Watt-hours (Wh) measure total stored energy, whereas Amperes (Amps) measure electric current rate. Dividing stored energy by operating voltage and discharge time in hours yields electric current: Amps = Wh ÷ V ÷ Hours.
Real-Life Wh to Amp Sizing Scenarios
Scenario 1: Deep Cycle Marine Battery Sizing
A 1,200 Wh marine battery operating at 12V DC discharges over a 5-hour period:
Amps = 1200 Wh ÷ 12 V ÷ 5 Hours = 20 Amps (Charge capacity = 100 Ah)
Scenario 2: Off-Grid Solar Power System Sizing
A 2,048 Wh solar battery operating at 24V DC discharges over an 8-hour period:
Amps = 2048 Wh ÷ 24 V ÷ 8 Hours = 10.67 Amps (Charge capacity = 85.33 Ah)
Step-by-Step Sizing Guide & Formulas
Wh to Amps Formulas:
DC Circuit: Amps = Wh ÷ (V × Hours)
AC Single Phase: Amps = Wh ÷ (V × Hours × PF)
AC Three Phase: Amps = Wh ÷ (√3 × V × Hours × PF)
Step 1: Identify energy (Wh = 1200 Wh), voltage (V = 12V), and runtime (Hours = 5 h).
Step 2: Calculate Ampere-hours (Ah): 1200 ÷ 12 = 100 Ah.
Step 3: Divide by runtime: 100 ÷ 5 = 20 Amps.
Final Answer: 1200 Wh at 12V operating over 5 hours delivers 20 Amps.
Converting Amperes (Amps) to Watt-hours (Wh) calculates total electrical energy by multiplying current, system voltage, and operating hours: Wh = Amps × V × Hours.
Real-Life Amps to Wh Sizing Scenarios
Scenario 1: Household Appliance Load Sizing
A 10 Amp single-phase appliance operates at 220V AC for 5 hours (PF = 1.0):
Wh = 10 Amps × 220 V × 5 Hours = 11,000 Wh (11.0 kWh)
Scenario 2: RV Deep Cycle Battery Capacity Sizing
A 100 Ah 12V deep-cycle battery provides energy storage:
Wh = 100 Ah × 12 V = 1,200 Wh (1.2 kWh)
Step-by-Step Sizing Guide & Formulas
Amps to Wh Formulas:
DC Circuit: Wh = Amps × V × Hours
AC Single Phase: Wh = Amps × V × Hours × PF
AC Three Phase: Wh = √3 × Amps × V × Hours × PF
Step 1: Identify current (Amps = 1 A), voltage (V = 240V), and runtime (Hours = 1 h).
Step 2: Multiply parameters: Wh = 1 × 240 × 1 = 240 Wh.
Final Answer: 1 Amp at 240V operating for 1 hour consumes 240 Wh.