Battery Storage Calculator

Size a battery storage system based on daily energy needs, backup duration, and depth of discharge.

kWh
days
%
USD/kWh

Required Battery Capacity

37.5 kWh

Usable Capacity30.0 kWh
Estimated System Cost18,750 USD
Tesla Powerwalls Equivalent3 units

Required Battery Capacity vs Daily Energy Requirement

सूत्र

## 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.

हल किया गया उदाहरण

A home needing 30 kWh/day with 1 day backup at 80% DoD and $500/kWh battery cost.

  1. 01Usable capacity: 30 * 1 = 30 kWh
  2. 02Total capacity: 30 / 0.80 = 37.5 kWh
  3. 03System cost: 37.5 * $500 = $18,750
  4. 04Powerwalls needed: ceil(37.5 / 13.5) = 3 units

अक्सर पूछे जाने वाले प्रश्न

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.

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