Battery Storage Sizing Guide

Complete guide to sizing your battery storage system. Learn about energy consumption analysis, battery technology comparison, and backup duration calculations for optimal performance.

Energy Consumption Analysis

Proper battery sizing starts with understanding your household's energy consumption patterns. This analysis forms the foundation for determining the optimal battery capacity for your needs.

Daily Usage

Average daily kWh consumption from your electricity bill

Peak Periods

High consumption times (typically 16:00-19:00)

Essential Loads

Critical appliances for backup power scenarios

Battery Technology Comparison

Lithium Iron Phosphate (LiFePO4)

Cycle Life:6,000+ cycles
Depth of Discharge:95%
Efficiency:95-98%
Warranty:10-15 years

Best for: Long-term reliability, daily cycling, and maximum usable capacity.

Lithium Nickel Manganese Cobalt (NMC)

Cycle Life:3,000-5,000 cycles
Depth of Discharge:90%
Efficiency:92-95%
Warranty:10 years

Best for: High energy density applications and compact installations.

Depth of Discharge Impact

Understanding depth of discharge (DoD) is crucial for battery sizing. DoD represents how much of the battery's capacity can be safely used without damaging the battery or reducing its lifespan.

50% DoD

Conservative

Maximum battery life, minimal usable capacity

80% DoD

Balanced

Good balance of capacity and longevity

95% DoD

Maximum

Full capacity utilization (LiFePO4 only)

Sizing Formula

Required Battery Capacity = Daily Energy Need ÷ Depth of Discharge

Example: 15 kWh daily need ÷ 0.95 DoD = 15.8 kWh battery capacity required

Backup Duration Calculations

Essential Load Backup Scenarios

1-Day Backup (Essential Loads Only)

Lighting:
2 kWh
Refrigeration:
3 kWh
Internet/Comms:
1 kWh
Total:
6 kWh

Recommended: 7-8 kWh battery capacity (with 90% DoD)

3-Day Backup (Extended Outage)

Essential loads:
6 kWh/day
3 days:
18 kWh
Safety margin:
20%
Total:
22 kWh

Recommended: 24-25 kWh battery capacity (with 90% DoD)

5-Day Backup (Full Independence)

Full house load:
12 kWh/day
5 days:
60 kWh
Solar contribution:
-20 kWh
Net need:
40 kWh

Recommended: 45-50 kWh battery capacity (with 90% DoD)

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