV, its just, well, complicated... I intend my next (and probably final) new car to be an EV but if I need to get something tomorrow or next year Id go hybrid as I dont think a lot of the above has been totally ironed out, certainly not in the UK it hasnt.

GreatApe

And I thought I was the king of rambling posts now I know how you lot feel haha

Solarchaser

^^:rotfl::rotfl::rotfl:^^

ABrass

Dodgy games with batteries can only be hidden for so long. With mass market EVs, (Leaf, Model 3, Model S, Zoe and maybe a few more) there's too many out on the road to hide substandard batteries.

With newer brands without the history (Jaguar, Audi, Porsche) it's harder to have confidence, but they're at least learning from others and avoiding the big obvious mistakes.

For me the battery fear should be dead and burried. People have been paranoid about them since the Toyota Prius was announced. With one possible exception (Nissan leaf pre lizard battery) it's not happens.

joefizz

Agreed about any dodgy games, it will all come out in the wash eventually, just as dieselgate did.


I dont see anything I posted as being 'dodgy' though more about early product lifecycle. Its not dodgy to put qc failed higher spec batteries in a lower spec'd car, just people need to take that into consideration when factoring in costs and it explains the profit differential from what would be expected. Its not as if that was hidden either as you can tell from public pronouncments and going through cost/weight data.
The attrition rates for leafs/zoes has been ridiculous but only in comparison to other ice vehicles, its not really that unusual for battery powered anything, hence why a lot of them offered lease schemes for the batteries, it was all predicted. Batteries have got better so theres no need to do this any more, you will still have a perfectly useable car 8-10 years on, it just wont be as good as when you bought it (as with any car).



Its just getting the job done for this stage in the lifecycle. Batteries arent new but the application of them in mass market vehicles is, so we will go through some iterative cycles to get to stability (in time for battery tech to change maybe and go through it all again - part of my theme for my posts in this thread)


Where it would get dodgy is if close to warranty ages (in another couple of years) software updates misrepresent soc or have the soc value as floating per available, not previously installed etc but like dieselgate that wont be too difficult to uncover.