You forgot to mention that you have been deeply and continually cycling those cells for the past 10yrs. They have far more full cycles on them than what would be expected on a normal cruising boat over the same time period.
You didn't mention how many times they caught fire, though...
- Closing in on 1200 cycles (would need to double check my notebook), most of those to right around 80% DOD (this is a boat-load of deep-cycles)
- Only ever back to 100% SOC, when cruising, every 10-20 cycles, in order to keep the Ah counter calibration in-check (just switched from a Link-Pro to the Balmar SG200 to eliminate the Ah counter calibration issues)
- Capacity tested every 50 cycles to 0% SOC
- Once 1000 cycles were attained I switched to every 100 cycles for capacity testing (the cells have been taken to 0% SOC no less than 30 times because we were messing around with "memory effect" testing on some of the test cycles)
- Batteries were only re-balanced once, at around 750 cycles, due to a BMS board glitch (I don't allow our charge voltage to reach balancing level)
- The cells were very well matched from the factory, something that is getting tougher to find today
- The cells have never been floated nor held at a high SOC for very long - we charge, then discharge we don't float, ever...
- The cells have rarely exceeded 85F
- When not in-use they are sitting somewhere between 30% SOC and 50% SOC..
- Charge rate has been about .35C for the last five years or so (solar has been all but turned off unless we need to slow our discharge).
- Just getting the boat ready on the mooring, with the engine warming up, can replenish more than a days worth of energy for us.
- The cells have only ever been charged to a max peak voltage of 13.9 (very short duration) then it drops to 13.8V for about 18 minutes, then OFF.
- At a charge voltage of 13.8V, tapering to about .025C over about 18 minutes or so, we can extract over 400Ah of capacity from the cells.
Oh yes and no fires
and the cells rarely if ever exceed more than a 1F differential from ambient temp even when charging at .35C or 35% of Ah capacity.
That said these cells are still pretty easy to damage $$$ if not used / charged correctly...