Thanks for your detailed and informative explanation on the BMS and what it does etc. I believe Hyundai release their battery top buffer over time so that after 3 years driving customers can still see 100% SOH or close to it. I'm assuming this means releasing 3kWh buffer of the 67kWh (I think) gross battery. VW I assume don't do this and therefore degradation will be noticeable after say 3 years for the ID3. If I was buying e.g a 3 Yr old ID3 I would want to see an SOH certificate. I would guess degradation would be in the 5% to 8% range or so - However it would be useful if someone could do some statistical sampling of 3 Yr old ID3s and establish what the statistical spread for SOH is likely to be.
This "full test" does not give the cell readout for each cell - here's what you get but I guess that's just the "quicktest" implying there's also a not so quick test.
89% health is probably ok and in expected range for a 2 year old car. Most of the capacity loss from batteries happens in first 2-3 years anyway, but unsure what to think about the amount of fast charging.
But i think you are right to ask for the test and I suspect it will become standard practice in the next few years if everyone asks for it, and I would just walk away if the dealer does not want to entertain the idea.
Carscanner will give you an estimated state of health reading, but I think a full test should give a readout for each individual cell and identify if any of them are degrading faster which could be an issue.
Bjorn Nyland on YouTube has done degradation tests on a lot of cars if you want more info https://youtube.com/playlist?list=PLqKx2qnB8Xv4jDGrgoNliG_5PaxqT9a_P&si=42Tr13eBMcZVu0iZ
This guy had 8% loss on his ID3 after 1 year and 22k kms https://youtu.be/_DSQw09Rl7c?si=YixxrWmmttvC4CI4
July 2023, 9500km.
Thanks - I have seen some debate elsewhere online as to whether that will give the same data or not. For example to do the official VW test, there's a bunch of requirements around charging to 100%, then leaving it for an hour etc, then doing the test. If I use an OBD dongle and the app will I get the remaining capacity of the battery and the rate of DC charging?
I'm a complete EV newbie as I'm sure you can tell but I can't get my head around why the dealers won't provide this - it's like providing the NCT certificate. Some are saying they will only do it if I pay a deposit. I am sure if I tell them I don't like the rate of DC charging they would be quick to argue again that "well it's under warranty".
Am I over thinking it?
As Elm said, just take the car for a test drive, plug in the dongle and you can read the info yourself using a free app called carscanner
If you have an android phone and an elm327 OBD adapter you can see it yourself
Hello Kind People.
I am in the market for a second hand ID.3 which appear more reasonable now that the arse has fallen out of the EV market a little. I've approached numerous VW Dealers and only 1 has provided a SOH for a second hand ID.3. The others are citing "battery is under warranty so don't worry about it" but I think I'd be stupid not to check out the SOH or the rate of DC/Fast charging. The one which I did see had a whopping 78% DC charge on it and 89% remaining capacity.
Is anyone else experiencing this? Should I just give up and go buy a pig in a blanket? Any advice?
So I think there's some creative accounting going on there from VW, but this is what seems to be going on
The Maximum Energy Content field seems to refer to the net capacity, not the gross capacity. In other words it seems to be the 58kWh, not the 62kWh
I don't know this for sure, but I've never seen one reading much higher than the net capacity, so it makes sense that it isn't the gross capacity
Okay so then onto the two percentages, display soc and BMS soc
Display soc is the percentage on the display, simple enough
But, the BMS is what controls the battery charging, and it's the true* measure of the battery capacity
*It actually isn't, I'll get to that in a second
So the car maintains a top buffer of 4% by only charging the battery to 96% of it's useable capacity. This allows for some degradation without impacting range and also gives you some regen braking at 100%
In comparison a Leaf has almost no top buffer and consequently has very little regen at full charge
Since owners would be annoyed that their car never goes above 96%, that's why the display SoC is scaled differently to give 100% with that top buffer
To confuse you even more, the bottom end of the scale also includes a buffer. I'm pretty certain that 0% on the display is around 3-4% BMS soc. That means the car won't immediately die when it hits 0% (looking at you Hyundai)
Why are they doing that now? Again several reasons, the main one is probably battery protection. As a battery depletes the voltage begins to drop so to maintain power you need to increase the current being pulled from the battery. To protect the battery the car will start to power limit as the battery depletes and will eventually stop when the voltage is too low
It's also a bit of a phycological trick, by putting 0% on the display at slightly more than the BMS soc then most sane owners will charge earlier and not run out of battery
This leads to the HV battery energy content field, which I think is based on the display SoC energy from 100-0%. One thing I've never figured out is if the GOM uses the Display SoC or BMS SoC to determine range
Okay, now for that statement about the BMS not actually knowing the true capacity of the battery. This is one of the more confusing aspects of batteries so bear with me
It isn't actually possible to truly know how much energy is in a battery at a given time. Unlike a fuel tank, you can't just look inside 😁
The only way to do it is to estimate it by finding the points at where the battery is full and empty and then measuring the amount of energy between those points
That's effectively what the BMS does, it monitors the battery voltage and if it drops too low (or if one cell gets too low) then it stops the battery discharging and then when the voltage is high enough it stops the battery charging
The way the BMS "knows" what full and empty are is to program it with the desired values, and the BMS SoC is based on this
If someone were to set the 100% voltage slightly lower and the 0% voltage slightly higher, then the overall effect would be that the BMS thinks the battery is smaller than it actually is
That's what I think VW have done, they've taken a 62kWh battery but told the BMS it only has 58kWh. And that's why none of the displays ever say 62kWh because nothing in the car knows how much power it has
Do I know any of this for sure? No, but it seems to fit based on what people have been seeing. We're definitely not going to get a straight answer from VW because that's pretty closely guarded trade secrets
From what I understand there are 2 buffers- 6% on bottom and 4% on top totalling 10% or 6.2kWh leaving 55.8 kWh available. I think the 96% BMS SOC reflects the fact that the battery has a 4% top buffer. You can eat into some of the bottom buffer below 0% SOC and can drive some 10 km or so before the car shuts down. So that can be added to the 55.8kWh to make 58kWh available in reality perhaps. You quote 51.8kWh available energy- what is the age and mileage on the battery?
