The BBs have a DISCHARGE capacity of 100Ah, but the cell count is actually like 125Ah or something, the BMS cuts them off by voltage drop, so you never fully discharge them (and damage them).
Same thing on charging, the BMS cuts them off from being over charged and damaged.
It's a quite well thought out design to make it virtually 'Idiot Proof'.
Under rating the cells, using bigger cells than advertised cost BB a little more money, same with low voltage disconnect and charge cut off BMS, but the battery actually does deliver 100Ah, many others don't, and some don't have the protections so it's "User Abuse" when it fails and you try to get warranty...
*IF* you were to build your own battery, you would need to put a low voltage cut off in so the cells weren't completely discharged, and use a BMS to cut off the charging to ensure they weren't overcharged.
I got some that were just the cell packs and killed them learning the hard way, I wish I'd seen Will's videos first not being familiar with LiFePo4 I cooked one set entirely with no high voltage cut off and 'Float' voltage way too high.
Even used, it was an expensive mistake through ignorance...
As for prismatic vs spiral, I'm reaching the end of 2 years in service.
I discharged, fully charged, and discharged again to tell exactly what each (numbered) cell would do.
At one year I did it again, and now I'm reaching 2 years to see how much the capacity degraded over those two years or working (but not abused) cells do.
If it's anything like the first year, about 1.5% of capacity in a year, it would take 15 years to knock them back to 80% of new at that rate!
We shall see...
