Solar Battery Sizing Guide: How to Choose the Right kWh for Your Home or Business
Mar 27, 2026
P
Peter Lu
Energy Storage Product Manager, GreenMore · Energy storage systems
Solar batteries are now a core part of modern energy systems, letting homeowners and businesses store excess solar power, reduce electricity bills and keep backup power during outages. One question comes up more than any other: How big should my solar battery be?
As a manufacturer of LFP home battery systems, commercial energy storage systems and solar-plus-battery systems, GreenMore sees correct sizing as the key to performance, safety and long-term return. This guide explains how to choose battery capacity from real energy needs, solar production and backup requirements.
What Battery Size Really Means
Battery size is measured in kilowatt-hours (kWh), which indicates how much energy the battery can store and deliver. The tiers below cover most situations:
Capacity
Typical application
5–10 kWh
Small homes, essential loads
10–20 kWh
Typical homes with solar
20–40 kWh
Large homes or partial off-grid
50 kWh+
Small businesses
100 kWh–5 MWh
Industrial and containerized BESS solutions
GreenMore designs modular systems that scale from 5 kWh residential energy storage to multi-MWh industrial LFP energy storage for factories and warehouses.
How to Calculate the Battery Size You Need
Battery sizing comes down to three factors: how much energy you use, how much your solar array produces and what you need to keep running.
Daily Energy Consumption
Check your electricity bill for daily kWh usage. Typical ranges:
Small apartment: 5–10 kWh/day
Medium home: 10–20 kWh/day
Large home: 20–40 kWh/day
Business: 50–300 kWh/day
Modern residential rooftop solar system
Solar System Size
Solar panels set the upper limit on how much energy you can store. As a rough guide, depending on local sunlight:
1 kW solar: 3–5 kWh/day
5 kW solar: 15–25 kWh/day
10 kW solar: 30–50 kWh/day
If the solar system is small, an oversized battery will not charge fully. A solar energy storage integration approach keeps PV and battery in balance.
Backup Power Requirements
Different users have different backup priorities:
Backup priority
Typical loads
Battery size
Essential loads
Refrigerator, lights, Wi-Fi
5–10 kWh LFP home battery
Whole-home backup
Air conditioning, pumps, kitchen appliances
15–30 kWh residential storage
Partial off-grid / rural
Frequent outages or weak grid
20–40 kWh modular residential ESS
Commercial backup
Shops, offices, small factories
50–200 kWh commercial ESS
Industrial
Warehouses, manufacturing, logistics
1–5 MWh containerized BESS
Recommended Battery Sizes for Common Scenarios
Scenario
Daily use
Recommended battery
Home with 5 kW solar
12–18 kWh
10–15 kWh home battery
Home with 10 kW solar
20–30 kWh
15–25 kWh LFP home battery
Home with frequent outages
15–25 kWh
20–30 kWh residential storage
Small business
50–150 kWh
50–200 kWh commercial ESS
Factory or warehouse
300–2,000 kWh
500 kWh–5 MWh industrial LFP storage
Why LFP Batteries Suit Solar Storage
GreenMore uses LFP (LiFePO₄) chemistry across residential and commercial systems because it offers:
Higher thermal stability
Longer cycle life
Better performance in hot climates
Safer operation for homes and businesses
Lower degradation over time
This makes LFP the preferred choice for solar-plus-battery installations. You can read more about how the systems are protected in our article on energy storage safety.
How GreenMore Helps You Size the Right System
GreenMore provides solutions across LFP home battery systems (5–30 kWh), commercial energy storage systems (50–500 kWh), containerized BESS solutions (1–5 MWh) and hybrid solar storage for homes and businesses.
Our engineering team supports installers and distributors with:
Load analysis
Solar production modeling
Backup power planning
System configuration and commissioning
Before choosing a battery, work through five questions: How much energy do I use per day? How much solar do I have? Do I want essential-load or whole-home backup? How long do outages last in my area? Do I plan to expand later? A modular residential or commercial system lets you add capacity as needs grow.
There is no single best battery size. The right capacity follows your energy use, solar production and backup needs. If you share your load profile, solar size and outage expectations with the GreenMore team, we will help you size the system rather than sell you the biggest one. Contact GreenMore or email export@gmsolarkit.com.
Frequently Asked Questions
How do I calculate the right solar battery size?
Battery size depends on daily consumption, solar output and backup requirements. Most homes need 10–20 kWh, while larger homes or off-grid systems may need 20–40 kWh.
What battery size suits a 5 kW solar system?
A 5 kW system typically pairs with a 10–15 kWh battery, depending on whether you want essential-load or whole-home backup.
What battery size suits a 10 kW solar system?
Most homes with 10 kW of solar choose a 15–25 kWh battery to maximize self-consumption and reduce bills.
What is the best battery chemistry for solar storage?
LFP (LiFePO₄) is preferred for its high safety, long cycle life and strong performance in hot climates.
Can I expand battery capacity later?
Yes. GreenMore's modular LFP systems let you start smaller and add capacity as energy needs grow.
What battery size do businesses typically need?
Small businesses often need 50–200 kWh, while factories and warehouses may need 500 kWh to multi-MWh containerized BESS.
P
Peter Lu
Energy Storage Product Manager, GreenMore
Peter helps homeowners, installers and distributors size solar batteries to actual loads rather than to a price list. He reviews daily consumption, solar production and backup priorities, and works with the engineering team to confirm that PV, battery and backup configuration are matched so the system charges fully, carries the right loads and can be expanded later without redesign.