EV battery degradation over time

SteelyDanJalapeno

A hotly debated and argued item is battery degradation on EVs are rightly so if you're spending a lot of money on a car it would be nice to know it's not useless out of warranty!

With that in mind I was close to zero getting home last night so I decided to squeeze out an additional few KMs around my road until getting back to the house at 1% 0km according my display, it didn't come to a halt so I could probably have squeezed out another few Km, but close enough.

I then plugged it into my Zappi and charged it overnight, looking at the kws it consumed to get to 100% it reports 58.45 kW.

This is on my 2.5 year old 70,000km ID3 58KW.

So the ID3 physically has 62kw of batteries with 58kw usable, I unfortunately don't have the same data from new for my car to see how much would be consumed when fully charged at new, I wish I did.

But I'm happy to see it pulling in 58.5 kWh, it looks my degradation has been very minimal if anything at all thus far.

This is with 2.5 years daily use and zero mammying of the battery in terms of charging, so we'll fill when we can from a mix of different charge points, but rapid would be rare maybe once a month, it's typically 7kw/h

Thoughts? And have you ever attempted a similar experiment?

spakman

Sorry to go slightly off topic, but what app are you using to view zappi stats?

SteelyDanJalapeno

Myenergi app and that's using a CT clamp to measure

AndyBoBandy

Are you accounting for 10% charging losses?

SteelyDanJalapeno

https://www.boards.ie/discussion/comment/121318299#Comment_121318299

No is that a given?

SharkMX

https://www.boards.ie/discussion/comment/121318299#Comment_121318299

I doubt they are. If the car is given 58kwh with only a 10% loss the car is only getting 52kwh into the battery.

More like 15% loss for me though when charging when i tried to measure the loss.

Good explanation here where they say the losses are somewhere between 10 and 25% when charging. If its 25% the OP will be unhappy to hear that his battery has only taken 43kwh on that charge.

https://go-e.com/en/magazine/ev-charging-losses

SteelyDanJalapeno

If I run back down to zero now and see the power consumed since last charge, that should measure the charge lose? Being the difference of today's value vs what it uses to drain from 100% to zero?

sh81722

https://www.boards.ie/discussion/comment/121318314#Comment_121318314

So you reckon we lost 15 kWh as heat on that session? Something in his setup must have been running red hot for those 8 hours the charge took.

SteelyDanJalapeno

https://www.boards.ie/discussion/comment/121318314#Comment_121318314

I wouldn't be too unhappy! VW warranty on the battery is 8 years or 160,000km, so a free replacement if it falls below 70% in that period

Casati

https://www.boards.ie/discussion/comment/121318383#Comment_121318383

How do you prove to the dealer it has fallen below 70%? Also do they have to provide a complete new battery or just bring it back up to over 70%?

sh81722

This is not totally relevant, but on my home battery system which is LFP based the charging losses have been approx. 5% per cycle based on the 1623.7 kWh charged vs. 1543.6 kWh the inverter reports since the battery was installed in April this year.

Screenshot_20231103_081839_Home Assistant~2.jpg

SteelyDanJalapeno

https://www.boards.ie/discussion/comment/121318414#Comment_121318414

Any VW EV servicing centre will have the ODIS tool to check battery health so I can request that.

The warranty will replace or repair back to between 70-78% depending on mileage

Casati

Great article on charging losses - something to be taken into account when working out the total cost to fuel an ev. Good tips there re thicker/ shorter cables

Water John

Would the fact that VW recommend charging to 70%, affect our warranty if we charge to 100%?

Its only my hunch but I think fast charging regularly might have a negative effect on the battery, longer term.

D_D

https://www.boards.ie/discussion/comment/121318314#Comment_121318314

But also to note, that when the system says you have 0% battery, there is in fact some held back kWh to allow you to keep going for a few additional km/miles. So charging from 0% doesn't take this hidden capacity into account, so I would say it is probably closer to the 10% losses, no way it'll be 25%.

In the article you linked, it seems the higher % charging losses are for cars with very large batteries (>100kWh).

SharkMX

https://www.boards.ie/discussion/comment/121318364#Comment_121318364

I dont know tbh. No idea where the power is lost. Im not a scientist who has investigated this with the proper equipment, but im sure if you look for it you can find it from properly tested and calibrated setups. I will tell you for sure that its not zero loss though.

Even sitting in my car the other day I glanced at the 2 readouts for the fun of it. Zappi says its giving 7. Car says its charging at 6.2. If i looked at it 5 minutes later both would probably be different again.

