What size inverter can I run off a 100Ah lithium battery?

A 100Ah lithium battery can safely power an inverter with a continuous wattage rating of 1,000–1,200W in a 12V system, assuming 80% depth of discharge and 90% inverter efficiency. Key factors include battery voltage (12V/24V/48V), peak surge capacity (e.g., 2,000W for motor startups), and discharge rate limits (typically ≤1C for LiFePO4). Always match inverter input voltage to battery voltage to prevent efficiency losses.

Best RV Battery for Dry Camping

How does battery voltage affect inverter sizing?

Battery voltage directly determines maximum power output (Watts = Volts × Amps). A 100Ah 12V battery provides 1.2kW continuous, while a 48V system delivers 4.8kW—critical for high-power appliances.

For example, a 12V 100Ah LiFePO4 battery with 1C discharge can theoretically supply 100A × 12V = 1,200W. However, practical limits apply: 80% depth of discharge reduces usable energy to 960Wh, and inverter inefficiency (typically 10–15%) further lowers available power. Pro Tip: Use 24V/48V systems for ≥2kW inverters—higher voltage reduces current draw, minimizing heat in cables. Transitioning to real-world applications, a 48V system running a 3kW inverter would require 3,000W ÷ 48V = 62.5A, well within a 100Ah battery’s 1C capability.

What safety margins prevent battery damage?

Maintain 20% headroom between inverter demand and battery capacity. Exceeding 1C discharge in LiFePO4 accelerates degradation—a 100Ah battery shouldn’t sustain >80A draw.

Practically speaking, a 1,200W inverter on a 12V system pulls 100A (1,200W ÷ 12V). With 80% safe discharge limit, maximum continuous load should be 960W (80A × 12V). Thermal considerations matter too—sustained high current heats cables and BMS components. Pro Tip: Install Class T fuses within 18″ of battery terminals—they interrupt 20,000A faults faster than breakers. Did you know? A 100Ah battery powering a 1,000W microwave (1,300W surge) needs inverter surge rating ≥150% of peak load.

How does inverter efficiency impact runtime?

Quality inverters achieve 90–95% efficiency vs. 70–85% in budget models. A 10% efficiency loss equals 10% shorter runtime for same load.

Consider this: A 1,000W load on a 12V system requires 1,000W ÷ 12V = 83.3A. With 90% efficient inverter, actual battery draw becomes 83.3A ÷ 0.9 = 92.6A—cutting runtime from 1 hour to 51 minutes. Pro Tip: Use pure sine wave inverters for sensitive electronics—modified sine models create harmonic losses reducing effective efficiency. Transitionally, energy-hungry devices like air compressors benefit from inverters with Eco modes that minimize idle consumption (often <1W).

Fasta Power Expert Insight

FAQs

Best Deep Cycle Battery for RVs