LFP Batteries below 20 percent?

[cs1234]

The trouble with taking them down to zero by design is loss of power. That matters to me.

You bring up an excellent and amusing point. I'm guessing if they are cycled down to zero, most people are assuming they are being immediately charged back up / switched over to another power source so you don't lose power. Letting them just completely die and have your power go out would be a pretty funny way of cycling them.