SteelyDanJalapeno

https://www.boards.ie/discussion/comment/121318349#Comment_121318349

Again thou wouldn't this be a close enough measure? If I consume let's say 53kws now to get back down to zero, safe enough to assume my battery usable capacity is down about 10% (hypothetical, I think my capacity is higher based on range I'm getting, but then that would mean your article is wrong in my case)

kanuseeme

This is interesting, I would have assumed 10% loss, I checked my app, 10.95 kwh, for 4% to 100%, usable battery 8.8 kwh out of 10 kwh,

Slow charging on lowest setting took 5 hours 50 minutes, loss was around 19%

in my case around 2 kwh lost, hardly notice that amount of heat over 6 hours , 15 kWh spread over how many hours spread over how many meters of cable inside/outside the car, the volume of the battery and inverters, solenoids etc. would that be even noticeable ?

sh81722

https://www.boards.ie/discussion/comment/121319118#Comment_121319118

You'd notice if 15 kWh of heat escaped in 8 hours. That's enough heat to boil about 60 litres of water.

SteelyDanJalapeno

Yeah I can't take my 120 litre water tank up to 60c with about 5kw!

Ev fan

My understanding is that the 3 main factors for battery degradation are

1. Normal ageing of the battery 2. No. Of charging/discharge cycles completed (directly related to mileage) 3. No. Of fast charging cycles done/ other potential detrimental incidences such as longer durations at 0/100% high/low temperature environmental impacts etc.

The truth is that real time data for battery degradation is only building up now with perhaps 3 years worth of data with the exception of Tesla (10 years data with Model S.The Tesla data suggests that degradation is generally highest in year 1 with much smaller degradation from years 2 onwards- assuming average mileage and normal driving patterns every year. As I understand it degradation is built-in and guaranteed based on the prevailing factors- however you can help to avoid excessive degradation by of course taking care not to abuse the car/battery in any way.

I think best guess for a cared for EV with proper bms after 3 years of average mileage would be somewhere in the (5 - 10%) range. Anything north of that would suggest some detrimental factor is in play. Of course real time data should be available soon- at least for 3 year old EVs.

kanuseeme

A quick calculation puts the id3 pack at around 300 litres in volume, its designed for liquid cooling, so its not insulated , I would imagine 15kwh spread over 8 hours would not be noticeable and thats assuming all that loss is just in the pack, spread that energy over every component and wire not in the pack.

As for degradation, a better assumption might be nearer 20% for charging loss instead of my initial 10%,

https://www.boards.ie/discussion/comment/121319277#Comment_121319277

Your inverter is only 5%, is it because the solar is DC and charges the battery? Can you charge it from AC and see what the loss is?

slave1

I've measure losses into my Tesla on a few previous occasions, around 8%. 20% losses and there is something wrong

liamog

I've Tessie monitoring my charging sessions, it records energy in vs energy added. Obviously it won't track any losses in cable running to the car.

kieran.

https://www.boards.ie/discussion/comment/121319510#Comment_121319510

3.5 year old 64 kW Kia E-Niro here 98,000km on the clock. Battery health 98.7%.

SteelyDanJalapeno

https://www.boards.ie/discussion/comment/121319830#Comment_121319830

The thread has been somewhat derailed by charge loss psuedoscience, a poorly written article with no data and a negative undertone on guessing degradation based on no real information on my car, I presume it's somewhat chomp fishing on a Friday.

Based on my range I'm still up around 95% or so, nowhere near 80%.

Anyway thread was more so to get other experiences in real degradation they have measured like yours! So thank you for bringing us back on topic!

liamog

https://www.boards.ie/discussion/comment/121320006#Comment_121320006

It's unfortunately par for the course with trying to guestimate your battery state of health. In theory it should get better under the Euro 7 regulations which will require manufacturers to provide standardised battery reporting via OBD devices.

liamog

Kind of interesting according to the Tessie stats my car has gone through 37.1 charging cycles with it's current mileage 11,407km. If the 3000 claimed cycle life for LFP chemistry holds up I've only got another 922,000km left of usable life.

TheAnalyst_

Wow thats a lot. Tesla would never lie so we can accept that value without question. How is the FSD working?

liamog

https://www.boards.ie/discussion/comment/121320129#Comment_121320129

It's a function of the battery chemistry not a claim by Tesla. LFP batteries are generally expected to maintain approx. 3000 cycles.

Dave_D_Rave

Sorry to hijack

I also have a SunSynk Inverter and battery

Where in the menu can you get the above info ?