EGbatt Guide · Performance

“6000 cycles” on a datasheet is real — but only at the conditions printed next to it. This guide shows what cycle life actually measures, what quietly shortens it, and how to turn a spec line into a realistic number of years.

Updated 2026 · 5 min read · Written by EGbatt application engineers

What “one cycle” means

A cycle is one equivalent full discharge and recharge, not necessarily 100%→0%→100%. Drawing 50% twice is one cycle. What matters is throughput (kWh moved), which is why warranties are increasingly written in throughput, not just cycles.

Depth of discharge is the biggest lever

Shallow discharges dramatically extend life. The table below is typical for LFP:

Cycle-life vs DoD (typical LFP)

Depth of dischargeTypical cycles to 80%Practical note
100% (0–100%)~3,000Worst case the spec quotes
80%~4,500Sweet spot for most designs
50%~6,000+Best $/cycle, common in solar
20%~8,000+Longest life, needs bigger bank

Temperature and C-rate

Life falls as cells run hot or are charged/discharged too fast. Keeping the bank between 15–35 °C and at or below the rated C-rate preserves most of the rated cycles. High sustained heat is the silent killer behind most premature field failures.

Estimating real service life

Take rated cycles × usable kWh per cycle × DoD factor, then divide by your yearly throughput. A 10 kWh home bank cycled once a day at 80% DoD (~3,600 kWh/yr) from a 4,500-cycle rating gives roughly 4,500 ÷ 365 ≈ 12 years of daily use. That is the number to trust, not the headline.

Key takeaways

DoD beats headline

80% DoD can outlive 100% DoD by 50%.

Heat shortens life

Keep the bank 15–35 °C for rated cycles.

Use throughput

Life ÷ yearly kWh = realistic years.

Capacity fades slowly

LFP fades gently, not a cliff.

Talk to an EGbatt engineer

Tell us your load, voltage and autonomy. We will size the pack, quote it, and flag the traps before you buy.

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Frequently asked questions

No. “End of life” is usually defined as 80% of rated capacity; the pack still works, just smaller.

Very slowly. Calendar aging is minor for LFP stored at ~50% SoC and cool — see storage guidance.

Because throughput, not cycle count, is what actually wears a cell — it is the fairer measure.