Battery degradation in EVs: Is there a software to measure it?

I am concluding that my battery has degraded by 0.41% after 15,000 Km and nearly 10 months. Which personally is quite impressive.

BHPian navinmra recently shared this with other enthusiasts.

With the 15,000 KM mark coming up for my Nexon EV Max in around 10 months, I wanted to find out if the battery had degraded, and if so by how much. I have heard on some forums that Tesla batteries degrade by 1% per year so that fueled my curiosity.

On a recent journey from Bangalore to Manipal, I used data from the dashboard and the mid point fast charger to arrive at the battery capacity (and therefore the degradation) It is crude but I want to share with you all to see if you had any reactions:

  • I started with 100% charge.
  • At 49% SOC, I charged to 86% on a Zeon DC fast charger (pic attached)
  • I reached my destination with 29% SOC after clocking 414.9 KM (pic attached
  • My efficiency for the trip was 105 Wh/km

Now the calculation:

  1. Total energy consumed on the trip = 105 Wh/Km X 414.9 km = 43.564 KWh
  2. In terms of SOC % total energy consumed = 51% + (86% - 29%) = 108%
  3. Therefore 100% capacity = 43.564/1.08 = 40.337 KWh

Now, we know that the Nexon EV Max battery capacity is 40.5 KWh. Therefore a capacity of 40.337 KWh translates to 99.59%

Therefore I am concluding that my battery has degraded by 0.41% after 15,000 Km and nearly 10 months. Which personally is quite impressive.

I know this is very crude back of the envelope calculation and does not take into count residual battery capacity (not all capacity is made available to tap into) etc, but hopefully that triggers some thoughts amongst you all

Here's what BHPian mally2 had to say on the matter:

Interesting way. Or you can ask the TASS to check the SoH on the next service schedule. I did mine for the tiago.ev @ 15k kms and the SoH was 99%. Since there is no further decimal I had to assume that the degradation is around 1% or less. There are others in the tiago community who have done 25-30k kms and it’s still at 99%

Here's what BHPian Redex had to say on the matter:

Many "degraded" batteries are actually down to the way the user charges the battery, especially in earlier models. The early software was not based on endless "top ups" but engineers assumed that users would drive until nearly empty then do a full recharge. Try, fully charging the vehicle then park it up off road, leave the heater and air con running until the system shuts down. Recharge and repeat. Then recharge and check the SOH. Slow charging whenever possible helps.

This is simple non technical advice, not going to get into the realms of battery repair.

Regards Neil

IMI Level 4 Diagnostics and Repair Qualification.

Here's what BHPian coldice4u had to say on the matter:

Battery degradation for the current Tata vehicles should be a non issue. I agree with the comments that batteries will outlast the car.

My Tiago EV at 14k kms showed a similar SOH of 99%. This is after one season of intense NCR summer and one season of prolonged NCR winter. I've exclusively slow charged during overnight charging and to 100% each time. If we can extrapolate!, i expect battery degradation to hit 10% at 150k kms,but its a bit early to see that long into the future. At 10% degradation, total range with AC will be 150-160kms.

Very very happy with the car, barring minor niggles. Nothing beats this car for a city use case. No issues observed. Bad FM again as reported on other Tata threads, thats Tata being stupid with cost cutting.

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