Comment by amluto

LFP’s flat discharge curve is actually kind of annoying: it makes it quite difficult to measure the state of charge of a cell. BMSes mostly need to track the SoC by counting coulombs, and balancing a series of cells may be challenging unless the SoC to reach the steeper part of the curve.

Meanwhile, most serious applications have power conversion circuitry, so a variable voltage may not be much of a problem.

The low-end “12V” LFP packs without real BMSes or power conversion that sort of pretend to be lead-acid batteries in RVs and such are awful designs and work pretty poorly, and their “24V” and “48V” cousins are not much better. It’s true that Na-Ion may not be an easy drop-in replacement. That being said, some people are working on Na-Ion as a lead-acid replacement for car starter batteries (and for low voltage systems in EVs), and they have a lot of potential in this application. (LFP doesn’t have adequate not temperature performance and lead-acid sucks for many reasons.)