Our watt hour calculator uses fundamental electrical formulas to determine energy consumption, battery capacity, and electricity costs. The calculator converts between watts, watt-hours, kilowatt-hours, and amp-hours, making it essential for solar system design, RV electrical planning, and off-grid applications.

Understanding Watt-Hours vs Amp-Hours

Watt-hours (Wh) measure total energy capacity regardless of voltage, making them ideal for comparing batteries of different voltages. Amp-hours (Ah) measure charge capacity at a specific voltage. A 12V 100Ah battery and a 24V 50Ah battery both contain 1200 Wh, despite different Ah ratings. Always convert to watt-hours when comparing batteries or sizing systems to ensure accurate capacity planning.

• Watt-hours are voltage-independent energy measurements
• Higher voltage systems are more efficient (less current, less loss)
• Lead-acid batteries: use only 50% capacity for longevity
• Lithium batteries: safe to use 80-90% capacity
• Account for inverter efficiency losses (10-15%)
• Cold temperatures reduce battery capacity by 20-40%

Sources & References