DELTA Pro Ultra X Battery

EcoFlow DELTA Pro Ultra X Battery is LFP (lithium-iron-phosphate) — the chemistry now standard in residential storage. LFP runs cooler, doesn't have the runaway-fire risk profile of NMC, and tolerates 100% depth-of-discharge without warranty hits. It's slightly heavier and slightly less energy-dense than NMC, but for stationary residential use those are non-issues. LFP is the right choice — it's what we'd recommend either way.

EcoFlow DELTA Pro Ultra X Battery is rated 6kWh and (per the manufacturer) full DoD is in-warranty. In practice we'd still plan to use ~95% to leave reserve for the BMS to balance cells and to handle the small efficiency loss at the very bottom of the discharge curve.

LFP cells typically rate at 6,000–10,000 cycles to 80% DoD, which is 19+ years at one cycle per day. Real residential use rarely fully cycles every day, so calendar aging (cells degrading over time regardless of use) is usually the practical limiter, not cycle count.

EcoFlow DELTA Pro Ultra X Battery is sold as a single fixed-capacity unit and not designed to be paralleled or stacked. To grow capacity, you'd add a second bank with its own (or shared) inverter — workable, but more complex than buying a stackable system from day one.