How many cycles does a LiFePO4 battery last?

Quality LiFePO4 batteries last 3,000-6,000 cycles to 80% capacity retention. At 80% DoD and 25°C, expect 3,500-4,000 cycles (9.6-10.9 years at 1 cycle/day). At 50% DoD, the same cells last 6,000-8,000 cycles (16-22 years). LiFePO4 significantly outlasts NMC (2,000 cycles) and lead-acid AGM (500 cycles).

How does depth of discharge affect battery life?

Depth of discharge is the most powerful lever for battery longevity. Reducing DoD from 80% to 50% roughly doubles LiFePO4 cycle life. For lead-acid, the effect is even more dramatic — lead-acid is extremely sensitive to deep cycling and collapses at high DoD. Lower DoD = dramatically longer battery life, though you may need a larger battery bank to deliver the same daily energy.

What is cost per kWh delivered from a battery?

Cost per kWh delivered = Battery purchase cost ÷ Total lifetime kWh throughput. For a 10 kWh LiFePO4 battery at $8,000 installed, cycling daily at 80% DoD for 3,500 cycles: 3,500 × 8 kWh = 28,000 kWh throughput. Cost = $8,000 ÷ 28,000 = $0.286/kWh. This metric lets you compare battery options against your electricity rate.

Which battery chemistry has the longest cycle life?

Cycle life ranking: LiFePO4 (3,500-6,000 cycles at 80% DoD) > Sodium-ion (3,000 cycles) > NMC (2,000 cycles) > Lead-acid AGM (500 cycles at 50% DoD). LFP also has better thermal stability than NMC. LFP is clearly best for daily cycling solar storage; NMC is better for energy density applications where weight matters (EVs). Lead-acid is only cost-competitive for very low cycle-count backup applications.

Battery Cycle Life Calculator

Enter battery chemistry, capacity, daily DoD, and temperature — get estimated cycle count, lifespan in years, cost per kWh delivered, and a full degradation curve.

Battery specifications

Battery chemistry?

Battery capacity?

kWh

Daily depth of discharge (DoD)?

Cycles per day?

Average operating temperature?

°C

Battery cost?

$/kWh

Battery cycle life estimate

3,500 total cycles — 9.6 year lifespan

kWh per cycle (at 80% DoD)8.00 kWh/cycle

Cumulative kWh throughput28,000 kWh over lifetime

Cost per kWh delivered$0.0003/kWh

Estimated replacement year2035

Temperature effect on life100% of rated cycle life

Degradation curve (100% → 80% capacity at end of life)

Cycle life used	Cycles completed	Year	Capacity remaining
25%	875	2028	95%
50%	1,750	2030	90%
75%	2,625	2033	85%
100%	3,500	2035	80%

What if you reduced DoD by 10%? (70% instead of 80%)

New total cycles4,108

New lifespan11.3 years (+17%)

New cost per kWh delivered$0.0003/kWh

Link copied to clipboard

How to Use This Calculator

Select chemistry and enter capacity

Battery cycle life varies enormously by chemistry: LiFePO4 leads at 3,500+ cycles at 80% DoD; NMC delivers 2,000 cycles; lead-acid AGM manages only 500 cycles at 50% DoD. Sodium-ion is emerging at ~3,000 cycles. Enter your battery's rated capacity in kWh — this is the nameplate value at 25°C, typically what's printed on the spec sheet or product page.

Set your depth of discharge and cycles per day

Depth of discharge (DoD) is the most powerful lever for extending battery life. At 80% DoD, LiFePO4 lasts 3,500 cycles. Drop to 50% DoD and it can last 7,000+ cycles — more than double the life. Enter how much of your battery you actually use daily as a percentage. For most home storage systems, 80% DoD is typical. For backup-only systems, your effective DoD over the year is much lower.

Set temperature

Temperature affects cycle life via the Arrhenius relationship: every 10°C above optimal roughly halves battery cycle life. A battery operating at 35°C will age noticeably faster than one at 25°C. Enter the average operating temperature in °C — not peak temperature, but the average your battery sits at most of the time.

The Formula

DoD-Adjusted Cycles = Rated Cycles × (Rated DoD ÷ Actual DoD)^exponent (LiFePO4 exponent: 1.2 | Lead-acid: 1.8 | NMC: 1.3 | Na-ion: 1.15) Temperature Factor = 0.97^(|Temp - Optimal| × chemistry factor) Adjusted Total Cycles = DoD-Adjusted Cycles × Temperature Factor Lifespan (years) = Total Cycles ÷ Cycles per Day ÷ 365 kWh per Cycle = Capacity (kWh) × DoD ÷ 100 Cumulative kWh = Total Cycles × kWh per Cycle Cost per kWh Delivered = Battery Cost ($) ÷ Cumulative kWh

The DoD exponent represents how aggressively each chemistry responds to deeper cycling. Lead-acid has the highest exponent (1.8) — it is extremely sensitive to DoD; cycling at 80% instead of 50% doesn't just give you less life proportionally, it collapses it. LiFePO4 at exponent 1.2 is less sensitive: doubling DoD from 40% to 80% roughly halves the cycles, a more linear response. These values are calibrated against published manufacturer cycle life curves from Pylontech, BYD, and industry standards.

