Discharge rate and depth of discharge are two different things. LiFePO4 (Lithium Iron Phosphate) batteries can be continually discharged to 100% and there is no long-term effect. (It is a good practice not to do so)
Most lead acid batteries experience a significantly reduced cycle life if they are discharged more than 50%.
That part was taken from Battle born battery FAQ.
I can confirm this claim with my experience with their batteries. I installed 4 of them in my trailer. Depleted them ~5% (not intentional) throughout the 3 year period I had the trailer. Before I list the trailer for sale I did a battery capacity test. and it was ~95% of the original capacity.
I can also confirm this with Regnogy batteries as well. I did install just one 100AH 12V in one of my previous trailers.
Also I have built LiFePO4 battery packs using individual cells and BMSs bought from AlliExpress. Have used them in electric go kart builds and discharged to 0% without any problem.
So maintaining LiFePO4 above 30% is just a myth coming from lead acid world. The important thing to remember here is to keep them around 50% when put in storage. (storage means compete disconnect) And they will retain that level for a very long period.
These are the exact reasons why LiFePO4 have become very popular these days. And also they are 50% lighter and safer to charge/discharge than Lithion-ion.
The BMS in a LiFePO4 battery should ensure that individual cells are maintained above the minimum voltage. I don't have enough data for the Renogy 48V 10KWh battery yet. But I have posted my initial test results here:
I will update that as I find more test data. In my recent test (after 10K miles on Van) I depleted the battery again to 5% with the same capacity results. No degradation at all.
With the Renogy 48V 10KWh battery I charge it to 50-60% and do the complete shut down even If I store the van for a week. Have stored it like this more than a month and had no issues. When you take out from storage charge it back to 100% using shore power. This will help to recalibrate the BMS.
Everytime I charge from shore power the alternator charging system (APS-500) as well as Firefly goes out from the CAN bus. You will see the Red lamp inside the battery switch compartment start blinking as well as firefly showing 0%. Solution is simple. Just turn the 12V switch OFF for 5sec and turn it back ON before you leave your camp site.
If you do not do a complete shut down I believe under cold weather battery internal heaters will kick in. They could deplete the battery.
As I am a battery enthusiast one of the things in my list to do is to take this magical battery apart and see how it is built. The weight of this battery pack is around the same range for 10KWh pack but the dimensions are around 50% give or take compared to building a similar capacity unit using say 4 2.5KWh batteries. Could be just the single BMS saving room for more battery cells.