Calculate amps per hour, convert amp hours to watt hours, and determine battery runtime with our comprehensive calculator. Perfect for battery sizing, electrical engineering, and power system design.
Common Battery Calculations
Calculate amp hours, convert to watt hours, and determine battery runtime
Efficiency accounts for inverter and system losses
Add 20% safety margin for battery longevity
Understanding the fundamental formulas and concepts behind amp hour calculations
Calculate amp hours for a 24W LED strip running 8 hours on 12V system:
65W laptop running 6 hours on 12V battery system:
120W RV fridge running 24 hours on 12V system:
Different battery types have varying amp hour capacities and characteristics
Traditional automotive and deep-cycle batteries
Lithium iron phosphate batteries
Absorbed Glass Mat sealed batteries
Gel electrolyte sealed batteries
Lithium-ion rechargeable batteries
Nickel-metal hydride batteries
Real-world scenarios where amp hour calculations are essential
Calculate battery needs for off-grid camping and RV adventures.
Size battery banks for solar energy storage systems.
Calculate backup time for uninterruptible power supplies.
Understand EV battery capacity and range calculations.
Battery sizing for boats and marine electronics.
Home backup power system calculations.
Quick reference for common battery capacities at different voltages
| Amp Hours (Ah) | 12V System | 24V System | 48V System | Common Use |
|---|---|---|---|---|
| 10Ah | 120Wh | 240Wh | 480Wh | Small UPS, Emergency lights |
| 35Ah | 420Wh | 840Wh | 1,680Wh | Car battery, Small solar |
| 50Ah | 600Wh | 1,200Wh | 2,400Wh | RV house battery |
| 100Ah | 1,200Wh | 2,400Wh | 4,800Wh | Deep cycle, Solar storage |
| 200Ah | 2,400Wh | 4,800Wh | 9,600Wh | Large RV, Off-grid home |
| 400Ah | 4,800Wh | 9,600Wh | 19,200Wh | Home backup, Large solar |
Common questions about amp hour calculations and battery capacity
Amp hours (Ah) is a unit of battery capacity that measures how much current a battery can deliver over time. "Amps per hour" is not a standard electrical term. When calculating amps per hour, you're typically looking at current consumption rate, which is measured in amperes (A). Amp hours = Amps × Hours.
To calculate amp hours from watts: First find the current by dividing watts by voltage (I = P ÷ V), then multiply by time in hours (Ah = I × t). For example: 120W device on 12V system for 5 hours = (120W ÷ 12V) × 5h = 10A × 5h = 50Ah.
Amp hours (Ah) measures current capacity over time, while watt hours (Wh) measures energy capacity. Watt hours = Amp hours × Voltage. Wh is more useful for comparing batteries of different voltages, while Ah is commonly used for batteries of the same voltage system.
Amp hour calculators provide theoretical results based on ideal conditions. Real-world factors like temperature, battery age, discharge rate, and system efficiency can affect actual performance. Always add a 20-25% safety margin to calculations for practical applications.
Yes, this amp hour calculator works for all battery types including lithium, lead-acid, AGM, and gel batteries. However, different battery chemistries have different usable capacity percentages (depth of discharge), which affects real-world runtime calculations.
Other useful tools for battery and electrical calculations
Convert power to energy over time
Calculate voltage, current, resistance, power
Estimate runtime based on load and capacity
Size solar panels and battery banks
Our battery experts can help you choose the right amp hour capacity for your specific application. Get professional consultation and custom battery solutions.