EV battery degradation over time

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

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).

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.

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

Sorry to hijack

I also have a SunSynk Inverter and battery

Where in the menu can you get the above info ?

I don't have a BEV but a PHEV with a 15.6kw/h battery (10.6 usable). I mainly used public chargers and I even have DC charging (up to 21kw) which was used daily for the first year.

The all electric range is more or less the same as when I bought it 3 years ago and for the first 2 years of life the battery was fully charged twice a day. This is backed up by the amount put into the battery as per my app logs (between 12 and 12.5kw/h as measured by charger) per full charge. The battery degradation seems minimal though I don't know if the Mercedes software eats into the unusable space a little to keep the range "stable".

The lease is up next year and I plan to request the battery health at that point (should have asked at the service last week to be honest). I've been incredibly happy with its performance and gives a lot of weight toward getting a Mercedes BEV when I eventually switch.

you said 15kwh,

SharkMX7:37 am

'' 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

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''

I said 19% from my experience with a BMW, others have tesla at 6 and 8%, the Merc is at 20%, I would tend to believe those tesla figures, as tesla cars are efficient,

The question is for VW and its loses while charging, the OP had no clue on allowing even for 10% which I had accepted as standard till I checked my own app.

I highly doubt its as good as a Tesla and would believe its closer to BMW or Mercedes in efficiency.

Only 1.3% degradation on that mileage/ age is exceptional- sounds like you have an excellent battery and BMS. Did the SOH reading come directly from the car or other measurement means?

The charging losses should be around 10% on AC. Below an example of charging losses for my MY. Wallbox reported 32.59kWh, Tessie shows 30.54kWh used and 29.52kWh charged. So 29.52/32.59 = 90.6% or 9.4% losses.

Also, I had 6.3% degradation with ab 40k km when the ID.3 1 ed was 2.5yo. This was measured by VW when they replaced 2 battery modules (that was a year ago). Chris from Battery Life reported ab 9% degradation after 3 years. And VW was cheeky to advertise as 58kWh usable while.in reality no one ever saw more than 54kWh due to hidden buffers.

For the average enthusiast querying the battery management system (BMS) for state of health (SOH) using an odb dongle and a phone app will get quite close to the true value and will be very closely related to manufacturer warranty.

Next Eco car/ Aviloo offer and indepedent test but it takes multiple full charge discharge cycles and it's probably relatively expensive and it's likely manufacturers may not believe their result for warranty.

These DIY charge discharge tests are not really scientific enough. You cannot see hidden buffers, and hidden buffers may be released as car ages, again masking degredation, so it's hard to know until significant degredation exists. I think most modem EVs will see little noticeable degredation up to 200,000km so it will not be an issue for most. Larger batteries also mean the number of full discharge cycles are likely to be less compared to older EVs.

The battery of the Kia e-Niro 64 kWh has an estimated total capacity of 67.5 kWh. Given that, the reduction would be approx 6.4% which is not to shabby for my milage to date .