How Long Does a 5kWh Battery Last ?

The question “How long will a 5kWh battery last?” is one of the most common among homeowners considering solar energy storage systems or backup power solutions. The answer isn’t a fixed number—it depends entirely on your appliances, energy load, and battery technology, such as LiFePO4 batteries or other types of lithium ion batteries.

A 5kWh (kilowatt-hour) battery can theoretically deliver:
· 5 kilowatts for 1 hour
· 1 kilowatt for 5 hours
· Or any similar combination
In practice, actual runtime depends on load, inverter efficiency, depth of discharge (DoD), and the battery’s health.

1. Light Load: Essentials During an Outage
For basic devices, a LiFePO4 5kWh battery can last surprisingly long.
10 LED lights (10W each): ~50 hours
Wi-Fi router + modem (20W): ~250 hours
Laptop/phone charging (25W): ~200 hours
55" LED TV (100W): ~50 hours
Combined Example: A 300W load (lights, internet, TV, phones) would run for ~16.5 hours.
2. Heavy Load: High-Power Appliances
Large appliances drain energy quickly.
Refrigerator (200W, cycles): 12–24 hours
Microwave (1,200W): 15 minutes = 0.3kWh
Electric kettle (1,500W): 10 minutes = 0.25kWh
Air Conditioner (1,500W): ~3.3 hours
Combined Example: A refrigerator (200W) + small space heater (1,500W) = 1,700W load → ~2.9 hours runtime.

Depth of Discharge (DoD):
Most LiFePO4 batteries are rated for 80–90% DoD. A 5kWh system may offer ~4–4.5kWh usable energy.
Inverter Efficiency:
Conversion from DC to AC loses 5–10%. Usable AC power is ~4.3kWh.
Battery Age & Health:
Capacity naturally declines over years of cycling.
Discharge Rate:
High discharge rates reduce usable capacity slightly due to internal resistance.

1. List your appliances.
2. Check their wattage (on labels or manuals).
3. Add up the total watts you want to run.
4. Apply DoD and inverter efficiency:
Usable Energy ≈ 5kWh × 0.9 × 0.95 = ~4.3kWh
5. Runtime = Usable Energy ÷ Total Load

A 5kWh lithium ion battery is an excellent choice for running lights, internet, refrigeration, and small appliances for 12–24 hours, making it ideal for residential solar energy storage systems. However, it is not suited for prolonged operation of high-power devices like heaters or AC units.
For larger households or heavy backup needs, upgrading to higher-capacity LiFePO4 battery systems or modular energy storage systems is recommended. Choosing a reliable lithium ion battery manufacturer ensures long cycle life, safety, and consistent performance.

At XIHO, we provide high-quality, customizable LiFePO4 energy storage batteries that meet global standards—helping homeowners achieve greater energy independence and peace of mind.