DoD vs Battery Lifespan Calculator

By a power law: halving DoD roughly triples Li-ion cycle count. An NMC pack rated 2,000 cycles at 85% DoD delivers ~5,500 cycles at 50%. This is why oversizing a battery (cycling it shallower) often costs less per delivered kWh over a decade.

Calendar aging runs regardless of use — typically 1.5–2.5%/yr for Li-ion, worse when hot or stored full. A lightly-cycled backup battery (0.1 cycles/day) hits 80% from calendar fade in 8–13 years no matter how few cycles it saw. The tool shows which clock runs out first for your duty.

By cycle count: LTO (15,000+) and vanadium flow (12,000+, DoD-insensitive) lead; LFP (3,000–6,000) is the practical champion for cost; NMC/NCA (1,500–2,500) trade life for energy density; lead-acid (400–1,200) trails but is cheap upfront. Match chemistry to your cycling intensity.

Throughput = capacity × DoD × cycles — the total energy a battery moves over its life. Warranties increasingly cap MWh throughput because it captures wear better than years or cycle counts alone. Compare price ÷ throughput across chemistries for the honest cost-per-kWh-delivered.