How Long Will A 100Ah Lithium Battery Typically Last?

A 100Ah lithium battery typically delivers 100 amp-hours of capacity, lasting 5–10 hours at 10A load or 1–2 days powering small off-grid systems. Actual runtime depends on discharge rate (C-rate), depth of discharge (DoD), and efficiency losses (≈15%). LiFePO4 variants maintain 80% capacity for 3,000–5,000 cycles, outperforming lead-acid by 4x. Pro Tip: Keep DoD ≤80% to maximize lifespan.

What defines a 100Ah lithium battery?

A 100Ah lithium battery stores 100 amp-hours at 12.8V (1,280Wh), using LiFePO4 or NMC cells. Key features include 10kg–15kg weight, 80–95% efficiency, and 1C continuous discharge. Common in RVs, solar storage, and marine use, they support 2,000–5,000 cycles at 80% DoD. Pro Tip: Avoid full discharges—LiFePO4 prefers partial cycles for longevity.

When considering runtime, 100Ah means delivering 5A for 20 hours or 20A for 5 hours, but actual capacity drops at >0.5C rates. LiFePO4’s flat discharge curve holds voltage above 12V until 90% DoD. For example, a 100Ah battery running a 500W fridge (40A) lasts ≈2.5 hours.

What factors affect lithium battery runtime?

Discharge rate, temperature, and system efficiency dictate runtime. High C-rates (e.g., 1C) reduce effective capacity by 15–20% vs 0.2C. At -20°C, capacity plummets 50%. Inverters lose 10–15% energy during DC-AC conversion. Pro Tip: Use pure sine wave inverters to minimize losses.

Beyond basic calculations, Peukert’s Law shows higher currents disproportionately drain capacity. A 100Ah battery at 0.1C (10A) delivers ≈95Ah, but at 1C (100A), only ≈70Ah. For example, an e-bike drawing 25A would run ≈3 hours instead of 4. Transitional systems like solar require derating for cloudy days—size batteries 30% larger than calculated. But what if loads vary? Lithium’s flat voltage curve maintains stable output until 90% discharge, unlike lead-acid’s steady decline.

How is 100Ah used in solar systems?

In solar setups, 100Ah batteries store 1.2–1.5kWh daily, powering lights (10W), fridges (100W), and routers (15W) for 8–12 hours. They pair with 200W–300W panels, needing 5–8 peak sun hours for full recharge. Pro Tip: Add a 40A BMS to prevent overcharge during high irradiation.

Assuming 85% efficiency, a 100Ah battery in a 24V system powers a 1kW load for ≈30 minutes. However, practical solar designs cap DoD at 50% for longevity—effectively 50Ah. For instance, a cabin using 2kWh/day needs four 100Ah batteries (12.8V × 100Ah × 4 = 5.12kWh). Transitionally, lithium’s 95% round-trip efficiency outperforms lead-acid’s 75%, reducing required panel size by 20%. Tables compare solar vs RV usage:

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