Thank you.Check the spec sheet.
The graph that describes the cycles to 80% capacity is the one you want.
Degradation follows the same curve as a discharge curve. Accelerated degradation at first followed by a long flat (ish) slide.
I'm not overly concerned about being limited to 267ah, I try to operate between a max 90% and a min of 20% soc, so full capacity doesn't really matter.
My concern was that my pack might be degrading faster than it should and I might find a similar drop again year on year.
If a faster fall at the start of usage, becomes a more gentle curve, then that puts my mind at rest.
Another contributor said similar, so thank you both.
I'll go and look up those graphs
So that is about a 4% capacity loss after only 67 cycles, which as you suspected is quite high. However, since there is no historic capacity data from when you initially received the cells, its difficult to determine if they were used or low capacity cells to begin with or have undergone accelerated aging for some reason.
Based on what others have experienced from various less than reputable sellers, my bet would be those cells were out of spec. when you received them. Your usage history does not indicate the cells were abused or operated in harsh conditions.
My cells were amongst the first offered by this supplier, since then I believe they test and label the cells with capacity, wh and resistance data.
Perhaps these early non labelled ones weren't as well QC'd
Anyway, thanks to everyone for the help.