Enter the Object Dimensions, Velocity, Fluid Properties, and Shape into the Drag Force Calculator to get the Drag Force, Drag Coefficient, Reynolds Number, Terminal Velocity, and Power Required to overcome drag.
Required Battery Capacity
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Battery Bank Size
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Usable Energy Storage
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Total Energy Required
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Battery storage requirements depend on your daily energy usage and desired backup days. Multiply your daily kWh usage by the number of backup days, then account for depth of discharge limits and system inefficiencies.
Lead acid batteries should only be discharged to 50% capacity, requiring roughly double the capacity of lithium batteries which can safely discharge to 80%. Lithium also has higher efficiency and longer lifespan.
List all your appliances with their power ratings in watts, estimate daily usage hours for each, then multiply watts × hours ÷ 1000 to get kWh per day. Add up all appliances for total daily usage.
Depth of discharge is how much of the battery's capacity you use before recharging. Limiting DoD to 50% for lead acid and 80% for lithium significantly extends battery life and maintains performance.
Most off-grid systems are designed for 3-5 days of autonomy to handle cloudy weather. Consider your local climate, backup generator availability, and critical vs non-critical loads when choosing autonomy days.
Higher voltages are more efficient for larger systems. Use 12V for small systems (<1000W), 24V for medium systems (1000-3000W), and 48V for large systems (>3000W) to reduce current and wire losses.
Typical system efficiency ranges from 80-90%, accounting for inverter losses, wiring losses, and battery inefficiencies. Use 85% as a conservative estimate, or 80% for systems with older equipment.