When selecting a solar battery for home or off-grid use, one key question is how long the battery can actually power daily loads. Battery capacity determines backup time, system stability, and overall cost. A system that is too small causes frequent outages, while an oversized one increases unnecessary investment. Understanding the real performance of 5kWh, 10kWh, and 15kWh batteries helps you choose the right solution.
What Does kWh Mean?
Battery capacity is measured in kilowatt-hours (kWh), which indicates stored energy rather than instant power. Power (kW) shows how strong the load is, while energy (kWh) shows how long it lasts. For example, a 1kW appliance running for one hour uses 1kWh. This means a 10kWh battery can run a 1kW load for 10 hours or a 500W load for 20 hours. The higher the load, the shorter the runtime.
Typical Home Consumption
Most households use between 4–10kWh per day depending on appliance usage. Basic loads include lighting, fans, a refrigerator, TV, router, and phone charging. Larger homes may add washing machines, pumps, or small air conditioners. Knowing your daily energy consumption is the first step to selecting the correct battery size and avoiding underperformance.
5kWh Battery: Basic and Emergency Backup
A 5kWh battery is suitable for small homes or essential backup only. It can power lighting, fans, TVs, WiFi, and a small refrigerator without problems. For a home consuming around 4–5kWh daily, this size provides roughly one day of electricity. Under continuous loads, it can supply 500W for about 10 hours or 1kW for 5 hours. This option is compact, affordable, and commonly used for cabins, rural houses, or entry-level solar systems.
10kWh Battery: Ideal for Daily Household Use
A 10kWh battery offers more flexibility and longer runtime, making it one of the most popular choices for family homes. It can support refrigerators, computers, washing machines, and multiple appliances simultaneously. If daily usage is about 5kWh, this battery can last up to two days without recharging. It can also run 1kW loads for 10 hours or 2kW for 5 hours. This capacity provides a good balance between cost, reliability, and comfort.
15kWh Battery: Extended Runtime and Heavy Loads
For larger houses or small commercial applications, a 15kWh battery delivers stronger backup capability. It can handle multiple refrigerators, pumps, tools, and occasional high-power appliances. With moderate consumption, it may provide two to three days of autonomy. Continuous loads of 1kW can run for about 15 hours. This size is ideal for villas, farms, shops, or fully off-grid projects where longer power supply is required.
Factors That Affect Runtime
In general, a 5kWh battery supports one day of basic use, 10kWh supports two days for an average home, and 15kWh covers heavier loads or extended backup. Smaller capacities focus on essentials, while larger systems offer greater comfort and stability. Matching storage to real demand ensures both performance and cost efficiency.
Actual battery life depends on several factors beyond capacity. Higher loads drain energy faster, while depth of discharge and battery efficiency determine how much energy is usable. Temperature and cable losses also impact performance. In addition, solar panels can recharge batteries during the day, significantly extending operating time. Proper system design improves overall reliability.
Choosing the Right Size LiFePO4 Battery
Modern LiFePO4 lithium batteries are widely used in solar systems because they provide higher usable capacity, longer lifespan, and lower maintenance compared to lead-acid batteries. They typically offer 90–95% usable energy and over 6000 cycles, which means more runtime and lower lifetime cost. For the same rated capacity, lithium batteries deliver more practical power and better efficiency.
Selecting the correct battery is simple: calculate your daily consumption and multiply by the number of backup days required. For example, 5kWh daily usage with two days of autonomy needs at least 10kWh storage. Small homes may choose 5kWh, standard households often select 10kWh, and off-grid or commercial users prefer 15kWh or more.
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Battery capacity directly determines how long your home stays powered during outages or off-grid operation. By understanding energy consumption and selecting the appropriate size—5kWh, 10kWh, or 15kWh—you can build a reliable, efficient, and cost-effective solar storage system that meets real-world needs.
We manufacture LiFePO4 energy storage batteries in 5kWh, 10kWh, 15kWh, and customized capacities, along with integrated inverter-battery solutions for residential and commercial projects. Contact us for OEM or bulk supply and tailored solar storage systems.