Just bought 16 Eve LF280K A grade; update on degradation after 15 months

cajocars said:

Surely they dropped more than what they made me save on electricity in one year. But one year ago, I was expecting energy prices to go higher than what actually happened.

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For me, it was 18 months and I've saved more than the reduction in price.

I've finally bought another EBC-A40L and I'm currently testing the same cells I tested 15 months ago.
They have since been cycled 224 times.

I'm using the same logic as before: charge to 3.65V with cut off current of 5A, wait 30 minutes, discharge till 2.5V

Here is a comparison of my first retested cell

Time of test; Capacity; Energy
December '22; 278.4 Ah; 900.27Wh
March '24; 266.00 Ah; 855.91Wh

Capacity lost 4.4%; energy lost 4.9%

The only differece is that the first test was carried out at around 19deg (indoor) and the second one at around 15deg (garage).




Edit 19Mar2024
Second cell (#9) measured 266.90 Ah, 858.68Wh
So at the moment a pretty even loss across these 2 cells

I have now tested the one I believe to be the least capacity cell, because it's the one triggering the low voltage protection when the pack is fully discharged.

I did not test this cell when new, so its original capacity is unknown.
Its current capacity is 263.30 Ah, 847.58Wh (test conditions as above, temperature 15deg C)

Re-test it at 25°C for consistency with spec sheet. There will be some capacity loss at 15°C vs 19°C of about 1%. Between 25°C and 15°C there could be 2 - 4% difference. Then there is calibration factor between 2 different capacity testers.