电池储能计算器
使用电池储能计算器评估家用或商业储能系统的容量需求和经济效益。输入用电量和电价参数，计算所需电池容量kWh、投资回报周期及节省金额。
Required Battery Capacity
37.5 kWh
Required Battery Capacity vs Daily Energy Requirement
公式
How to Size Battery Storage
Battery systems are sized based on energy needs and desired backup duration.
Formula
Usable Capacity = Daily kWh * Backup Days
Total Capacity = Usable / Depth of Discharge
Depth of discharge (DoD) limits how much battery capacity you actually use. Most lithium batteries recommend 80-90% DoD to maximize lifespan.
计算示例
A home needing 30 kWh/day with 1 day backup at 80% DoD and $500/kWh battery cost.
- 01Usable capacity: 30 * 1 = 30 kWh
- 02Total capacity: 30 / 0.80 = 37.5 kWh
- 03System cost: 37.5 * $500 = $18,750
- 04Powerwalls needed: ceil(37.5 / 13.5) = 3 units
常见问题
What is depth of discharge?
Depth of discharge (DoD) is how much of the battery capacity you use. An 80% DoD on a 10 kWh battery means you use 8 kWh. Lower DoD extends battery life.
How long do home batteries last?
Most lithium-ion home batteries are warranted for 10-15 years or 3,000-5,000 cycles. After that, they retain about 70-80% of original capacity.
Can batteries pay for themselves?
In areas with time-of-use rates, batteries can save $50-200/month by storing cheap off-peak electricity. Combined with solar, payback can be 7-12 years.