Calculate Your Home Battery Storage Size
This Home Battery Storage Calculator helps homeowners, solar installers, and energy consultants find the correct battery bank capacity for any residential application. Use the appliance load table to add your household loads, or choose one of the four preset scenarios — Essential Backup, Full Home Backup, Solar Self-Consumption, or Off-Grid Home — to pre-fill a realistic starting point. Adjust individual load values to match your actual usage, then set your backup duration, depth of discharge, and inverter efficiency to get a precise recommended battery size in both kilowatt-hours and amp-hours.
Home battery storage has three distinct use cases, each requiring a different sizing approach. Essential backup protects critical circuits — refrigerator, lights, phone charging, and a few fans — during grid outages, typically requiring 3–7 kWh. Full home backup keeps all circuits running including air conditioning and cooking appliances, typically requiring 10–20 kWh. Solar self-consumption stores daytime solar generation for evening use, typically sized for one to two days of average daily consumption. This calculator handles all three by letting you set the backup duration and load profile that matches your goal.
🏠 Home Battery Storage Calculator
Select a scenario to pre-fill loads, then adjust to match your home
| Appliance / Load | Watts (W) | Hours/Day | Daily Wh |
|---|
Home Battery Storage by Use Case
Home battery storage requirements vary significantly depending on the goal — short-term backup for essential circuits, full-home resilience, or complete grid independence. The cards below show typical system specifications for the most common residential battery storage scenarios.
🔋 Essential Backup
Powers critical circuits only: refrigerator, lights, phone charging, internet router, and a few fans. Designed for overnight outages without air conditioning or cooking appliances.
🏠 Full Home Backup
Powers all circuits including air conditioning, electric cooking, washer/dryer, and entertainment. Designed for multi-day outages with full household functionality maintained.
☀️ Solar Self-Consumption
Stores excess daytime solar generation for evening and overnight use, maximising solar self-use and minimising grid import. Sized for one to two days of average consumption.
🌄 Off-Grid Home
Full energy independence with no grid connection. Sized for three to five days of autonomy to handle extended cloudy periods. Paired with large solar array and backup generator.
💡 Tiny Home / ADU
Accessory dwelling unit or tiny home with smaller loads and modest solar. Often a compact wall-mounted all-in-one inverter-battery system for simplicity and space saving.
🌐 Grid-Tied + Storage (Hybrid)
Grid-connected home with battery storage for peak shaving, time-of-use arbitrage, and backup. Hybrid inverter manages grid, solar, and battery simultaneously with smart charging.
Home Battery Size Reference by Home Type
The table below provides typical daily energy consumption, recommended battery storage size, and backup duration for common home types and sizes. These are general guidelines — actual consumption varies significantly based on climate, appliance efficiency, occupants, and usage habits.
| Home Type | Daily kWh | Essential Backup | Full Home Backup (1 day) | Off-Grid (3 days) | Typical Battery |
|---|---|---|---|---|---|
| Apartment / Small Unit | 5–10 kWh | 3–5 kWh | 6–12 kWh | 18–36 kWh | 48V 100–200Ah |
| Small Home (1–2 bed) | 10–15 kWh | 4–7 kWh | 12–18 kWh | 36–54 kWh | 48V 200–300Ah |
| Medium Home (3 bed) | 15–25 kWh | 5–10 kWh | 18–30 kWh | 54–90 kWh | 48V 300–500Ah |
| Large Home (4–5 bed) | 25–40 kWh | 8–12 kWh | 30–48 kWh | 90–144 kWh | 48V 500Ah+ |
| Tiny Home / ADU | 3–7 kWh | 2–4 kWh | 4–8 kWh | 12–24 kWh | 48V 100Ah |
| Off-Grid Cabin | 5–15 kWh | N/A | 6–18 kWh | 18–54 kWh | 48V 200–400Ah |
| Home with EV Charger | 25–50 kWh | 5–10 kWh | 30–60 kWh | 90–180 kWh | 48V 500Ah+ |
Home Appliance Energy Consumption Reference
Accurate battery sizing starts with knowing the real energy consumption of each appliance in your home. The table below lists typical power draw and daily energy consumption for the most common household appliances. Use these figures when filling in the load table in the calculator above.
| Appliance | Typical Watts | Typical Hours/Day | Daily Wh | Notes |
|---|---|---|---|---|
| Refrigerator (modern) | 100–200W avg | 24h cycle | 1000–1500 Wh | Compressor cycles ~30–50% of time |
| Freezer (chest) | 80–150W avg | 24h cycle | 500–1000 Wh | Well-insulated, lower duty cycle |
| Air Conditioner (1.5 ton) | 1200–1800W | 6–10h | 7200–18000 Wh | Largest load in most homes |
| Air Conditioner (mini-split) | 700–1200W | 6–10h | 4200–12000 Wh | More efficient than window units |
| Ceiling Fan | 30–75W | 8–14h | 240–1050 Wh | Per fan; many homes have 3–5 |
| LED Lights (per room) | 8–15W | 4–8h | 32–120 Wh | Multiply by number of rooms/fixtures |
| Television (50–65") | 80–150W | 4–8h | 320–1200 Wh | LED/OLED; smart TVs vary |
| Internet Router + Modem | 15–30W | 24h | 360–720 Wh | Always-on load |
| Laptop Computer | 45–90W | 6–10h | 270–900 Wh | Per device |
| Desktop Computer | 150–400W | 6–10h | 900–4000 Wh | Plus monitor: add 50–100W |
| Microwave Oven | 900–1500W | 0.3–1h | 270–1500 Wh | Short high-power use |
| Electric Kettle | 2000–3000W | 0.1–0.3h | 200–900 Wh | Multiple uses per day |
| Washing Machine | 500–1500W | 1–2h | 500–3000 Wh | Per wash cycle |
| Water Pump | 300–750W | 1–3h | 300–2250 Wh | Pressure pump; duty cycle varies |
| Phone Charger | 10–20W | 4–6h per device | 40–120 Wh | Per device; multiply for household |
Why LiFePO4 for Home Battery Storage
Safe for Indoor Installation
LiFePO4 (lithium iron phosphate) is the safest lithium chemistry available for home use. Unlike NMC or NCA chemistries, LiFePO4 does not undergo thermal runaway under normal conditions or even under moderate abuse. It does not catch fire or produce toxic gases when overcharged or physically damaged. This is why LiFePO4 is the chemistry used in virtually all residential wall-mount battery systems designed for indoor installation in living spaces, garages, and utility rooms.