Dont know if this helps but I charged mine to 80% tonight, from 14%, and got the following from Car Scanner:
Maximum Energy Content of the traction battery: 53150Wh
HV Battery energy content: 39350Wh
The battery content reading at 80% would indicate my max content for the battery to be only 49187Wh by my calculation!! over 20% missing from 62000Wh.
Ill charge to 100% tonight and update. I do have high mileage(110000kms) and it has been giving 300km range @100%, thereabouts, but the maths do look worrying.
Maybe the car needs to be ran down very low and back up to 100% a couple of times to give a more accurate reading??
Charged the car to 100% this evening. Ran Car Scanner. Cable was still plugged in, but not charging.
Results.
SOC Display: 100.03
SOC BMS : 96%
Maximum Energy Content of the traction battery: 55800Wh
HV Battery energy content: 51825Wh
Do those figures point to an issue with something?
It's supposed the be a 62,000Wh battery with 58,000Wh useable, but only has a max of 55,800Wh, and of that it's only holding 51,825Wh.
That's as near as makes no difference 10kWh that I've no access to, 16%.
You’ll get a small discount if you repay early. I think I had ab €200 off for 6 months. Don’t forget to chase them up for the final monthly payment as you still have to pay your monthly bills (settlement will not include any monthly payments made after the issue date). VWFS is very “forgetful” when it comes to refunding you the overpayments. I think they actually owed me 2x months.
No worries, I had to do something similar when paying off my ID.4
When you make the payment it takes until the next month for the portal to be updated , but you can give them a call after a few days to see the transfer went through
Thanks. That’s really useful info. Much appreciated.
When you get a buyer, you can get a personal loan pretty quickly and then pay off the balance using a bank transfer, then pay back the loan within a day or so as soon as the car sells
If you login to the VWFS portal there's an option to request an early repayment balance which has the instructions to pay it off. The balance is valid for a month and it's free, so you can request one as soon as you put your car up for sale
Definitely will be. Just a matter of when. It’s on 0% atm so to sell privately I’d need to take out a loan at around 6% to buy it out. Then hope it sells relatively quickly. Each month I hold off I’m knocking the capital down and praying that it’s depreciating at a slower rate.
Let us know if your moving it on 👍🏻
Currently at 19. Will be 17 when the pcp runs out.
What's the settlement figure?
A 212 family pro with 55k on the clock. Not that I got that far. First mention of VW and they launch into a tirade about how Volkswagen ruined it for everyone 😂
Which ID.3 do you have @remoteboy ?
Coming to the end of my PCP on the ID3 in a few months. Went to a few dealers over the weekend (Hyundai, Kia, Cupra) to see what else is out there and nearly got chased out of the showrooms when I said I had a Volkswagen to trade 😂.
Looks like a lot of them got burned taking ID4s as trade-ins. Think I might be looking at a private sale when the time comes.
Power output also varies and there's a 'pro performance' variant too just in case it wasn't confusing enough. Listed in the technical data section of the brouchures.
Thanks again, another level to add to the naming.
Yeah I suspect they're keeping the production of the older motor and screen going while they wind down production
The new motor seems to be having production bottlenecks so there'll be no changes until they clear up
It's pretty clear that ID.3 sales are not at the rate VW wants them to be, so they might be forced to upgrade anyway
Ah yes, the confusing VW nomenclature
The PRO refers to the battery size of 58kWh
It goes like this
PURE: 45kWh (never available in Ireland)
PRO: 58kWh (all of the Life, Family, Style, Tech and Business are this battery size)
PRO S: 77kWh (the Tour models are this battery size)
I asked because I seen a 2021 ID3 in the cars for sale forum, and it's a PRO.
Yet PRO doesn't appear in that 2021 brochure.
Thanks, yeah I find them all a bit hard to follow.
It was easy in the early days. 1st. 1st plus. And 1st Max. Each added about 7k but increased the already fairly good spec on the base 1st.
After that I lost it so no help really..🤣
