In recent years, lithium-ion batteries have become the preferred choice for applications such as electric bicycles, recreational vehicles, solar energy storage systems, and ships. Among them, the 48V 100Ah battery is one of the most common options. So you may wonder how long a 48V 100Ah lithium battery can last? I will provide a detailed answer to this question in this guide.
Calculate the Total Energy of a 48V 100Ah Battery
To estimate runtime, we first calculate the total energy stored in the battery.
Formula:
Battery energy (Wh) = battery voltage (V) × battery capacity (Ah)
For a 48V 100Ah battery:
48V × 100Ah = 4800Wh (or 4.8kWh)
This means the battery can store about 4.8 kilowatt-hours of electricity when fully charged.
Combine With Power Consumption to Estimate Runtime
Next, we need to compare this stored energy to the total load or device power consumption.
Formula:
Runtime (hours) = Total Energy (Wh) ÷ Load Power (W)
Examples:
- For a 500W load: 4800Wh ÷ 500W = 9.6 hours battery runtime.
- For a 1000W load: 4800Wh ÷ 1000W = 4.8 hours battery runtime.
In real-world systems using inverters, some energy is lost due to conversion inefficiency. Typical inverter efficiency is around 90–95%, so the actual runtime will be slightly shorter.
Consider Practical Influencing Factors
While theoretical calculations are useful, real runtime depends on several factors:
1. Depth of Discharge (DOD)
To extend battery life, most manufacturers recommend using about 80% of the capacity instead of a full discharge.
Usable energy = 4800Wh × 0.8 = 3840Wh.
At 500W load: 3840Wh ÷ 500W = 7.68 hours battery runtime.
2. Cycle Life and Aging
Lithium ion batteries typically have a cycle life of 3000–5000 charge discharge cycles. Over time, capacity decreases, reducing usable hours.
3. Temperature Effects
Cold temperatures reduce efficiency, while high heat accelerates aging. Optimal use is usually at 20–25°C.
Apply the Formula to Real Scenarios
The general formula is:
Runtime (hours) = Battery Voltage × Battery Capacity (Ah) × DOD ÷ Load Power (W)
Example scenarios:
- Electric bike (250W motor): 4800 × 0.8 ÷ 250 ≈ 15.36 hours (theoretical; actual depends on riding conditions).
- Home solar storage (1kW load): 4800 × 0.8 ÷ 1000 ≈ 3.84 hours.
- RV appliances (800W load): 4800 × 0.8 ÷ 800 ≈ 4.8 hours.
This shows how different discharge rates and loads affect how long a battery can sustain devices.
How to Extend the Lifespan of a 48V 100Ah Battery
Apart from runtime, users also care about overall lifespan. A 48V lithium battery can typically last 8–10 years with proper use. To maximize performance:
Avoid deep discharge
Keep the battery between 20%–80% charge for longer cycle life.
Proper storage
If unused for a long period, keep it at 40%–60% charge to protect the cells.
Temperature management
Operate in moderate conditions to avoid stress on the cells.
Use a Battery Management System (BMS)
A good BMS protects against overcharge, over-discharge, and unsafe discharge rates.
Compared with lead acid batteries, which often last only 500–1000 cycles, lithium iron phosphate batteries and other lithium ion chemistries are far more durable.
Conclusion: How Long Does a 48V 100Ah Lithium Battery Last?
A 48V 100Ah lithium battery can typically provide a runtime of several hours to more than 15 hours on a single charge, depending on power consumption, discharge rates, and inverter efficiency. In terms of overall lifespan, most lithium ion batteries of this size can deliver 3000–5000 charge and discharge cycles, or about 8–10 years of service life, far exceeding traditional lead acid batteries. Contact us now to learn about lithium battery maintenance or to get a lithium battery quote.