6000+ Cycles for 15+ Years of Life
Premium LiFePO4 home storage batteries are rated for 4000–6000 cycles to 80% capacity retention. A home storage system cycled once per day — typical for a solar self-consumption application — completes 365 cycles per year. At 6000 cycles, this equates to over 16 years of daily operation before the battery reaches its rated end-of-life capacity. This far exceeds the lifespan of any lead-acid, NMC, or older lithium chemistry alternative in the same role.
Flat Discharge Voltage for Stable Power
LiFePO4 maintains a nearly flat voltage between 90% and 20% state of charge, typically staying between 51V and 53V for a 48V pack throughout most of its discharge cycle. This means your inverter operates within its optimal input voltage range for nearly the full capacity of the battery. Lead-acid alternatives sag from 52V to below 44V, forcing the inverter to operate at reduced efficiency and potentially dropping out of operation before the battery is fully discharged.
Fast Charge from Solar or Grid
LiFePO4 accepts charge at up to 0.5–1C continuously, meaning a 200Ah 48V LiFePO4 battery can be fully recharged from a solar array or grid charger at 100–200A in two to four hours. This fast charge acceptance is critical for solar storage systems where the daily charge window is limited to peak sun hours. Lead-acid alternatives require 8–10 hours for a full charge and must be bulk-charged at a fraction of the LiFePO4 rate to avoid damage.
Compact Rack-Mount Form Factor
Modern 48V LiFePO4 home storage batteries are available as self-contained rack-mount modules in 5 kWh, 10 kWh, and 15 kWh sizes that stack vertically and connect in parallel to scale capacity without adding complexity. A 30 kWh battery bank occupies less than 1 square metre of floor space in a standard 19-inch server rack. This makes LiFePO4 rack batteries practical for garage, utility room, and basement installations with minimal footprint.
Compatible with All Major Hybrid Inverters
LiFePO4 48V battery systems communicate with major hybrid inverters — including Victron, Growatt, SolarEdge, Fronius, SMA, and Deye — via CAN bus or RS485 protocols. This allows the inverter to read state of charge, cell voltage, temperature, and alarm data directly from the battery BMS and automatically optimize charging and discharging based on solar forecast, time-of-use tariffs, and household demand. This intelligent integration is not available with lead-acid or basic lithium alternatives.
Designing Your Home Battery System
A home battery storage system consists of four core components: the battery bank, the hybrid inverter/charger, the solar panels (if solar-coupled), and the electrical integration with the home's main panel. The battery bank is sized using the calculator on this page. The hybrid inverter must be rated for the peak AC load the home will draw from the battery — typically 3–10 kW for a standard home, and up to 15 kW for homes with high peak loads from air conditioning, pumps, or EV charging. The inverter must also be rated for the battery's maximum charge and discharge current.
The electrical integration involves connecting the battery system to a critical loads panel or the main panel through the hybrid inverter, with transfer switching that allows automatic switchover from grid to battery during an outage. Most hybrid inverters handle this automatically without manual intervention — when the grid goes down, the inverter detects the loss within a fraction of a second and switches the home to battery power. The seamless transition is especially important for sensitive electronics, medical equipment, and home office equipment that cannot tolerate even brief interruptions.
Installation should be performed by a licensed electrician familiar with battery storage systems. In most jurisdictions, grid-tied battery installations require a permit, utility notification, and approval from the grid operator. Many utility companies have specific requirements for interconnection of home battery systems, particularly systems that can export power to the grid. Check with your local utility and permitting authority before installing. Safety standards for home battery storage are covered by UL 9540, IEC 62619, and applicable local electrical codes.
Solar Paired with Home Battery Storage
Solar panels paired with home battery storage create a system that generates energy during the day, stores excess generation for evening and overnight use, and provides backup during outages. For a home using 15 kWh per day, a 6–8 kW solar array in a good sun location generates 30–40 kWh per day in summer, far exceeding consumption and potentially exporting excess to the grid. In winter or during cloudy periods, the array may generate less than daily consumption, and the battery provides the buffer between days. Battery storage sized for one to two days of consumption bridges most short-duration solar shortfalls.
The ratio of solar capacity to battery capacity affects system performance significantly. Under-sizing solar relative to battery means the battery rarely reaches full charge. Under-sizing battery relative to solar means excess solar is wasted or exported at low feed-in tariff rates. A common starting point for solar storage systems is to size the battery to store approximately 50–70% of the solar array's average daily generation, leaving headroom for the battery to absorb morning generation peaks and deliver energy through the evening. The calculator above helps find the minimum battery size — a practical installed size often adds 20–30% more to this calculated minimum.
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