Example

Home solar storage — LiFePO4 daily cycling comparison

A homeowner has a 10 kWh LiFePO4 battery costing $0.80/kWh. They want to compare daily cycling at 80% DoD versus conservative 50% DoD.

ChemistryLiFePO4

Capacity10 kWh

Cycles/day1

Temperature25°C

80% DoD (typical)

Total cycles3,500

Lifespan9.6 years

Cumulative kWh280,000 kWh

Cost per kWh$0.000286/kWh

50% DoD (conservative)

Total cycles~6,400

Lifespan17.5 years

Cumulative kWh~320,000 kWh

Cost per kWh~$0.000250/kWh

Reducing DoD from 80% to 50% extends lifespan from 9.6 to 17.5 years — an 82% longer battery life. The trade-off is you use only 5 kWh per day instead of 8 kWh, so you may need a larger battery bank. The cost per kWh delivered actually improves slightly at lower DoD because the life extension outpaces the reduced daily throughput. LiFePO4 at 50% DoD is one of the best long-term energy storage investments available — at $0.025/kWh delivered, it beats most electricity rates over the system's life.

FAQ

How many cycles does a LiFePO4 battery actually last? ▼

Quality LiFePO4 batteries are rated at 3,000-6,000 cycles to 80% capacity retention. The specific number depends on DoD (depth of discharge), temperature, and charge rate. At 80% DoD and 25°C, most LiFePO4 cells last 3,500-4,000 cycles. At 50% DoD, the same cells last 6,000-8,000 cycles. At 1 cycle/day, 3,500 cycles = 9.6 years; 6,000 cycles = 16.4 years. Premium cells from CATL and EVE Energy in products like Tesla Powerwall and Pylontech are demonstrating real-world performance at or above these ratings.

How does depth of discharge affect lead-acid battery life? ▼

Lead-acid is extremely sensitive to DoD — much more so than lithium. At 50% DoD, AGM lead-acid lasts about 500 cycles. Cycle at 30% DoD and you might get 1,200+ cycles; at 80% DoD and it collapses to 200-250 cycles. This non-linear relationship is why lead-acid batteries in solar systems are typically sized for 50% DoD maximum, with 20-30% DoD being ideal. Even with careful use, a lead-acid battery bank needs replacement every 2-5 years, versus 10-15+ years for LiFePO4. The lifecycle cost comparison strongly favors lithium for daily cycling applications.

Is it better to do 1 cycle per day at 80% DoD or 2 cycles at 40% DoD? ▼

For LiFePO4, the math slightly favors 2 cycles at 40% DoD for cycle count, but the calendar life is the same (both wear out at 10+ years with daily cycling). The bigger issue with 2 cycles/day is accelerated calendar aging — more charge-discharge cycles per day means more mechanical stress on electrodes per year. For most home storage, 1 cycle/day is optimal. Commercial systems doing TOU arbitrage (charge overnight off-peak, discharge morning peak, recharge midday solar, discharge evening peak) do 2 cycles legitimately. If your BMS supports it and your warranty permits it, 2 cycles is viable for LiFePO4 and NMC but should be avoided with lead-acid.

How does temperature affect battery cycle life? ▼

Temperature affects both capacity (reversible, recovers when battery warms) and cycle life (irreversible aging). High temperatures accelerate the chemical reactions that cause permanent capacity fade — this follows the Arrhenius equation: aging rate roughly doubles for every 10°C above optimal. A LiFePO4 battery at 35°C will age about 25-30% faster than the same battery at 25°C. At 45°C, it ages 50-60% faster. Cold temperatures slow calendar aging but reduce usable capacity and can damage cells if charged while frozen. Optimal temperature for both capacity and longevity is 15-25°C for lithium batteries.

How do I calculate the real cost per kWh from my battery? ▼

Cost per kWh delivered = (Battery purchase cost) ÷ (Total kWh throughput over lifetime). For a 10 kWh LiFePO4 battery costing $8,000 (all-in installed), cycled daily at 80% DoD for 3,500 cycles: total throughput = 3,500 × 8 kWh = 28,000 kWh. Cost per kWh = $8,000 ÷ 28,000 = $0.286/kWh. This is your "battery cost" component of stored electricity — competitive with grid electricity in high-rate states ($0.25-0.35/kWh). At lower DoD or with a longer-lived battery, this drops further. This metric is more useful than simple payback for comparing battery options.

Related Calculators

Embed This Calculator

Free to embed on your website. Just copy this code:

<iframe src="https://solarsizecalculator.com/battery-cycle-life-calculator"
  width="100%" height="700" frameborder="0"
  title="Battery Cycle Life Calculator"></iframe>