Realistic Cycle life?

[sunshine_eggo]

Do manufacturers specify fully charging batteries cause degradation?

No, BUT some qualify their cycle rating with a SoC range, i.e., 10% to 90% SoC. Here's the Rev B Eve 280 cells:

 

[timselectric]

No, BUT some qualify their cycle rating with a SoC range, i.e., 10% to 90% SoC. Here's the Rev B Eve 280 cells:

View attachment 203538

I'll see your scope, and raise you 3.

 

[RCinFLA]

Is that really how it works? I was told by a tech support guy at a solar retailer that every time the batteries discharge, no matter how far down, and then get recharged, that's a cycle.

Different Li-Ion cathode chemistry. Nickel based positive cathode are much weaker than LFP cathode. These are Li-Ion cells that charge to 4.2vdc.

Technically it is the lattice support structure in the cathode material. LFP has iron that provides vertical support 'pillars' to prevent lattice damage at full state of charge. On NCA, NMC, etc. cells, lithium provides most of vertical support to lattice. When fully charged and most of lithium has left the cathode it is a like a multi-level parking garage with most of the vertical support pillars removed. If there are areas where cathode lattice collapses it causes permanent cathode degradation.

Downside is the lower cell voltage from LFP cathode resulting in lower energy density.

 

[ScrotusGobbleBottom]

like a mult-level parking garage with most of the vertical support pillars removed

Excellent way to say that!