How long will a 100Ah battery run an appliance that requires 3000w?

A 100Ah battery can theoretically power a 3000W appliance for approximately 0.4 hours (24 minutes) under ideal conditions, assuming a 12V system. However, real-world factors like battery voltage, depth of discharge (DoD), and inverter efficiency significantly reduce runtime. For example, a 12V 100Ah lithium battery (1200Wh) running a 3000W load through an 85% efficient inverter delivers only ~14 minutes (0.23 hours). Pro Tip: Always check your battery’s continuous discharge current rating—3000W at 12V requires 250A, exceeding most batteries’ safe limits.

What Is a 48V Server Rack Battery and Its Benefits

How does voltage affect runtime calculations?

Voltage determines energy capacity (Wh = V × Ah). A 48V 100Ah battery stores 4,800Wh—quadruple the energy of a 12V system. For 3000W loads, higher-voltage systems reduce current draw, improving safety and efficiency. For example, 3000W at 48V requires 62.5A vs. 250A at 12V.

Practically speaking, voltage directly impacts both runtime and system design. A 48V 100Ah LiFePO4 battery with 90% DoD and 95% inverter efficiency provides 4,800Wh × 0.9 × 0.95 = 4,104Wh usable energy. Divided by 3,000W, this yields ~1.37 hours (82 minutes). Warning: Never exceed your battery’s maximum discharge rate—lithium batteries typically handle 1C (100A for 100Ah), but 3000W at 48V needs 62.5A, which is manageable. What if you use lead-acid? At 50% DoD and 80% efficiency, runtime drops to 0.67 hours (40 minutes).

Why is inverter efficiency critical?

Inverter losses convert 10–15% of energy to heat. A 3000W load with an 85% efficient inverter actually draws 3,529W (3,000 ÷ 0.85) from the battery. This dramatically shortens runtime—a 12V 100Ah battery’s 1,200Wh becomes 1,020Wh after 85% efficiency, yielding just 20 minutes at full load.

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