I have flown with both an LFP and SLA battery in my ship for 5 years. I alternate which one is primary and which one is secondary on each flight. A PowerSonic 12V14Ah SLA vs Powerizer 12V15Ah LFP. With all my instruments running the SLA voltage drops below the minimum requirements of my radio by 5 hours. My LFP has never failed to power everything up to a 7 hour flight.. The SLA gets replaced after 3 years. My LFP is six years old and still working perfectly.

When I fly in very cold conditions (0C) the SLA is usually not driving my radio by three hours. Again, the LFP has run up to six hours without any significant voltage drop.