Firstly it is important that the battery periodically hits 100% and 10% - at least weekly for the 100%, and at least monthly for the 10%. This is needed for the voltage calibration (at 100% and 10%) and balancing (which takes place at 96% and near 10%).
Typically I run up to about 85-90% on most days, and down to 15-20% on most nights, but I will hit 100% / 10% on days when calibration is needed, and also on days where I know I will need the power, or the PV forecast is particularly low (so generally speaking I cycle more in winter than in summer).
At least on my battery pack, from a warranty viewpoint, the throughput warranty will cover 92% of a full cycle daily (a full cycle being from 10% to 100% and back down, so 92% of that would be maybe 18%-92% for example). 16.5kWh nominal capacity, 15kWh usable capacity, and the throughput warranty covers about 14kWh daily charge and discharge. So I don't think there is much to be gained by doing **less** than that since calendar degradation will also affect the battery regardless of how much you use it. So I aim to average that much usage over the long term. I use home assistant to track the warranty usage, do the calibration cycles, etc.
If in doubt about automating the calibration cycles, it is better to simply use the full range every day rather than doing it manually (which will result in forgetting, and the loss of voltage calibration and balance). While there
is a small advantage for longevity of limiting the range on LFP chemistry, it is minimal compared to NMC and other chemistries which are much more affected by SoC extremes.
Other factors which affect LFP battery degradation are:
* Cell temperature (it doesn't like getting too hot, so I have fans which will turn on if the bms_cell_temp_high goes too high).
* Charge speed (so I control the charge speed to charge at the minimal speed required to hit my SoC target at the target time)
* Calendar degradation (regardless of how much you use the battery).
The BMS will also make adjustments as needed to charge speed and so forth based on the temperature and SoC, I just go one step beyond that. Controlling the charge speed and turning on the fans seems to be very effective at keeping the cell temperature in the reasonable range, even in the middle of summer.
There are some references here:
* Calendar aging
https://www.mdpi.com/1996-1073/14/6/1732
* Insights for understanding multiscale degradation of LiFePO4 cathodes
https://www.sciencedirect.com/science/a ... 1722000283
* Degradation of LFP batteries at 100% SoC
https://iopscience.iop.org/article/10.1 ... 111/ad6cbd
But overall I think the most important thing you can do, is to stop the batteries getting too hot in summer by proper ventilation and limiting the charge rate.